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364 Cards in this Set
- Front
- Back
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Robert Hooke |
with crude compound microscope studying cork. named cells |
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Anton van Leeuwenhoek |
first to view living cell under microscope |
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Rudolph Virchow |
demonstrated that diseased cells could arise from normal cells in normal tissues |
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4 tenets of cell theory |
1. all living things composed of cells 2. the cell is basic functional unit of life 3. cells arise only from preexisting cells 4. cells carry genetic info in form of DNA, passed on from parent to daughter cell |
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what makes cell eukaryotic |
contain true nucleus enclosed in membrane |
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cytosol |
allows for diffusion of molecules throughout the cell, semifluid, where organelles are suspended |
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nucleus |
contain all genetic material necessary for replication. surrounded by nuclear membrane/envelope (double membrane), has nuclear pores within it that allow for two way exchange between cytoplasm and nucleus |
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nucleolus |
subsection of nucleus where ribosomal RNA (rRNA) is synthesized, darker spot in nucleus |
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mitochondrial membranes |
outer membrane - barrier b/w cytosol and inner environment inner membrane- has infoldings called cristae that increase surface area available for ETC enzymes. |
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intermembrane space |
space between inner and outer membranes |
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mitochondrial matrix |
space inside inner membrane. pumping of protons from matrix to intermembrane space create a proton-motive force. when flow through ATP synthase back into matrix, generate ATP via oxidative phosphorylation |
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mitochondria |
semi-autonomous. own genes, replicate independently of nucleus via binary fission (cytoplasmic/extranuclear inheritance). thought to have evolved from anaerobic prokaryote engulfing an aerobic prokaryote, creating symbiotic relationship. capable of killing cell (apoptosis) by release enzymes from ETC |
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lysosomes |
membrane-bound, contain hydrolytic enzymes capable of breaking down substrates, including those ingested by endocytosis and cellular waste products. |
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autolysis |
enzymes of lysosome that are normally sequestered, released and results in apoptosis |
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endoplasmic reticulum (ER) |
series of interconnected membranes touching nuclear envelope. numerous invaginations which create complex structures in central lumen |
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rough endoplasmic reticulum (RER) |
studded with ribosomes that perform translation of proteins destined for secretion directly into its lumen |
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smooth ER (SER) |
primarily for lipid synthesis and detoxification of certain drugs/poisons. transports proteins from RER to golgi apparatus |
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Golgi apparatus |
stacked membrane-bound sacs (cisternae). where cellular products are modified by addition of carbs/phosphates/sulfates or addition of signal sequence to direct delivery to particular cellular location. products packaged in vesicles. those destined for secretion, vesicle merge with cell membrane and release contents via exocytosis |
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peroxisome |
contain hydrogen peroxide, breaks down very long chain fatty acids via B-oxidation. participate in synthesis of phospholipids and contain some of the pentose phosphate pathway enzymes |
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cytoskeleton |
provide structure to cell and conduit for transport of materials. 3 types = microfilaments, microtubules, intermediate filaments |
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microfilaments (3 functions) |
solid polymerized rods of actin in bundles that 1. resist compression/fracture (protecting the cell). also 2. used to generate force for movement by interacting with myosin (muscle contraction). 3. form the cleavage furrow ring that divide daughter cells in cytokinesis |
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microtubules and their three functions |
hollow polymers of tubulin. 1. primary pathways along which motor proteins kinesin and dynein carry vesicles. compose cilia and flagella. Mitotic spindle |
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kinesin |
eukaryotic motor proteins that travel plus end of the microtubule that they are on (i.e., away from the center of the cell). gain energy by hydrolysis of ATP |
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dynein |
motor proteins that travel negative end of microtubule (toward center of cell) gain energy by hydrolysis of ATP |
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cilia |
projections from cell made of microtubules. involved in movement of materials along surface of cell |
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flagella |
made of microtubules. move the cell itself. |
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9 + 2 structure |
shared structure of cilia and flagella. nine pairs of microtubules form outer ring with two microtubules in center. only in eukaryotic organelles of motility (bacterial different structure) |
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centrioles |
found in centrosome region of cell. organizing centers for microtubules, structures as nine triplets of microtubules with a hollow center. from opposite poles of cell, organize mitotic spindle. microtubules emanate from centrioles and attach to chromosomes via complexes called kinetochores, then able exert force to pull sister chromatids apart |
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intermediate filaments |
diverse group of filamentous proteins. many involved in cell-cell adhesion or maintenance of cytoskeleton integrity. withstand great tension, keeping cell structure more rigid. anchor organelles. specific to cell and tissue type |
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4 important intermediate filaments |
keratin, desmin, vimentin, lamina |
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what are the four tissues types |
1. epithelial 2. connective 3. muscle 4. nervous tissue |
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epithelial tissues |
cover body and line cavities, protecting against desiccation and pathogen invasion. in particular organs, also involved in absorption, secretion, sensation. often polarized, one side faces lumen/outside world and other side interacts with underlying blood vessels/structural cells |
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basement membrane |
underlying layer of connective tissue that tightly joins epithelial cells |
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parenchyma |
functional parts of organ, generally made up of epithelial cells. |
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3 examples of perenchyma |
1. nephrons in kidney 2. hepatocytes in liver 3. acid-producing cells of stomach |
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simple epithelia |
one layer of cells |
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stratified epithelia |
multiple layers |
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pseudostratified epithelia |
appear to have multiple layers because of differences of cell height but are actually just one layer |
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cuboidal epithelial cells |
cube shaped |
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columnar epithelial cells |
long and thin |
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squamous epithelial cells |
flat and scale like |
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Stroma |
made up of all the parts without specific functions of the organ - for example, connective tissue, blood vessels, nerves, ducts, etc. The other part, the parenchyma, consists of the cells that perform the function of the tissue or organ. |
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Connective tissue |
cells within produce and secrete materials such as collagen and elastin to form extracellular matrix |
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6 examples of connective tissue |
1. bone 2. cartilage 3. tendons 4. ligaments 5. adipose tissue 6. blood |
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defining features of prokaryotes |
include all bacteria and some archaea. no membrane-bound organelles. genetic material is single circular molecule of DNA in "nucleoid region". no membrane bound organelles. single-celled organisms but may live in colonies that share signals about environment |
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monera |
initial categorization heading for archaea and bacteria together |
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extremophiles |
archaea that lives in conditions of extreme temperature, acidity, alkalinity, or chemical concentration. |
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archaea unique feature |
use of alternative energy sources. while some photosynthetic, others chemosynthetic (able to generate energy from inorganic compounds including sulfur and nitrogen based compounds like ammonia) |
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similarities b/w archaea and eukaryotes |
1. start translation with methionine 2. contain similar RNA polymerases 3. DNA associated with histones |
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similarities of archaea and bacteria |
1. single circular chromosome that divides by binary fission or budding 2. overall similar structure 3. archaea can be resistant to antibiotics |
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defining characteristics of bacteria |
have cell membranes and cytoplasm. some have flagella or fimbriae (similar to cilia). antibiotics take advantage of flagella and ribosomal specificity to kill bacteria and spare other cells. outnumber all plants and animals combines |
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mutualistic symbiotes |
both humans and bacteria benefit from relationship (ex. gut bacteria that produce vitamin K and biotin (vitamin b7). prevent overgrowth of harmful bacteria) |
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pathogens/parasites |
provide no advantage to host but rather cause disease. pathogenic bacteria can live intra or extracellularly |
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cocci |
spherical bacteria (ex. strep) |
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bacilli |
rod shaped bacteria (ex. e coli) |
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spirilli |
spiral shaped (ex. syphilis) |
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obligate aerobes |
bacteria that require oxygen for metabolism |
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anaerobes |
bacteria that use fermentation or some other form of cellular metabolism that does not require oxygen |
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obligate anaerobes |
bacteria that can't survive in oxygenated environments because produces reactive oxygen-containing radicals that lead to cell death |
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facultative anaerobes |
bacteria using oxygen for aerobic metabolism if present, switch to anaerobic metabolism if not. |
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aerotolerant anaerobes |
bacteria unable to use oxygen for metabolism but not harmed by its presence |
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prokaryotic envelope |
combination of cell wall (outer barrier that provides structure and control movement of solutes via concentration gradients) and cell membrane/plasma membrane (composed of phospholipids similar to eukaryotes) |
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two types of prokaryotic cell wall |
determine by Gram staining (crystal violet stain followed by counterstain with safranin) gram positive: envelope absorbs crystal violet stain (appear deep purple). can harbor pathogen from organism's immune system gram negative: envelope absorbs safranin and appears pink-red |
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structure of gram-positive cell walls |
thick layer of peptidoglycan (polymeric made of amino acids and sugars). contains lipoteichoic acid with unknown purpose (supposed that activates human immune system ) |
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structure of gram-negative cell wall |
very thing, less peptidoglycan. in addition to cell wall and membrane, also have outer membranes (contain phospholipids and lipopolysaccharides [trigger immune response in human beings]) |
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prokaryotic flagella structure |
propel toward food or away from toxins/immune cells. bacteria can have 1+. has filament (hollow helical structure composed of flagellin [globular protein]). has basal body (anchors flagellum to cytoplasmic membrane, motor of flagellum, rotating at rates up to 300 Hz). has hook (connects filament and basal body so that when basal rotates, it exerts torque on filament) |
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prokaryotic dna |
singular circular chromosome. not coiled around histones (though histones present in archaea). dna can be acquired from external sources via small circular structures called plasmids (may confer advantage such as antibiotic resistance). |
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notable differences in prokaryotes of cytoskeleton, mitochondria, and ribosomes |
1. no mitochondria, cell membrane instead used for ETC/ATP generation 2. cytoskeleton much more primitive than eukaryote 3. ribosomes are different sizes (30S and 50S subunits, not 40S and 60S like euks) |
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binary fission in prokaryotes |
simple asexual reproduction. circular chromosome attaches to cell wall and replicates while cell continues to grow in size. plasma membrane and cell wall grow inward along midline and produce two identical daughter cells. fewer events than mitosis so occur more rapidly |
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virulence fctors |
traits that increase how pathogenic a bacterium is (toxin production, projections that allow it to attach to certain kinds cells, evasion of host immune system) introduced by plasmids. |
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episomes |
subset of plasmids capable of integrating into genome of bacterium |
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transformation (bacterial genetic recombination) |
integration of foreign genetic material into host genome. material most frequently comes from other bacteria (not viral vectors) that upon lysing spill their contents to neighbors. carried out by gram-negative rods |
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conjugation (bacterial genetic recombo) |
sexual reproduction. two cells form conjugation bridge that allow gene transfer, made from sex pili (appendages on donor male). unidirection from donor male (+) to recipient female (-). allow rapid acquisition of antibiotic resistance or virulence factors thru colony. |
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sex factors |
plasmids that contain genes necessary for bacterial conjugation. can become integrated into host genome and once that happens the entire genome replicates (Hfr/high frequency of recombination). donor attempt to transfer that entire copy but bridge usually break before who sequence moved. |
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F (fertility) factor |
Sex factor in E coli. bacteria that possess it are F+ cells and without are F- cells. F+ cell replicates factor and donates to convert recipient into F+ as well. |
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transduction (bacteria genetic recombo) |
host bacteria genes incorporated into bacterial virus (bacteriophage/vector) and then carried into different bacterial host, who will then incorporate those genes |
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vector |
virus that carries genetic material from one bacterium to another. bacteriophage accidentally trap segment of host DNA during assembly of daughter bacteriophages. then transferred and integrated into genome of next host. |
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transposons (bacteria genetic recombination) |
genetic elements capable of inserting and removing themselves from genome. not limited to prokaryotes. if inserted within coding region, gene may be disrupted. |
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lag phase |
bacterias initial adaptation to new local conditions |
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exponential phase/ log phase |
exponential increase in number of bacteria in a colony after they have adapted |
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stationary phase |
slowing of bacterial reproduction as reduction of resources |
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death phase |
when bacteria have exceeded ability of environment/depleted resources necessary for supporting numbers |
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3 structures of virus |
1. genetic material (circular or linear, single or double strand, dna or rna) 2. protein coat (capsid. sometimes surrounded by envelope 3. sometimes envelope containing lipid (made of phospholipids and virus-specific proteins. sensitive to heat, detergents, desiccation, thus easier to kill) |
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role of host cell to virus |
cell that virus must utilize to express and replicate genetic info. need hosts ribosomes to carry out protein synthesis. host's machinery will produce viral progeny (virions) that can be released to infect additional cells |
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bacteriophages and how they infect host |
do not actually enter bacteria. simply inject their genetic material, leaving remaining structures outside infected cell. use tail sheath (body of virus) as syringe to inject genes. tail fibers (legs of virus) help bacteriophage to recognize and connect to correct host. |
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positive sense (single-stranded rna viruses) |
genome may be directly translated into functional proteins by ribosomes of host cell, just like mRNA |
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negative sense (single-stranded rna virus) |
requires synthesis of an rna strand complementary to the negative-sense rna strand, which then used as template for protein synthesis. must have rna replicase in virion. |
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retroviruses |
enveloped, single-stranded rna viruses whose virion contain two identical rna molecules and enzyme reverse transcriptase (synthesizes dna from single-stranded rna). dna then integrates into host cell genome. infect host indefinitely, only cure is to kill host. |
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viral infection via enveloped virus |
only specific cell set. virus bind to specific receptor and then brought into proximity to permit interaction, sometimes b/c cell mistake virus for nutrient/useful molecule and endocytose virus.. enveloped virus fuse with plasma membrane of host, allow entry of virion. |
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viral infection via non-enveloped virus |
use of tail fibers and their enzymatic activity to allow for both penetration of the cell wall and formation of pores in cell membrane. |
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translation for DNA viruses |
must go to nucleus in order to be transcribed to mRNA. mRNA then go to cytoplasm where translated to proteins |
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translation of positive-sense RNA viruses |
genetic material stay in cytoplasm where translated to proteins |
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translation of negative-sense RNA viruses |
require synthesis of complementary rna strand via rna replicase which then translated to form proteins (in cytoplasm) |
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translation of retroviruses |
reverse transcriptase converts the retroviral RNA genome into double-stranded DNA. This viral DNA then migrates to the nucleus and becomes integrated into the host genome. Viral genes are transcribed and translated |
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progeny assembly of viral RNA translation |
many of proteins translated are structural capsid proteins and allow for creation of new virions in cytoplasm. viral genome replicated and packaged within capsid. |
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progeny assembly of retroviruses |
added detail: viral genome must be returned to original form so new copies of single-stranded RNA must be transcribed from the DNA that entered the host genome. |
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3 forms of viral progeny release |
1. cell death caused by budding that eventually uses up cell membrane 2. lyse from being too full of virions. disadvantageous because virus can no longer use cell for life cycle 3. Exocytosis |
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productive cycle |
virus that has produced virions but maintained the life of the host cell for future use |
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lytic cycle |
when bacteriophages use host cell's machinery with no regard for its survival. cell eventually lyses and other bacteria can be infected |
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provirus/prophage |
if virus does not lyse bacterium, it integrate into host genome and begin the lysogenic cycle(instead of lytic cycle which destroys cell host). Lay low in host’s dna, being passed on to daughter cells. Later event can eject it and begin lytic cycle |
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lysogenic cycle |
virus replicate as bacterium reproduces because it continues on in bacteria's replicated genome. |
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what happen to provirus/prophage as it leaves bacterium's genome? |
though can remain in genome indefinitely, envrionmental factors (radiation, light, chemicals) cause it to leave genome and revert to lytic cycle. on the way out, can capture parts of the bacteria's genome and transduce these genes to another bacteria |
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superinfection |
simultaneous infection by multiple phages. infection with one strain generally makes a bacterium less susceptible to this |
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prions |
subviral, infectious proteins. cause disease by triggering misfolding of other proteins, often turning a-helical to b-pleated sheet (drastically reducing solubility of protein and its ability to degrade misfolded proteins). protein aggregates form |
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viroids |
an infectious entity affecting plants, smaller than a virus and consisting only of nucleic acid (short circular single-stranded RNA) without a protein coat. bind to RNA sequences and silence genes. |
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diploid |
autosomal cells (2n). two copies of each chromosome. 46 total chrom. in humans |
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haploid |
(n) germ cells. only one copy of each chromosome. 23 total chrom. in humans |
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cell cycle |
series of phases during which eukaryotic cell grows, synthesizes DNA, and divides. derangements of cell cycle can lead to unchecked cell division and possibly cancer |
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4 stages of cell cycle |
1.G1 2.S 3.G2 4.M |
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interphase and state of chromatin during this time |
G1, S, and G2. where actively dividing cell spends 90% of time. chromosomes in less condensed form (chromatin) |
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Go stage |
offshoot of G1 where cells simiply live without any prep for division |
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G1 stage: presynthetic gap |
cells create organelles while also increasing size. |
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restriction point |
G1/S: containing proper complement of DNA. if damage has been done to DNA, cell is arrested by protein p53 |
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S (synthesis) stage |
cell replicates its genetic material. then bind these two identical chromatids together at region called centromere. ploidy of cell not changed though 92 chromatids present (still considered 46 chromosomes) |
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S/G2 stage checkpoint |
another quality control checkpoint. cell checks that there are enough organelles and cytoplasm to divide, and that there were no errors made in dna replication |
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M stage: mitosis |
prophase, metaphase, anaphase, telophase, and then cytokinesis |
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G2/M checkpoint |
mainly ensuring adequate size and organelles, also controlled by p53 |
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cyclins |
proteins whose concentrations vary during different stages of cell cycle |
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cyclin-dependent kinases (CDK) |
family of proteins that bind to cyclins and create activated CDK-cyclin complex. complex can then phosphorylate transcription factors needed to carry out cell cycle |
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transcription factors |
proteins that promote transcription of genes |
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cancer |
when cell cycle control becomes damaged/deranged but cells are allowed to undergo mitosis. |
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TP53 |
gene that produced p53. mutation can lead to cancer as cell cycle not stopped to repair damaged dna. |
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tumors |
masses that result from cancer cells undergoing rapid cell division. eventually cells produce factors like proteases to destroy basement membranes allowing cells to pass into other tissues/vessels |
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metastasis |
distant spread of cancer cells through bloodstream or lymphatic system |
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somatic cells |
cells not involved in sexual reproduction |
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prophase (3 steps) |
1. condensation of chromatin into chromosomes 2. centriole pairs separate and move toward opposite poles of cell to form spindle fibers (of microtubules) 4. nuclear membrane dissolve, allowing spindle fibers to attach to kinetochores |
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centrioles |
paired cylindrical organelles located outside nucleus in region known as centrosome. responsible for correct division of DNA |
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microtubules organizing centers |
1. centrosome 2. basal body of flagellum or cilia |
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asters |
These star-shaped structures sometimes form around each pair of centrioles during mitosis. Asters help to manipulate chromosomes during cell division to ensure that each daughter cell has the appropriate complement of chromosomes |
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kinetochores |
protein structures located at the centromeres that serve as attachment points for "kinetochore fibers" of the spindle apparatus |
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centromere |
the region of a chromosome to which the microtubules of the spindle attach, via the kinetochore, during cell division. |
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metaphase |
kinetochore fibers interact with fibers of spindle apparatus to align the chromosomes at the metaphase plate (equatorial plate) |
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anaphase |
centromeres split so that each chromatid has its own distinct centromere, allowing sister chromatids to separate. they are pulled toward opposite poles by shortening of kinetochore fibers |
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telophase |
spindle apparatus disappears, nuclear membrane reforms around each set of chromosomes, nucleoli reappear, chromosomes uncoil |
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nucleolus |
largest structure in the nucleus of eukaryotic cells. It is best known as the site of ribosome biogenesis. Nucleoli also participate in the formation of signal recognition particles and play a role in the cell's response to stress |
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cytokinesis |
separation of cytoplasm and organelles, so each daughter cell survive independently. can only happen 20-50 times in life of cell. |
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gametocytes |
germ cells. diploid |
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gametes |
haploid sex cells |
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meiosis I |
homologous chromosomes separate generating haploid daughter cells via reductional division |
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meiosis II |
separation of sister chromatids via equational division. haploid to haploid |
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homologues |
paired chromosomes, one from each parent (maternal #15 and paternal #15) |
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prophase I (4 steps, 1 different than mitosis) |
1. chromatin condenses into chromosome 2. spindle apparatus forms 3. nucleoli and nuclear membrane disappear 4. chromosomes crossing over (genetic recombination, create unique pool of alleles) |
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synapsis |
in prophase I. when homologous chromosomes (at this point consist of two sister chromatids) meet and intertwine |
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tetrad |
the four chromatids (two pairs of sisters) that exist on one plane during prophase I of meiosis |
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synaptonemal complex |
group of proteins that hold together homologous chromosomes as they are in synapsis |
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chiasmata |
breaking points of chromatids of homologous chromosomes so they can exchange equivalent pieces of dna via crossing over (single, double, more) |
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Mendel's second law (of independent assortment) |
inheritance of one allele has no effect on the likelihood of inheriting certain alleles for other genes |
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metaphase I |
tetrads align on metaphasal plate, each chromosome attached to separate spindle fiber by kinetochore |
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anaphase I |
1. homologous pairs separated to opposite ends of cell |
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disjunction |
the separation of paternal chromosome from maternal homologue in anaphase 1 |
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Mendel's first law (of segregation) |
distribution of maternal/paternal homologues to daughter cells is random |
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segregation |
separating of two homologous chromosomes in mitosis and meiosis |
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telophase I |
1. nuclear membrane forms around each new nucleus (each chromosome still consist of two sister chromatids) 2. cytokinesis |
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interkinesis |
between meiosis 1 and 2, short period of rest when chromosomes partially uncoil |
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prophase II |
1. nuclear envelope dissolves 2. nucleoli disappear 3. centrioles migrate to opposite poles 4. spindle apparatus begins to appear |
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metaphase II |
chromosomes line up on metaphasal plate |
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anaphase II |
1. centromeres divide, separating chromosomes into sister chromatids 2. chromatids pulled to opposite poles by spindle fibers |
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telophase II |
1. nuclear membrane forms around each new nucleus 2. cytokinesis = 4 haploid daughter cells produced from one gametocyte |
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x chromosome |
carries sizeable amount of genetics, mutations here can cause sex-linked (x-linked) disorders. females have options to be either homozygous/heterozygous. males hemi. |
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hemizygous |
males with respect to the genes on their x chromosome, since they only have one. x-linked disorder expressed with only one allele. |
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carriers |
females carrying a diseased allele on x-chromosome but not exhibiting disease |
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y chromosome |
carries very little genetic info. |
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SRY (sex-determining region Y) |
codes for transcription factor that initiates testis differentiation and thus formation of male gonads |
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testes |
what primitive gonads develop into |
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seminiferous tubules |
where sperm are produced, here they are nourished by sertoli cells. |
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interstitial cells of Leydig |
in testes, secrete testosterone and other male sex hormones (androgens) |
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scrotum |
external pouch that houses testes below penis. maintain temp of 2-4* lower than body. raised and lowered by layer of muscle around vas deferens (ductus deferens) to maintain proper temp for sperm develop |
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epididymis |
on top of testes. where sperm flagella gain motility and where sperm stored until ejaculation |
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path of ejaculation |
from epididymis through vas deferens to ejaculatory duct (at posterior edge of prostate), then through urethra and then exit body |
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seminal fluid and three places its components are made |
produced by seminal vesicles, prostate gland and bulbourethral gland, mixes with sperm as they pass through reproductive tract |
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seminal vesicles |
contribute fructose to nourish sperm and give mild alkalinity to seminal fluid so sperm can survive relative acidity of female reproductive tract |
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prostate gland |
give fluid mild alkalinity to survive female reproduc. tract |
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bulbourethral (cowper's) glands |
produce clear viscous fluid that cleans out remnants of urine and lubricates urethra during sexual arousal |
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semen |
combo of sperm and seminal fluid |
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spermatogenesis |
formation of haploid sperm through meiosis occurring in seminiferous tubules. result in four functional sperm per spermatogonia |
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spermatogonia |
diploid stem cells in men. Not yet gametocytes |
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primary spermatocytes |
spermatogonia after replicated genetic material (s stage). diploid |
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secondary spermatocytes |
haploid cells that result after first meiotic division. |
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spermatids |
haploid cells that result after meiosis II |
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spermatazoa |
matured spermatids |
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structure of sperm |
1. head (contain genetic material, covered by cap called acrosome, derived from golgi apparatus, necessary to penetrate ovum) 2. midpiece (generate ATP from fructose, contain mitochondria) 3. flagellum (for motility) |
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ovaries |
female gonads that produce estrogen and progesterone, located in pelvic cavity, consist of thousands of follicles |
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follicles |
multilayered sacs that contain, nourish, protect immature ova (eggs) |
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steps of ovulation |
egg released/ovulated into peritoneal sac (line abdominal cavity), drawn into fallopian tube/oviduct (lined with cilia to propel egg forward), travel toward uterus |
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uterus |
muscular site for fetal development |
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cervix |
lower end of uterus that connects to vaginal canal |
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vaginal canal |
where sperm deposited during intercourse |
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vulva |
external female anatomy |
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oogenesis |
production of female gametes. meiosis I characterized by unequal cytokinesis (one secondary oocyte and one polar body). secondary oocyte then remains arrested in metaphase II unless fertilized and polar body generally doesn't divide further |
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primary oocytes |
all oogonia (diploid stem cells) present at birth that have already undergone DNA replication (46 chromosomes, 92 chromatids), arrested in prophase I |
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menarche/menstrual cycle |
one primary oocyte per month will complete meiosis I, producing a secondary oocyte and a polar body. cyclic rise and fall of estrogen and progesterone levels |
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zona pellucida |
layer surrounding oocyte itself (directly outside cell membrane). acellular mixture of glycoproteins that protect oocyte and contain compounds necessary for sperm binding |
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corona radiata |
outside zona pellucida. layer of cells that adhere to oocyte during ovulation. when both this layer and zona pellucida are penetrated by acrosomal enzymes of sperm cell, meiosis II triggered. |
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ovum |
egg cell with large quantities of cytoplasm and organelles (including mitochondria), donating everything to zygote except other half of dna. |
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zygote |
diploid unit created upon completion of meiosis II after fusing of haploid pronuclei of sperm and ovum |
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gonadotropin-releasing hormone (GnRH) |
hormone released from hypothalamus at puberty. it then triggers anterior pituitary gland to make/release follicle-stimulating hormone (FSH) and luteinizing hormone (LH). these hormones then stimulate production of sex hormones in other places in the body |
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stages of androgen production (throughout male's life) |
1. production triggered by Y chromosome during fetal period (9 weeks after fertilization until birth) permits male sexual differentiation 2. production low in infancy/childhood 3. testosterone spike at puberty (start sperm production, negative feedback with hypothalamus and anterior pituitary) 4. testosterone decline with age |
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roles of FSH and LH in male puberty |
FSH: stimulates sertoli cells and triggers sperm maturation LH: cause interstitial cells (leydig) to produce testosterone |
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estrogen's 3 purposes in lifetime |
1. stimulate development of reproductive tract in utero 2. at puberty, secreted in response to FSH. maintain female reproductive system and cause secondary sexual characteristics. 3. thicken lining of uterus (endometrium) each month in prep for zygote implantation |
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progesterone role when preggo and not preggo |
non-preggo: secreted by corpus luteum. involved in development and maintain of endometrium but not its original thickening (Due to estrogen).
preggo: supplied by placenta at end of first trimester as corpeus luteum shriveled |
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corpus luteum |
remnant follicle that remains after ovulation. secretes progesterone in response to LH. |
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4 phases of menstruation |
1. follicular phase 2. ovulation 3. luteal phase 4. menstruation |
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follicular phase YouTube “female reproductive cycle” by Armando hasudungan |
begin when menstrual flow (shedding of uterine lining of previous cycle) begins. Spike of gnrh increase FSH and LH; LH kept at low level by estrogen (produced by maturing follicles) and FSH’s initial spike at begin of phase eventually trails off thru phase due to increase of estrogen. Primary oocyte (meiosis 1 prophase) to secondary (meiosis 2 metaphase) which upon release from ovary =ovum |
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decidua |
thick layer of mucus membrane (modified endometrium) which lines uterus during pregnancy, shed after birth. estrogen works to not only grow this but also vascularize and glandularize |
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ovulation |
levels of estrogen from late follicular phase has risen to a threshold that sudden converts it from negative feedback system to positive, increasing release of GnRH, LH, and FSH. The LH induces ovulation, release ovum from ovary into peritoneal cavity |
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luteal phase |
LH cause ruptured follicle to form corpus luteum that secrete progesterone. this progesterone will maintain uterine lining (after estrogen has thickened it). its high levels create negative feedback with GnRH, FSH, and LH, preventing ovulation of multiple eggs |
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menstruation |
when implantation does not occur, corpus luteum loses LH stimulation and progesterone levels decline. uterine lining sloughed off. loss of estrogen/progesterone remove block on GnRH so that cycle can restart |
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human chorionic gonadotropin (HCG) |
secreted by blastocyst that implants in uterine lining. maintains corpus luteum (which will secrete estrogen and progesterone necessary for maintain uterine lining) HCG levels decline in second trimester as placenta able to secrete progesterone and estrogen (negative feedback to GnRH) |
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menopause |
ovaries become less sensitive to FSH and LH, lead to ovarian and endometrium atrophy. cease menstruation, negative feedback on FSH and LH removed, so two hormones levels in blood rise. |
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ampulla |
widest part of fallopian tube where fertilization of egg can occur 24 hours after ovulation (which happens about day 14 of menstrual cycle). |
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acrosomal apparatus |
tubelike structure from sperm that makes direct contact with secondary oocyte's cell membrane. pronucleus then freely enter oocyte after meiosis II completes. |
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cortical reaction |
release of calcium ions after penetration of cell membrane by sperm. depolarizes membrane of ovum which prevent fertilization by multiple sperm and increases metabolic rate of newly formed diploid zygote |
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fertilization membrane |
depolarized and impenetrable membrane of newly formed diploid zygote |
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dizygotic/fraternal twins |
form from fertilization of two different eggs released by one ovulation cycle by two different sperms. each have own placenta, chorion, and amnion. if close enough placenta may overgrow onto each other. no closer genetic relation that brother/sis |
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monozygotic/identical twins |
single zygote splits into two. identical genomes |
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conjoined twins |
monozygotic twins where single zygote fails to completely divide |
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monochorionic/monoamniotic twins |
share same amnion and chorion. riskiest of combinations. type of twinning determined on when zygotic separation occurred |
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monochorionic/diamniotic twins |
own amnion but same chorion |
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stages of prenatal development |
1. zygote: when egg and sperm combine 2. morula: approx 60 hours after fertilization after cleavage into 16ish cells 3. blastocyst: group of 200-300 cells entering the uterus 4. embryo: name once it implants in uterine wall 5. fetus: after 8 weeks since fertilization |
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dichorionic/diamniotic twins |
own amnions and chorions |
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cleavage |
zygotic (stage 1) rapid mitotic cell divisions performed during move to uterus for implantation. first cleavage = transition from monocellular zygote to multicellular embryo. cell group stay same size for first few cleavages. |
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indeterminate cleavage |
result in cells that can still develop into complete organisms. monozygotic twin formation |
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determinate cleavage |
result in committed to differentiating into certain type of cell |
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morula |
transition from embryo to this solid mass of cells after several divisions |
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blastulation |
after morula formed, this process turns it into blastula (hollow ball of cells with fluid-filled inner cavity known as blastocoel) |
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blastocyst |
mammalian blastula name. zone pellucida disintegrate. have two different cell groups: 1. trophoblast cells: comprise outer wall/blastoderm 2. inner cell mass/embryoblast: protrude from/next to blastocoel (inner cavity) and give rise to organism itself |
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trophoblast cells |
surround blastocoel (fluid filled cavity of blastula) and give rise to chorion and later placenta (two outermost regions holding developing fetus). interface b/w maternal blood supply and embryo. form chorionic villi |
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chorion |
extraembryonic membrane that develops into placenta. covered in villi, fingerlike projections that penetrate endometrium, the part that develop into fetal half of placenta |
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umbilical cord |
connect embryo to placenta. consist of two arteries and one vein encased in gelatinous substance |
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umbilical cord's arteries and vein |
vein: carry freshly oxygenated blood rich with nutrients from placenta to embryo. arteries: carry deoxygenated blood and waste to placenta for exchange |
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allantois 2 roles |
involved in early fluid exchange between embryo and yolk sac. remnants from this, along with yolk sac form umbilical cord |
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allantois |
involved in early fluid exchange between embryo and yolk sac. remnants from this, along with yolk sac form umbilical force |
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amnion |
surround allantois. thin tough membrane filled with amniotic fluid. shock absorption during pregnancy. surrounded by protective chorion |
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gastrulation |
generation of three different cell layers after cell mass implants in uterus. and formation of notochord (primitive streak) within endoderm. |
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gastrula |
when it is a hollow cup-shaped structure having three layers of cells. |
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archentreron |
membrane invagination into the blastocoel (during gastrulation) which later develops into the gut. |
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blastopore |
the opening of the archenteron that either develops into anus (in deuterostomes) or mouth (protostomes) |
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primary germ layers |
cells that migrate into remaining area of blastocoel and develop three layers |
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ectoderm (and what 4 parts it develop into) |
outermost layer of primary germ layers. turn into 1. integument (skin and its appendages), 2. lens of eye, 3. nervous system (including adrenal medulla [part of sympathetic]), and 4. inner ear I Love No Ectoplasm |
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mesoderm (and what 7 develop into) |
middle layer of primary germ layers. develop into 1. adrenal cortex 2. circulatory, 3. most of excretory systems, 4. gonads, 5. muscular and connective tissues of digestive and 6. respiratory systems, 7. musculoskeletal A Mesoderm Can Evolve Greatly During Ripening |
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selective transcription in utero |
only genes needed for particular kind of cell are transcribed. |
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selective transition in utero |
only genes needed for particular kind of cell are transcribed. |
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induction in utero |
ability of one group of cells to influence fate of other nearby cells. mediated by chemical substances known as inducers which diffuse from organizing cells to responsive cells |
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neurulation |
development of nervous system from ectoderm. 1. notochord induces overlying ectodermal cells to slide inward to form neural folds around a neural groove 2. neural tube formed once neural folds meet 3. neural crest cells migrate into mesoderm to form PNS 4. ectoderm migrate over neural tube to make NS |
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neurulation |
development of nervous system from ectoderm. 1. notochord induces overlying ectodermal cells to slide inward to form neural folds around a neural groove 2. neural tube formed once neural folds meet 3. neural crest cells migrate to form PNS 4. ectoderm migrate over neural tube to make NS |
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neural crest cells (6 developments) |
at tip of each neural fold that migrate outward to form peripheral nervous system: 1. sensory ganglia 2. autonomic ganglia 3. adrenal medulla 4. schwann cells 5. calcitonin-produce cells of thyroid 6. melanocytes in skin The Mesoderm Must Shift Ground |
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teratogens |
substances that interfere with development, defects or death of embryo. genetics can influence effects of teratogen. other influences include route of exposure, length of exposure, rate of placental transmission of teratogen, identity of teratogen |
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deleterious maternal health issues |
1. over/underexposure created by her body (diabetic, overexpose to sugar lead to oversized fetus with hypoglycemia [levels insulin to high]) 2. lack folic acid lead to prevent closure of neural tube = spina bifida or anencephaly |
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morphogens |
specific mRNA and protein molecules that result in cell determination. more effective to responsive cells nearby that receive high concentrations. also different kinds can combine to create specific signal |
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differentiation |
changing of structure, function, biochemistry of cell to match the cell type is determined to be |
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stem cells |
cells that have not yet differentiated or which will give rise to other cells that will differentiate. exist in embryos and adults |
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potency |
determines which tissues a particular a stem cell can differentiate into |
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totipotent |
cells can give rise to both tissues of embryo or placenta. trophoblasts |
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pluripotents |
after cells have differentiated into 3 germ layer, now pluripotents can turn into anything excluding placental structures |
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multipotent |
after cells become more specialized, differentiate into different cell types within particular group |
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responder/responsive cell |
cell that receives induction. must be competent (able to respond to inducing signal) |
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autocrine |
signals act on same cell that secreted the signal |
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paracrine |
signals act on cells in local area |
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justacrine |
signals not usually involve diffusion but rather a feature of a cell directly stimulates receptors of adjacent cells |
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endocrine |
signal secreted hormones that travel through bloodstream to distant tissue |
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growth factors |
common inducers, peptides that promote differentiation and mitosis in certain tissues. |
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reciprocal development |
induction that is two-ways |
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cell migration |
ability to disconnect from adjacent structures and migrate to anatomically correct location |
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apoptosis |
programmed cell death that occurs at various times in development. triggered by apoptotic signals or preprogramming |
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apoptotic blebs |
cell division into many self-contained pieces that can then be digested by other cells. allow for recycling of materials. contained by membranes that prevent release of harmful substances into extracellular environment |
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necrosis |
cell death as a result of an injury. internal substances leaked |
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regenerative capacity |
ability of an organism to regrow certain parts of body |
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complete regeneration |
lost or damaged tissues replaced with identical tissues (liver close to complete regen) |
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incomplete regeneration |
newly formed tissue is not identical to tissue that was injured/lost (heart has little regen at all, kidneys have moderate but easily overwhelmed) |
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senescence |
biological aging characterized by disruption of metabolism and eventually death. due to accumulation of chemical/environmental insults. at cellular level, failure of cells to divide normally after approximately 50 divisions in vitro (outside body). due to shortening telomeres. |
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telomeres |
end of chromosomes that help reduce loss of genetic info and help prevent DNA from unraveling (due to high concentration of G and C). shorten during each round of DNA synth. |
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telomerase |
some germ cells, fetal cells, tumor cells express this enzyme (a reverse transcriptase) that synthesizes ends of chromosomes, preventing senescence |
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fetal hemoglobin (HbF) |
fetal blood cells contain different hemoglobin than adults that has greater affinity for oxygen |
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functions of placenta |
1. diffusion of nutrients and waste between mother and fetus via use of gradient 2. immune protection, crossing of antibodies 3. act as endocrine organ, producing progesterone, estrogen, and hCG (all vital for maintain pregnancy) |
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difference between adult/somatic versus umbilical arteries |
mother's arteries go away from heart, carrying O2 rich blood child arteries go away from heart, carrying deoxygen mother's veins, toward heart low oxygen child vein toward heart with oxygen |
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foramen ovale |
one-way valve (shunt) that connects right atrium to left atrium, so blood entering right atrium from inferior vena cava flow straight into left atrium and then pumped through aorta into systemic circulation directly, circumventing right ventricle. functions because fetus (unlike adults) has more pressure in right side of heart |
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ductus venosus |
*bypass liver, which isn't significant in utero* shunt blood returning from placenta via umbilical vein directly to inferior vena cava. Help skip portal vein and hepatic vein, so it can take oxygen rich blood straight to heart |
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milestones of first trimester |
1. heart beat at 22 days, as well as eyes, gonads, limbs, liver around same time 4. eight weeks, bones formed, brain developed-ish (embryo=fetus) 5. end of third month, 9 cm long
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milestones of first trimester |
1. heart beat at 22 days, as well as eyes, gonads, limbs, liver around same time 2. week 5 10mm, week 6, 15mm 3. cartilaginous skeleton into bone by 7th week 4. eight weeks, bones formed, brain developed-ish (embryo=fetus) 5. end of third month, 9 cm long |
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milestones of second trimester |
1. tremendoush growth 2. movement w/n amniotic fluid 3. face human appearance 4. toes and fingers elongate 5. end of trimester, 30-36cm long |
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parturition and the two hormones involved |
vaginal childbirth via rhythmic contractions of uterine smooth muscle triggered by prostaglandins and oxytocin |
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parturition |
vaginal childbirth via rhythmic contractions of uterine smooth muscle triggered by prostaglandins and oxytocin |
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3 stages of birth |
1. cervix thinning and amniotic sac rupture (water breaking) 2. strong uterine contractions that result in birth of fetus 3. afterbirth: placenta and umbilical expelled |
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neurons |
specialized cells capable of transmitting electrical impulses and then translating those electrical impulses to chemical signals |
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cell body (soma) of neuron |
contains nucleus. location of endoplasmic reticulum and ribosomes |
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dendrites |
appendages emanating from soma. receive incoming messages from other cells |
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axon hillock |
integrate incoming signals ("sum" excitatory or inhibitory) and if excitatory enough (reach threshold), initiate action potential |
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action potentials |
all-or-nothing messages. electrical impulses down the axon to the synaptic bouton |
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axon |
long appendage that terminates in close proximity to a target structure (muscle, gland, another neuron) |
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myelin |
insulation of mammalian nerve fibers. prevent signal loss or crossing of signals. |
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myelin sheaths |
maintain electric signal within one neuron. increase speed of conduction in axon. |
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oligodendrocytes |
in CNS. produce myelin |
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Schwann cells |
produce myelin in peripheral nervous system |
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nodes of Ranvier |
small breaks in myelin at intervals along the axon. expose axon membrane |
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nerve terminal/synaptic bouton (knob) |
end of axon. enlarged and flattened to maximize neurotransmission |
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synaptic cleft |
small space into which the terminal portion of axon releases neurotransmitters which bind to dendrites of postsynaptic neuron |
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synapse |
combo of nerve terminal, synaptic cleft, postsynaptic membrane |
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nerve |
multiple neurons bundled together in peripheral nervous system. sensory, motor, or mixed (carry both sensory and motor info) |
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ganglia |
cells bodies of neurons of same type clustered together |
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nuclei of nervous system |
cell bodies of neurons in same tract |
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nuclei |
cell bodies of neurons in same tract |
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glial cells/neuroglia |
cells that myelinate and support neurons |
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4 types of glial cells |
1. astrocytes 2. ependymal cells 3. microglia 4. oligodendrocytes |
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astrocytes |
nourish neurons and form blood-brain barrier |
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ependymal cells |
Nervous tissue cells (not neurons but instead neuron-supporting cells) that line ventricles of brain and produce cerebrospinal fluid, physically supports brain (shock absorber) |
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ependymal cells |
line ventricles of brain and produce cerebrospinal fluid, physically supports brain (shock absorber) |
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microglia |
phagocytic cells that ingest and break down waste products and pathogens in CNS |
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oligodendrocytes (CNS) & Swann cells (PNS) |
product myelin around axons |
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resting membrane potential |
electrical potential difference (voltage) between inside of neuron and extracellular space. approx. -70mV inside (negative because of neg charged proteins within cell and greater permeability of membrane to K+ compared with Na+) |
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Na+/K+ ATPase |
maintains negative internal environment of neuron. transports 3 Na+ out of cell for every two K+ into the cell at expense of one ATP (b/c both moving against their gradient). primary active transport |
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neuron depolarization |
raised membrane potential (Vm) due to excitatory input that makes neuron more likely to fire an action potential |
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threshold value |
usually around -55 to -40 mV. happens when axon hillock receives enough excitatory input to depolarize, triggering action potential. By activating sodium channels |
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threshold value |
usually around -55 to -40 mV. happens when axon hillock receives enough excitatory input to depolarize, triggering action potential. |
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summation |
additive effect of multiple signals (excitatory and inhibitory) which can come from several presynaptic neurons. |
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temporal summation |
multiple signals are integrated during a relatively short period of time |
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electrochemical gradient of sodium in a firing neuron |
promotes migration of sodium into cell via voltage-gated sodium channels opened when cell reached threshold. more negative interior as well as lower concentration of sodium encourages them to flood in |
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inactivated sodium (Na+) channels |
when Vm approaches +35. Inactivation gate block activation gate |
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deinactivated sodium (Na+) channels |
when brought back near resting potential (a more negative value bc repolarization). Prevent reopening to enforce a refractory period |
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deinactivated sodium (Na+) channels |
when brought back near resting potential |
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closed sodium (Na+) channels |
before the cell reaches threshold and after inactivation has been reversed |
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open sodium (Na+) channels |
from approximately +35 mV to the resting potential |
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voltage-gated potassium (K+) |
after voltage-gated sodium channels have allowed enough Na+ to depolarize the cell, potassium channels open, favoring efflux of potassium, restoration of negative membrane potential (repolarization) |
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hyperpolarization |
efflux of K+ causes overshoot of resting membrane potential. makes neuron refractory to further action potentials |
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impulse propagation |
the movement of action potential traveling down axon to initiate neurotransmitter release. AP continue in wavelike fashion as subsequent segments are depolarized and local sodium channels opened (then momentarily refractor so info can flow in one dirxn. finally reach nerve terminal |
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impulse propagation |
the movement of action potential graveling down axon to initiate neurotransmitter release. AP continue in wavelike fashion as subsequent segments are depolarized and local sodium channels opened (then momentarily refractor so info can flow in one dirxn. finally reach nerve terminal |
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axon size's effect on action potential speed |
increased length: higher resistance and slower conduction greater crossectional area: faster propagation, reduced resistance (more significant of the two structural factors) |
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saltatory conduction |
membrane only permeable to ion movement at nodes of Ranvier thus signal hops from node to node |
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increased intensity of neurological stimulus |
does not result in increased potential difference of action potential, simply increased frequency of firing |
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presynaptic vs. neuron |
pre: neuron preceding synaptic cleft post: after SC |
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effector |
postsynaptic cell (gland or muslce) |
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process of neurotransmitter release |
increase of calcium from voltage-gated Ca+ channels triggers fusion of membrane-bound vesicles (holding neurotransm.) to fuse with cell membrane at synapse, exocytose contents |
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two types of postsynaptic receptors |
1. ligand-gated ion channels: will polarize or depolarize postsyn. cell 2. G protein coupled receptor: cause either changes in cAMP levels or influx of Ca+ |
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acetylcholinesterase (AChE) |
enzyme that breaks down acetylcholine (ACh) left in synaptic cleft |
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reuptake carriers |
bring neurotransmitters left in synaptic cleft back into presynaptic neuron (used on serotonin (5-HT), dopamine (DA) and norepinephrine (NE)) |
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three ways to deal with neurotransmitters left in synaptic cleft |
1. enzymatic breakdown 2. reuptake 3. diffusion out of cleft (ex. nitric oxidie [NO] which is gaseous signaling molecule) |
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sensory neurons/afferent neurons |
transmits sensory info from receptors to spinal cord and brain |
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motor neurons/efferent neurons |
transmit motor info from brain and spinal cord to muscles and glands |
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interneurons |
between other neurons and are the most numerous. predominantly in brain and spinal cord and are linked to reflexive behavior |
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supraspinal |
reflex that requires input from brain or brainstem |
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central nervous system |
brain and spine |
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white matter |
axons encased in myelin sheaths |
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grey matter |
unmyelinated cell bodies and dendrites |
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4 divisions of spinal cord |
from top to bottom: cervical thoracic lumbar sacral |
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structure of spinal cord |
white matter outside the cord and grey matter deep within. contains axons of motor and sensory |
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spinal cord structure dorsal vs ventral |
axons (white matter) on outside, motor and interneuron cell bodies (grey matter) within. sensory neurons bring info from periphery from dorsal side of spinal cord. motor neurons exit spinal cord ventrally |
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spinal cord structure |
axons (white matter) on outside, motor and interneuron cell bodies (grey matter) within. sensory neurons bring info from periphery from dorsal side of spinal cord. motor neurons exit spinal cord ventrally |
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dorsal root ganglia |
bunch of cell bodies of sensory neurons. near but outside the spinal cord |
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peripheral nervous system |
nerve tissues and fibers outside the brain and spinal cord. 31 pairs spinal nerves, 10 of the 12 pairs cranial nerves (olfactory and optic considered outgrowths of CNS) |
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somatic nervous system |
sensory and motor neurons of PNS, distributed throughout skin, joints, muscles. motor neuron of this system goes directly from spinal cord to muscle without synapsing |
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autonomic nervous system |
offshoot of PNS, regulate heartbeat, respiration, digestion, glandular secretions (involuntary muscles). two neurons in series required to deliver messages from spinal cord |
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preganglionic neuron |
soma in the CNS and its axon travels to a ganglion in the PNS where synpases on cell body of postganglionic neuron |
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parasympathetic nervous system And its main hormone |
main role to conserve energy. acetylcholine responsible for its pathways, released by both preganglionic and postganglionic neurons. vagus nerve (cranial nerve X [10]), responsible for much of parasympathetic innervation of thoracic and abdominal cavity |
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parasympathetic nervous system |
main role to conserve energy. acetylcholine responsible for its pathways, released by both preganglionic and postganglionic neurons. vagus nerve (cranial nerve X [10]), responsible for much of parasympathetic innervation of thoracic and abdominal cavity |
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reflex arc |
transmission by sensory neurons up to spinal cord where it connects with interneurons that relay signal back to muscles (where they can react before brain has processed info) |
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monosynaptic reflex arc |
single synapse between the sensory neuron that receives the stimulus and motor neuron that responds to it. (ex knee-jerk reflex) |
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knee-jerk reflex |
stretching of patellar tendon send signal up sensory (afferent, presynaptic) neuron to spinal cord where interfaces with motor (efferent, postsynaptic) neuron that contracts the quadriceps muscles |
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polysynaptic reflex arc |
at least one interneuron between sensory and motor neurons (ex. withdrawal reflex) |
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withdrawal reflex |
leg's extremity that is directly injured will stimulate monosynaptic pulling away by hip/hamstring muscles, however for other foot to remain planted firmly, signal go through several interneurons before directing quad muscles to extend |
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virion |
What you call a virus when it is yet to infect host cell |
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virion |
virion is an entire virus particle consisting of an outer protein shell called a capsid and an inner core of nucleic acid (either ribonucleic or deoxyribonucleic acid—RNA or DNA). The core confers infectivity, and the capsid provides specificity to the virus. |
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proteases |
factors produced by tumor cells that can digest basement membranes, encouraging metastasis |
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Angiogenic stimulators |
encourage blood vessel formation in tumor |
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gonads |
organ that produces gametes (testis or ovaries) |
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M checkpoint |
occurs near the end of the metaphase stage of mitosis. The M checkpoint is also known as the spindle checkpoint because it determines whether all the sister chromatids are correctly attached to the spindle microtubules. |
