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86 Cards in this Set
- Front
- Back
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To what does the term tonicity refer?
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ability of a solution to make a cell change it's shape through osmosis
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Compare the solute concentrations of hypotonic hypertonic and isotonic solutions.
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Hypotonic - fewer solutes than cell
Hypertonic - more solutes than cell Isotonic - same as cell |
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If a cell is placed into an isotonic solution, what will happen?
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Nothing
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If a cell is placed into a hypertonic solution what will happen?
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Cell will shrivell/crenate
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If a cell is placed into a hypotonic solution, what will happen?
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Cell will swell and burst (lyse)
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Compare the solute concentration of the following: a 1 mM glucose solution; a 1 mM CaCl2 solution; and a 1 mM NaCl solution.
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Glucose - 1 mOsm sltn
CaCl2 - 3 mOsm sltn NaCl - 2 mOsm sltn |
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what is (are) the clinical applications of the concept of owmolarity of solutions?
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Making/checking IV concentrations - must be isotonic or close
hypertonic can help with edema (get water out of xtracellular space Hypotonic can help rehydrate |
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Compare and contrast simple diffusion and facilitated diffusion.
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Simple - non-polar solutes, straight through phospho bilayer, moves down conc. gradient
Facilitated - polar or too large, carrier mol. or membrane channel, moves down conc. gradient |
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What is transport maximum?
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the highest/fastest rate that a certain solute can be transported
happens when solute is in high conc. so all of the carrier mol. are being used |
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What happens to facilitated diffusion when a solute's transport maximum is reached?
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Saturation occurs
when solute is bound to all available carriers |
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Describe primary and secondary active transport.
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Both - Move solutes against conc gradient; require energy
Primary - directly uses ATP Secondary - energy comes from Na and H gradients; powered by the primary transporter |
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Compare and contrast primary active transport and facilitated diffusion.
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Primary active - against conc. gradient; needs energy; uses a channel; can't be saturated
Facilitated - uses a channel; flows with conc. gradient; can be saturated; often uses carrier molecules |
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Describe the function of the Na/K pump.
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A primary active transporter
Sets up a chemical and electrical gradient, which helps with other forms of transportation Powers secondary transporters |
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Identify and describe the 3 main types of endocytosis.
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Receptor-mediated endocytosis - ligand receptor binding in clathrin coated pit
Phagocytosis - ingesting large things using pseudopods Pinocytosis - uses pseudopods to sip the extracellular fluid |
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What is the main function of receptor-mediated endocytosis?
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Bringing molecules into the cell that have very low conc.
Ex. hormones, iron, LDL's |
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What is the role of the clathrin-coated pit regions of the plasma membrane?
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They bind to the specific molecules that the cell wants to take in.
Helps concentrate mol. in a small area |
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Which of the various types of endocytosis is highly selective?
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Receptor-mediated endocytosis
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Identify and describe the two general components of the cytoplasm.
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Cytosol - high K, low Na, hight proteins and enzymes, metabolic substrates (metabolic acids, glucose, fatty acids)
Cytoplasmic Organelles - membranous and non-membrainous; cellular machinery Inclusions - fat molecules, melanin, nutrient granules |
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What is the general function of the cell's nucleus?
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- Repository of Cell's genetic material
- structural and functoinal characteristics of cell determined here |
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Describe the nuclear envelope.
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- Double phospholipid bilayer
- Outer membrane layer continuous with ER - like the mitochondrial membrane - Outer membrane studded with ribosomes - Large nuclear pores where membranes fuse together - Selectively permeable proteins around pores |
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Of what material(s) is/are chromatin composed?
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- 1/2 DNA
- 1/2 Histone proteins |
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What is a nucleosome?
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- A DNA strand wrapped loosely twice around 8 histone proteins
- Condenses to form chromatin fibers/strands - Separated by sections of linker DNA |
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What happens to chromatin during cell division?
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- Condense dramatically
- becomes visible to the microscope |
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Name and describe the 2 primary subdivisions of the cell cycle.
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- Somatic cell division - mitosis and cytokinesis
Reproductive cell division - gametogenesis |
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Name and describe the significant events of the three subphases of interphase.
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G1 phase - rapid growth, duplication of cellular organelles, centriole replicatoin begins
S Phase - "Synthesis" Growth, DNA replication G2 Phase - last min. protein synthesis; centriole replication finished |
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Explain why DNA replicatoin is described as semiconservative.
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DNA splits and a new strand is built on to each of the old strands so you have one old and one new part to each strand.
It makes identical copies |
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Name and describe the significan events of the stagest of mitosis.
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Interphase - growth and replication
Prophase - chrom. condense, centrioles move to ends, nuclear membrane breaks down Metaphase - Chrom. alligned Anaphase - Chrom moved to ends of cell Telophase - nuclear membrane forms, cytokinesis, chrom. decondense |
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Briefly describe how p53 and maturation-promoting factor (MPF) help regulate the cell cycle.
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- p53 - codes for protein that stops the cell in G1 phase; activated when the dna is dammaged; attempts to repair; if unsuccessful, apoptosis is induced
- MPF - cyclin proteins rise during interphase; high level of cyclins makes complex with cdk2 to form MPF Drives cells into mitosis; during mitosis, cyclins are destroyed by proteosomes |
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Compare and contrast benign and malignant neoplasms.
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Benign - neoplasm contained in connective tissue capsule
Malignant - not contained; replicating uncontrollably; can metastasize/invade other tissues; can stimulate angiogenesis Both have abnormal cell cycles |
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Where does meiosis occur?
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In gametes
The sperm and the ovum |
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Describe the process of meiosis, noting the significan events that occurr in each stage.
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Prophase 1 - homologous chrom. align; synapsis occurs
Metaphase 1 - line up randomly at equator Anaphase 1 - tetrads split Telophase - cytokinesis; nuclear membrane etc Interkinesis - interphase minus the chrom. replication Meiosis 2 - same as 1 except it splits up the sister chromatids |
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At what stage does synapsis occur?
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Prophase I
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Name and describe the genetic recombination that occurs during Prophase I.
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- Homologous chrom. align, forming tetrads
- they cross over, exchanging genetic material b/w the pared maternal and paternal chrom. - Increases genetic variability |
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Explain why Meiosis I is described as reduction division.
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- Because the chrom. number goes from 2n to n
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Identify the significant differences b/w meiosis and mitosis.
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Mitosis - 2 identical cells created; no crossing over; daughter cells duploid; happens in most cells
Meiosis - synapsis, 4 different daughter cells; 8 phases long; haploid cells created |
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Based on the process of meiosis, distinguish b/w oogonia, primary oocytes, secondary oocytes and ova
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Oogonia - female germ cell before meiosis begins
Primary oocytes - Meiosis arrested at prophase 1 Secondary oocytes - Meiosis 1 complete; arrests in metaphase II Ova - general term for egg in the female reproductive system |
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Describe the histological differences between a morula and a blastocyst.
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- Morula - solid mass of identical cells surrounded by the zona pellucida
- Blastocyst - hollow ball with 32+ cells filled with fluid; hatches from zona pellucida; cells begin to differentiate into the trophoblast and the inner cell mass |
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What are the two types of cells which make up a blastocyst?
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Trophoblast - forms outer protective layer
Inner cell mass - they are eccentric/clump on one side, and will become the embryo |
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What is the function of the trophoblast?
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- Outer layer that preserves and protects the inner cell mass
- Secretes enzymes to break down zona pelucida - Helps blastocyst embed in uterine wall |
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What role does human chorionic gonadotropin (hCG) play in sustaining pregnancy?
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Helps maintain the uterine lining
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How has knowledge of human chorionic gonadotropin (hCG) become clinically and commercially useful?
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It is used to detect for pregnancy
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From what embryonic structure does the bilaminar embryonic disk originate?
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The inner cell mass
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Identify the three primary germ layers and descrive which tissues ultimatly derive from each.
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Endoderm - the epithelial linings of the digestive, respiratory and urogenital systems and the glands associated with them
Ectoderm - structures of nervous system and skin epidermis Mesoderm - everything else; muscle, bone, cartillege, etc. |
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Identify the four extraembryonic membranes and describe the function of each.
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Amnion - membrane that surrounds the amniotic cavity
Yolk sac - forms part of digestive tract, makes earliest blood cells, origin of reproductive cells Allantois - structural base for umbillical cord, later part of urinary bladder Chorion - Encloses embryo and everything else, secretes hCG; forms fetal portion of placenta |
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Hydrophilic
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Molecules that interact with water and charged molecules
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Hydrophobic
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Molecules that interact only with nonpolar molecules
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Receptor
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A nerve ending specialized to respond to stimuli
Protein that binds specifically with other molecules |
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What are the basic tenets of cell theory?
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- Cells come from other cells; they don't spontaneously generate
- Cells are the smallest unit of life - The individual and collective activities of the cells are what what life depends on |
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What are the three major parts of the generalized cell?
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Nucleus
Cytoplasm Plasma membrane |
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What theory explains the structure of the plasma membrane?
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The fluid mosaic model
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Describe the basic structure of the plasma membrane.
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Phospholipid bilayer with hydrophobic tails on interior of membrane and hydrophilic heads on exterior
Proteins embedded in membrane Glycocalyx on outside of membrane |
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What chemical compounds make up the plasma membrane?
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Phospholipids
Integral proteins Peripheral proteins Glycocalyx Cholesterol Glycolipids |
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Describe the chemical structure of a phospholipid molecule.
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Hydrophilic head
Two hydrophobic tails that are fatty acid chains |
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Identify the two distinct types of proteins associated with the plasma membrane.
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Integral proteins - embedded in lipid bilayer; transmembrand and embedded halfway
Peripheral proteins - loosely attached to integral proteins on outside of cell |
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Describe the structure and function of integral and peripheral proteins.
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Peripheral - anchoring the cell; stabilizing the cell membrane
Integral - transport across membrane |
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What are the primary functions of the plasma membrane?
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Selective permeability - which and how quickly substances enter and exit the cell
Boundaries of cell Set up gradients - electrical, concentration |
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Explain why the plasma membrane is described as selectively permeable.
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Allows passage of certain molecules and not others
Able to control what enters/exits, rather than simply distinguishing by size, like semi-permeable membranes |
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What is the major difference between active and passibe processes for moving materials across the cell membrane?
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Active - uses ATP; usually transports mol. against conc. gradients
Passive - energy comes from kinetic energy and possibly electrochemical gradients |
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Identify and describe each of the passive processes of membrane transport. How are they similar to, and different from, each other?
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Simple diffusion - non-polar mol.; freely move down conc. gradients through membrane
Facilitated diffusion - doesn't require energy; cells too large/polar to go through membrane; diffuse through protein channels or membrane while attatched to carrier molecules |
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How does the concentration gradient influence the diffusion of materials across a membrane?
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Always flow down a conc. gradient, unless there is some type of active transport
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Describe the condition of equilibrium. Is there any movement of molecules across a membrane when equilibrium is acheived?
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Still movement, just NO net movement across membrane
Movement each direction is equal |
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What factors, other than the concentration gradient, influence the rate of diffusion?
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Size of molecule
Temperature Distance to diffuse Surface area that mol. are diffusing across Size of conc. gradient |
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What are the different ways in which materials diffuse across the plasma membrane, based on their size and lipid-solubility?
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Simple diffusion - small non-polar
Facilitated diffusion - larger polar molecules Active diffusion - larger polar molecules |
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How is osmosis similar to diffusion?
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Occurs down conc. gradient
Can go straight through plasma membrane BUT Diffusion of solvent as opposed to a solute |
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What conditions must be present for osmosis to occur?
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Water must have a conc. gradient
Selectively permeable membrane - lets water diffuse and not any other substances Osmotic pressure must be low enough to not equal the overall hydrostatic pressure |
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When does osmosis stop?
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When water conc. is equal on both sides of membrane
When pressure is great enough to stop continuing diffusion |
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What is osmotic pressure?
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Force that solutes exert in the solution
It is opposed to the hydrostatic pressure in osmosis |
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Describe the function of each of the organelles found in the generalized cell.
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Mitochondria - ATP production
Rough ER - Makes all proteins secreted from cells; integral proteins and phospholipids Smooth ER - Metabolism of lipids and carbs; synthesis of cholesterol, lipid part of lipoproteins, steroid based hormones, fat; detox of drugs Golgi apparatus - modify, concentrate and package proteins and lipids made in RER Lysosomes - digest molecules:bacteria, worn our organelles, glycogen, non useful tissues, bone (to release Ca) Peroxisomes - oxidase neutralizes free radicals to H2O2, catalase converts it to H2O |
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Describe the structure of each of the organelles found in the generalized cell.
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Mitochondria - elongated fluid (matrix) filled sacs; inner membrane has lots of folds (cristae); contain DNA and RNA; can replicate
Rough ER - studded with ribosomes; peptides extend through ER membrane to inside where they're modified Smooth ER - continuous with RER; no ribosomes Golgi apparatus - flattened membranous discs; near nucleus; vesicles but off RER fuse with cis face; bud off trans face Lysosomes - Spherical vesicles with digestive enzymes Peroxisomes - contain powerful detox enzymes |
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Identify and describe the function of the three types of cytoskeletal elements.
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Microfilaments - strengthens cell surface, resists compression; lots in muscle cells; used for cytokinesis
Intermediate filaments - resists pulling forces; stabilize organelle position; Microtubules - general cell shape; used in reproduction; used for organelle transportation; dyneins and kinesins |
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Identify and describe the structure of the three types of cytoskeletal elements.
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Microfilaments - actin arranged into dense cross-linked web; just inside membrane
Intermediate filaments - tough, stable, insoluble protein fibers Microtubules - slender; hollow tubes; made out of tubulin |
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What are the differences (structure and function) between cillia and flagella?
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Cillia - hair like; motile; large numbers; move material past cell surface
Flagella - one; longer cellular projection; moves cell |
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What is the composition of a ribosomal subunit?
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Proteins
rRNA |
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What is the composition of a ribosome?
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2 unequally-sized subunits that fit together
Site of protein synthesis |
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What are the differences (structure and function) between free and fixed ribosomes?
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Free - Make soluble proteins that function in cytosol and that are taken in to mitochondria
Fixed (to membrane bound organelles) - proteins for cell membranes and exocytosis |
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What is the endoplasmic reticulum?
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Interconnecting membranes that extend thru cytoplasm
Fluid filled cavities (cisternae) Continuous with plasma membrane |
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What are the differences (structure and function) between the rough and smooth ER?
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Rough - Studded with ribosomes which make/feed proteins into RER; RER modifies extreted proteins, and cell membrane proteins
Smooth ER - Continuous with RER, no ribosomes; metabolism of lipids and carbs |
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Describe the structure and function of the Golgi complex.
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Structure - flattened membranous discs; near nucleus
Function - modifies, condentrates and packages proteins and lipids made in RER Fuse with cis face, modified, tagged, bud off trans face |
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Identifu and describe the contents and destination of the three types of vesicles packaged by the golgi complex.
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Secretory vesicles - proteins destined fo rexport
Membrane renewal vesicles - incorporated into plasma membrane Transport vesicles - enzymes transferred to lysosomes |
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What is the difference between primary and secondary lysosomes?
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Primary - inactive enzymes
Secondary - primary has fused with a phagosome; enzymes are activated during fusion to digest contents |
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Compare and contrast lysosomes, peroxisomes, and proteasomes.
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Lysosomes - digestive enzymes; abundant in phagocytes; digest almost anything; membrane made to keep acid in, but put digestive products out
Peroxisomes - enzymes detox harmful materials; oxidase converts to H2O2; catalase converts to H2O; not made by golgi; found in liver and kidney Proteasomes - found in cytosol and nucleus; remove and recycle damaged/excess cytosolic proteins; ubiquitin tags proteins for digestion; peptide bonds broken in core of proteasome |
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Describe a mitochondrion (structure and function).
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Structure - elongated fluid filled sacs; double phospholipid bilayer membrane; outer = smooth, inner= cristae/folds; have DNA and RNA
Function - ATP production/ respiration |
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What is the relationship between a cell's metabolism and it's mitochondrial density?
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High metabolism = high mitochondrial density
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What kind(s) of cells have an abundance of mitochondria?
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Liver and kidney
Very few in unchallenged lymphocytes |
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What is the function of adenosine triphosphate (ATP)?
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An energy storing molecule that is made by the mitochondria and is broken down to ADP for every energy requiring action in the cell
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Where are ribosomes made?
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Inside the nucleolus of the nucleus
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