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136 Cards in this Set

  • Front
  • Back
THE CELL THEORY
1-cell is the basic structural unit of life

2-activity of an organism depends on the individual cell and collective activities of its cells

3- biochemical activities are determined by number of specific subcellular structures

4- continuity of life has a cellular basis
3 PARTS OF HUMAN CELLS
1- plasma membrane (semi permeable)

2- cytoplasm (inside the cell)

3- nucleus (DNA replication)
INTRACELLULAR
inside the cell
EXTRACELLULAR
outside the cell
PLASMA MEMBRANE

(3 parts)
1- fluid mosaic model- lipid bilayer with proteins imbedded

2- hydrophilic head- attracts H2O

3- hydrophobic tail (make up interior of membrane)

**plasma membrane plays a dynamic role in cellular activity. There are lots of metabolic processes and the membrane provide biological markers for cell-cell recognition

**cholesterol helps stabilize membrane fluidity
GLYCOLIPIDS
phospholipids with attached sugar groups
FUNCTIONS OF PLASMA MEMBRANE
transport (hydrophilic channel, hyrdolyze ATP to pump material)

enzymatic activity

receptors for signal transduction (bonding site for specific chemical messengers, like hormones)

intercellular joining

cell to cell recognition

structural support (for keeping proper shape and position)
INTEGRAL PROTEINS
proteins that are firmly inserted in the lipid bilayer

**most protrude from both sides of the membrane as TRANSMEMBRANE PROTEINS
PERIPHERAL PROTEINS
proteins that are loosely attached
GLYCOCALYX
carbohydrate rich area at the cell surface (glycolipids and glycoproteins); provides biological markers for cells to recognize each other and interact
MICROVILLI
finger-like extensions of the plasma membrane that increase cell surface area. found only in cells involved with absorption
MEMBRANE JUNCTIONS (3)
tight junction
desmosomes
gap junction
TIGHT JUNCTION
impermeable (watertight) junction of interlocking proteins surrounding the cell
DESMOSOMES
anchoring junctions

consists of internal protein plaque and external linker proteins
GAP JUNCTIONS
"open junction" allows cellular communication and interaction due to connexons (hollow protein channels) that allow substances to pass between cells. These come together to form intercalated discs
INTERSTITIAL FLUID
derived from the blood; extracellular fluid
SELECTIVELY PERMEABLE
describes plasma membrane

allows only certain substances to pass through
PASSIVE PROCESSES
doesn't require ATP
DIFFUSION
tendency for molecules or ions to disperse evenly

moves from HIGH to LOW concentration, forming concentration gradient (difference in concentration). Influenced by Molecule size and Temperature.
3 CATEGORIES OF DIFFUSION
simple diffusion
facilitated diffusion
osmosis
SIMPLE DIFFUSION
lipid soluble substances diffusing directly through the lipid bi-layer. still uses concentration gradient (HI to LO) to move in a cell

only for NON-POLAR and LIPID SOLUBLE substances

(ex/ O, CO2)
FACILITATED DIFFUSION
large polar molecules like simple sugars
glucose and amino acids

small lipid-insoluble solutes (aka water soluble) diffuse thru channel proteins. The solutes cant get through the lipid bilayer without help, so proteins create a channel to help them get thru. Still uses HI to LO concentration gradient but it needs a helping protein.

piggy backing: binds to protein carrier and gets moved across
OSMOSIS
diffusion of water across a semipermeable membrane

the solute (if any) dissolved in the water is left behind

occurs when the concentration of water is different on opposite sides of a membrane
FILTRATION
water diffusing through a membrane due to hydrostatic pressure (back-pressure)

forms a pressure gradient

ex/ garden hose with small holes
ACTIVE PROCESSES (2)
Transport powered by ATP

Active Process
Vesicular Transport
SODIUM-POTASSIUM PUMP
difference in concentration between NA and K within and outside the cell

forms a membrane potential
ENDOCYTOSIS
particles moving within the cell
EXOCYTOSIS
particles moving outside the cell
PHAGOCYTOSIS
cellular eating

pseudopodia engulf solids and brings them into the cells interior
PINOCYTOSIS
cellular drinking; aka fluid-phase-endocytosis / bulk phase endocytosis

plasma membrane infolds, bringing extracellular fluid and solutes into the interior of the cell
MEMBRANE POTENTIAL
electrical energy caused by separation of 2 oppositely charged particles; or voltage across a membrane
RESTING MEMBRANE POTENTIAL
all resting body cells found in this state

results mostly from Na and K concentration gradients across the membrane due to:

1) differential permeability of the plasma membrane to Na and K

2) Na K pump
CAMs (cell adhesion molecules)
glycoproteins that:
-anchor cells to the extracellular matrix and each other
-assist in the movement of cells past one another
-direct white blood cells to injured or infected areas
-respond to tension at the cell surface
LIGANDS
signaling chemicals that bind specifically to membrane receptors
G-LINKED PROTEIN RECEPTORS
the middleman responder

ligand binds to a receptor molecule
receptor activates G-linked protein
G linked protein stimulates an effector protein

effector produces 2nd messenger
enzymes trigger cell response
CELL LIFE CYCLE: 2 PHASES
interphase
S-phase
INTERPHASE
growth and replication of DNA
S PHASE
stage of interphase where DNA is replicated
BEFORE A CELL CAN DIVIDE, WHAT MUST FIRST HAPPEN?
DNA must be replicated
ORDER OF DNA REPLICATION (5)
1) DNA helicase untwists the helix

2) RNA primers form DNA polymerase 3, DNA polymerase 1, and DNA ligase

3) DNA polymerase 3 starts from primer, positions the strands and links them together

4)DNA polymerase 1 then replaces the primer

5)DNA Ligase splices short segments of DNA together
ROLE OF RNA (3)
tRNA
mRNA
rRNA
PROMOTER
must be present for transcription to occur
RNA POLYMERASE
enzyme that oversees the synthesis of mRNA
CODON
codes for amino acids on mRNA
TRANSLATION
-nucleic acids are translated into the language of proteins

-occurs in cytoplasm

tRNA comes and transfers amino acids and forms anticodon
APOPTOSIS
programmed cell death
GLYCOPROTEINS
have attached carbohydrate chains
OSMOLARITY
total concentration of solute particles in a solution
OSMOTIC PRESSURE
pressure required to resist further water entry into a cell

in plant cells this creates internal pressure and stops net water movement

animal cells shrink or swell in response to osmotic imbalances
TONICITY
measure of the ability of a solution to change cell shape or tone by promoting water flow
HYPERTONIC
solution w higher concentrations of solutes than the concentration inside the cell

cell filling up with water
HYPOTONIC
solution with lower concentrations of solute than what is inside the cell

water leaving a cell
ISOTONIC
solution with same concentration of solutes as what is inside the cell
ACTIVE PROCESS

1) SYMPORT SYSTEM
2 substances are moved across a membrane in the same direction
ACTIVE PROCESS

2) ANTIPORT SYSTEM
2 substances are moved across a membrane in opposite directions
ACTIVE PROCESS

3) SECONDARY ACTIVE TRANSPORT
use of an exchange pump indirectly to drive the transport of other solutes

ex/ NA K pump
VESICULAR TRANSPORT
transport of large particles and macromolecules across plasma membranes in membrane vessicles
VESICULAR TRANSPORT

1) EXOCYTOSIS
moves subtances from interior of cell to extracellular space
VESICULAR TRANSPORT

2) ENDOCYTOSIS
enables large particles and macromolecules to enter the cell (several varieties)
RECEPTOR MEDIATED ENDOCYTOSIS
uses receptors in clathrin-coated puts as the major mechanism for specific uptake of macromolecules
ROLES OF MEMBRANE RECEPTORS

(PROTEINS AND GLYCOPROTEINS)
Contact signaling
electrical signaling
chemical signaling
G protein linked receptors
CONTACT SIGNALING
important in normal tissue development and immunity
ELECTRICAL SIGNALING
voltage-regulated "ion gates" in nerve and muscle tissue respong to voltage changes
CHEMICAL SIGNALING
signal chemicals (ligands) binding to membrane receptors
G-PROTEIN LINKED RECEPTORS
binding of ligand activates G protein, causing the release of a 2nd messenger (ex/ cyclic AMP)
OPERATION OF A G-PROTEIN
extracellular ligand (first messenger) binds to a specific membrane receptor

receptor protein activates G protein which relays message to an effector protein

effector is enzyme whice produces 2nd messenger

2nd messenger activates kinase

activated kinase triggers variety of cellular responses
DEOXYRIBONUCLEIC ACID (DNA)
double stranded helical molecule found in nucleus of a cell

replicated itself before the cell divides

provides instructions for protein synthesis
STRUCTURE OF DNA
the nucleotide is composed of:
N-containing base
pentose sugar
phosphate group
4 NITROGEN BASES THAT MAKE NUCLEOTIDE STRUCTURE
A adenine
G guamine
C cytosine
T thymine
CHROMATIN: DNA ORGANIZATION
threadlike strands of DNA and Histones

arranged into units called nucleosomes

condenses to form chromosomes when the nucleus starts to divide
DNA REPLICATION
begins s-phase of interphase

DNA helices begin unwinding from the nucleosomes
HELICASE ENZYME / SEMICONSERVATIVE REPLICATION
begins with replisome

untwists the double helix and exposes the complimentary strands

each nucleotide strand serves as a template for building a new complementary strand

entire process called semiconservative replication
REPLISOME
formation of complex proteins which starts the process of DNA replication
RNA PRIMERS
short segments of RNA

formed by the replisome

initiates DNA synthesis
DNA POLYMERASES
continue from the primer to add complementary nucleotides to each template and replaces the RNA primer with DNA nucleotides
DNA LEADING STRAND
DNA LAGGING STRAND
leading strand is continuous strand of DNA that continues on in one direction

lagging strand is discontinuous and is the ending side of the leading strand
GENES
segments of DNA carrying instructions for the polypeptide chain
TRIPLETS
groups of 3 nucleotide bases forming the genetic alphabet

code for the amino acids of a polypeptide
EXONS
characteristics; coding regions of DNA that
INTRONS
junk DNA; matching/non coding triplets
ROLE OF mRNA
carries genetic information from DNA to the ribosomes in the cytoplasm
ROLE OF rRNA
structural component of ribosomes
TRANSCRIPTION
occurs inside nucleus

1st process of re-writing DNA to RNA form in order to bring to ribosomes in the cytoplasm

transfer of information occurs in nucleus

complimentary copy of DNA is made as mRNA
URACIL (U)
base in RNA that takes the place of T (thymine) in DNA strand
PROMOTER SEQUENCE
signals the start of RNA synthesis
TRANSCRIPTION FACTORS
activate the gene to be transcribed and bind to the promoter
ROLES OF RNA POLYMERASE
oversees synthesis of mRNA

unwinds DNA and adds proper RNA nucleotides

transcribes DNA triplets into mRNA codons (3 base sequences on RNA)
EDITING RNA
1st copy (pre-mRNA) has coding exons and non coding introns; the same regions as found in DNA

spliceosomes produce functional RNA
SPLICEOSOMES
RNA- protein complexes

remove introns from the pre-mRNA to produce functional mRNA
PROTEIN SYNTHESIS: TRANSLATION
1) binding of specific aminoacyl-tRNA to complimentary mRNA codon at the "A-Site" (aminoacyl-tRNA always moves into the A-Site

2) new amino acid is added to the polypeptide chain as a peptide bond, formed between the amino acids

3) ribosome moves one codon to the right, and the unchanged tRNA moves from P site to E site

4) tRNA is released from the E-site; ribosome is ready for another cycle
RIBOSOMES
rRNA binds base pairs; turns into mRNA when it leaves the nucleus
mRNA CODONS
3 base sequences on mRNA copied from DNA triplets
TRANSFER RNAs (tRNAs)
bind amino acids and pair with codons of mRNA at the ribosome
ANTICODONS
3-base sequences on tRNA

pair with codons on mRNA

amino acids brought to the
ribosome by tRNA form a polypeptide chain
BONUS: BE ABLE TO LIST TRIPLETS FROM DNA TO COMP. DNA, mRNA, tRNA, AND FINAL POLYPEPTIDE CHAIN
DNA to complimentary DNA is just opposite of AGTC

mRNA is the same as original DNA strand, just change the T to U because its the RNA code

tRNA is coded off of the mRNA, its the anticodon sequence (opposite of mRNA sequence)

look at the chart and the mRNA strand will code for an exact polypeptide chain
INFORMATION TRANSFER AND THE GENETIC CODE
DNA triplets are transcribed into mRNA codons by RNA polymerase

codons base pair with tRNA anticodons at the ribosomes

amino acids are peptide bonded at the ribosomes to form polypeptide chains (protein)
POLYPEPTIDE CHAINS (PROTEINS)
amino acids peptide bonded at the ribosomes
THE GENETIC CODE
RNA codons code for amino acids according to this genetic code

some codos serve as start and stop signals for translation

redundancy in the genetic code means many mutations are inconsequential
CODON CHART
Start: AUG (MET)

Stop: UAA, UGA, UAG
SIGNAL MECHANISM OF PROTEIN SYNTHESIS
mRNA / ribosome complex is directed to rough ER by a signal - recognition particle (SRP)

polypeptide grows into rough ER

protein is released into the rough ER and folds into a 3D conformation

protein is enclosed in a transport vessicle and moves toward the golgi apparatus
DEVELOPMENTAL ASPECTS OF CELLS
all cells of the body contain the same DNA but develop into specialized cells of the body

genes of specific cells are turned on or of determining the proteins that are made in that cell

cell differentiation
CELL DIFFERENTIATION
development of specific and distinctive features in cells
CELL AGING: WEAR AND TEAR THEORY
attributes aging to chemical damage and formation of free radicals that have cumulative effects throughout cell life
CELL AGING: GENETIC THEORY
attributes aging to cessation of mitosis that is programmed into our genes
CELL AGING: TELOMERES
ends of chromosomes which are eroded with each division, resulting in the end of cell division
GENERAL TYPES OF TISSUE
epithelial
connective tissue
muscular
nervous
2 FORMS OF EPITHELIAL TISSUE
covering/lining epithelium
glandular epithelia
FUNCTION CHARACTERISTICS OF EPITHELIAL TISSUE
protection, absorption, secretion, excretion, filtration, sensory reception

CHARACTERISTICS
cellularity
special contacts
polarity
support by connective tissue
vascularity
regeneration
CELLULARITY
composed almost entirely of cells
SPECIAL CONTACTS
held together by tight junctions and desmosomes
POLARITY
apical and basal surfaces

(apex: above free surface)
(basal: bottom; in basement membrane)
WHAT FORMS A BASEMENT MEMBRANE?
basal-connective tissues
VASCULARITY
avascular; simple diffusion

innervated; controlled by and communicates with nervous system
REGENERATION
rapidly replaces cells lost by cell division
TYPES OF GLANDULAR EPITHELIA
enodcrine and exocrine glands
EXOCRINE GLANDS
secretes hormones outside the body or onto body surfaces

ex/ mucous, sweat, oil, salivary glands (goblet cells also)
ENDOCRINE GLANDS
any gland which secretes hormones in the bloodstream

ductless glands produce hormones

secretions enter extracellular space then the blood to affect other organs
EXOCRINE GLANDS: MODES OF SECRETION
merocrine glands

holocrine glands
MEROCRINE GLANDS
products are secreted by exocytosis

(ex/ sweat, salivary glands)
HOLOCRINE GLANDS
products are secreted by the rupture of gland cells, and all of its contents spill outside of the cell

(ex/ sebaceous glands)
CUTANEOUS MEMBRANE
skin (stratified squamos epithelium)
= protective role

any stratified epethelial tissue is doing some sort of protective role
MUCOUS MEMBRANE
mucosae

inside lining of lungs, trachea, digestive, and respiratory tracts
(all of these are open cavities to the outside world)
SEROUS MEMBRANE
found in ventral body cavity

make serous fluid (which protects organs by adding extra cushion by surrounding them with fluid)

acts like a barrier

(ex/ pleura, pericardium, peritonium)
CONNECTIVE TISSUES
have MESENCHYME as their common tissue of origin
(varying degrees of blood supply for each type)

non-living extracellular matrix, consisting of ground substance and fibers

ex/ areolar, adipose, cartilage, (hyaline, elast, fibro) bone, blood, dense connective tissue (regular/irregular)
GROUND SUBSTANCE
unstructured material that fills space between cells
FIBERS
collagen (tensile strength)
elastic
reticular (thin branching collagen)
NERVOUS TISSUE
nervous system composed of brain, spinal cord, nerves

have neurons with long cellular processed and neuroglia (supportive cells)

transmits electrical signals between brain, spinal cord, and nerves
MUSCLE TISSUE (3)
contains actin and myosin (myofilaments) responsible for muscle contraction

3 types: skeletal, cardiac, smooth
TISSUE REPAIR
inflammation
organization
regeneration / fibrosis
INFLAMMATION
caused by tissue damage

redness, heat, swelling, pain
blood clot formation
ORGANIZATION
restored blood supply

blood clot is replaced with formation of granulation tissue
REGENERATION / FIBROSIS
surface epithelium regenerates

fibrous tissue matures from granulation tissue
DEVELOPMENTAL ASPECTS
primary germ layers: ectoderm, mesoderm, endoderm

3 layers of cells form during embryonic development, which specializes to form 4 primary tissues

epithelial tissues arise from all 3 germ layers
ECTODERM
creates nervous tissue
MESODERM
creates muscle and connective tissue
ENDODERM
creates mucosae