Biology Exam 2

Front 1

phylogeny

Back 1

evolutionary family tree; three domains: archaea, bacteria, eukaryota

Front 2

problem of exchange

Back 2

surface area:volume ratio decreases as volume increases, which limits necessary exchange across membrane so cells change shape (often "flat")

Front 3

problem of concentration/diffusion

Back 3

diffusion is inherently slow and non-directional, and concentration gradients are needed for energy (i.e. the case of Na+/K+) which is difficult in large cells (solute/volume) to accelerate reactions --> cells are compartmentalized to make life fast enough and increase concentration within organelles, but this costs energy to build membranes (endergonic)

Front 4

ribosomes

Back 4

complex of RNA + proteins used to synthesize proteins; floats in cytoplasm then attaches to rough ER

Front 5

rough ER

Back 5

contains receptors for entry of selected proteins; network of branching sacs with ribosomes associated for lipid synthesis

Front 6

Golgi apparatus

Back 6

receptors for products of ER, made of flattened cisternae; used for protein processing (i.e. glycosylation)

Front 7

glycosylation

Back 7

attachment of glycans (carbohydrates) to functional group of another macromolecule i.e. lipids or proteins

Front 8

smooth ER

Back 8

network of branchign sacs & enzymes for synthesizing phospholipids

Front 9

peroxisomes

Back 9

contains transporters for selected macromolecules and enzymes that catalyze oxidation reactions --> processing of fatty acids

Front 10

lysosomes

Back 10

contains proton pumps and inside acid hydrolases which catalyze hydrolysis reactions --> digestion and recycling

Front 11

vacuoles

Back 11

varies (pigments, oil, carbs, H20, toxins) for various storage purposes

Front 12

mitochondria

Back 12

double membrane; inside are enzymes that catalyze oxidation-reduction reactions (ATP synthesis)

Front 13

chloroplasts

Back 13

double membrane plus membrane bound sacs in interior, contains enzymes that catalyze redox reactions to produce ATP and sugars via photosynthesis

Front 14

cytoskeleton

Back 14

no membrane; actin filaments, intermediate filaments, and microtubules; gives structural support, movement of materials

Front 15

plasma membrane

Back 15

single membrane with transport/receptor proteins; selective permeability to maintain intracellular environment

Front 16

cell wall

Back 16

no membrane, carbohydrate fibers running through carb or protein matrix

Front 17

protein "address label"

Back 17

sequence of amino acids, often near the N or C-terminus, that binds with receptor proteins at destination (R-group interactions)

Front 18

two modes of protein transport

Back 18

non-directional (diffusion of soluble proteins) and directional (secretory pathway; uses cytoskeleton)

Front 19

vesicle

Back 19

small, watery bag surrounded by phospholipid bilayer

Front 20

chaperone protein

Back 20

proteins within rough ER and cytoplasm (for ribosomes) to create proper R-group interactions

Front 21

endosome

Back 21

membrane bound vesicle created from the folding in of the plasma membrane; used to bring foreign objects to lysosomes for degradation

Front 22

microtuble

Back 22

hollow tube formed from tubulin dimers (proteins); motor proteins kinesin and dynein

Front 23

microfilament

Back 23

double helix of actin monomers (proteins); gives cells shape; motor protein myosin

Front 24

intermediate filaments

Back 24

strong fiber composed of intermediate proteins; gives nucleus structure

Front 25

microtubule/microfilament dynamics

Back 25

one side is more conducive to adding proteins (+ side) so there is net movement of micrtobulues/microfilaments; takes energy since it's anabolic (GTP or ATP); ex. kinesin carries vesicles from ER --> Golgi --> plasma membrane (some motor proteins move from + end to - end)

Front 26

cilia/flagella movement

Back 26

composed of microtubules that are moved by dynein motor proteins; 9 + 2 arrangement of microtubule; cilia/flagella move when microtublules slide past one another

Front 27

movement of cell

Back 27

microfilaments are anchored to plasma membrane, so + - growth makes cells move

Front 28

muscle movement

Back 28

tropomyosin covers myosin binding sites until Ca+2 is present, which allows for troponin to bind and exposes myosin binding sites; ATP allows for movement of motor proteins along actin to "flex" muscle

Front 29

4 categories of cell-cell connections

Back 29

1. tight junctions*

2. adherens junction

3. desmosomes*

4. gap junction

Front 30

tight junctions

Back 30

cells linked by membrane proteins to form a waterproof barrier (used in bladder, intestine, etc.)

Front 31

desmosomes

Back 31

cells loosely linked by proteins attached to intermediate filaments but can resist sheer forces; used in "stress" layers i.e. skin and muscle (transmembrane proteins that "hook" into each other)

Front 32

extracellular matrix

Back 32

fiber are proteins excreted by cells; cells hang onto membrane with transmembrane proteins; sugars are also part of extracellular matrix

Front 33

membrane-permeable cell signals

Back 33

small nonpolar signaling molecules (i.e. steroids) pass through cell membrane and bind to receptor protein, which changes shape to activate cell (i.e. turn on gene production)

Front 34

membrane-impermeable cell signals

Back 34

nonpolar molecule binds to transmembrane receptor protein with polar/charged R-groups, which changes shape (R-group) and activates cell via signal transduction

Front 35

G-protein coupled receptor

Back 35

ligand binds to receptor which phosphorylates G protein (goes from GDP to GTP) which can now bind to enzyme to change ATP to cAMP

Front 36

receptor kinase

Back 36

kinase is phosphorylated and binds to enzyme; all enzymes that add phosphate are kinase

Front 37

Gap 1

Back 37

growth; cell starts at 1/2 volume; prepares for DNA synthesis, ER, mitochondria, peroxosomes, membrane all grow; needs nucleotides and energy for S phase

Front 38

G0

Back 38

cell not progressing through cycle; most cells are in G0 (neurons are permanently after puberty)

Front 39

S Phase

Back 39

synthesis, DNA replication; mitochondria are semi-autonomous but they also replicate

Front 40

Gap 2

Back 40

growth; preparation for mitosis

Front 41

prophase

Back 41

chromosomes condense from chromatin fibers; centrosomes radiate microtubules (break original structure) and migrate to poles to make mitotic spindle

Front 42

prometaphase

Back 42

microtubules of mitotic spindle attach to chromosomes

Front 43

metaphase

Back 43

chromosomes align in center of the cell

Front 44

anaphase

Back 44

sister chromatids separate and travel to opposite poles (centromere splits)

Front 45

telophase

Back 45

nuclear envelope reforms and chromosomes decondense

Front 46

anaphase dynamics

Back 46

motor proteins attached to kinetochore walk towards the minus end of the microtubule as the + end disassembles into tubulin subunits

Front 47

cytokinesis (telophase)

Back 47

microfilaments responsible for cell division; myosin proteins squeeze with actin, create contractile ring

Front 48

spindle assembly checkpoint

Back 48

cell will enter anaphase if all chromosomes are attached to mitotic spindle

Front 49

DNA replication checkpoint

Back 49

at end of G2, cell will enter mitosis if chromosome replication is successful and no DNA damage

Front 50

chromosome

Back 50

compacted chromatin

Front 51

chromatin

Back 51

DNA packaged around a histone (protein)

Front 52

DNA damage checkpoint

Back 52

enter S phase if nutrients are sufficient, growth factors (signals from other cells) are present, cell size is adequate, DNA is undamaged

Front 53

cell "switches"

Back 53

Cyclins bind to and activate cyclin-dependent kinases to control progression through thecell cycle; CDKs phosphorylatetarget proteins involved in promoting cell division

Front 54

semi-conservative replication

Back 54

the double helix in each sister chromatid contains one new strand of DNA and one old strand of DNA

Front 55

directional replication

Back 55

DNA polymerase moves 3' to 5' along old strand to synthesize new strand 5' to 3'

Front 56

helicase

Back 56

enzyme that separates DNA strands in double helix

Front 57

topoisomerase

Back 57

enzyme that relieves twisting forces

Front 58

Okazaki fragments

Back 58

on lagging strand, DNA is replicated in fragments because of 3' to 5' directionality; RNA primase is continually added in replication; DNA polymerase then replaces ribonucelotides with deoxyribonucleotides and DNA ligase closes gap in sugar-phosphate backbone

Front 59

replication bubble/replication forks

Back 59

directionality means that DNA synthesis creates many "bubbles" along the strand of DNA where synthesis is happening in two directions

Front 60

benign tumor

Back 60

cells continue to divide, but they aren't invasive

Front 61

malignant tumor

Back 61

cells divide and spread to adjacent/distant tissues through lymphatic vessels and blood vessels

Front 62

mestastasis

Back 62

cell detachment (eliminate protein which breaks junctions via signaling) and cell movement via lymphatic vessels/blood vessels to other tissues

Front 63

light microscope vs. electron microscope

Back 63

light electron uses light (photons) to view structures larger than a wavelength of light, so we can see large structures but can't identify them. electron microscopes allow for visualization of anything larger than an electron, so better resolution and smaller structures (but they must be dead)

Front 64

replication bubble vs. replication fork

Back 64

replication fork is created by unwinding (helicase/topoisomerase) of DNA. replication bubble is composed of two forks and it gets bigger over time