Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
133 Cards in this Set
- Front
- Back
|
gibbs free energy |
amount of energy available to do work; describes spontaneity of reaction |
|
|
enthalpy |
dH; total energy in a molecule |
|
|
exothermic |
releases heat; products have less energy than reactants; dH negative |
|
|
endothermic |
absorbs heat; products have more energy than reactants; dH positive |
|
|
entropy |
dS; amount of disorder in system |
|
|
2nd law of thermodynamics |
in isolated system, entropy always increases & d-S is always positive |
|
|
how are gibbs free energy, enthalpy, & entropy related? |
dG=dH - T(dS); T in K |
|
|
exergonic |
describes entropy; reaction is spontaneous & has -dG |
|
|
endergonic |
describes entropy; reaction is non-spontaneous & has pos. dG |
|
|
non-spontaneous reaction |
neg. dG |
|
|
spontaneous reaction |
pos. dG |
|
|
mechanisms for energetic coupling of reactions |
1. redox reactions 2. atp transfer of phosphate groups |
|
|
redox reactions |
- type of energetic coupling - reduction: become negative (gains electrons) - oxidation: become positive (lose electrons) |
|
|
energetic coupling |
occurs b/t endergonic/non-spontaneous rxns & exergonic/spontaneous rxns |
|
|
reduction |
- become negative - electrons move closer to atom being reduced (bond length shorter) - gain potential energy - increased number of C-H bonds (more C-H bonds = more potential energy) |
|
|
oxidation |
- become positive - electrons move further away from atom being oxidized (bond length longer) - lose potential energy - increased number of C-O bonds |
|
|
electron carriers |
electron acceptor; readily donates high-energy molecules to other molecules ex. NADH, FADH2 |
|
|
NAD+ |
oxidized form of NADH; less energy than NADH |
|
|
NADH |
reduced form of NAD+; more energy than NAD+ |
|
|
FADH |
oxidized form of FADH2; less energy than FADH2 |
|
|
FADH2 |
reduced form of FADH; more energy than FADH2 |
|
|
atp hydrolysis |
- type of energetic coupling - ATP reacts w/ water - bond b/t outermost P group & rest of molecule broken --> high energy P released - extremely exergonic |
|
|
enzymes |
lowers activation energy (Ea) for rxn; doesn't change dG |
|
|
do enzymes make endergonic reactions spontaneous? |
no; doesn't change dG |
|
|
low substrate concentration (enzyme-catalyzed) |
speed of rxn increases quickly |
|
|
medium [substrate] (enzyme-catalyzed |
increase in speed of rxn slows down |
|
|
high [substrate] (enzyme-catalyzed) |
rxn rate reaches plateau at max speed |
|
|
factors affecting enzyme function |
-temperature -inhibition -pH |
|
|
temp/pH effects (enzyme) |
enzyme less effective outside of ideal temp/pH; can become denatured if temp/pH gets too high/low |
|
|
competitive inhibition |
regulatory molecule binds in active site on enzyme & substrate can't bind |
|
|
allosteric activation |
active site becomes available for sub. binding when regulatory molecule binds to different site on enzyme; beneficial conformational change |
|
|
allosteric inhibiion |
active site becomes unavailable for sub. binding when regulatory molecule binds to different site on enzyme; detrimental conformational change |
|
|
how are enzymes regulated? |
covalent & noncovalent modifications |
|
|
covalent modifications |
-reversible or irreversible depending on type of modification -ex. phosphorylation |
|
|
non-covalent modifications |
-reversible or irreversible depending on type of modification -ex. cleavage of peptide bonds in 1* structure; allosteric regutlation |
|
|
glycolysis (location)
|
cytosol |
|
|
pyruvate processing (location) |
matrix of mitochondria |
|
|
citric acid cycle (location) |
matrix of mitochondria |
|
|
electron transport chain/oxidative phosphorylation (location) |
intermembrane space of mitochondria |
|
|
inputs (glycolysis) |
2 atp (needed to get process started), 2 nad+, 4 adp, glucose |
|
|
outputs (glycolysis) |
2 adp, 2 nadh, 2 h+, 4 atp, 2 pyruvate net: 2 atp |
|
|
inputs (pyruvate processing) |
2 pyruvate, 2 nad+, 2 coenzyme a (CoA-SH) |
|
|
outputs (pyruvate processing) |
2 nadh, 2 acetyl coa, 2 co2) |
|
|
inputs (citric acid cycle) |
2 acetyl coa, 6 nad+, 2 fadh, 2 adp, water |
|
|
outputs (citric acid cycle) |
4 co2, 6 nadh, 2 fadh2, 2 atp, h+ |
|
|
where in cellular respiration does feedback inhibition occur? |
citric acid cycle |
|
|
feedback inhibition (citric acid cycle) |
-rxn rates high when atp needed -rxn rates low when atp surplus |
|
|
what would happen if feedback inhibition was removed (citric acid cycle)? |
excess of cac product/atp would be made |
|
|
in aerobic respiration, does inhaled o2 chemically combine w/ c to make co2? |
-no; co2 produced in citric acid cycle, pyruvate processing -o2 combines w/ h+ in etc --> water |
|
|
where do the high energy electrons come from that enter etc of mitochondria? |
electron carriers (fadh2 & nadh produced in glycolysis, pyruvate processing, & citric acid cycle) |
|
|
what do fadh2 & nadh do with their high energy electrons? |
transfer them to o2 (acts as final electron acceptor) --> o2 able to combine w/ h present (b/c of proton gradient) & make water |
|
|
complex I |
nadh oxidized |
|
|
complex II |
fadh2 oxidized |
|
|
complex III |
electrons passed to cytochrome c then C4 |
|
|
complex IV |
o2 combines w/ h+ to make water |
|
|
does the electron transport chain produce atp? |
no; job is to create proton gradient that fuels atp synthase using transfer of electrons |
|
|
which has more energy: nadh or fadh2? |
nadh; each transfer of electrons decreases potential energy present in those electrons |
|
|
electron transport chain |
pumps h+ from mitochondrial matrix out to intermembrane space |
|
|
chemiosmosis |
pumps h+ from intermembrane space back into mitochondrial matrix to generate atp |
|
|
atp synthase |
uses proton gradient from etc & rotational force to generate atp |
|
|
inputs (etc) |
10 nadh, 2 fadh2, 02, h+ |
|
|
outputs (etc) |
water, proton gradient |
|
|
inputs (chemiosmosis) |
h's from proton gradient, 25 adp, 25 Pi |
|
|
outputs (chemiosmosis) |
25 atp |
|
|
net yield of aerobic respiration |
29 atp per glucose molecule |
|
|
purpose of fermentation |
regenerate nad+ to fuel glycolysis |
|
|
fermentation |
-occurs in absence of o2 (final electron acceptor) -takes pyruvate from glycolysis & creates lactate (ethanol in yeast)n |
|
|
net yield (anaerobic respiration) |
2 atp per molecule of glucose |
|
|
what energy sources other than glucose can be used in respiration? |
fats & phospholipids, proteins |
|
|
where do they enter the pathway (fats/phospholipids)? |
pyruvate processing |
|
|
where do they enter the pathway (proteins)? |
citric acid cycle |
|
|
energy source for anaerobic respiration/fermentation (fats/phospholipids)? |
yes |
|
|
energy source for anaerobic respiration/fermentation (proteins) |
no, enters at citric acid cycle so no pyruvate made |
|
|
function (citric acid cycle) |
create nadh & fadh2 for etc; create substrates for a.a. synthesis |
|
|
photosynthesis
|
-2 sets of reactions: light-capturing & calvin cycle rxn's -both sets of rxns linked (products of one are sub.'s for other) |
|
|
inputs (light-capturing rxns) |
sunlight, h2o, adp, nadp+, h+ |
|
|
outputs (light-capturing rxns) |
atp, nadph, o2 |
|
|
inputs (calvin cycle rxns) |
nadph, atp, co2 |
|
|
outputs (calvin cycle rxns) |
nadp+, h+, adp, sugars |
|
|
purpose (light-capturing rxns) |
create substrates for calvin rxns |
|
|
purpose (calvin cycle rxns) |
make simple sugars from co2 |
|
|
where do the o2 atoms released from plants come from? |
water |
|
|
how would poisoning etc from light-capturing rxns affect calvin cycle rxns? |
no energy source to fuel rxns; buildup of co2; no simple sugars would be made |
|
|
location (light-capturing rxns) |
on thylakoid membrane |
|
|
location (calvin cycle rxns) |
in stroma |
|
|
mitochondria & chloroplasts (similar) |
-energy powerhouses -double membrane -use etc to generate atp -atp synthase |
|
|
mitochondria & chloroplasts (different) |
-etc uses nadp+ & nadph (chloroplasts) vs. nad+ & nadh (mitochondria) -presence of photosystems in chloroplasts -chemiosmosis (mitochondria) |
|
|
location (photosystem II & cytochrome complex) |
thylakoid membrane |
|
|
location (photosystem I & atp synthase) |
membranes outside of granum |
|
|
stages of calvin cycle rxns |
1. fixation 2. reduction 3. regeneration |
|
|
higher energy: 5 g3p or 3 rubp? |
rubp > g3p; but have same amt. of energy b/c energy lies in # c's in molecule |
|
|
chromosome |
single, dna double helix wrapped around histone protein to form dimers |
|
|
chromatid |
replicated chromosome |
|
|
sister chromatids |
replicated chromosomes still attached at centromere; still 1 chromosome though |
|
|
homologous chromosomes |
-chromosomes similar in size, shape, & alleles for same gene; similar not identical -present in diploid organisms |
|
|
where during cell cycle are chromosomes duplicated? |
s phase |
|
|
mpf |
-m phase-promoting factor -made of cyclin & cdk subunits |
|
|
if [mpf cdk] is constant across cell cycle, how can it be a trigger for initiating m-phase? |
-mpf cdk + mpf cyclin = active mpf & initiation of m-phase |
|
|
what causes [mpf] to decline sharply during m-phase? |
cyclin subunit marked for destruction by ubiquitins produced in anaphase --> destroyed by proteasomes |
|
|
where in cell cycle are checkpoints found? |
after g1, before m, during mitosis |
|
|
g1 checkpoint |
pass if cell is right size, has right nutrients, social signals present, & no dna damage |
|
|
g2 checkpoint |
pass if chromosomes have replicated correctly, activated mpf is present, & no dna damage |
|
|
m-phase checkpoints |
-pass if chromosomes have attached to spindle apparatus -pass if chromosomes have properly separated & mpf absent |
|
|
defects in cancerous cells |
1. make cell growth proteins active when they shouldn't be 2. prevent tumor suppressor genes from shutting down cell cyclet |
|
|
tumor suppressor genes |
-regulatory proteins that control cell group & repairs dna damage -ex. p53 |
|
|
growth factors |
polypeptides or small proteins that stimulate cell division |
|
|
function (growth factors) |
needed for healthy cells to pass g1 checkpoint; cancer cells don't need externally supplied growth factors & pass g1 checkpoint anyways |
|
|
how many different alleles can the same gene of a diploid plant have? |
2 alleles |
|
|
diploid |
-2 types of each type of chromosomes -2 alleles for each gene; one in each homolog |
|
|
crossing over |
-occurs in meiosis 1 -chromatids from chiasma exchange parts of chromosomes b/t mom & dad homologs |
|
|
chiasma |
-forms meiosis 1 -joining of non-sister chromatids at certain locations to form x -needed for crossing over to happen |
|
|
why doesn't crossing over happen in mitosis? |
non-sister chromatids are never joined |
|
|
s-phase |
chromosomes condense & duplicate; chromosomes now made of sister chromatids |
|
|
prophase |
chromosomes condense; mitotic spindles begin to form |
|
|
prometaphase |
nuclear envelope breaks down; spindles attach to chromosomes at kinetochore |
|
|
metaphase |
chromosomes line up at metaphase plate in middle of cell |
|
|
anaphase |
sister chromatids separate into daughter chromosomes; chromosomes start pulling towards poles; spindles shorten at kinetochore |
|
|
telophase |
nuclear envelope reforms; chromosomes decondense |
|
|
cytokinesis |
action-myosin ring between 2 cells tightens & separates cytoplasm --> 2 daughter cells (2n) |
|
|
e2f |
regulatory protein important for passing g1 checkpoint; triggers expression of genes needed for s-phase when activated |
|
|
rb |
tumor suppressor protein; keeps e2f inactive |
|
|
1 chromosome = |
1 dna double helix |
|
|
early prophase 1 |
chromosomes condense; spindles appear; nuclear envelope starts to break down; pairing of homologous chromosomes |
|
|
synapsis |
pairing of homologous chromosomes |
|
|
late prophase 1 |
chiasmata visible; nuclear envelope gone (can be multiple chiasmata b/ non-sister chromatids) |
|
|
metaphase 1 |
tetrads lined up at metaphase plate |
|
|
tetrad |
pairs of homologous chromosomes; also called bivalents |
|
|
anaphase 1 |
homologs separate & start moving towards poles (homologs made of sister chromatids) |
|
|
telophase 1 & cytokinesis |
daughter chromosomes at opp. poles; spindles shorten at kinetechores --> 2 daughter cells (2n) |
|
|
prophase 2 |
spindles form |
|
|
metaphase 2 |
chromosomes line up at metaphase plate |
|
|
anaphase 2 |
sister chromatids separate & start moving to opp. poles |
|
|
telophase 2 & cytokinesis |
nuclear envelope reforms; 4 daughter cells (n) |
