Chapter 6 Flashcards
Cellular Respiration
photosynthesis
light energy —> chemical energy (sugar)
photosynthesis is done by what types of organisms ?
- plants
- algae
- some protists
- some prokaryotes
cellular respiration
chemical energy (sugar) —> ATP
cellular respiration is done by what types of organisms ?
practically all organisms
respiration
breathing; exchanging O2 and CO2
OIL RIG
Oxidation Is Lost
Reduction Is Gain
at the end of cellular respiration O2 becomes what ?
reduced to water (O2 —> H2O)
at the end of cellular respiration glucose becomes what ?
oxidized to CO2 (c6h12o6 —> CO2)
is cellular respiration an exergonic / endergonic reaction ?
exergonic
- the chem. energy in the bonds of glucose is released
what percent of energy produced is usable and released as heat ?
34% is usable
66% is released as heat
cellular respiration equation ?
C6 H12 O6 + 6O2 —> 6CO2 + 6H2O + ATP
how many g of energy, in the form of glucose, does the brain need each day ?
120 g
the brain uses what percent of all energy consumption ?
20%
innate bodily functions and maintaining cells uses what percent of all energy consumption ?
75%
kilocalories
kcal / cal; energy unit
- a quantity of heat = to 1000kcal
- quantity of heat required to raise 1kg of H2O by 1°C
what is the energy (kcal) requirement also known as ?
basal metabolic rate (BMR)
avg adult needs how many kcal per day?
2200 kcal
kcal needed per day is dependent on what factors ?
- age
- sex
- activity level
how do cells extract energy from fuel (glucose) ?
by transferring electrons
redox reactions
reduction-oxidation reactions; electrons lost (oxidized) from one substance and added (reduced) to another
oxidation
loss of electron; always goes with reduction
reduction
gain of electrons; always goes with oxidation
what shows the transfer of electrons between substances ?
the movement of hydrogen atoms
NAD+
coenzyme that accepts electrons
- shuttles electrons in redox reactions
what does NAD+ turn into when it accepts electrons ?
NADH
dehydrogenase
transfers 2 H atoms from fuel —> NAD+ = NADH
what happens to the fuel when it is acted on by dehydrogenase ?
oxidized; it is losing electrons to dehydrogenase
what happens to the NAD+ when it is acted on by dehydrogenase ?
reduced; it is gaining electrons from dehydrogenase
ETC
electron transport chain; multiple electron carriers that shuttle electrons for a series of redox reactions
what is at the end of the ETC and why is it that substance ?
O2, because O2 is extremely electronegative and it attracts the electrons down the ETC
what is released during the ETC and what are those substances released used for ?
releases controlled amounts of ATP to produce ATP
1 glucose produces around how much ATP ?
32 ATP
stages of cellular respiration ?
1) glycolysis
2) pyruvate oxidation & citric acid cycle
3) oxidative phosphorylation
glycolysis
- w/o O2 in cytosol
- 9 total enzymatic reactions
- produces ATP by substrate-lvl phosphorylation
- breaks down glucose into two pyruvate
how much investment is needed to start glycolysis for cellular respiration ?
2 ATP
NET yield of glycolysis ?
- 2 ATP
- 2 NADH
- 2 pyruvate
substrate-lvl phosphorylation
form ATP by transferring phosphate group to ADP
intermediates
compounds formed between the initial / final product
steps of glycolysis in the “investment phase” ?
stages 1-4
Stage 1-3 of glycolysis
stage 1 and 3 = ATP is added into glucose
stage 4 of glycolysis
6C glucose splits into 2 3C G3P chains
steps of glycolysis in the “energy payoff phase “
stages 5-9
how many times does energy pay off phase run from 1 glucose ?
2 times; glucose is split into 2 G3P
- stages can run twice
stage 5 of glycolysis
redox reaction generates NADH
- 2 phosphate groups add to G3P
- 2 NAD+ gain electrons from G3P
stages 6-9 of glycolysis
ATP and pyruvate is produced
stage 6 = 2 ADP gains phosphate groups from G3P
stage 8 = H2O leaves
stage 9 = 2 ADP gains phosphate groups from G3P
in glycolysis, how many total substrate phosphorylation reactions occur for 1 glucose molecule ?
4 total;
stage 6 = 2 reactions
stage 9 = 2 reactions
how many times can pyruvate phosphorylation and citric acid cycle run per 1 glucose molecule ?
2 times;
- from the two pyruvate made form glycolysis
pyruvate oxidation
- needs O2 in mitochondria
- turns pyruvate into acetyl CoA
stages 1-3 of pyruvate oxidation
stage 1 = 1 CO2 leaves
stage 2 = NAD reduced into NADH + H+
stage 3 = coenzyme A joins
NET yield of 1 turn of pyruvate oxidation ?
1 NADH + H+
NET yield of pyruvate oxidation w/ 1 molecule of glucose ?
2 NADH + H+
stage1 of citric acid cycle
acetyl CoA (2C) joins oxaloacetate (4C) to make citrate (6C)
- NAD+ reduced NADH + H+
stage 2-3 of citric acid cycle
NADH, CO2 made during redox reaction
- CO2 leaves
- NAD+ becomes reduced to NADH + H+
stage 3 of citric acid cycle
ATP made during redox reaction
- ADP + P reduced to ATP
stage 4 of citric acid cycle
FADH2 made during redox reaction
- FAD reduced FADH2
stage 5 of citric acid cycle
H2O joins
stage 6 of citric acid cycle
NADH made during redox reaction
- NAD+ reduced to NADH + H+
NET yield of one turn of the citric acid cycle
- 1 ATP
- 3 NADH + H+
- 1 FADH2
NET yield of citric acid cycle w/ one molecule of glucose ?
- 2 ATP
- 6 NADH + H+
- 2 FADH2
how much CO2 and ATP has been produced in glycolysis, pyruvate oxidation and citric acid cycle ?
- 6 CO2 (all in stage 2)
- 4 ATP (2 from each)
total number of NADH and FADH2 produced from glycolysis, pyruvate oxidation and citric acid cycle ?
- 10 NADH (2 : 2 : 6)
- 2 FADH2 (only citric acid cycle)
oxidative phosphorylation
- w/ oxygen
- intermembrane of mitochondria
- ETC
- chemiosmosis
how does the ETC in oxidative phosphorylation work ?
- electrons carriers (NADH / FADH2) transport electrons through ETC
- 3 locations of electron transfers which actively transports(H+ ions) electrons into intermembrane space
- all heading towards O2 at end of ETC
- O2 then reduced to H20 by leftover H+ ions w/o electrons
how does chemiosmosis in oxidative phosphorylation work ?
- H+ ions in intermembrane space diffuse through ATP synthase back into mitochondrial matrix
- ATP synthase’s internal rod rotates w/ diffusion of H+ ions
- rotation activates sites that phosphorylate ADP —> ATP
ATP synthase
group of membrane proteins in chemiosmosis working with the ETC
- uses energy of H+ ion concentration to produce ATP
what affect would the absence of O2 have on oxidative phosphorylation ?
no O2 to pull electrons from electron carriers (FADH2 NADH) = electrons (H+) could not be harnessed to make ATP
what step is majority of ATP produced in ?
step 3; oxidative phosphorylation
- 90% of ATP is made here
NET yield of oxidative phosphorylation ?
about 28 ATP
where is O2 used in cellular respiration ?
in step 3; oxidative phosphorylation
where is CO2 produced in cellular respiration ?
in step 2; pyruvate oxidation and citric acid cycle
fermentation
harvesting ATP w/o O2
- only step 1 glycolysis is used
- anaerobic path to recycle NADH —> NAD+
lactic acid fermentation
glycolysis w/ reduction of pyruvate —> lactate
- muscle cells and certain bacterial cells
- make cheese / yogurt
how does lactic acid fermentation work ?
2 pyruvate reduced by the 2 NADH from glycolysis
- NADH —> NAD+ ; recycled back to glycolysis for reuse
alcoholic fermentation
glycolysis w/ reduction of pyruvate —> ethyl alcohol
- yeast and certain bacterial cells
how does alcoholic fermentation work ?
2 pyruvate reduced by 2 NADH from glycolysis
- 2 CO2 leave
- NADH —> NAD+ ; recycled back to glycolysis for reuse
obligate anaerobes
require anaerobic conditions / poisoned by O2; only fermentation
- prokaryotes in stagnate H2O / deep in soil
facultative anaerobes
can do both fermentation / oxidative phosphorylation
- yeast for beer / wine
- will prefer oxidative phosphorylation since more efficient
glucose fed yeast cell is moved from aerobic to anaerobic conditions, to continue making ATP at the same rate as anaerobic conditions, how would glucose consumption rate need to change ?
would need to consume the glucose 16x as fast in the anaerobic condition compared to the aerobic condition
- only 2 ATP anaerobically vs. 32 ATP aerobically (2 x 16 = 32)
why is glycolysis assumed to be an ancient metabolic pathway ?
- occurs universally (fermentation / respiration
- does not require oxygen
- does not occur in membrane close organelle
where are sugars from carbohydrates used in cellular respiration ?
glucose (glycolysis)
where are fatty acids from fats used in cellular respiration ?
acetyl CoA (pyruvate oxidation)
where is glycerol from fatty acids used in cellular respiration ?
G3P (glycolysis)
where are amino acids from proteins used in cellular respiration ?
- pyruvate (glycolysis)
- acetyl CoA (pyruvate oxidation)
- oxaloacetate (citric acid cycle)
how does rotenone (rat poisoning) affect cellular respiration ?
displaces O2 in oxidative phosphorylation
- prevents H+ from attaching to last electron carrier (O2)
how does cyanide / carbon monoxide affect cellular respiration ?
displaces O2 in oxidative phosphorylation
- prevents H+ from attaching to last electron carrier (O2)
how does DNP affect cellular respiration ?
causes H+ to leak through membrane
- less and less H+ going to ATP synthase = less ATP made
how does oligomycin affect cellular respiration ?
prevents ATP synthase from occurring