ch 9 cellular respiration

Biology 2 with Ewing at California State University - Sacramento

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By: josephine severino
Created: 2011-04-09
Size: 39 flashcards
Views: 6

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pathway of energy

-energy flows into an ecosystem as sunlight and leaves as heat

-photosynthesis generates oxygen and organic molecules for cell respiration

-cells use chemical energy in organic molecules to generate ATP, which powers work

fermentation

-partial degradation of sugars that occurs without oxygen

aerobic respiration

-consumes organic molecules and oxygen, yields ATP

anaerobic respiration

-similar to aerobic but consumes compounds other than oxygen

-uses ETC with a final electron accepter other than O2, such as sulfate

chemical reaction of cell respiration

-C6H12O6 + 6 O2 --> 6 CO2 + 6 H20 + energy (ATP & heat)

how is energy stored in organic molecules released?

-by the transfer of electrons in chemical reactions

redox reactions

-chemical reactions that transfer electrons between reactant molecules

-oxidation: substance loses electrons, oxidized

-reduction: substance gains electrons, reduced

reducing agent

-substance that is oxidized

-electron donor

oxidizing agent

-substance that it reduced

-electron acceptor

what is oxidized in cell respiration?

-the fuel (like glucose)

what is reduced in cell respiration?

-the oxygen

NAD+

-coenzyme used in the initial transfer of electrons from organic molecules

-an electron acceptor, used as an oxidizing agent

-each NADH (reduced form of NAD+) contains stored energy tapped to synthesize ATP

electron transport chain

-passes down electrons in series of steps

-oxygen pulls electrons down chain in energy-yielding tumble

-energy yielded used to generate ATP

stages of cellular respiration

-glycolysis

-citric acid cycle

-oxidative phosphorylation

glycolysis

-breaks down 1 glucose molecule into 2 pyruvate molecules

-occurs in the cytoplasm

citric acid cycle

-completes breakdown of glucose

-occurs in mitochondrial matrix

oxidative phosphorylation

-accounts for the most of the ATP synthesis

-why? because it is powered by redox reactions

-occurs in the cristae of mitochondrion

how is ATP produced in glycolysis and citric acid cycle?

-substrate level phosphorylation

what links glycolysis to citric acid cycle?

-the conversion of pyruvate to acetyl coA

net values of citric acid cycle

-oxidizes organic fuel derived from pyruvate

-1 ATP

-3 NADH

-1 FADH2

how does acetyl group join the cycle?

-by combining with oxaloacetate to form citrate

-then the cycle spends the next 7 steps decomposing citrate back to oxaloacetate

what is the final electron acceptor of ETC?

-oxygen

-accepts electron to form water

cytochrome

-proteins with an iron atom

-passes electrons to oxygen

function of the chain

-break large free energy drop from food to O2 into smaller steps that release energy in manageable amounts

chemiosmosis

-use of energy in a H+ gradient to drive cellular work

movement of H+ in ETC

-when electron reaches ETC, proteins pump H+ from mitochondrial matrix to intermembrane space

-H+ then moves back cross the membrane passing through channels in ATP synthase

function of ATP synthase

-uses the exergonic flow of H+ to drive phosphorylation of ATP

proton motive force

-energy stored in H+ gradient couples the redox reactions of ETC to ATP synthesis

energy flow in cellular respiration

-glucose --> NADH --> ETC --> proton motive force --> ATP

-about 38 ATPs are produced

fermentation

-uses phosphorylation instead of ETC to generate ATP

-consists of glycolysis + reactions that that generate NAD+, which can be reused in glycolysis

-types: alcohol and lactic acid

alcohol fermentation

-pyruvate is converted to ethanol in 2 steps / the first step releases CO2

-performed by yeast

-used in brewing, wine making, and baking

lactic acid fermentation

-pyruvate reduced to NADH

-forms lactic acid as end product

-no CO2 released

-fungi and bacteria do this to make cheese and yogurt

-muscle cells do this to generate ATP when there's no oxygen

fermentation vs. aerobic respiration

-both use glycolysis to oxidize glucose to pyruvate

-diff final electron acceptors: fermentation uses organic molecules (like pyruvate or acetaldehyde)

-fermentation makes 2 ATP / respiration makes 38 ATP

obligate anaerobes

-carry out fermentation or anaerobic respiration

-can't survive in the presence of O2

facultative anaerobes

-ex: yeast and many bacteria

-can survive using either fermentation or cell respiration

-pyruvate is a fork that leads to 2 alternative catabolic routes

what is the origin of glycolysis?

-it occurs in nearly all organisms

-probably evolved in ancient prokaryotes before there was O2 in the atmosphere

proteins and catabolism

-must be digested into amino acids

-amino groups can be fed into glycolysis or citric acid cycle

fats and catabolism

-digested to glycerol & fatty acids

-glycerol used in glycolysis

-FAs used in generating acetyl coA

regulation of respiration via negative feedback

-low ATP conc = respiration speeds up

-high ATP conc = respiration slows down

-catabolism regulated through enzymes at strategic points in the pathway

About this deck

By: josephine severino
Created: 2011-04-09
Size: 39 flashcards
Views: 6

About StudyBlue

“I have used this website for three exams, and I see a huge difference in my test results.”
Naj