5.7 Respiration Flashcards
State the four stages of respiration.
Glycolysis
Link reaction
Krebs cycle
Oxidative phosphorylation
What are the 3 stages of glycolysis?
Phosphorylation of glucose to hexose bisphosphate
Splitting hexose biphosphate into 2 triose phosphates
Oxidation of triose phosphates to pyruvate
What is the end product of glycolysis- the first stage of respiration?
2 X Pyruvate
Describe the link reaction (4)
Carboxyl group removed
This decarboxylation and then dehydrogenation produces an acetyl group
NAD becomes reduced
The acetyl group combines with enzyme A making acetyl CoA (that carries the acetyl group to the krebs cycle)
Describe the krebs cycle, including how many carbons are in each compound.
Acetyl group released from CoA combines with oxaloacetate (4c) forming citrate (6c)
citrate decarboxylated dehydrogenated forming 5c compound
decaarboxylated dehydrogenated again forming 4c compound
substrate level phosphorylation when this 4c compound binds temporarily with CoA produces 1 ATP
dehydrogenated makes oxaloacetate
Where does glycolysis occur
cytoplasm of cell
where does the krebs cyce occur
mitochondrial matrix
where does the link reaction occur
mitochondrial matrix
Where does oxidative phosphorylation occur?
inner mitochondrial membrane
Describe the process of oxidative phosphorlyation. (5)
Hydrogen splits into protons and electrons electrons along electron transport chain energy is produced to pump protons into intermembrane space creates proton gradient protons diffuse down concentration gradient flow through ATP synthase Protons are accepted by oxygen
How many stages are there in the Krebs cycle?
6
How many molecules of rNAD are formed from one turn of the krebs cycle
3
How many molecules of rFAD are formed from one turn of the krebs cycle?
1
How many molecules of C02 are formed from 1 turn of the Krebs cycle?
2
What does NAD do in respiration?
Hydrogen acceptor (consequently it becomes reduced)
Which stages of respiration are aerobic?
Link reaction
Krebs cycle
Oxidative phosphorylation
What happens to the pyruvate in anaerobic conditions? (3)
Converted to lactate or ethanol
rNAD is reoxidised so glycolysis can continue, generating 2 ATP
How can carbohydrates be changed to be used in respiration? (1)
isomerase enzyme change them to glucose for respiration
Why are lipids a better respiratory substrate than carbohydrates?
because they have more protons for oxidative phosphorylation
How are lipids used in respiration? (4)
fatty acid combined with CoA
transported to matrix, broken to 2 acetyl groups each attached to CoA
this beta oxidation pathway generates rNAD/rFAD
acetyl groups released from CoA, enter krebs cycle
How are proteins used in respiration? (2)
excess AA deaminated in liver (remove amine group resulting in urea) leaves a keto acid
keto acid enters respiration as pyruvate/acetate and enters krebs cycle
What is the formula for the respiratory quotient? (1)
RQ= CO2 produced/ O2 consumed
What properties of the mitochondrial inner membrane allow chemiosmosis to occur? (2)
it contains ATP synthase
large surface area
impermeable to H+ ions
Why would a larger number of propton pores in the inner mitochondrial membrane result in a person less likely to gain weight? (6) UNFINISHED QUESTION
more proton pores means more H+ will leak back across the inner mitochondrial membrane
so less H+ will go through ATP synthase for every molecule of NAD, so these people need to produce more NAD***UNFINISHED ANSWER
What are the 3 types of phosphorylation?
PHOTO
OXIDATIVE
SUBSTRATE LEVEL
Why don’t maggots need such well developed transport systems and exchange surfaces as flies? (3)
larger SA:V
so shorter diffusion distance
Flies need more ATP for movement/flyinf/higher metabolic rate
flies have hard exoskeleton
