Bioenergetics

Question 1

What are the 4 main stages of respiration?

Answer 1

Glycolysis, Link factors, Kreb’s cycle and oxidation phosphorylation

Question 2

What are the 4 stages of glycolysis?

Answer 2

Phosphorylation, Lysis, Phosphorylation again without ATP, and dehydrogenation and formation of ATP

Question 3

What happens during stage 1 of glycolysis?

Answer 3

Phosphorylation: 2 ATP molecules release phosphate which binds to the single glucose molecule, this then becomes hexose bisphosphate

Question 4

Where does glycolysis take place?

Answer 4

In the cytoplasm

Question 5

Explain stage 2 of glycolysis?

Answer 5

Lysis: The hexose bisphosphate destabilizes and produces two triose phosphates

Question 6

What happens during stage 3 of glycolysis?

Answer 6

Phosphorylation again: Free inorganic phosphate ions bind to the triose phosphates which makes them become triose bisphosphates

Question 7

Explain stage 4 of glycolysis?

Answer 7

Dehydrogenation and formation of ATP: 4 phosphate ions are released and become ATP molecules. 2 reduced NADH molecules are released. The triose bisphosphates become dehydrogenated and produce two pyruvates

Question 8

Where do the pyruvates from glycolysis travel to after completed stage?

Answer 8

The matrix in the mitochondria

Question 9

What do the pyruvates undergo in the matrix (first step of the link reaction)

Answer 9

Oxidative decarboxylation (CO2 is removed along with hydrogen)

Question 9

Where is the mitochondria is ATP produced?

Answer 9

Inner mitochondrial membrane

Question 10

What is released whilst the pyruvates are forming an acetyl group?

Answer 10

CO2 and NADH

Question 11

What is formed as the final product in the link reaction?

Answer 11

Acetyl Coenzyme A

Question 12

The third stage of respiration?

Answer 12

The Kreb’s cycle

Question 13

How many times does the link reaction occur?

Answer 13

Twice as there are two pyruvate molecules from glycolysis

Question 14

Products of the link reaction?

Answer 14

2 Acetyl CoA, 2 Carbon Dioxide, 2 NADH

Question 15

What happens to the CO2 released in the link reaction?

Answer 15

It is a waste product

Question 16

Where do the NADH released in the link reaction go?

Answer 16

To the electron transport chain

Question 17

Cristae in mitochondria role?

Answer 17

Increase surface area for oxidative phosphorylation

Question 18

The rhyme to remember the Kreb’s cycle?

Answer 18

DENA DENA A FA NA

Question 19

The first step of the Kreb’s cycle?

Answer 19

Acetyl group from link reaction combines oxaloacetate to make citrate

Question 20

What happens to citrate in the Kreb’s cycle?

Answer 20

Its is dehydrogenated and decarboxylated to release CO2, NADH and a 5C compound (DENA)

Question 21

Which compound releases ATP in the cycle?

Answer 21

The 4C compound that was made from the 5C compound

Question 22

What happens after the 4C compound releases ATP?

Answer 22

It releases FADH and NADH to become oxaloacetate to start the cycle all over again

Question 23

The fourth stage of respiration?

Answer 23

Oxidative Phosporylation

Question 24

First step of OP?

Answer 24

The NADH and FADH from Kreb's cycle release their hydrogen atoms

Question 25

What happens to the hydrogen atoms released from NADH and FADH?

Answer 25

They split into protons and electrons, the electrons go into the membrane

Question 26

The electron transport chain?

Answer 26

3rd stage, electrons move into membrane complexes from hydrogen atoms, they move along the membrane transferring energy at each carrier protein

Question 27

Where do the hydrogen protons go during OP?

Answer 27

Pumped into the inner membrane space building a pH gradient (acidic inside)

Question 28

Role of ATP synthase during OP?

Answer 28

Moves the protons back to the matrix, rest of membrane is still IMPERMEABLE to them

Question 29

What does the movement of hydrogen protons drive?

Answer 29

The synthesis of ATP from ADP and inorganic phosphate

Question 30

Where do the protons and electrons go after ATP synthase?

Answer 30

They combine with oxygen and form water as the final product

Question 31

The two ways to produce ATP?

Answer 31

Substrate level phosphorylation and Chemiosmosis

Question 32

Process of chemiosmosis?

Answer 32

Protons flow through ATP synthase and drive rotation of head piece causing ADP + Pi to form ATP

Question 33

The force used to drive formation of ATP?

Answer 33

Protonmotive force

Question 34

Why is water an essential product of respiration?

Answer 34

Maintains proton and electron gradient, allows flow of protons

Question 35

Why is oxygen essential in aerobic respiration?

Answer 35

Without it NADH and FADH cannot be re-oxidized for reuse, means no coenzymes in Link reaction or Krebs, also maintains gradient

Question 36

The two types of anaerobic respiration?

Answer 36

Lactate fermentation and ethanol fermentation

Question 37

Where does lactate fermentation occur?

Answer 37

In muscle cells of mammals

Question 38

Where does ethanol fermentation occur?

Answer 38

Yeast, plants and fungi

Question 39

Characteristics of anaerobic respiration?

Answer 39

NO oxygen included, lower ATP yield and occurs in the cytoplasm

Question 40

Outline the process of lactate fermentation?

Answer 40

Pyruvates get oxidized by reduced NAD providing it with hydrogen, then pyruvate becomes lactate

Question 41

What is a hepatocyte?

Answer 41

Liver cell

Question 42

What catalyzes the oxidization of pyruvate?

Answer 42

Lactate dehydrogenase

Question 43

What occurs if there is a build up of lactate?

Answer 43

Oxygen debt

Question 44

What does hydrogen become in lactate fermentation?

Answer 44

Hydrogen acceptor for NAD

Question 45

Hepatocytes, what do they do?

Answer 45

Converts lactate into pyruvates or glycogen, high O2 then pyruvates used for Link and Kreb's, removal of lactate = heavy breathing, O2 replaces lactate that was converted into pyruvates which results in oxygen debt and fatigue.

Question 46

Outline the process of ethanol fermentation?

Answer 46

Pyruvate from glycolysis get decarboxylated by decarboxylase to become ethanal, the ethanal then oxides with NAD and is converted into ethanol dehydrogenase to become ethanol

Question 47

Yeast is described as what?

Answer 47

A facultative anaerobe

Question 48

What is a facultative anaerobe?

Answer 48

Will aerobically respire to make ATP but when low O2 will switch to anaerobic respiration

Question 49

What are mammals described as?

Answer 49

Obligate aerobe

Question 50

What is an obligate aerobe?

Answer 50

Only synthesizes ATP in presence of O2, products need O2 to be broken down

Question 51

Why is anaerobic respiration useful?

Answer 51

Oxidizes NAD so glycolysis can continue and dehydrogenation reactions

Question 52

What are some other respiratory substrates?

Answer 52

Triglycerides and proteins

Question 53

How are triglycerides a respiratory substrate?

Answer 53

They can be hydrolyzed back into fatty acids and glycerol, can be converted into pyruvate to be used in Kreb's cycle as Acetyl CoA

Question 54

How are proteins a respiratory substrate?

Answer 54

Hydrolyzed into amino acids and deamination before entering respiratory pathway via pyruvate

Question 55

Equation to work out the respiratory quotient (RQ)?

Answer 55

CO2 produced/O2 consumed