Biology- respiration wha

What are the 4 stages of respiration in order

Glycolysis, the link reaction, the Krebs cycle and oxidative phosphorylation

Where does glycolysis occur

In the cytoplasm

What is the first step of glycolysis

Glucose is turned into hexose bisphosphate by turning 2 molecules of ATP to ADP

Whats the second stage of glycolysis

Hexose bisphopshate breaks down into triose phosphate

Whats the final stage of glycolysis

Triose phosphate is turned into pyruvate by removing 2 hydrogens and turning NAD to reduced NAD and removing 4 phosphate groups to phosphorylate 4 molecules of ADP

Where does the link reaction occur

In the matrix of mitochondria

Whats the first stage of the link reaction

Pyruvate forms acetate by loosing CO2 and a hydrogen to form reduced NAD

Whats the second stage of the link reaction

Acetate combined with coenzyme A to form acetyl coenzyme A

Where does the Krebs cycle occur

In the matrix of mitochondria

Whats the first stage of the Krebs cycle

Oxaloacetate accepts the acetyl group from acetyl coenzyme A forming citrate

What happens to citrate in the Krebs cycle to reforms oxaloacetate

It’s forms 2x CO2, 3x reduced NAD, 1x reduced FAD and 1 x ATP

What are NAD and FAD

Coenzymes

Where does oxidative phosphorylation occur

In the inner mitochondrial membrane

What happens during oxidative phosphorylation

Reduced NAD and FAD diffuse to the cristae and are oxidised by dehydrogenases releasing H+ and e-, the electrons then pass along electron carriers in the electron transport chain releasing energy, the energy is used to actively transport protons across the membrane into the intermembrane space, they form an electrochemical gradient and diffuse into the mitochondrial matrix through ATP synthase catalysing the phosphorylation of ADP, oxygen acts as the final electron accepter forming water

How many molecules of ATP are produced in glycolysis

2 ATP molecules

How many molecules of ATP are formed in the Krebs cycle

1 molecule of ATP

How many molecules of ATP are produced by each reduced NAD in the electron transport chain

3 ATP

How many molecules of ATP are produced by reduced FAD in the electron transport chain

2 molecules of ATP

What happens to pyruvate in the lactate pathway

reduced NAD donates 2 hydrogens to pyruvate forming lactate which can be converted back into pyruvate in the presence of oxygen

What happens to pyruvate in the ethanol pathway

Pyruvate looses CO2 forming ethanal which accepts hydrogens to form ethanol

Which organisms utilise the ethanol pathway

Yeast

Which organisms utilise the lactate pathway

Humans

What are some similarities in anaerobic respiration in mammals and yeast

Glycolysis occurs in the absence of oxygen, only 2 ATP molecules are made per molecule of glucose, glucose is only partially broke down, reduced NAD is used up, the end products are toxic if left to build up

What are the differences between anaerobic respiration in yeast and mammals

In mammals pyruvate is reduced but in yeast ethanal is reduced, in mammals no CO2 is made in yeast it is, in mammals lactic acid is made in yeast ethanol is made

Whats the RQ equation

CO2 produced/O2 consumed

Whats the RQ of carbohydrates

1

Whats the RQ of proteins

0.9

What’s the RQ of lipids

0.7

Why is more O2 consumed when respiring lipids

Because more NAD is used and so more O2 molecules are required to act as final electron acceptors

What apparatus can be used to measure RQ

A respirometer