lecture 8 - cellular respiration

Question 1

Where does cellular respiration occur?

Answer 1

In the cytoplasm and mitochondria of Plant and Animal cells.

Question 2

What do cells need energy from cellular respiration for? (4)

Answer 2

Mechanical work, making new materials, transport, maintain order

Question 3

What is the overall equation for the breakdown of glucose in cellular respiration?

Answer 3

glucose + 6 oxygen -> 6 carbon dioxide + 6 water + energy

Question 4

What is the chemical formula for glucose?

Answer 4

C6H12O6

Question 5

What is the typical size of a mitochondrion?

Answer 5

1-10µm

Question 6

How many mitochondria are in each cell? What is this dependent on?

Answer 6

1-1000. The energy demand of the cell.

Question 7

What are the features of mitochondria structure?

Answer 7

Mitochondrial DNA, ribosomes, outer membrane, inner membrane (with folds - cristae), mitochondrial matrix

Question 8

What are the three stages of cellular respiration?

Answer 8

Glycolysis, Pyruvate oxidation and the Citric Acid cycle, Oxidative phosphorylation.

Question 9

Where does glycolysis occur?

Answer 9

In the cytoplasm/cytosol of the cell.

Question 10

What is the process of glycolysis?

Answer 10

Glucose is broken down into pyruvate, generating 2 ATP, and high energy electrons which are transferred to the high energy electron carrier NAD+, making it into NADH. (2NADH are formed)

Question 11

What is glucose converted to in glycolysis?

Answer 11

Pyruvate

Question 12

How many carbons do pyruvate molecules have?

Answer 12

3

Question 13

What is pyruvate converted into in the second stage of cellular respiration?

Answer 13

Acetyl CoA

Question 14

What process forms 2 Acetyl CoA?

Answer 14

Pyruvate oxidation

Question 15

What does pyruvate oxidation release/form?

Answer 15

2 Acetyl CoA, 2 Carbon dioxide, higher energy electrons in 2 NADH

Question 16

What substance goes into the Citric Acid cycle?

Answer 16

Acetyl CoA

Question 17

What does the Citric Acid cycle output (for 2 Acetyl CoA)?

Answer 17

6 NADH, 2 FADH2, 4 CO2, 2 ATP

Question 18

What are the high energy electron carriers released from the citric acid cycle?

Answer 18

NADH and FADH2

Question 19

What are the two parts of Stage 3 of cellular respiration?

Answer 19

Electrons transport & proton gradient, Chemiosmosis

Question 20

How are high energy electrons moved to the inner mitochondrial membrane in Phase 3 of cellular respiration?

Answer 20

Via electron carriers (NADH and FADH2) that move through protein complexes (I to IV)

Question 21

What causes protons to flow through the semi-permeable membrane in Stage 3 of cellular respiration?

Answer 21

The flow of electrons/electron carriers through protein complexes (i to iv) causes H+ to be pumped by proteins against its concentration gradient into the intermembrane space.

Question 22

Why is there a gradient across the inner mitochondrial membrane?

Answer 22

H+ accumulate on the inter membrane space, creating a proton gradient.

Question 23

What is the second phase of stage 3 of cellular respiration?

Answer 23

Chemiosmosis

Question 24

What is chemiosmosis?

Answer 24

The inter mitochondrial membrane contains ATP synthase which synthesises ATP, by converting ADP.

Question 25

What is the equation for the production of ATP in chemiosmosis?

Answer 25

ADP + Pi -> ATP

Question 26

Why is ATP used to provide the cell with energy?

Answer 26

It provides a controlled release of energy, which can be harnessed in a useful way.

Question 27

How is water produced in cellular respiration?

Answer 27

At the end of the electron transport chain of protein complexes, hydrogen ions combine with oxygen to form 6H2O

Question 28

What is the relative pH of the inner mitochondrial space?

Answer 28

Low