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

What determines the amount of mitochondria in the cell

Answer 6

The energy demand of the cell. (eg muscle cells)

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

Stage 1: Glycolysis

Answer 9

-cytosol
-glucose converted into smaller pyruvate
-generates 2ATP
-Electrons transferred to high energy electron carrier, NADH

Question 10

Stage 2: Pyruvate Oxidation and Citric Acid Cycle

Answer 10

-mitochondrial matrix
-Pyruvate converted to acetyl CoA
-Acetly CoA enters Citric Acid Cycle
-Carbon dioxide is released
-Output: ATP, NADH FADH

Question 11

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

Answer 11

Electrons transport Chain and Chemiosmosis

Question 12

Stage 3: ETC, What causes protons to flow through the semi-permeable mitochondrial inner membrane in Stage 3 of cellular respiration?

Answer 12

-Electron carriers( NADH FADH) shuttle high energy electrons through protein complexes (i to iv)
-as these electrons move through protein complexes, protons H+ are pumped across membrane into intermembrane space
-proton gradient is produced

Question 13

Why is there a gradient across the inner mitochondrial membrane?

Answer 13

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

Question 14

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

Answer 14

Chemiosmosis

Question 15

What is chemiosmosis?

Answer 15

-Inner membrane hold ATP synthase
-Proton gradient across membrane powers ATP synthesis
-ATP synthase converts ADP + Pi –> ATP
-ATP is produced

Question 16

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

Answer 16

ADP + Pi -> ATP

Question 17

Why is ATP used to provide the cell with energy?

Answer 17

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

Question 18

How is water produced in cellular respiration?

Answer 18

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

Question 19

What is the relative pH of the inner mitochondrial space?

Answer 19

Low