Metabolism

Question 1

What is anabolism?

Answer 1

Synthesis of simple products to complex products

Question 2

What is catabolism?

Answer 2

Breakdown of complex products to simpler products

Question 3

What are metabolism pathways controlled by?

Answer 3

Enzymes (protein catalysts)

Question 4

What are cofactors (coenzymes)?

Answer 4

-Additional chemistry to help catalyse a reaction
-Can be permanently attached to the enzyme as a prosthetic group
-Can come on and off when required using reversible binding

Question 5

What pathways does carbohydrate catabolism involve?

Answer 5

-Glycolysis
-Krebs cycle
-Electron transport chain

Question 6

What is glycolsis?

Answer 6

The breakdown of the 6 carbon glucose to 2x 3 carbon pyruvate

Question 7

Where does glycolysis occur?

Answer 7

Cytoplasm

Question 8

What type of reaction is glycolysis?

Answer 8

Anaerobic (can occur without oxygen)

Question 9

What is used to activate glycolysis?

Answer 9

2 ATP molecules are required to activate the glucose

Question 10

What occurs as the glucose splits?

Answer 10

-Energy from the glucose molecule is stripped out and stored in an NADH hydrogen carrier
-Energy is in the form of ATP

Question 11

What is the net produce of glycolysis?

Answer 11

-4 ATP, 2 net gain
-2 pyruvate
-2 NADH

Question 12

How does the splitting of glucose occur?

Answer 12

-Adenosine triphosphate (ATP) donates a phosphate group to glucose mol.

-Another phosphate group is then added to the fructose molecule (5C)

-Breaks down to 2x glyceraldehyde 3 phosphate (3C)

-Energy is removed and produces 2 pyruvate

Question 13

What enzyme catalyses the addition of a phosphate group to glucose?

Answer 13

Hexokinase

Question 13

What enzyme catalyses the addition of a phosphate group to fructose?

Answer 13

Phosphofructokinase

Question 14

What enzyme catalyses the production of pyruvate?

Answer 14

pyruvate kinase

Question 15

What is NAD+?

Answer 15

-Nicotinamide adenine dinucleotide
-A hydrogen ion carrier

Question 16

What is FAD?

Answer 16

-Flavine adenine dinucleotide
-hydrogen ion carrier

Question 17

What is ATP?

Answer 17

-Adenosine Triphosphate
-Energy is stored within the bonds between phosphates

Question 18

What is the first fate of pyruvate?

Answer 18

-Liver can convert pyruvate to glucose via gluconeogenesis
-Occurs in areas where there is a high demand for glucose, e.g. brain

Question 19

What is the second fate of pyruvate?

Answer 19

-Absorption of ammonia into the pyruvate
-Ammonia is toxic so fuses with pyruvate to form amino acid alanine

Question 20

What is the fate of pyruvate when there is an absence of oxygen?

Answer 20

-Anaerobic respiration
-Pyruvate converts to ethanol
-Occurs in yeast cells
-Pyruvate converts to lactic acid in animals

Question 21

What is the fate of pyruvate in the presence of oxygen?

Answer 21

-Aerobic respiration
-Crosses into mitochondria
-Converts to acetyl coA and enters kreb cycle

Question 22

What is coenzyme A?

Answer 22

-Nucleotide with adenine base
-Carrier of 2 carbon units

Question 23

Where does the krebs cycle occur?

Answer 23

Mitochondria

Question 24

What occurs to acetyl CoA in the krebs cycle?

Answer 24

-The 2C molecule is fed in and the 2 carbons are oxidised forming CO2

Question 25

What is released when acetyl CoA is oxidised in the krebs cycle?

Answer 25

The energy comes out as hydrogen ions and is picked up by NADH and FADH2 carriers

Question 26

What happens to the 2 carbons from the acetyl CoA in the krebs cycle?

Answer 26

Combine with the 4 carbon oxaloacetate and forms a 6 carbon molecule

Question 27

What happens to the 6 carbon molecule in the krebs cycle?

Answer 27

-A carbon is lost forming a 5 carbon molecule -Comes out as CO2

Question 28

What happens to the 5 carbon molecule in the krebs cycle?

Answer 28

-A carbon is lost forming a 4 carbon molecule -Comes out as CO2

Question 29

What is released throughout the krebs cycle?

Answer 29

-Energy is released as hydrogen -Picked up by NADH and FADH2 carriers -Used in electron transport chain

Question 30

What occurs in the electron transport chain?

Answer 30

-NADH and FADH2 hydrogen carriers are fed in -Oxygen combines with hydrogen -Produces water and ATP

Question 31

Where does the electron transport chain occur?

Answer 31

Mitochondria

Question 32

What is transported through the proteins of the ETC?

Answer 32

Electrons from the bonds between NAD/FAD and the hydrogen ions

Question 33

What is the final electron acceptor in the ETC?

Answer 33

Oxygen

Question 34

How is water formed in the ETC?

Answer 34

Electrons combine with hydrogen and oxygen

Question 35

How is the chemical gradient created in the ETC?

Answer 35

-Energy is stripped from the electrons as they pass through the chain -Proteins can then pump hydrogen ions down the gradient

Question 36

How is ATP synthesised in the ETC?

Answer 36

-ATP synthase uses energy from the H+ gradient -Puts it in the ATP storage molecule