Week 1- Metabolism 2

Question 1

LO:Describe anaerobic ATP formation through glycolysis

Answer 1

Glucose → Pyruvate

NET:

• 2ATP (1 from each)
• 2NADH (1 from each)

Pyruvate → Lactic Acid

(Lactate dehydrogenase)

Overall:

• 2NADH (1 from each pyruvate)

NET:

• 2ATP
• 4NADH (remember ETC doesn’t work in anareobic)

Question 2

What are the phases of aerobic respiration?

Answer 2

1) Glycolysis
2) Link reaction
3) Krebs cycle
4) Electron transport chain

Question 3

What is the structure of the mitochondria?

Answer 3

Outter Membrane

Intermembrane space

Inner Membrane

• ATP Synthase within inner membrane

Matrix

Question 4

What are the 3 ways Acetyl-CoA can be formed?

Where Is Acetyl Co-A formed?

Answer 4

Carbohydrates

Triglycerides

Proteins

Inside Mitochondria

Question 5

What happens during Glyolysis from CARBOHYDRATES?

Where does it occur?

What are the products?

Answer 5

Occurs:

Cytoplasm

What happens:

(Glycolysis)

Carbohydrate → Sugar → Glucose → Pyruvate

NET:

• 2 ATP
• 2 NADH

Question 6

What happens during the link reaction?

Where does it occur?

Answer 6

Oxidative decarboxylation:

Pyruvate → Acetyl-CoA

(Pyruvate dehydrogenase)

• 2CO₂ (one from each pyruvate)
• 2NADH (one from each pyruvate)

NET (as if from glycolysis):

• 2ATP
• 4NADH
• 2CO₂

Occurs:

Acetyl CoA + NADH formed INSIDE mitochondria

Question 7

What happens to Triglycerides to form Acetyl Co-A?

Answer 7

Triclycerides → Glycerol + Fatty Acids

Glycerol:

Undergoes Glycolysis

Fatty Acids:

Beta oxidation form:

• Pyruvate OR
• Acetyl Co-A

FADH₂ + NADH given off

Question 8

What happens to PROTEINS to form products of respiration?

Answer 8

Proteins → AA (gives off NH₃) →

PYRUVATE/ ACETYL- CoA / KREBS CYCLE (different aa form different products)

Requires Deamination before glucose/lipid synthesis:

• Achieved through transamination reaction before urea formation
• Urea = main nitrogen contraining compound excreted through kidneys

Question 9

What are AA required for?

Answer 9

Proteins (structural, catalytic, signalling)

Peptides (intra- and inter-cellular communication)

Important sources of carbohydrates during fasting, trauma, sepsis

Question 10

What happens during Amino Acid degradation?

Draw an equation

Answer 10

-

Question 11

What happens during the Krebs Cycle?

Where does it occur?

Answer 11

Occur:

Mitochondria

Happens:

Acetyl CoA combines with Oxaloacetate = 6C molecule

Overall (half from eachAcetyl CoA):

• 4 CO₂
• 6 NADH
• 2 FADH₂
• 2 ATP

NET:

• 6CO₂
• 10 NADH
• 2 FAHD₂
• 4 ATP

Question 12

What is the role of the Krebs cycle?

Answer 12

• Cellular respiration
• Other metabolic processes
• Disposal of amino groups through urea formation

Question 13

What happens during the electron transport chain?

Where does it occur?

Answer 13

ECT: Energy of electrons from NADH and FADH₂ used to pump protons across the mitochondrial inner membrane across their concentration gradient

• Electron carriers (NADH + FADH₂) drop off electrons
• Electrons pass through the protein carries (1,3,4)
• Energy pumps H+ (donated from NADH + FADH₂) via protein carriers matrix → intermembrane space
• H+ down conc gradient ATP Synthase: ADP + P_i → ATP

Question 14

What is Oxidative Phosphoryation?

Answer 14

Where ATP produced from transfer of electrons from NADH + FADH₂ by electron carrier proteins

Question 15

How is ATP transported outside mitochondria?

Answer 15

ATP-ADP Carrier

ETC coupled to ATP synthesis

ATP synthase = About 3 protons: 1ATP

Fourth proton symported with each ATP out, across inner membrane, in exchnage for 1ADP

Question 16

What happens during uncoupling?

Answer 16

Proton influx can be uncoupled from ATP synthesis by UCP1

H+ back through UPC1 + turns it into heat. Non shivering thermogenesis. Useful in brown adipose tissue (more present in babies, they can’t shiver)

Question 17

How many ATP are made in aerobic respiration?

Answer 17

10 NADH → 30 ATP

2 FADH₂ → 4 ATP

plus 4 ATP (link reaction + glycolysis)

38 ATP