B1 Metabolism & Nutrition

Question 1

What are the constituents of the average UK diet?

Answer 1

MACRONUTRIENTSCarbohydrateFatProteinDietary FibreVariety of MICRONUTRIENTS

Question 2

What’s the difference between macronutrients and micronutrients?

Answer 2

Macronutrients-structural and energy-giving caloric components offoods,include carbohydrates, fats and proteins.Micronutrients-vitamins, minerals, trace elements, phytochemicals, and antioxidants essential for good health.

Question 3

What are carbohydrates?

Answer 3

Starch + sugars

Question 4

What is the difference between ATP formation via aerobic respiration and via glycolysis?

Answer 4

Aerobic respiration doesn’t produce lactate/ ethanolGlycolysis (which does make 2 molecules of ATP)ends with pyruvate which is reduced tolactate or converted to ethanol

Question 5

Where does the body’s energy primarily come from?

Answer 5

Oxidation of carbohydrate and fatCarbohydrate - 4kcal/gFat - 9kcal/g

Question 6

What’s the nutrition difference between starch and sugars?

Answer 6

Starch has a higher energy content than sugars

Question 7

What is the the difference between glycogen, fat and protein as energy stores?

Answer 7

Fat - Long-term / Infinite (adipose tissue)Glycogen - Short-term / FiniteProtein - Source of glucose in absence of carbohydrate

Question 8

True or false? The body can store protein and alcohol

Answer 8

FALSE

Question 9

True or false? The brain has a specific requirement for glucose?

Answer 9

TRUE

Question 10

What is the common intermediate of proteins, carbohydrates and fats?

Answer 10

Acetyl CoA

Question 11

What are theother names for the Krebs cycle?

Answer 11

Citric Acid Cycle Tricarboxylic Acid Cycle (TCA) Krebs Cycle

Question 12

Where are the coenzymes NAD and FAD derived from?

Answer 12

Niacin and Riboflavin

Question 13

Where is glucose derived from?

Answer 13

Blood; the breakdown of glycogen

Question 14

How can lactate be converted into glucose/ glycogen in the liver?

Answer 14

Gluconeogenesis (via Cori Cycle)- The reverse (ish) of the glycolysis reaction, but GTP is required along with ATP

Question 15

What are the conditions under which ketone bodies are formed?

Answer 15

Fasting state

Question 16

Why is glycolysis essential for red blood cells?

Answer 16

They have no mitochondria

Question 17

Why is glycolysis essential for the kidney medulla?

Answer 17

The blood supply is poorer than the cortex

Question 18

Why is glycolysis essential for the eye?

Answer 18

Blood vessels/ mitochondria would obscure light

Question 19

What molecules can be converted into glucose/glycogen via gluconeogenesis?

Answer 19

Lactate Amino acids Glycerol

Question 20

What is the next best alternative when there is no carbohydrate available for energy?

Answer 20

Gluconeogenesis - converting amino acids/ lactate/ glycerol into glucose/glycogen

Question 21

There are two pathways acetyl CoA can follow. What are they?

Answer 21

Fed - through to Krebs cycleFasting - Conversion into ketone bodies (liver)

Question 22

How do A/L/G participate in gluconeogenesis?

Answer 22

They can all be converted into pyruvate

Question 23

How are fatty acids involved in metabolism?

Answer 23

They can be oxidised via beta- oxidation in the mitochondriaThe acetyl CoA formed can then join the Krebs cycle

Question 24

What is the pentose phosphate pathway? (PPP)

Answer 24

Pathway which provides pentoses for DNA/ RNA synthesisProvides NADPH for fat synthesis

Question 25

When does ketogenesis take place?

Answer 25

High rate of fatty acid oxidation in the liverWhen metabolism is impaired

Question 26

Give examples of ketone bodies

Answer 26

AcetoacetateBeta hydroxybutyrateAcetone

Question 27

Why are ketone bodies used as the alternative energy source to glucose, rather than fat.

Answer 27

Ketone bodies are water soluble (so can cross the bloodstream to the brain), fatty acids are insoluble in water.

Question 28

How are ketone bodies excreted?

Answer 28

UrineThe lungsThey can be converted back to acetyl CoA

Question 29

What is the difference between the fed state and the fasting state?

Answer 29

Fed- Ample fuels entering from the gutFasting- Utilization of the body’s reserves

Question 30

What increases with increasing starvation?

Answer 30

Ketone bodies and free fatty acids