B1 Metabolism & Nutrition Flashcards Preview

Phase I Medicine > B1 Metabolism & Nutrition > Flashcards

Flashcards in B1 Metabolism & Nutrition Deck (30):
1

What are the constituents of the average UK diet?

MACRONUTRIENTSCarbohydrateFatProteinDietary FibreVariety of MICRONUTRIENTS

2

What's the difference between macronutrients and micronutrients?

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

3

What are carbohydrates?

Starch + sugars

4

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

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

5

Where does the body's energy primarily come from?

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

6

What's the nutrition difference between starch and sugars? 

Starch has a higher energy content than sugars

7

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

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

8

True or false? The body can store protein and alcohol

FALSE

9

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

TRUE

10

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

Acetyl CoA

11

What are the other names for the Krebs cycle?

Citric Acid Cycle Tricarboxylic Acid Cycle (TCA) Krebs Cycle

12

Where are the coenzymes NAD and FAD derived from?

Niacin and Riboflavin

13

Where is glucose derived from?

Blood; the breakdown of glycogen

14

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

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

15

What are the conditions under which ketone bodies are formed?

Fasting state

16

Why is glycolysis essential for red blood cells?

They have no mitochondria

17

Why is glycolysis essential for the kidney medulla?

The blood supply is poorer than the cortex

18

Why is glycolysis essential for the eye?

Blood vessels/ mitochondria would obscure light

19

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

Lactate Amino acids Glycerol

20

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

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

21

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

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

22

How do A/L/G participate in gluconeogenesis?

They can all be converted into pyruvate

23

How are fatty acids involved in metabolism?

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

24

What is the pentose phosphate pathway? (PPP)

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

25

When does ketogenesis take place?

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

26

Give examples of ketone bodies

AcetoacetateBeta hydroxybutyrateAcetone

27

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

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

28

How are ketone bodies excreted?

UrineThe lungsThey can be converted back to acetyl CoA

29

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

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

30

What increases with increasing starvation?

Ketone bodies and free fatty acids