Metabolism

Question 1

How long do glycogen stores last and what happens when they run out

Answer 1

18-30 hours usually and after they are depleted gluconeogenesis starts using non-carb precursors in the liver and kidneys

Question 2

What is done to the glycerol produced from hydrolysis of triglycerides

Answer 2

It is phosphorylated by glycerol kinase to glycerol phosphate

Question 3

What is the Cori cycle

Answer 3

Lactate is produced in the exercising muscle this is transferred to the liver where it is converted to pyruvate then glucose and transported back to the muscle

Question 4

What can alanine be transanimated into

Answer 4

Pyruvate

Question 5

What enzyme is used in the conversion of alanine to pyruvate

Answer 5

Pyruvate kinase and 2 others

Question 6

Why can glycogen be so easily mobilised

Answer 6

Because it has a reducing end at the end of every branch

Question 7

What does the enzyme glycogen phosphorylase catalyse

Answer 7

The attachment of phosphate groups onto glycogen producing glucose phosphate

Question 8

What does glycogen debranching enzyme do and why

Answer 8

Removes carbons 1-6 bonds thereby splitting up the branches allowing for the glycogen phosphorylase to attach more easily

Question 9

What can glucose 6 phosphate be used for

Answer 9

Addition to glycogen
It CANNOT be turned into glucose

Question 10

What are the 2 traditional divides in metabolism

Answer 10

Catabolic - breaking
Anabolic - making

Question 11

What is a metabolite

Answer 11

An intermediate/output from a metabolic process

Question 12

What 2 ways can glucose enter a cell

Answer 12

1. Na+ independent facilitated diffusion transport
2. ATP-dependent Na+ monosaccharide transport

Question 13

What enzyme phosphorylates glucose to prevent it from leaving the cell

Answer 13

Hexokinase in most tissue
Glucokinase in the liver

Question 14

What are the 2 phases of glycolysis

Answer 14

Energy investment (first 5) phase
Energy generation phase

Question 15

What enzyme involved in step 3 of glycolysis phosphorlyates fructose-6-phosphate for the second time
And why is this important

Answer 15

Phosofofructokinase
This acts as an important control point

Question 16

What enzyme reduced pyruvate

Answer 16

Lactate dehydrogenase

Question 17

What molecule can be oxidatively decarboxylated into acetyl CoA

Answer 17

Pyruvate

Question 18

In what stage do the oxidative catabolism of carbs, fats and amino acids

Answer 18

The tricarboxylic acid cycle (TCA)

Question 19

How long are fatty acids normally in higher plants and animals

Answer 19

C16 or C18

Question 20

What initiates the mobilisation of fats

Answer 20

Hormone sensitive lipases

Question 21

What does the carnitine shuttle do

Answer 21

Transports fatty acyl-CoA’s across the impermeable mitochondrial membrane

Question 22

What is acetyl CoA a positive allosteric cofactor of

Answer 22

Pyruvate carboxylate

Question 23

Roughly how many ATP can be produced from the hydrolysis of 1 16 carbon long fatty acid

Answer 23

Around 120 but this does vary from person to person

Question 24

In the liver some acetyl-CoA is converted to ketone bodies what are these used for

Answer 24

Energy source for the heart and skeletal muscle

Question 25

What is the first step in the biosynthesis of fatty acids

Answer 25

The transfer of an acetate unit from mitochondrial acetyl CoA which is produced from oxidative carboxylation of pyruvate

Question 26

What is an alpha keto acid

Answer 26

An amino acid with the amine removed

Question 27

To catabolise amino acids what is removed first

Answer 27

The amine group (lost in urine as urea)

Question 28

What molecule “tags” proteins for degradation

Answer 28

Ubiquitin

Question 29

How many different overlapping systems for amino acid transport are there

Answer 29

7

Question 30

What can amino acids be classed as

Answer 30

Glucogenic, ketogenic or both

Question 32

The balance between use storage and release of fuel molecules is determined by what

Answer 32

Hormones and the central nervous system

Question 33

What is shown during the absorbative state

Answer 33

Elevated insulin to glucagon levels Readily available substrates

Question 34

What are the three states of metabolism

Answer 34

Absorbative Fasting Starvation

Question 35

What is the name of the process when we drastically increase fuel use and protein synthesis

Answer 35

A hypercatabolic state

Question 36

What are the three main forms of cellular energy currency

Answer 36

1. Thioester bond containing compounds 2. Reduced coenzymes 3. ATP

Question 37

Where is the electron transport chain located

Answer 37

The inner mitochondrial membrane

Question 38

What are the 2 mobile electron carriers in the electron transport chain

Answer 38

Coenzyme Q Cytochrome C

Question 39

How many protein complexes are in the electron transport chain and what do each of them do

Answer 39

4 Complex 1: pumps 4 electrons across the membrane Complex 2: accepts electrons from FADH and transfers all e- to coenzyme Q Complex 3: manages the transfer of e- between CoQ and cytochrome C Complex 4: accepts e- from cytochrome C and transfers them to oxygen

Question 40

Why is chlorophyll able to absorb light energy so well

Answer 40

It had a highly conjugated bonded system

Question 41

What are the 2 reaction centers for photosynthesis

Answer 41

Photosystem 1 (which oxidises water) and photosystem 2 (which reduced NADP+)

Question 42

Roughly how many subunits does photosystem 2 have

Answer 42

20

Question 43

What does cytochrome b6f catalyse

Answer 43

The transfer of electrons from plastoquinol to plastocyanin