MCBG S17 Energy Reactions In Cells

Question 1

Define metabolism

Answer 1

Processes which derive energy and materials from food studs and use them to support repair, growth and activity of the tissue of the body to sustain life.

Question 2

Some biochemical pathways are restricted to cells and some are limited to _________ within cells.

Answer 2

compartments

Question 3

What are the 4 main features of a metabolic pathway?

Answer 3

Start point
Intermediates - metabolites
End points
Interconnections

Question 4

What are the 2 types of pathway?

Answer 4

Catabolic and anabolic.

Question 5

What are 2 properties of catabolic reactions?

Answer 5

Large amounts of energy released from chemical bond breaking

Oxidative - release H atoms as reducing power.

Question 6

What is reducing power used for?

Answer 6

Biosynthesis

ATP synthesis

Question 7

What are 3 propertied of anabolic pathways?

Answer 7

Large components from smaller ones
Energy used from ATP
Reductive - H used up.

Question 8

What is BMR?

Answer 8

Basal metabolic rate - energy required by an awake individual during physical, digestive and emotional at 18 degrees Celsius.

Question 9

What is muscular work?

Answer 9

Energy used to power skeletal and cardiac muscle.

Question 10

Specific dynamic action of food

Answer 10

Energy used to ingest, digest and absorb food.

~150kcal

Question 11

If deltaG is less than 0 what does it mean?

Answer 11

Reaction is spontaneous

Exergonic reaction

Question 12

If deltaG is more than 0 what does this mean?

Answer 12

Not spontaneous
Requires energy input
Endergonic

Question 13

How do NAD+ and NADP+ become reduced?

Answer 13

Form NADH/NADPH and a proton.

Question 14

What vitamins are found in NAD+ NADP+ and FAD?

Answer 14

B vitamins

Question 15

When concentration of ATP is high what type of pathway is activated?

Answer 15

Anabolic

Question 16

What is an alternative name for adenylate kinase and why is its fucntion?

Answer 16

Myokinase

converts 2 molecules of ADP to a molecule of ATP and AMP

Question 17

Why does myokinase function further signal low energy?

Answer 17

Because one of its products is AMP which is a low energy signal.

Question 18

Name 4 high energy signals

Answer 18

ATP
NADH
NADPH
FADH2

Question 19

Name 5 low energy signals

Answer 19

ADP
AMP
NAD+
NADP+
FAD

Question 20

When supply exceed demands what is energy stored in the form of?

Answer 20

Macromolecules such as glycogen and TAGs

Question 21

What is the use of creatine phosphate?

Answer 21

Can be used as an energy store unlike ATP which is constantly cycled.

Question 22

What does creatine kinase do?

Describe how this enzyme can be used to make ATP when demand outstrips supply.

Answer 22

Catalyses the reversible reaction between creatine and phosphocreatine.

When demand high - reverse reaction - phophate from phosphocreatine transferred to ADP to produce ATP and creatine.

ATP can be hydrolysed for energy.

Question 23

What can creatine kinase be a clinical marker of?

Answer 23

MI

Question 24

Creatine and phosphocreatine can both spontaneously degrade to form ________.

Answer 24

Creatinine

Question 25

Where is creatinine filtered and excreted?

Answer 25

In the kidney and excreted in the urine.

Question 26

What are some clinical uses for measuring creatinine in the urine?

Answer 26

• Creatinine excretion per 24 hours is proportional to muscle mass of the individual.
• Creatinine concentration is a marker of urine dilution - used for comparison to pregnancy hormones for example hCG.