Energy Reactions in Cells

Question 1

Define metabolism

Answer 1

Inter conversion of biological molecules in small chemical steps to support repair, growth and activity of tissues to sustain life

Question 2

Where can cell metabolism occur?

Answer 2

• All cells
• Some cells
• Cell compartments

Question 3

What are the 4 stages of a metabolic pathway?

Answer 3

• Start Point
• Intermediate (Metabolite)
• End Point
• Interconnections

Question 4

Define a Catabolic Reaction and name 3 characteristics

Answer 4

Large molecules are broken down into smaller molecules

• Release free energy
• Oxidative
• Release H atoms

Question 5

Define an Anabolic Reaction and name 2 characteristics

Answer 5

Synthesis of larger cellular components from Metabolites

• Uses energy from catabolism
• Reductive

Question 6

What do all biological metabolic pathways release?

Answer 6

CO2 and H2O

Question 7

What are the 4 products of Catabolic Metabolism and give an example of each

Answer 7

Building Block Materials - Sugars, Amino Acids, Fatty Acids
Organic Precursors - Acetylcholine CoA
Biosynthetic Reducing Power - NADH, NADPH
Energy for Cell Function - ATP

Question 8

What is Biosynthetic Work?

Answer 8

Energy required for the anabolic synthesis of cellular components

Question 9

What is Transport Work?

Answer 9

Maintenance of ion gradients and nutrient uptake at membranes

Question 10

Name 3 types of specialised function work that require energy and give an example of each

Answer 10

Mechanical Work - Muscle contraction
Electrical Work - Nervous impulse conduction
Osmotic Work - Kidney

Question 11

What 3 elements add up to give a person’s energy requirement?

Answer 11

• Basal Metabolic Rate
• Activity
• Specific Dynamic of Food

Question 12

What are the two types of Chemical Bond Energy?

Answer 12

Exergonic - Release of energy and spontaneous

Endergonic - Require energy

Question 13

Describe Exergonic and Endergonic energy in terms of free energy

Answer 13

Exergonic has free energy < 0

Endergonic has free energy > 0

Question 14

What is a Redox Reaction?

Answer 14

Oxidation accompanied by Reduction

Question 15

What does oxidation release in redox reactions?

Answer 15

Chemical bond energy

Question 16

What are Hydrogen Carrier Molecules?

Answer 16

They carry electrons and protons from oxidation

Question 17

What is constant in Hydrogen Carrier Molecules?

Answer 17

Total concentration of oxidised and reduced carriers

Question 18

Name 2 processes that use Hydrogen Carrier Molecules

Answer 18

• ATP Production

- Biosynthesis

Question 19

What are the 3 major Hydrogen Carrier Molecules?

Answer 19

• NAD
• NADP
• FAD

Question 20

How is reducing power converted to energy currency?

Answer 20

Oxidative Phosphorylation

Question 21

What energy powers phosphorylation of ADP?

Answer 21

Energy released in Exergonic reactions

Question 22

What happens when ATP levels are high?

Answer 22

Anabolic pathways are activated

Question 23

What happens when there is low ATP and high ADP/AMP?

Answer 23

Catabolic pathways are activated

Question 24

What enzyme converts ADP to ATP and AMP?

Answer 24

Adenylate Kinase

Question 25

What is the purpose of Creatine Phosphate?

Answer 25

Allows immediate use of high energy stores

Question 26

How is Creatine Phosphate produced?

Answer 26

Reaction catalysed by Creatine Kinase and phosphorylated by ATP

Question 27

What is special about the formation reaction of Creatine Phosphate?

Answer 27

It is easily reversible allowing it to quickly respond to varying levels of ATP

Question 28

What is the value of Creatine Kinase in diagnosis?

Answer 28

• Released from cardiac myocytes when damaged

- High level in the blood indicative of an MI

Question 29

What is Creatinine and how is it produced?

Answer 29

• Breakdown product of Creatine

- Produced by a spontaneous reaction at a constant rate

Question 30

Name 2 clinical applications of Creatinine measurement

Answer 30

• Measure of muscle mass

- Marker of urine dilution