IMMS 2 Flashcards
Define metabolism
Chemical processes by which an organism uses food/water etc to grow, heal and maintain life.
How much energy do carbohydrates provide?
4 kcal/g
How much energy do proteins provide?
4 kcal/g
How much energy does alcohol provide?
7 kcal/g
How much energy do lipids provide?
9 kcal/g
Where is excess fat stored?
Adipose tissue
Where are excess carbohydrates stored?
As glycogen in liver and muscle
Where is excess protein stored?
In muscle
Define basal metabolic rate (BMR)
Energy needed to maintain basic bodily functions. Around 1 kcal/kg body weight/hour.
What factors increase BMR?
- Increased BMI
- Hyperthyroidism
- Naturally higher temperature
- Infection/ fever
- Stimulants
- Exercise
- Pregnancy
What factors decrease BMR?
- Increasing age
- Being female
- Dieting or starvation
- Hypothyroidism
- Decreased muscle mass
- Drug use
Describe the ATP-ADP Cycle
ATP contains 3 P groups. ATPases phosphorylate it to remove one P group. Fuel sources in the body are broken down to release P groups. These are added back to ADP to produce ATP. Repeat.
What is the rate-limiting enzyme in glycolysis?
Phosphofructokinase-1
Why does acidosis inhibit glycolysis?
Because acidosis inhibits the action of PFK1, the rate-limiting enzyme in glycolysis.
Where does glycolysis occur?
The cytoplasm (cytosol) of a cell
What happens to pyruvate in anaerobic respiration?
It is converted to lactate. Produces 2 reduced NAD and 2 ATP. The enzyme lactate dehydrogenase is used.
Outline the link reaction
Pyruvate (3C) – loss of CO2, addition of NAD–> Acetate (2C) – addition of Co A–> Acetyl Co A (2C)
Where does the Krebs’ Cycle occur?
In the mitochondrial matrix
What is the rate limiting enzyme in the Krebs’ Cycle?
Isocrate dehydrogenase
Where does oxidative phosphorylation take place?
Inner mitochondrial matrix (on cristae)
Where are fatty acids activated, and then where are they passed on to?
Activated in cytoplasm, passed on to mitochondria.
Outline fatty acid activation
Fatty acid – add ATP –> acyl adenylate – add HS-CoA and remove AMP. acyl-Co A synthetase enzyme –> acyl-Co A
How are fatty acids transported into the mitochondria for oxidation?
By the carnitine shuttle
When does ketogenesis occur?
When there are high levels of fatty acid oxidation, and the generated acetyl-Co A exceeds capacity of Krebs’, so undergoes ketogenesis instead.
