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.
Where does ketogenesis occur?
Hepatocytes of the liver.
How does ketoacidosis occur?
- When an insulin-dependent diabetic’s dose is inadequate/ they become insulin resistant.
- Due to alcohol abuse.
What happens to pH, pO2, pCO2 and HCO3 levels during ketoacidosis?
pH dec.
pO2 increased
pCO2 dec.
HCO3 dec.
Define an acid
Proton donor: HA H+ + A-
Define a base
Proton acceptor: B + H+ BH+
What is the body’s optimum pH?
7.4
What is the body’s acceptbale pH range?
7.35 - 7.45
Write the equilibrium for acid/base balance in the body
CO2 + H2O H2CO3 HCO3- + H+
Describe the key features of respiratory acidosis
- Decreased ventilation.
- Increased CO2.
- Lower pH.
Describe the key features of respiratory alkalosis
- Increased ventilation.
- Decreased CO2.
- Higher pH
Describe the key features of metabolic acidosis
- Decreased metabolism of acid.
(- Increased [H+].) - Decreased [HCO3-].
- Lower pH.
Describe the key features of respiratory alkalosis
- Increased metabolism of acid.
(- Decreased [H+].) - Increased [HCO3-].
- Higher pH.
What is a reactive oxygen species (ROS)?
Reactive molecules/free radicals containing oxygen.
What is a free radical?
A species with an unpaired electron in its outer orbital.
Write the equation of the formation of an ROS
O2 –> O2- –> H2O2 –> OH –> H2O (loses e- each time)
Write the Fenton Reaction
H2O2 + Fe2+ –> Fe3+ + OH- + OH*
Write the Haber-Weiss Reaction
O2- + H2O2 –H+–> O2 + H2O + OH
What are the 4 defences against free radical damage within the body?
- Antioxidant enzymes
- Antioxidant vitamins
- Cellular compartmentalisation
- Repair
What is a respiratory burst?
Rapid release of the ROS superoxide, which then generates other ROS’s during phagocytosis to destroy bacteria by damaging its membrane.
Write the equation for a respiratory burst
O2 –(NADPH in, use NADPH Oxidase)–> O2- –>H2O2 –> HOCl (add Cl- and use myeloperoxidase) and OH (Fe2+ oxidised to Fe3+ = Fenton reaction)
What does Alcian Blue stain and what colour is it?
- Polysaccharides
- GAGs
- Cartilage
- Blue/purple colour
What does Eosin stain and what colour is it?
- RBCs
- Cytoplasmic proteins
- Purple colour
What does Haematoxylin stain and what colour is it?
- Nuclei
- RNA
- Dark blue colour
What does PAS stain and what colour is it?
- Polysaccharides
- Glycoproteins
- Glycolipids
- Beige/ purple colour
What is the H&E stain a combination of?
Haematoxylin and Eosin
