What are the risk factors associated with heart disease
- High salt intake
- High cholesterol
- High blood pressure
- Lack of exercise
Why do areas of the heart muscle die during a myocardial infarction?
- Reduced blood flow in coronary artery, blocked
- Less O₂ supplied
- Respiration drops so cells die
How are bacteria destroyed by phagocytes?
- Phagocyte engulfs bacteria to form phagosome
- Lysosomes fuse to it, emptying contens
- Release enzymes, that hydrolyse bacteria
What possible features could bacteria have that are never present in white blood cells?
- Cell wall
- Circular DNA
- DNA without histones
- 70S ribosomes (smaller)
What are the adaptations of epithelial cells for absorption?
- Microvilli -> increase SA
- Mitochondria -> supply ATP for co-transport
- Vesicles -> to bring carrier proteins to membrane
How does absorption of glucose into the epithelial cell lead to water moving into cell?
- Lowers Ψ
- Gradient created
- Water moves into cell by osmosis
Why does the thickness of the ventricular walls increase during systole?
- They are contracting
- Causes an increase in ventricular pressure
Why does blood flow in the aorta increase when ventricular pressure in the heart increases?
- Ventricle pressure rises, blood starts to flow into aorta
- Pressure above that in aorta causes AV to open
How do you calculate heart rate?
Exam qu: A dog's blood flow in the aorta rises 4 times in 2 seconds. What is the dog's HR?
- Calculate beats per second (beats/sec)
- Multiply by 60
- 4beats ÷ 2sec = 2beats/sec
- 2 × 60 = 120BPM
Why does maltase only break down maltose (into glucose)?
- Tertiary structure
- Means that the active site complementary to maltose
- By induced fit
- Enzyme is a catalyst
- Lowers activation energy
- By forming an E-S complex
Describe non-competitive inhibition of an enzyme.
- Non-comp inhib binds to allosteric site on enzyme
- Changes shape of active site
- Substrate no longer complementary so E-S complex cannot form
- Cannot be overcome by more substrate
Describe competitive inhibition of an enzyme.
- Comp inhib has similar shape to substrate
- Competes for the active site
- Can be overcome by more