Wednesday 9th January 2013 Flashcards
Explain how downward movement of the diaphragm leads to air entering the lungs. 2 marks
- Increase volume
- Lowers pressure
- Air pushed in by outside pressure
Pulmonary ventilation equation? 1 mark
Tidal volume * ventilation rate
Function of the mitochondria? 1 mark
- Aerobic respiration
This photograph was taken using a transmission electron microscope. The structure of the organelles visible in the photograph could not have been seen using an optical (light) microscope. Explain why. 2 mark
- Low resolution
- Wavelength is too long
Monosaccharides that make up sucrose? 1 mark
- Glucose
- Fructose
Monosaccharides that makeup lactose? 1 mark
- Galactose
- Glucose
Where is amylase produced and what are the products? 1 mark
- Pancreas
- Maltose
Where is maltase produced and what are the products? 1 mark
- Maltase
- Produces glucose
Cholera bacteria produce toxins which increase secretion of chloride ions into the lumen of the intestine.
Explain why this results in severe diarrhoea (watery faeces). 3 marks
- Water lost into gut/water moves into gut/ water leaves cells;
- Low(er) water potential of intestine/gut (lumen);
- Osmosis/movement down a WP gradient;
- Less/not enough water (re)absorbed;
The water potential of solution B with starch was higher (less negative) than the water potential of solution A with glucose.
Explain why.
- Starch is not very soluble
- Does not dissolve well
Addition of a phosphate group to the non-functional form of TK leads to the production of the functional form of TK.
Explain how. 2 marks
- Phosphate changes the active site/ shape of the enzyme
- It is now complementary to the substrate and can form E-S complexs
The binding of the functional form of TK to its substrate leads to cell division. Chronic myeloid leukaemia is a cancer caused by a faulty form of TK. Cancer involves uncontrolled cell division.
Suggest how faulty TK leads to chronic myeloid leukaemia. 2 marks
- Faulty TK has a functional active site without phosphate.
- TK not controlled by phosphate.
Using all of the information, describe how imatinib stops the development of chronic myeloid leukaemia. 2 marks
- Non-competitive inhibitor
- Causes TK to be in non-functional form = active site not formed.
- So, uncontrolled cell division stopped
Name the blood vessel to which the artificial heart is connected. 1 mark
- Aorta
In these patients, the right ventricle still produces sufficient blood flow to keep the patient alive.
Suggest why the left ventricle requires the help of the artificial heart but the right ventricle does not. 2 marks
- Left ventricle pumps to the whole body.
- Left ventricle does most work.
The groups of men selected for this investigation were matched.
Other than being men, suggest one factor for which they should have been matched. 1 mark
- Age
- No heart condition
Explain why the pulse recordings in the doctor’s surgery were taken when the men were lying down. 1 mark
- Patients were at risk
- Not moving
The pulse felt in the artery in the wrist can be recorded and used to measure heart rate.
Suggest why the pulse felt can be used to measure heart rate. 2 marks
- Caused by pressure
- From one contraction
The portable heart rate monitor recorded the men’s heart rates continuously.
This gave more reliable mean heart rates than those obtained by recording the pulse in the wrist for 1 minute.
Suggest why it is more reliable. 2 marks
- More data collected from the monitor.
- Human errors can cause errors.
- Monitor records HR over a range of activities during the day/pulse rate only records for a single set of conditions
People with AIDS die because they are unable to produce an immune response to pathogens (lines 2– 4).
Explain why this leads to death. 3 marks
- Susceptible to other infections
- Pathogens cause disease
- Damage cells
- Release toxins
Explain why each of the following means that a vaccine might not be effective against HIV.
HIV rapidly enters host cells (lines 6 –7). 2 marks
- HIV enters cells before antibodies can destroy it
- Antibodies cannot enter cells to destroy HIV.
HIV shows a lot of antigenic variability (lines 7– 8). 2 marks
- Antigen on HIV changes
- Specific antibody so the receptor no longer binds to new antigen.
So far, these types of vaccine have not been considered safe to use in a mass vaccination programme (lines 14 – 15).
Suggest why they have not been considered safe. 3 marks
- The inactive virus may become active
- The non-pathogenic virus may mutate and harm cells
- Genetic information from HIV may harm cells
- People may become HIV positive after the vaccine
Some substances can cross the cell-surface membrane of a cell by simple diffusion through the phospholipid bilayer.
Describe other ways by which substances cross this membrane. 5 marks
OSMOSIS
- From a high to low water potential
- Through water channels
ACTIVE TRANSPORT
- Protein pumps
- Against concentration gradient
- Using ATP from respiration
Atheroma formation increases a person’s risk of dying. Explain how. 5 marks
- Atheroma is fatty material
- In wall of artery
- Higher risk of blood clot
- Blocks cornary artery
- Less oxygen to the heart
- Reduces respiration
- Causes a heart attack
- Blocks artery to the brain
- Causes stroke
