Unit 1 Flashcards
(100 cards)
what is the intermolecular force that explains many of the important properties of water is (1 mark)
hydrogen bonds
suggest why glucose is soluble in water (2 marks)
- glucose is a polar molecule
- forms hydrogen bonds with water
suggest how triglycerides are transported in water (2 marks)
- triglycerides are insoluble in water (non polar/hydrophobic)
- transported as lipoproteins (HDL and LDL)
- formed in vesicles/micelles
the role of thrombin in the blood clotting process is to (1 mark)
catalyse the conversion of fibrinogen to fibrin
the ion required in the conversion of prothrombin to thrombin is (1 mark)
calcium
blood clots form only when required because the clotting factors used are (1 mark)
present in an inactive form in the blood
describe how the human lung is adapted for rapid gas exchange (5 marks)
- folded into large number of alveoli
- providing a high SA
- walls of alveoli/capillary are thin
- the walls are made from a single layer of flattened cells
- the thin wall decrease diffusion distance
- extensive network of capillaries
- maintains concentration gradient
suggest why blood clots, formed in the pulmonary thrombosis, reduce gas exchange in the lungs (2 marks)
- reduced blood flow to the lungs via the arteries
- decrease in concentration gradient
- decrease in diffusion rate
suggest reasons for the different death rates in different countries (3 marks)
- genetic differences
- ethnic differences
- healthcare differences
- lifestyle differences (stress/smoking/alcohol consumption)
- dietary differences
- different age profiles
explain why statins reduce the risk of CVD (2 marks)
- inhibits cholesterol synthesis/ production of cholesterol in the liver
- reducing total blood cholesterol levels
- raises HDL : LDL ratio
- lowers LDL levels
state the risks of using statins to treat CVD (2 marks)
- muscle inflammation/pain
- joint inflammation/pain
- kidney damage/ failure
- liver damage/failure
- depression
- nausea
- constipation
- cataracts
- diabetes
- allergies
- skin inflammation (skin rash)
- respiratory problems
in phospholipids, the fatty acid tails are (1 mark)
- non-polar
- hydrophobic
in phospholipids, the fatty acid tails are formed from (1 mark)
carbon and hydrogen only
in phospholipids, each fatty acid is joined to glycerol by (1 mark)
ester bond
suggest how cholesterol affects membrane fluidity (3 marks)
- combines with the fatty acid tails
- holds/pulls the fatty acid chains together
- reducing the movement of the phospholipid/ fatty acid tails
red blood cells swell and burst if placed in water, explain why this happens (3 marks)
- water diffuses into the cell
- by osmosis
- from a region of high water potential/concentration (outside the cell) to a region of low water potential/concentration (inside the cell)
- stress on membrane components increases
- overcomes the adhesion between molecules
recessive allele (1 mark)
- it is only expressed in the homozygous condition
- it is only expressed in the absence of the dominant allele
gene mutation (1 mark)
- alteration of the DNA
- change in the base sequence
‘a change in the base sequence of DNA’
explain how a mutation can result in a change in activity of an enzyme (5 marks)
- change in the DNA triplet/codon
- results in different amino acids/amino acid sequence/ primary structure
- different R groups/ different position of R groups
- this may change the bonding
- change in folding
- therefore changing the shape/structure of the active site
- enzyme is unable to combine with the substrate
name a test that could be used to find out if an unborn baby has a disease (1 mark)
- chronic villus sampling
- amniocentesis
suggest why testing for a disease on an unknown baby is not offered to all pregnant women (1 mark)
- rare condition
- there may be no family history of this condition
- cost availability for testing
give the disadvantages of carrying out genetic tests on unborn children (1 mark)
- risk of harming the baby
- risk of miscarriage
- risk of abortion
- risk of inaccurate results (false negative/ false positive)
- difficulty in getting insurance
explain why animals need a heart and circulation (4 marks)
- small SA to vol. ration
- overcome limitations of diffusion
- heart is needed to pump blood around the body
- transport of oxygen and glucose
- removal of carbon dioxide/ waste products
- high metabolic rate
- high energy demand
describe the structure of the aorta and how it relates to its function (4 marks)
- thick wall (contains collagen)
- able to withstand pressure
- wall of aorta contains elastic fibers/ elastic tissue
- allowing the wall of the aorta to stretch and recoil
- recoil helps maintain high pressure/ rapid flow
- semilunar valves present at the start of the aorta that prevents back flow of the blood during diastole