Biology Revision Unit 1 May 2Nd

Front 1

structure and functional significance of artery?

Back 1

structure:
1, relatively thick wall
2, smooth muscle
3, elastic fibres
4, lined with smooth layer of endothelial cells
5, narrow lumen

Hint 1

Function:
1, withstands high blood pressure
2, alters diameter of lumen to vary blood flow
3, allow walls to stretch when blood is pumped into the artery and then recoil, smoothing blood flow
4, low friction surface to ease blood flow

Front 2

structure and functional significance of capillaries?

Back 2

structure:
1, very thin wall, just one cell thick

Hint 2

funtion:
1, allows rapid exchange between blood and tissues

Front 3

structure and functional significance of veins?

Back 3

structure:
1, relatively thin wall
2, very little smooth muscle or elastic fibres
3, wide lumen
4, valves

Hint 3

funtion:
1, blood under low pressure
2, no pulse of blood so no stretching and recoiling
3, large volume acts as blood reservoir
4, stop backflow

Front 4

list three ways in which hydrogen bonds are important in giving water its properties

Back 4

1, they make it a liquid by holding molecules together.
2, they hold molecules together giving it cohesion.
3, they allow it cling to other substances, adhesion

Front 5

which part of a water molecule is slightly negative and which is slightly positive?

Back 5

the oxygen carries the +, the hydrogen the -

Front 6

whats the reason of valves in heart open and close?

Back 6

due to pressure differences between one side and the other (pressure gradients)

Front 7

atherosclerosis process?

Back 7

1, damage to endothelial lining of artery (eg by smoking, high blood pressure)
2, inflammatory response, white blood cells move into the artery wall
3, cholesterol builds up, leading to formation of atheroma
4, build-up of calcium salts and fibres leading to plaque formation
5, narrowing of artery
6, raised blood pressure
7, damage to endothelial lining(positive feedback phenomenon)

Front 8

risk of suffering from CVD is increased by?

Back 8

1, genetic factors
2, age
3, gender
4, high blood pressure
5, lifestyle factors - diet, exercise and smoking

Front 9

CVD treatment and risks associated with their use: diuretics(antihypertensive)

Back 9

Function:
1, increase volume of urine
2, lowers blood volume and pressure

Hint 9

Risks:
1, very occasional dizziness
2, nausea
3, muscle cramps

Front 10

CVD treatment and risks associated with their use: beta blockers(antihypertensive)

Back 10

Function:
1, block response of heart to hormones and make contractions less frequent and less powerful

Hint 10

Risks:
1, possible link with diabetes

Front 11

CVD treatment and their risks: ACE inhibitors (antihypertensive)

Back 11

function:
1, block the production of angiotensin (ACE stands for angiotensin converting enzyme) which normally causes arterial constriction and a rise in blood pressure

Hint 11

risks:
1, cough
2, dizziness
3, heart arrhythmia
4, impaired kidney function

Front 12

CVD treatment and their risks: statins

Back 12

function:
1, lower cholesterol level in the blood by blocking the liver enzyme that makes cholesterol

Hint 12

risks
1, muscle aches, nausea, constipation and diarrhoea, very rarely inflammation reactions can occur which, even more rarely, fatal; also, again rarely, liver failure; also people may stop trying to eat a healthy diet, leaving it all to the statins

Front 13

CVD treatment and their risks: anticoagulants, eg warfarin

Back 13

function:
1, reduce risk of clot formation

Hint 13

risks
1, risk of uncontrolled bleeding; dosage control is essential

Front 14

CVD treatment and their risks: platelet inhibitory drugs eg aspirin, clopidogrel

Back 14

function:
1, make plateles less sticky

Hint 14

risks
1, aspirin irritates the stomach lining and can cause serious stomach bleeding; using clopidogrel with aspirin can make the risk even greater

Front 15

relate structure to function in glucose, sucrose, amylose and amylopectin

Back 15

glucose - has reactive group so good for respiratory substrate

sucrose - reactive groups joined to each other so unreactive, so good for transport function in plants

amylose and amlopectin - both have compact structure so can fit lots of lucose into small space, good for storage, large so do not dissolve, no osmotic effect, cannot pass through membranes so good again for storage, held together by glycosidic bonds so easily hydrolysed, amylopectin hydrolyses more rapidly due to branched structure

Front 16

compare LDL and HDL

Back 16

LDL:
1, formed from saturated fats, protein, cholesterol
2, bind to cell surface receptors, which can become saturated leaving the LDLs in the blood
3, associated with formation of atherosclerosis
4, should be maintained at low level

HDL:
1, formed from unsaturated fats, protein, cholesterol
2, transport cholesterol from body tissues to liver where it is broken down
3, reduced blood cholesterol levels, discourages atherosclerosis
4, should be maintained at high level

Front 17

why are young women less likely to suffer from CVD than men?

Back 17

oestrogen gives women some protection from CVDs before the menopause. then the risk in both sexes is about the same.

Front 18

what is the cause of link between smoking and CVD?

Back 18

chemicals in cigarette smoke cause arteries to constrict thus raising blood pressure, they can physically damage the lining of arteries leading to atherosclerosis.

Front 19

list the key features of a good study used to determine health risk factors

Back 19

large sample size, ethical, representative sample, valid measurement techniques used, methods used reliable (eg standardised procedures or operatives the same)

Front 20

in the lungs of humans, the rate of diffusion is maximised by adaptations of the gas exchange surfaces:

Back 20

1, surface area. many alveoli give a huge surface area
2, concentration gradient. well supplied with constantly circulating blood which carries oxygen away and carbon dioxide to the surface. breathing keeps oxygen concentration high and carbon dioxide concentration low.
3, thickness of gas exchange surface. very thin. just one flattened epithelial cell in thickness, reducing the distance for diffusion.

Front 21

draw the DNA structure

Back 21

5'end and 3'end

Front 22

compare DNA and RNA

Back 22

DNA: double stranded, sugar is deoxyribose, bases ACTG
RNA: single stranded, sugar is ribose, bases ACUG

Front 23

how CF cause problems in gas exchange?

Back 23

1, mucus accumulates in the lungs, bacteria trapped in mucus increase the possibility of infection
2, mucus can block bronchioles, which reduces the number of alveoli in contact with fresh air so reduces the surface area for gas exchange

Front 24

how CF cause problems in digestion?

Back 24

1, mucus blocks the pancreatic duct, so digestive enzymes can't reach the duodenum (small testine) and food is not properly digested. this leads to tiredness and difficulty in gaining weight.
2, enzymes trapped within the pancreas cause fibrosed cysts and damage to insulin-producing cells, leading to diabetes.

Front 25

how CF cause problems in reproduction?

Back 25

1, in women, mucus can block the cervix preventing entry of sperm.
2, in men, the vas deferens (sperm duct) is either missing or blocked with mucus, so sperm cannot leave the testes.

Front 26

list three factors which affect perception of risk

Back 26

personal experiences, not weighing one risk against another, peer pressure, remoteness, fatalistic

Front 27

an amino acid consists of?

Back 27

a central (or alpha) carbon atom attached to an amino group, NH2, a carboxylic acid group, COOH, a hydrogen atom and a variable side group (R group)

Front 28

whats the difference between hydrolysis and denature of proteins?

Back 28

proteins can be broken down or hydrolysed when the peptide bonds between amino acids are broken. this is what happens when a protein is digested in the gut.

denatured when the 3-dimentional shape is disrupted. this can be due to breakage of H bonds when the molecule vibrates more at higher temperatures, or changes in pH which break ionic bonds between R side chains.

Front 29

are there any two amino acids that cannot join together?

Back 29

no, because all have NH2 at one end and COOH at the other, and it is between these that the peptide bond is formed.

Front 30

in measuring the initial rate of an enzyme reaction, state three factors which should be controlled if you are trying to investigate the effect of changing substrate concentrations.

Back 30

enzyme concentration, temperature, pH, volume of solutions

Front 31

water's structure?

Back 31

1, a molecule of water (H2O) is one atom of oxygen (O) joined to two atoms of hydrogen (H2) by shared electrons.
2, because the shared negative hydrogen electrons are pulled towards the oxygen atom, the other side of each hydrogen atom is left with a slight positive charge.
3, the unshared negative electrons on the oxygen atom give it a slight negative charge.
4, this makes water a dipolar molecule - it has a negative charge on one side and a positive charge on the other.
5, the negatively charged oxygen atoms of water attract the positively charged hydrogen atoms of other water molecules.
6, this attraction is called hydrogen bonding.

Front 32

relate the structure of water to its ability to transport substances

Back 32

1, in a water molecule, the shared electrons are pulled closer to the oxygen atom than the hydrogen atoms. this makes the molecule dipolar, which makes water a good solvent for other dipolar molecules.
2, substances can be transported more easily when dissolved in a solvent like water.
3, water is also cohesive due to its polar nature. this helps water to flow, which means it can transport substances.

Front 33

starch?

Back 33

1, cells get energy from glucose. plants store excess glucose as starch (when a plant needs more glucose for energy it breaks down starch to release the glucose)
2, starch is a mixture of two polysaccharides of a-glucose - amylose and amylopectin.
3, starch is also insoluble in water, so it doesn't cause water to enter cells by osmosis (which would make them swell). this makes it good for storage.

Front 34

amylose and amylopectin?

Back 34

amylose: a long, unbranched chain of glucose joined together with 1,4 glycosidic bonds. the angles of the glycosidic bonds give it a coiled structure, almost like a cylinder. this makes it compact, so it's really good for storage because you can fit more in to a small space.

amylopectin: a long, branched chain of glucose that contains 1,4 and 1,6 glycosidic bonds. its side branches allow the enzymes that break down the molecule to get at the glycosidic bonds easily. this means that the glucose can be released quickly.

Front 35

how? and draw a diagram showing a reversible reaction with correct reactants and products of how glycosidic bonds are formed and broken?

Back 35

1,glycosidic bonds are formed in condensation reactions.
2, a hydrogen atom from one monosaccharide combines with a hydroxyl/OH group from another monosaccharide.
3, this releases a molecule of water.
4, glycosidic bonds are broken by hydrolysis.
5, a molecule of water reacts with the glycosidic bond to split the monosaccharide molecules apart.
P79,P6

Front 36

how? and draw a diagram showing a reversible reaction with correct reactants and products of how triglycerides are formed and broken?

Back 36

1,triglycerides are made from a single glycerol molecule and three molecules of fatty acids.
2, they are formed by condensation reactions.
3, ester bonds form between each fatty acid molecule and the glycerol,
4, producing a molecule of water for each fatty acid added to break apart each ester bond.
P79, P8

Front 37

how? and draw a diagram showing a reversible reaction with correct reactants and products of how peptide bonds are formed and broken?

Back 37

1, two amino acids join together in a condensation reaction.
2, a peptide bond forms between the carboxyl group of one amino acid and the amino acid group of the other amino acid.
3, a molecule of water is released.
P10

Front 38

why the enzyme substrate complex lowers the activation energy?

Back 38

1, if two substrate molecules need to be joined, being attached to the enzyme holds them close together, reducing any repulsion between the molecules so they can bond more easily.
2, if the enzyme is catalysing a breakdown reaction, fitting into the active site puts a strain on bonds in the substrate, so the substrate molecule breaks up more easily.

Front 39

an experiment was carried out to find out the effect of increasing the enzyme concentration on the initial rate of a reaction. using your knowledge, predict the outcome of the experiment and explain your answer.

Back 39

1, as the enzyme concentration is increased, the initial rate of reaction will increase up to a point.
2, this is because the more enzyme molecules tre are in a solution, the more likely a substrate molecule is to collide with one of them and form an enzyme-substrate complex.
3, but if the amount of substrate is limited, increasing the concentration of enzyme will have no further effect.

Front 40

describe the strucutre of heart and how it relates to its functions.

Back 40

1, the left ventricle of the heart has thicker, more muscular walls than the right ventricle, because it needs to contract powerfully to pump blood all the way round the body. the right side only needs to get blood to the lungs, which are nearby.
2, the ventricles have thicker walls than the atria, because they have to push blood out of the heart whereas the atria just need to push blood a short distance into the ventricles.
3, the atrioventricular (AV) valves link the atria to the ventricles and stop blood flowing back into the atria when the ventricles contract.
4, the semi-lunar (SL) valves link the ventricles to the pulmonary artery and aorta, and stop blood flowing back into the heart after the ventricles contract.
5, the cords attach the atrioventricular valves to the ventricles to stop them being forced up into the atria when the ventricles contract.

Front 41

explaination why alcohol concentration increase the permeability?

Back 41

alcohol dissolves the lipids in the cell membrane so the membrane become more permeable.

Front 42

how the mammalian lungs adapted for efficient gaseous exchange?

Back 42

1, many alveoli provide a large surface area for diffusion to occur across.
2, the alveolar epithelium and capillary endothelium are each only one cell thick, giving a short diffusion pathway.
3, all the alveoli have a good blood supply from capillaries - they constantly take away oxygen and bring more carbon dioxide, maintaining the concentration gradient.
4, breathing in and out refreshes the air in the alveoli, keeping the concentration gradients high.

Front 43

describe the semi-conservative method of DNA replication

Back 43

1, the DNA helix unzips
2, each strand acts as a template
3, individual free DNA mononucleotides join up along the template strand by complementary base pairing.
4, DNA polymerase joins the individual mononucleotides together.
5, hydrogen bonds then form between the bases on each strand.
6, two identical DNA molecules are produced.
7, each of the new molecules contains a single strand from the original DNA molecule and a single new strand.

Front 44

describe the process of protein synthesis

Back 44

1, transcription happens inside the nucleus and translation happens in the cytoplasm.
2, the hydrogen bonds between the two DNA strands of a gene break
3, and the DNA molecule uncoils at that point
4, one of the strands (antisense strand) is used as a template to make an mRNA copy using complementary base pairing
5, the mRNA moves out of the nucleus and attaches to a ribosome in the cytoplasm.
6, tRNA molecules with complementary bases to the triplets on the mRNA attach themselves to the molecule using complementary base pairing.
7, the amino acids attached to the tRNA molecules are joined together by peptide bonds, forming a polypeptide chain
8, and the tRNA molecules move away
9, this process continues until there's a stop signal on the mRNA.

Front 45

give differences between the structure of vein and the structure of a capillary

Back 45

1. walls of veins more than one layer of cells and capillaries one layer ;
2. walls of veins contain connective tissue / smooth muscle / collagen / elastic tissue, capillaries do not ;
3. veins have valves in them and capillaries do not ;
4. veins do not have pores but capillaries do;
5. veins have wide lumen, capillaries have narrow lumen

Front 46

explain how the structure of an artery relates to its function

Back 46

1. wide wall to withstand blood under high pressure ;
2. narrow lumen&recoil to maintain high pressure ;
3. elastic fibres& folded lining&smooth muscle to allow vessel to stretch ;
4. smooth lining reduces friction ;

Front 47

suggest an explanation for the effect of higher ethanol concentration greater intensity of red coloration

Back 47

1. disruption of membrane ;
2. ethanol is a non–polar solvent ;
3. lipids dissolve in alcohol;
4. increase in ethanol causes solution to be less polar ;
5. orientation of phospholipids depends on water around it ;

Front 48

describe what the student should have done to reduce the red coloration in the tube containing only water

Back 48

rinse pieces thoroughly /dab pieces dry

Front 49

there was some red coloration in the tube containing only water. suggest an explanation.

Back 49

1. cells and membranes damaged by cutting up of pieces;
2. as a result pigment could leak out of vacuoles and cells;

Front 50

suggest variables which should be kept constant during the experiment of effect of alcohol concentration on the permeability of beetroot membranes.

Back 50

temperature,
surface area / volume (of beetroot),
part,
age,
variety,
storage,
source,
volume of ethanol,
same {wavelength / filter}

Front 51

explain why the phospholipid molecules form a bilayer

Back 51

1. fatty acids / tails are hydrophobic / non-polar ;
2. so orientate themselves away from water / polar
environment ;
3. phosphate / heads are hydrophilic / polar ;
4. so can interact with water / polar environment ;
5. cytoplasm / tissue fluid as the polar environment ;

Front 52

describe the structure of starch and explain why this structure makes it a suitable molecule for storing energy

Back 52

1. amylose and amylopectin ;
2. details of amylose e.g. straight chain, spiraled, 1-4 links ;
3. details of amylopectin / starch e.g. branched, 1-4 and 1-6 links ;
4. it is easily hydrolysed ;
5. compact structure ;
6. leading to more glucose in a smaller space in a cell ;
7. being insoluble and large ;
8. leading to it not diffusing out of cells, having little or no
osmotic effect

Front 53

name the bond that joins the two a-glucose molecules together

Back 53

glycosidic bond

Front 54

a blood clot may form when a lbood vessel wall becomes damaged. cell fragments called __ stick to the wall of the damaged blood vessels forming a plug. a series of chemical changes occur in the blood. resulting in __ being converted into thrombin. thrombin is an __ that catalyses the conversion of __ into long insoluble strands of __. these strands form a mesh that trap __ to form the clot.

Back 54

platelets, prothrombin, enzyme, fibrinogen, fibrin, cells/erythrocytes/platelets/thrombocytes.

Front 55

statins are a group of cholesterol-reducing drugs that act by inhibiting this enzyme. suggest which of the two drugs, drug A or drug B, is more likely to be a statin. give reasons.

Back 55

1. drug A ;
2. the total cholesterol and LDL levels are lower ;
3. statins inhibit cholesterol synthesis ;
4. statins result in more LDL receptors on liver cells ;
5. so less LDL in the blood ;

Front 56

risks of treatments using statins.

Back 56

1, gastrointestinal {problems / cancer} e.g. constipation, bowel complaints,
2, joint / muscle problems e.g. cramps, myositis, pain, myopathy, muscle breakdown,
3, liver problems,
4, kidney problems,
5, mental health problems e.g. depression,
6, reduced vitamin uptake,
7, respiratory cancer

Front 57

using the information in the graph, describe how the incidence of heart disease is affected by age and gender.

Back 57

1. the general increase in heart disease with age ;
2. more 18-44 year old females develop heart disease than males ;
3. in all other age groups more males have heart disease than
females ;
4. greatest difference between females and males in the group 65 – 74 ;
5. credit manipulation of figures ;

Front 58

explain the term correlation

Back 58

when one variable changes there is also a change in an
accompanying variable

Front 59

describe the evidence shown in this graph that suggests there is a correlation between cigarette smoking and the number of deaths from lung cancer.

Back 59

1. the shape of the two graphs is similar / change in
number of deaths from lung cancer similar to change in
number of cigarettes smoked
2. the changes in number of deaths is approximately
the same number of years after the changes in cigarette
smoking ;

Front 60

give additional pieces of information that would increase the validity of any conclusions made from this study

Back 60

1, sample size: number of people in survey,
2, location: where the survey was carried out,
3, variables: occupation,their family medical history, age, did they smoke,information on lifestyle;

Front 61

use your knowledge of the structure of the lung and its adaptations for gas exchange to explain why a person with emphysema has problems with gas exchange.

Back 61

1. reduced diffusion of gases ;
2. this results in less / slower exchange of gases ;
3. decrease in surface area of alveoli;
4. destruction of capillaries results in less surface area of
capillaries;
5. also less blood flow;
6. less oxygen carried by blood;
7. effect on concentration gradient ;

Front 62

draw a diagram of amoni acid

Back 62

R
H2N C COOH
H

Front 63

how enzyme reaction takes place?

Back 63

1. formation of enzyme – substrate complex ;
2. substrate binds with active site of enzyme;
3. bonds being broken / bonds made / induced fit
/ lowers activation energy;
4. adding the OH group to the phenylalanine R group ;
5. product released from enzyme active site ;
6. as product no longer binds to active site ;

Front 64

describe how somatic gene therapy may have been carried out to treat phenylketonuria in these mice

Back 64

1. use of normal alleles / gene;
2. coding for enzyme;
3. introduction of allele / DNA / gene into target cells ;
4. into DNA / chromosome / nucleus ;
5. use of vector to introduce gene into cells;
6. named vector e.g. virus, liposomes ;
7. mode of delivery of vector e.g. nebuliser, spray , injection ;

Front 65

suggest what treatment the control group of mice may have been given in this investigation

Back 65

water / saline / virus (only) / (empty) liposomes / vector (only) / use of placebo

Front 66

explain the advantages of glycogen as an energy storage molecule in the human body

Back 66

1, large molecule(therefore cannot pass out of cells), made up of many monomers and compact structure allows storage of large amounts of energy in a cell
2, insoluble therefore does not have an osmotic effect
3, inert so not affected by other reactions in cells
4, can be hydrolysed to release large amounts of energy and glucose when required

Front 67

suggest how the data shown in the graphs do not fully support this hypothesis.

Back 67

there is conflicting evidence, italy has high BP but low death rates.

Front 68

suggest and explain the advice a doctor might provide to a person with a BMI value of over 40.

Back 68

1, increase level of exercise
2, which increases metabolic rate/uses more energy
3, which increases weight loss
4, change in diet
5, decrease saturated fat intake
6, therefore reducing blood cholesterol level
7, low carbohydrate diet/reduce alcohol intake/reduce sugars in diet
8, to restrict calorie intake
9, to reduce risk of type 2 diabetes
10, lowers blood pressure
11, reduces risk of cardiovascular disease

Front 69

name the part of the cell where RNA nucleotides are combined to form strands of mRNA

Back 69

nucleus

Front 70

in one body cell, a mutation occurs that changes the third base, cytosine, into guanine in this sequence of mRNA. (it became a stop signal), describe and suggest the potential effect this mutation could have on the protein (RNA polymerase) produced.

Back 70

1, change in amino acid sequence/primary structure of the protein
2, Tyr replaced by a stop codon/UAG
3, polypeptide chain/protein would be shorter
4, protein would have a different shape/structure/fold differently
5, protein would not function normally
6, RNA polymerase not functioning would mean that no/less transcription wuold take place
7, no/less RNA could be synthesised by this cell
8, no/fewer proteins could be made by this cell

Front 71

CF is caused by a mutaion in a gene coding for a membrane protein. explain why people suffering from CF find it difficult to digest their food.

Back 71

1, CFTR protein defective
2, chloride ions remain in cells
3, mucus lacks water/is very sticky
4, mucus blocks pancreatic duct
5, fewer enzymes released into the small intestine
6, lower concentration of enzymes / fewer active sites
7, fewer collisions between substrate and the active site of the enzymes

Front 72

explain how gene therapy could enable cells lining the lung to function normally in CF suffers.

Back 72

1, use vector to inject functional gene codes for CFTR protein in cell membrane
2, CFTR protein allows chloride ions to leave the cell and sodium ions diffuse out of cells
3, lowers water potential in the lumen/airways and draws water out of the cells by osmosis
4, thus mucus is kept runny

Front 73

using the information in the graph, describe what the results of this trial show.

Back 73

1. control / no treatment / placebo results in mean increase in volume of plaque;
2. drug / treatment causes a decrease in plaque volume
3. 70 mm3 difference in means;
4. the error bars show plaque
increased in some and decreased in others ;
5. length of error bars show the
change in plaque size was more varied in the treatment group e.g treatment group
has a greater range of data ;

Front 74

suggest reasons why the results of this trial do not indicate that this drug could be useful in treating patients with atherosclerosis.

Back 74

1. small sample size e.g. only 20 in each group, only 40 people tested in
total, not enough data ;
2. there is no indication of
statistical significance / the error bars overlap ;
3. 2 months is a very short period of time ;
4. there is no evidence that the
reduction in volume is permanent ;
5. other variables not taken into account ;

Front 75

location of semilunar valves and function?

Back 75

1. base of aorta ;
2. prevents backflow of blood into heart / ventricles during diastole / atrial systole ;

Front 76

location of elastic fibres and function?

Back 76

1. middle layer of wall of vessel / in the muscle layer ;
2. allows stretching / recoil / description;
3. to prevent damage of the aorta to maintain the pressure of the blood

Front 77

in each DNA strand, the mononucleotides are held together by ? bonds?

Back 77

phosphodiester/phosphoester/covalent

Front 78

give reason why many animals have a circulatory system?

Back 78

it overcomes limitations of diffusion / it is
involved in transport / heat transfer

Front 79

explain why a mammalian heart is divided into a right side and a left side?

Back 79

1. it keeps oxygenated and
deoxygenated blood separate ;
2. this results in as much oxygen as possible being carried to the tissues / cells
3. different pressures in each side / need for different pressures explained ;

Front 80

using the information given above and your knowledge of gene mutation, suggest why a person with beta thalassaemia has symptoms of anaemia

Back 80

1. mutation causing
different base sequence ;
2. different sequence of amino
acids / primary structure ;
3. β chain / haemoglobin /
protein / polypeptide being the wrong shape
4. haemoglobin no longer binds oxygen / binds
less oxygen ;
5. less / no oxygen supplied to the cells;
6. respiration;
7. breathlessness due to body trying to take in more oxygen ;
8. tiredness due to lack of energy ;

Front 81

how gene therapy could be carried out to treat thalassaemia?

Back 81

1. use of normal / correct allele
/ gene;
2. for haemoglobin / β chain;
3. introduction of gene / allele/
DNA into cells ;
4. cells named as bone marrow ;
5. use of vector to introduce gene into cells;
6. named vector e.g. virus, liposome ;
7. appropriate mode of
delivery of vector e.g. injection into bone marrow ;
8. need for repeated treatment ;

Front 82

describe an experiment you have carried out to investigate the permeability of cell membranes

Back 82

1. beetroot ;
2. washing beetroot thoroughly;
3. waterbath to maintain temperature;
4. range / at least 5 temperatures / alcohol concentrations;
5. appropriate controlled variable named e.g.
length of time, size of beetroot ;
6. indication of what is being used to judge
permeability colour of solution,
absorbance, transmission ;
7. description of how permeability can be
assessed e.g. use of colorimeter, standard
solutions ;
8. repeats / replicates ;

Front 83

use your knowledge of the structure and properties of cell membranes to explain the results of this investigation

Back 83

1. phospholipid bilayer ;
2. hydrophobic nature of bilayer / tails;
3. non-polar molecules / molecules that have high solubility in oil compared with water will pass through the membrane more readily
OR
idea that polar molecules / molecules with low solubility in oil relative to water will pass
through less readily ;
4. permeability linked to readiness to dissolve ;
5. fluidity / movement of
phospholipids ;

Front 84

describe its structure of omega 3

Back 84

1. COOH/ carboxylic/ acid}
grouping at one end ;
2. long hydro carbon chain;
3. 18 carbons / 17 carbons in hydrocarbon chain;
4. polyunsaturated ;
5. 3 carbon-carbon double bonds / 4 double bonds ;
6. kinked structure;

Front 85

give one difference between the structure of omega 3 and omega 6

Back 85

1. omega 3 has 3 carbon-carbon double bonds /
4 double bonds, omega 6 has 2 / 3 ;
2. omega 3 has less hydrogens;
3. omega 3 is kinkier / shorter ;
4. omega 3 less saturated;

Front 86

dietary factors that increase the risk of CVD?

Back 86

1) high salt / sodium
2) high cholesterol
3) high saturated fat / high trans-fat
4) high calories
5) high alcohol
6) low fibre / low NSP
7) low antioxidants / low vitamin C / low vitamin E ;

Front 87

risk of antihypertensives?

Back 87

blood pressure falls too low / coughs / swelling of
ankles / impotence / tiredness / constipation /
headache / confusion / depression / excessively
low heart rate / allergy / stroke / provoked type II
diabetes / frequent urination / fainting / dizziness
/ vomiting / dry mouth / breathing difficulties /
irregular heart rate / chest pain / hives / rash /
dehydration / reduced circulation effects / low
potassium / blurred vision

Front 88

primary structure?

Back 88

1. sequence of amino acids ;
2. joined by peptide bonds ;

Front 89

explain the importance of the primary strcture of an enzyme to its function

Back 89

1. primary structure determines 3D folding;
2. types of amino acids determine types of bonds, either disulphide bridge, hydrogen bond or ionic bond
3. position of amino acids determines position of bonds
4. two cys amino acids form bonds ;
5. shape of active site is determined by position of amino acids ;
6. shape of active site being
correct to bind to substrate ;
7. amino acids / R groups
involved in chemical reaction;
8. globular/ soluble / enzyme molecules being relatively short /small / made up of relatively few amino acids ;
9. globular / soluble proteins/
enzyme having relatively high number of polar / small amino acids / R groups;
10. polar R groups facing
outwards ;

Front 90

mRNA?

Back 90

1, mRNA as a copy of the genetic code / DNA ;
2. of the protein being synthesized;
3. moves out of the nucleus to ribosomes
4. it acts as a template / has the instructions for translation ;

Front 91

tRNA?

Back 91

1, translation ;
2. binds to an amino acid / takes the amino acid
to the ribosome / mRNA ;
3. tRNA being specific to amino acid ;
4. holds the amino acid in place

Front 92

the bond between a phosphate and suger is?

Back 92

phosphodiester bond

Front 93

disaccharides can be split by?

Back 93

hydrolysis of glycosidic bonds

Front 94

amylose is an example of a ?

Back 94

polysaccharide

Front 95

the role of starch is?

Back 95

store energy in plants

Front 96

proteins are polymers of amino acids joined by peptide bonds formed between the ?

Back 96

carboxyl group and the amino group

Front 97

the 3d structure of a protein is held together by?

Back 97

disulphide bridges, hydrogen and ionic bonds

Front 98

the ? returns deoxygenated blood back to the heart from the body?

Back 98

vena cava

Front 99

the ? carries oxygenated blood away from the left ventricle to the cells of the body

Back 99

aorta

Front 100

explain how the properties of phosphate contribute to the structure of the cell membrane

Back 100

1. hydrophilic / polar / charged
part ;
2. hydrophobic / non polar /
uncharged part ;
3. orientation of molecule in
relation to water;
4. aqueous environment is on two sides / cytoplasm and environment / tissue fluid;

Front 101

describe the role of proteins in active transport?

Back 101

1. molecule binds protein
/ carriers ;
2. protein / carrier changes shape ;
3. molecules move against a concentration gradient;
4. use of ATP / energy ;

Front 102

describe the role of proteins in facilitated diffusion?

Back 102

5. proteins as channels / gates / pores / carriers;
6. channels can open or close / carriers change shape ;
7. for large / polar / charged molecules to pass through membrane;
8. molecules move down a concentration gradient;