Bio topic 1 PPQ wrong

Explain why a mammal born with a hole in their heart will be easily tired due to lack of energy (3)

• Less oxygen available for aerobic respiration 

• Deoxygenated blood mixes with oxygenated blood 

• Therefore reducing concentration of oxygen in blood circulating the body 

• Because some deoxygenated blood does not leave the right ventricle/ is transferred to left ventricle/does not go to lungs/ goes to repairing tissue

Diet is one factor that affects the development of CVD. Explain how the diet of a person could affect the development of CVD. (4)

• higher salt intake

• increases blood pressure

• high blood pressure causes damage to endothelium (of artery)

• high intake of cholesterol/saturated fat

• high (LDL’s/saturated fat) linked to (athreoma/plaque formation)

Calculate heart rate from this graph (2)

Cardiovascular disease (CVD) is a major cause of death and disability in the UK. It has been suggested that magnesium ions are involved in regulating the ratio of HDL to LDL in the blood. (i) Describe the role of LDLs in the development of atherosclerosis. (3)

• (LDL/lipoproteins carry) cholesterol in the blood

• Cholesterol is deposited to form atheroma

• in the edothelium of an artery

Cardiovascular disease (CVD) is a major cause of death and disability in the UK. It has been suggested that magnesium ions are involved in regulating the ratio of HDL to LDL in the blood. (ii) explain how astherocsclerosis can cause damage to heart muscle (3)

• Narrowing of (lumen of ) coronary artereis

• reduces blood flow/oxygen to the cardiac muscle

• which reduces aerobic respiration

Thrombophilia is a condition that increases the risk of blood clots forming. This condition increases the risk of venous thromboembolism (VTE), a condition where a blood clot forms in a vein. Thrombophilia due to the production of overactive factor V can be inherited. Factor V is involved in the conversion of prothrombin to thrombin. (i) Describe the role of thrombin in blood clotting (3)

• thrombin is an enzyme

• which catalyses the conversion of fibrinogen into fibrin

• a mesh of fibrin traps platelets/red blood cells to form a clot

Thrombophilia is a condition that increases the risk of blood clots forming. This condition increases the risk of venous thromboembolism (VTE), a condition where a blood clot forms in a vein. Thrombophilia due to the production of overactive factor V can be inherited. Factor V is involved in the conversion of prothrombin to thrombin. (i) Explain why a mutation in the gene coding for the protein factor V may increase the risk of VTE (3)

• mutation in the gene changes the sequence of the amino acids in the factor V molecule

• Overactive factor V will increase the production of thrombin

• increases blood clotting

An ischaemic stroke occurs when a blood vessel in the brain is blocked by a blood clot. Explain how a blood clot could form in a blood vessel. (4)

• collagen is exposed when a wall of blood vessel is damaged

• leading to the release of thromboplastin

• thromboplastin catalyses conversion of prothrombin to thrombin

• thrombin catalyses conversion of fibrinogen to fibrin

• fibrin forms a mesh of fibres and traps red blood cells to form a clot

• fibrin forms a mesh that collects platelets/ RBCs

• Tranexamic acid prevents plasmin digesting fibrin/ stops breakdown of fibrin

• allowing clots to remain in place

Describe how very high blood pressure could result in atherosclerosis.

• high blood pressure damages endothelium of artery

• causing an inflammatory response

• white blood cells/cholesterol accumulate/atheroma forms

• calcium salts and fibrous tissue build up/ formation of a plaque

What is an anticoagulent?

Medication that prevents blood clots

A heart attack may occur when a coronary artery is blocked with a blood clot. The risk of this can be reduced by treatment with platelet inhibitors. Explain why platelet inhibitors would reduce the risk of a heart attack. (2)

• platelet inhibitors reduce the risk of blood clots forming

• therefore less likely that coronary arteries/ blood flow to heart muscle will be blocked

What are the 2 methods for determining is a person is obese?

• If BMI is over 30

• Waist to hip ratio

Describe how high blood pressure could be reduced by medication and lifestyle changes.

• treatment with antihypertensive medication

• reduce salt intake

• stop smoking

• increase excercise

• reduce weight

Explain the effect that a diet high in salt could have on a person's risk of developing cardiovascular disease (5)

• diet high in salt increases risk of CVD

• high salt intake causes higher blood pressure

• which increases risk of damage to endothelium of artery/ atherosclerossi

• therefore increases risk inflammatory response

• leading to increased risk of atheroma/plaque formation

• narrowing of arteries increases risk of blood pressure/ reduces blood flow to cardiac muscle

27.7%, 28%

• Increasing number of months of breastfeeding decreases the percentage of children with obesity

• There is a large drop in obesity when children are breastfed for (3-5 months/ more than 2 months)

• equal number of males and females

• larger sample size

• name a suitable controlled variable e.g. same starting blood pressure/ body mass/ diet/ exercise level

The incidence of obesity is increasing in some populations. High levels of sugars, such as fructose, in processed food could be contributing to this increase. Explain why high levels of sugars in a person's diet could lead to obesity

• energy intake is higher than energy output

• excess energy/sugars can be stored as/ converted to fat

• leading to weight gain (greater than overweight)

• obesity is indicated by a BMI above 30/ waist to hip ratio greater than 0.85 in women or 1 in men)

• as heart rate increases, so does incidence of both conditions

• relationship between heart rate and CHD quantified

• relationship between heart rate and cancer quantified

• greater increase in incidence of cancer with increased heart rate

• at a heart rate >99bpm there is a reduction in incidence pf both conditions/plateaus/little difference

Give two reasons why there were different numbers of people in each resting heart rate group.

• mid heart beat is more common in the general population/heart rate is normally distributed in the population

• fewer people available at low and high rate because of other health risks

Give two reasons why the number of people in each resting heart rate group did not affect the validity of this investigation.

• still statistically a large sample size

• wide range of heart rate considered

• percentage incidence used rather than numbers

• blood test to measure (HDL and LDL/ cholesterol) levels

• higher HDL:LDL decreases risk/high cholesterol increases risk

• measurement of (height and mass/ waist and hip size)/ calculation of (BMI/wait:hip)

• (BMI above 30/ waist:hip above 1) increases risk

• correlation between the number of risk factors and deaths due to CVD

• deaths due to CVD is higher for diabetics than non-diabetics

• Increased thrombin production as CVX concentration increases

• The relationship between CVX concentration and rate of thrombin production is not (directly proportional/linear)

• Little difference between control and 0.5ngcm^-3 (CVX)/greatet increase from 5ngcm^-3 to 50ngcm^-3

• no significant difference/standard deviations overlap between control and 0.5

• greater thrombin production leads to faster/increased conversion of firinogen to fibrin

• greater thrombin production leads to faster/increased clotting of blood

On the graph, draw a line to show the effect of halving the concentration of thrombin

Explain the effect of changes in the initial rate of reaction on the time taken for a blood clot to form

• the slower the initial rate of reaction the longer it will take for a clot to form

• because fibrin will be produced more slowly

• fibrinogen concentration is higher in individuals with CVD

• compare an individual’s fibrinogen concentration with values in the table

• no overlap between fibrinogen concentrations for those with CVD compared with those without CVD

Explain the results of the investigation (6)

Lipids and carbohydrates are found in both plants and animals. The carbohydrate content of vegetables ranges from 3 to 35%. However, meat contains little to no carbohydrate. Milk is the only food source from animals that contains a significant amount of carbohydrate. Although plant material contains a higher proportion of carbohydrate than animal tissues, it has been claimed that carbohydrates are more important to animals than they are to plants. Assess the relative importance of carbohydrates to plants and animals. (9)

Explain how the structure of glycogen allows it to be an energy store. (3)

• polymer of glucose

• to provide glucose for respiration

• branched/contains 1,6 glycosidic bonds/ has many terminal ends for rapid hydrolysis

• compact to allow large amount of glucose/energy to be stored in a small space/insoluble therefore no osmotic effect on cells

Explain how the structures of amylopectin and glycogen make them suitable for storing energy.

• branched therefore can be rapidly hydrolysed (to release glucose)

• compact so more energy/glucose can be stored

• insoluble therefore does not affect osmosis

• molecules too large to diffuse across cell surface membrane

• increases blood cholesterol

• because triglyceride is saturated

• lipoprotein is an LDL

• lipoproteins transport cholesterol

• LDL binds to receptors on cell surface membranes/ LDL accumulates in blood if receptors overloaded

Name them

Monosaccharides join to form disaccharides and polysaccharides. Compare and contrast the structure of a disaccharide with glycogen.

similarities

• both contain carbon, hydrogen and oxygen

• both contain glycosidic bonds

• both contain glucose

Differences

• glycogen contains 1,4 and 1,6 glycosidic bonds whereas disaccharides only contain one type of glycosidic bond

• glycogen only contains glucose whereas disaccharides can contain glucose and other monosaccharides

Mucopolysaccharides are complex molecules found in the human body. Mucopolysaccharides can be broken down by enzymes. Describe how an enzyme could break down the polysaccharide component of mucopolysaccharides.

• polysaccharide made up of many monosaccharide components

• joined together by condensation reactions/glycosidic bonds

• only 1,4 glycosidic bonds present/ no 1,6 glycosidic bonds present

Blood plasma contains glucose dissolved in water. Glucose is a polar molecule that is taken up by muscle cells and used in the synthesis of glycogen. Glucose is used in the synthesis of glycogen in muscle cells. (i) Describe the formation of glycogen from glucose.

• joined together in a condensation reaction

• forming 1,4 and 1,6 glycosidic bonds

Describe how the structure of glycogen is related to its function as a storage molecule

• branched molecule for more rapid hydrolysis

• compact so more can be stored

Sweating is a thermoregulatory mechanism. A student stated that loss of heat when sweating is related to the dipole nature of water molecules. Justify this statement. (3)

• the water has an uneven distribution of charge (making it a dipole)

• so water forms hydrogen bonds with other water molecules

• and it requires a lot of heat/thermal energy to break these bonds

• and allow water to evaporate taking the heat energy with it high latent heat of evaporation

Explain how the properties of water make it an ideal transport medium.

• water is a solvent

• because water molecules surround polar molecules/ion/hydrogen bonds form between water molecules and solute molecules

• water is liquid so has the ability to flow

• both have a double/closed circulatory system

• both have 2 atria, arteries, veins and capillaries

• Snake heart has only one ventricle whereas human heart has 2/snake heart does not have a complete septum/wall between the ventricles/sides of heart whereas human heart does

• In snake heart the oxygenated and deoxygenated blood mix (in the ventricle) whereas they do not mix in a human heart

Explain why a snake needs a heart (2)

• to pump blood to supply oxygen/glucose to body cells/to remove carbon dioxide/waste from the body

• by mass transport

• because a small surface area to volume ratio does not allow diffusion to occur at a sufficient rate

• both have the same volume

• animal a has a larger surface area

• animal a has a larger surface area to volume ratio

• so sufficient surface area in animal a for diffusion

• distance to cells in centre of a is shorter than for b allowing quicker/sufficient diffusion/shorter diffusion distance

What would you use as a control for the daphnia experiment and why?

pond water to compare with the caffeine solutions/to show normal/resting heart rate

What are two variables that should be controlled for the daphnia practical?

• temperature of solution/ acclimatisation time - b/c e.g. cold temp decreases heart rate

• same sex/size/age of ghost shrimp

• so caffeine would affect ghost shrimp equally/to produce more valid results

IGNORE SPECIES

11.3/11.32%

Problem with blood vessels

The baby survived because of the hole in the septum of the heart. Explain how the hole in the septum allowed this baby to survive.

• the hole allows oxygenated and deoxygenated blood to mix (between the 2 ventricles)

• oxygenated blood travels to the body/enters aorta/dexoygenated blood travels to the lungs/enters pulmonary artery

• providing some oxygen for respiration

Comment on the effects of dopamine alone and dopamine with caffeine on the heart rate of Daphnia in this investigation.

• adding caffeine to dopamine increases heart rate

• adding/increasing the concentration of dopamine increases heart rate

• larger increase when both are used together at a higher concentration

• no overlap between error bars indicates significant difference between dopamine and dopamine with caffeine/overlap between error bars indicates no significant difference between dopamine concentrations

Devise a procedure that could have been used to produce the results shown in the graph. (5)

• daphnia immobilised on cavity slide

• acclimatisation time in (control/dopamine/dopamine and caffeine) solution

• use of cocentration from graph

• suitable method for counting and recording heart rate

• use daphnia of same (species/age/sex/size)

• repeats and calculation of mean/standard deviation

As levels of activity increase, the heart can respond to the changing demand for oxygen. During the cardiac cycle there are pressure changes in the chambers of the heart. Explain how pressure differences in the heart ensure efficient pumping of the blood into the arteries.

• pressure increases in the ventricles

• greater pressure in the ventricles than in the atria/arteries

• causes the atrioventricular valves to close

• causing the semilunar valves to open/forcing blood into the arteries

validating statement:

• investigation involved rats inhaling nicotine which humans do during smoking

• rats are mammals so can extrapolate to humans

Not validating the statement

• nicotine inhaled (for both conc) leads to vasocontriction and then vasodilation and then returns to original diameter

• blood pressure for 1mg nicotine concentration increases and decreases but drops below original value

• presence of nicotine leads to no adrenaline release which increases heart rate

• blood pressure for both nicotine concentrations increases and decreases

• no referenece to rats inhaling smoke only nicotine

• rats are not the same as humans

• sample size is too small to make a valid statment

comment whether you agree or disagree with statement

Atrial systole

In graph A, the blood pressure inside the ventricle changes between 0.0 and 0.45 seconds. Explain how these changes in blood pressure occur in this part of the cardiac cycle. (4)

• from 0s (to 0.05s) pressure increases due to atrial systole

• ventricle fills with blood (from the atrium/due to atrial systole

• after atrial systole finishes (from 0.05s to 0.1s) there is a fall in ventricular pressure

• from 0.1s to (0.32s) there is an increase in pressure due to ventricular systole

• (from 0.32) ventricular pressure decreases due to ventricular diastole

Explain the term causal relationship (1)

The idea that a change in one variable will directly result in the change of another variable

Lipoproteins are composed of phospholipids, cholesterol and proteins. (i) Proteins are made up of amino acids. Describe how amino acids join together to form the three-dimensional structure of a protein. (4)

• reference to peptide bonds (joining amino acids)

• between amino group (of one amino acid) and carboxyl group (of another)

• the sequence of amino acids is the primary structure of the protein

• reference to folding (of primary structure) held together by bonds

• disulfide bridges/ hydrogen bonds / ionic bonds / Van Der Waals forces

• between the R groups

• high blood pressure has fallen overall

• high blood cholesterol has fallen overall

• obesity has risen overall

• obesity was the lowest risk factor but is now the highest

• credit use of manipulated figures (ONLY CREDIT OVERALL CHANGE FIGURES)

Other than obesity, high blood pressure and high blood cholesterol what are the factors which increase the risks of CVD?

• being male

• increase in age

• lack of exercise / inactivity

• smoking

• genetics

• high alcohol consumption

• high salt diet

• high saturated fat intake

• stress

• diabetes

Describe how glucose moves into cells by facilitated diffusion (2)

• carrier protein (in cell surface membrane)

• (glucose moves from) high to low concentration

• glucose binds to (carrier) protein / (Carrier) protein changes shape to move glucose (across the membrane)

Draw a diagram to show the molecules produced when two molecules of R join together during a condensation reaction.

(i)

• idea that on;y one factor has changed

• if intake went up, increase risk obesity a risk factor / if intake went down could decrease CHD risk

(ii)

• both diets decrease the risk

• both diets have less saturated fats

• saturated fat associated with heart disease

• idea that changing to unsaturated lipids has the greater effect

• idea that excess carbohydrates may be stored as saturated lipids

• idea that unsaturated lipids change HDL/LDL ratio

Explain how the structure of the aorta relates to its function (3)

• idea that there is a thick wall / lots of collagen / thick layers / thick tunica media

• idea that it needs to avoid rupture / to withstand high pressure

• elastic / muscular / layer / fibres / wall

• control flow of blood / maintain blood pressure / elastic recoil

• smooth endothelial wall

• to reduce friction / resistance

• semi lunar valave present

• to prevent backflow (during diastole)

• large lumen

• idea of accommodating large volumes of blood

• branches

• to supply blood to different parts of the body including the coronary arteries

A stroke can be caused by cardiovascular disease (CVD) affecting arteries leading to the brain. Callum's family has a history of strokes. (i) Explain why a blood clot in an artery leading to the brain could cause a stroke. (3)

• idea of reduced blood flow / bleeding

• less / no oxygen / glucose reaches brain

• idea of less / no areabic respiration

• idea of less / no ATP produced

• idea that brain needs lots of energy / ATP to function

• lactic acid produced from anaerobic respiration

• lactic acid inhibits enzymes / toxic

Some foods and drinks contain plant statins. Explain the benefits of plant statins to human health (2)

• lower blood cholesterol

• idea of inhibition of cholesterol synthesis in liver

• reduce risk of CVD

Explain how the dipolar nature of water is essential for living organisms (2)

• water can form hydrogen bonds

Any one from

• water is a solvent / ions / polar molecules can dissolve / be transported / in water

• reference to cohesion / adhesion

• idea of hydrogen bonds holding water together as a liquid so that it can move in mass flow systems

• suitable reference to specific heat capacity

• idea of distribution of thermal energy around body

• reference to high latent heat of vaporisation

Explain why any small animals such as daphnia have a heart (3)

• reference to mass flow

• name a suitable substance transported e.g. oxygen

• comment on blood pressure / fast movement of blood to cells

• idea of increased concentration gradient of solutes e.g. oxygen

• idea that diffusion alone would be too slow

• has high metabolic rate

Explain why the atrioventricular valves need to close (2)

• ventricle needs to contract and force blood into the aorta / pulmonary artery / arteries

• so valves need to close to prevent backflow into the atria on contraction

Explain how the structure of an artery is related to its functions (3)

• reference to elastic fibres

• allow stretching to accommodate high pressure / allow recoil to maintain high pressure

• reference to folded endothelium

• allow stretching to accomodate higher pressure

• reference to smooth muscle

• idea that muscle can contract / exert pressure

• reference to smooth lining / endothelium

• reduce friction / resistance to blood flow

• reference to narrow lumen

• to maintain high blood pressure

• reference to collagen

• idea that it avoids rupture / damage