Topic 1: Lifestyle, Health And Risk

Question 1

Why do mammals have a heart and circulatory systems?

Answer 1

Mammals Ned a heart and circulatory system so
- essential substances such as O2 and CO2 to enter and leave the body in sufficient quantities
- to overcome the limitations of diffusion sue to a high SA:V ratio and large diffusion distance.
- high metabolic requirements.

Question 2

What are the main features of a transport system?

Answer 2

• blood vessels
• directional
• transport medium
• Maintenances of concentration gradient through separation of oxygenated and deoxygenated blood.

Question 3

Properties of water and how it relates to its function

Answer 3

Water act as a transport medium in the body as they are
- polar solvents (uneven distribution of charge)
- water is a liquid and cohesive due to formation of hydrogen bonds providing it with the ability to ‘flow’
- high specific heat capacity minimising temperature fluctuations in organisms.

Question 4

Structure of arteries and relation to their function

Answer 4

Artistries function is to carry oxygenated blood away from the heart (except pulmonary artery) they have
Small lumen > to maintain high blood pressure
Outer collagen > provides protection and prevents damage
Thick muscle layer > maintain high blood pressure through muscular contractions.
Elastic fibres > increase flexibility and allow for elastic recoil.
Endothelium lining > rescues friction and maintains high blood pressure

Question 5

Structure of veins and relation to function

Answer 5

Veins carry deoxygenated blood to the heart (except pulmonary vein) they have a
Large lumen > provide low pressure
Valves > to prevent the back flow of blood.

Question 6

Structure of capillaries and function

Answer 6

Essentially in the gas exchange system they are
1 cell thick to decrease diffusion distance
Lumen 1 cell wide > allowing blood to be oxygenated
High abundance > increase blood flow

Question 7

Cardiac diastole

Answer 7

This is when all chambers of the heart are relaxed and pressure inside the heart decreases. Semilunar valves close to prevent the back flow into the Ventricles.

Question 8

Atrial systole

Answer 8

Atria contracts forcing the atrioventricular valves to open causing blood to flow into ventricles.
Pressure in the ventricles increase.

Question 9

Ventricular systole

Answer 9

Ventricles contract causing the atrioventricular valves to close (preventing the back flow into the atrium) and the semilunar valves to open allowing blood to flow through the arteries.

Question 10

Structure of the heart

Answer 10

The heart is made up of four separate chambers two atria located at the top of the heart and two ventricles and the bottom of the heart.
Vena cave > carries deoxygenated blood to the heart
Pulmonary artery > carries de-oxygenated blood to the lungs
Pulmonary Vein > carries oxygenated blood to the heart
Aorta > carries oxygenated blood to the body cells
Atrioventricular valve > prevent back flow into the atria
Semilunar valve > prevent back flow into the ventricles
Tendons > prevent inversion of valves
Septum > separates oxygenated and deoxygenated blood
Coronary arteries > supply’s oxygen to the cardiac muscle
Cardiac muscles > maintain as blood pressure through muscular contractions.

Question 11

Development of atherosclerosis

Answer 11

1. Endothelium wall damaged (high blood pressure or toxins for cigarettes)
2. An inflammatory response starts and white blood cells leave the blood and move into the artery wall.
3. These cells accumulate chemicals from the blood (cholesterol) creating a fatty deposit called an atheroma.
4. A plaque forms when the white blood cells, cholesterol, calcium and salt hardens.
5. Plaques narrow the lumen of the artery to become narrower, increasing blood pressure and starting a positive feedback.

Question 12

Blood clotting cascade

Answer 12

1. Blood vessels becomes damaged
2. Platelets attach to expose collagen fibres.
3. Platelets release thromboplastins
4. Thromoplastins activates and enzyme that catalyses the conversion of the protein prothrombin into thrombin.
5. Thrombin then catalyses the conversion of fibrinogen into fibrin.
6. Fibrin form an insoluble mesh of fibres over the damaged artery trapping platelets, red blood cells and debris creating a blood clot.

Question 13

Factors that increase the risk of cardiovascular disease

Answer 13

Genetics > e.g. a genetic predisposition to high blood pressure
Age > arteries become less elastic due to age
Diet high in cholesterol or salts > Increases risk of endothelium damage and atherosclerosis
Smoking > nicotine narrows the arteries rising blood pressure increasing blood pressure. Realises adrenaline raising blood pressure.
Alcohol consumption > increases blood pressure increases risk of endothelium damage and atherosclerosis.
Physical inactivity > results in obesity
Obesity > increase blood pressure

Question 14

Features of a good epidemiological study

Answer 14

• Clear aim
• large and representative sample (no selection bias)
• long time period
• valid and reliables results (does the yield accurate results)

Question 15

What is risk?

Answer 15

Risk is the definition as the chance or probability that a harmful event will occur. The statistical chance of a risk taking place needs to be supported by scientific evidence gained form research.

Question 16

Perceptions of risk and why

Answer 16

Risk can be overestimated because of
- misleading information - unfamiliarity with the event
- personal experience of an event
- the event causing severe harm
Risk can be underestimated
- lack of information
- misunderstanding of factors causing risk
- harm being non-immediate

Question 17

What is the the energy budget?

Answer 17

It is the amount of energy taken in by an organism minus the amount of energy the organism transfers during life processes.
Energy input - energy output = energy budget

Question 18

Energy balance

Answer 18

The difference between caloric intake and caloric output.
If input is greater then output = excess energy is stored as fat/glycogen leading to weight gain.
If output is greater than input = Fat/glycogen used in respiration to fulfil energy requirements resulting in weight loss.

Question 19

Monosaccharides

Answer 19

Simple sugars such as glucose, fructose and galactose that monomer units.
They monosaccharides join together in a condensation reaction to form a polysaccharides chains held together by 1,4 and 1,6 glycosidic bonds.
C - - O
H / I \ H
\ / H \ /
C C
/ \ OH H / \
HO \ I I / OH
C - - C

Question 20

Disaccharide

Answer 20

A disaccharide is formed when two monosaccharides join together in a condensation reaction (releasing a molecule of water), held together by glycosidic bonds.
Common examples are
Maltose > two molecules of glucose found in germinating seeds
Lactose > glucose and galactose, found in human diets and found in milk
Sucrose > glucose and fructose, form of sugar found in plants.
H H
/ \
C C
\ /
O

Question 21

Function of disaccharides

Answer 21

They priced the body with a quick release energy source as they are only made up of two monosaccharide they are easily broken down by enzymes and hydrolysed.

Question 22

Structure of a polysaccharide

Answer 22

Polysaccharide are repeat chains of many monosaccharides joined together by glycosidic bonds in a condensation reaction. They may branched (break down faster) or unbranched (more suitable for cellular structures as compact and easy to store).
Examples include starch, glycogen and cellulose.

Question 23

What is starch?

Answer 23

Starch is the storage polysaccharide of plants. They are insoluble. There are two types amylose and amylopectin.

Question 24

What is the structure of amylose?

Answer 24

Unbranched helix shaped chain with 1,4 glycosidic bonds between A-glucose molecules.
The helix shape enables it to be more compact and thus maximising energy storage.

Question 25

What is the structure of amylopectin?

Answer 25

A branched molecule containing 1,4 and 1,y glycosidic bonds between a-glucose molecules.
The branching makes it easily hydrolysed for use during cellular respiration.

Question 26

What is glycogen?

Answer 26

Glycogen is a storage polysaccharide for animals and fungi. It is insoluble and highly branched polysaccharide held to together by 1,4 and 1,6 glycosidic bonds.
The branched stature means it can be easily hydrolysed and has a coil structure maximising storage.

Question 27

What are the properties of lipids?

What are the roles of lipids?

Answer 27

Lipids are macromolecules that contain carbon, hydrogen and oxygen.
- They are non-polar and hydrophobic (insoluble in water).
- compact and high energy
- conduct heat slowly
They play an important role in energy yield, energy storage, insulation and hormonal communication.

Question 28

What are saturated lipids?

Answer 28

Contain no carbon - carbon doubles bonds, meaning the form unbranched linear chains.
Contain more energy as they have stinger intermolecular forces and have a higher melting point.

Question 29

What are unsaturated lipids?

Answer 29

Contain carbon - carbon double bonds meaning they form branched and have weaker intermolecular forces meaning a lower melting point and contain less energy.

Question 30

What is the structure of a triglyceride?

Answer 30

A types of lipids comprised of one molecule of glycerol and three fatty acid jointed by a condensation reaction held together by ester bonds. They can be broken down by a hydrolysis reaction.

Question 31

What is cholesterol?

Answer 31

A soluble lipid made in the body That is transported as two types of of lipoproteins, high density lipoproteins (HDL) and low density lipoprotein (LDLJ.

Question 32

What are HDLs?

Answer 32

These are considered ‘good’, and consist of unsaturated fats.
They transport cholesterol from the body tissues to the liver to be broken down. Thai is turn reduced blood cholesterol levels.

Question 33

LDLs

Answer 33

LDLs contain saturated fat, they are considered ‘bad cholesterol’. There role in to transport cholesterol from the liver into the bloodstream increase blood cholesterol.
LDLs bind to cell receptors on the cell surface member and enabling them to be taken up by the cells. An excess on LDLs results in a blockage of these membrane receptors causing blood cholesterol to rise.

Question 34

What is the body mass index (BMI)?

Answer 34

BMI = Weight (KG) / height (m2).
This number can then be co:oared to a chart to indicate if an individual underweight, overweight of obese.

Question 35

Waist to hip ratio

Answer 35

Measures distribution of fat in the body. It the circumference of the waist in cm divided by the circumference of the hips in cm.

Question 36

How can CVD risk be reduced?

Answer 36

• dietary changes to consume less unsaturated fats and salts
• stop smoking
• regular exercise
• reduce drinking

Question 37

Benefits and risks of Statins

Answer 37

+ Lower blood cholesterol by blocking the enzyme that produces LDLs. Reduces the risk of endothelium damage and atherosclerosis
- Can cause nausea and vomiting

Question 38

Benefits and risks of anti hypertensives

Answer 38

+ Reduces blood pressure refusing risk if endothelium damage by blissing the r,ease of adrenaline and reduce strength of heart contractions.
- cause dizziness, vomiting and nausea and light head ness if blood pressure drops to low.

Question 39

Benefits and risks of anti-coagulants

Answer 39

+ Reduces blood clot formation but blocking the synthesis of clotting factors and relates of vit K.
- dizziness , vomiting and irritation of the stomach lining leading to un controllable internal bleeding.

Question 40

Benefits and risks of platelet inhibitors

Answer 40

+ Reduces blot clot formation by making platelets less sticky.
- nausea, vomiting, dizziness, damage to stomach lining leading to uncontrollable internal bleeding.

Question 41

What are the control, independent and dependent variables in the daphnia practice?

Answer 41

Control > volume of caffeine solution, time spend in caffeine solution and size of the daphnia
Independent > concentration of caffeine solution
Dependent > Beats per minutes of the daphnia

Question 42

Method of the daphnia practice

Answer 42

1. Make 5 dilutions of caffeine solution as will different concentrations.
2. Place cotton wool on slide to restrict daphnia movement.
3. Add a daphnia
4. Use paper to absorb excess water and leave daphnia to acclimatise for 5 minutes.
5. Observe and counts BPM using a counting app on phone.
6. And the fist caffeinated solution, leave to acclimatise and record BPM.
7. Repeat with other caffeine concentrations.

Question 43

Why use daphnia for code prac 1?

Answer 43

• visible hearts
• can absorb chemicals from a surrounding solution quickly
• can’t feel pain due to undeveloped nervous system
• there are invertebrate and so high abundance.

Question 44

What are the control, independent and dependent variables for Vitamin C practical?

Answer 44

Control > volume of DCPIP solution, concentration of DCPIP, age of food.
Independent > type of food
Dependent > volume of juice required to decolorisation DCPIP.

Question 45

Method of measuring the Vitamin C content of drink?

Answer 45

1. Add 1cm3 of a known concentration of DCPIP to a convivial flask.
2. Fill a burette with the juice and record volume.
3. Add juice drop by drop shots continuously stirring and DCPIP has turned from blue to colourless.
4. Record ending volumes and calculate volume of juice used to decolourise DCPIP.
5. Record Ona calibration curve.
6. Repeat with other food types and juices.