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A Biology A-level > T1 - Lifestyle, health, and risk > Flashcards

T1 - Lifestyle, health, and risk Flashcards

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1
Q

Open circulatory system

A

A simple heart pumps blood between cavities. Blood circulates in open areas. Substances diffuse between blood and cells.

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2
Q

Closed circulatory system

A

Blood is enclosed within vessels, generating higher pressure. Blood travels from arteries to arterioles to capillaries and returns by venules to veins.

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3
Q

Single circulatory system

A

Carbon dioxide diffuses from blood out, oxygen diffuses into the blood.

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4
Q

Double circulatory system

A

The right ventricle pumps deoxygenated blood to the lungs, left ventricle pumps oxygenated blood round the body. Leads to a high metabolic rate.

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5
Q

What are the properties of water that make it a good transport medium?

A
  • Water is polar as hydrogen is slightly positive and oxygen is slightly negative, forming a dipole. Other polar substances can easily dissolve in water.
  • The specific heat capacity of water is very high to maintain homeostasis. Meaning that a lot of energy is required to change the temperature of the water, therefore minimising temperature fluctuations in living things.
  • Water has a high boiling point due to the hydrogen bonds.
  • Hydrogen bonding between water molecules creates cohesion and adhesion, which enables effective transport of water and dissolved substances through xylem vessels.
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6
Q

Atrial systole

A
  • Atria fill with blood from the Vena Cava/Pulmonary Vein.
  • Atrioventricular valves open because pressure in the atrias are higher than in the ventricles.
  • Blood flows into the ventricles. Atria contract.
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7
Q

Ventricular systole

A
  • Ventricles fill with blood.
  • Semi-lunar valves open due to higher pressure in ventricles than in arteries, and atrioventricular valves close
  • Ventricles contract.
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8
Q

Cardiac diastole

A
  • Low pressure.
  • Atria and ventricles relax.
  • Semi-lunar valves close.
  • Coronary arteries fill.
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9
Q

What is atherosclerosis

A
  1. The endothelium becomes damaged.
  2. There is an inflammatory response causing white blood cells to move into the artery wall.
  3. A fatty deposit (atheroma) builds up.
  4. Calcium salts and fibrous tissues build up, causing a plaque.
  5. The artery loses elasticity, narrows and hardens.
  6. Causes a rise in blood pressure and damaging endothelium more - positive feedback.
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10
Q

Consequences of atherosclerosis

A
  • Increases chance of blood clots blocking the artery.
  • Cells are permanently damaged.
  • May result in heart attack, stroke, tissue death
  • An artery may burst due to build up of blood.
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11
Q

What is the process of blood clotting

A
  • A series of cascading reactions
  • When a blood vessel is damaged, sticky platelets attach to exposed collagen fibres
  • Platelets release the protein thromboplastin.
  • This activates an enzyme which catalyses inactive prothrombin into active enzyme thrombin in the presence of vitamin K and Ca2+ ions.
  • Thrombin then catalyses soluble fibrinogen into insoluble fibrin.
  • Fibrin network traps platelets and red blood cells to form a clot.
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12
Q

Risk factors of CVD

A
  • Age
  • Heredity
  • Physical environment
  • Social environment
  • Lifestyle
  • Behavioural choices
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13
Q

What must a study have?

A
  • A clear aim
  • A representative, large sample
  • Controlled variables
  • Valid and reliable results
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14
Q

How are disaccharides formed?

A
  • Monosaccharides are joined together in a condensation reaction, producing water.
  • They are joined by a glycosidic bond.
  • They can be split by hydrolysis.
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15
Q

Formation of starch

A
  • Found in plants.
  • Starch is made up of amylose, which is an unbranched chain
  • has 1,4 glycosidic bonds and is coiled thus compact - storing lots of energy.
  • Amylopectin, branched and 1,6 and 1,4 glycosidic bonds.
  • branches allows for rapid hydrolysis quickly releasing energy
  • Starch is low solubility in water and is compact.
  • Can store lots of glucose because it is compact
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16
Q

Formation of glycogen

A
  • Made up of alpha glucose.
  • Has numerous side branches allowing rapid hydrolysis.
  • 1,4 and 1,6 glycosidic bonds.
  • large and compact meaning it can store lots of energy
  • Stored in the liver and muscles.
  • Used by bacteria, fungi and animals as an energy store.
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17
Q

Triglycerides

A
  • Insoluble in water but soluble in organic solvents.
  • Made up of a glycerol backbone and three fatty acid tails, linked by ester bonds in a condensation reaction producing three molecules of water.
18
Q

Difference between saturated and unsaturated lipids

A
  • Saturated lipids are found in animal fats. They are straight, long chains with no double bonds. Solid at room temperature.
  • Unsaturated lipids are found in plants and have double bonds, causing links in the chain, preventing it from packing closely together.
19
Q

Low-density lipoproteins LDL

A
  • Triglycerides, proteins and cholesterol combine.
  • Transports cholesterol to body cells. May be deposited in artery walls causing atheromas.
  • LDL receptors in liver determine if excess LDLs need to be broken down
20
Q

High-density lipoproteins

A
  • Triglycerides with a higher percentage of protein and a lower percentage of cholesterol.
  • Transports cholesterol from body tissue to the liver, where it can be broken down.
  • Lowers blood cholesterol levels and reduces plaques formed from atherosclerosis.
21
Q

Describe smoking as a risk factor

A
  • Carbon monoxide binds to haemoglobin instead of oxygen, reducing the supply to cells, increasing heart rate.
  • Nicotine produces adrenaline, increases heart rate, causes arteries and arterioles to constrict, raises blood pressure.
  • Chemicals in smoke damage the endothelium of arteries.
  • Linked with reduced HDL
22
Q

The benefits of exercise

A
  • Halves the risk of CHD.
  • Raises HDL cholesterol.
  • Reduces the development chance of Type 2 diabetes.
23
Q

Describe stress as a risk factor

A

Releases adrenaline, arteries and arterioles constrict, raises blood pressure.

24
Q

Describe salt as a risk factor

A

Kidneys retain water, higher fluid levels leads to higher blood pressure.

25
Q

Describe alcohol as a risk factor

A
  • Leads to an irregular heartbeat, direct tissue damage, and increases risk of CVD.
  • Moderate consumption linked with raised HDL levels.
26
Q

Describe ACE inhibitors

A
  • Antihypertensives.
  • Reduces synthesis of protein (angiotensin II) which causes vasoconstriction.
  • Reduces vasoconstriction which lowers blood pressure.
  • side effects: dizziness, cough, heart arrhythmia
27
Q

Describe diuretics

A
  • Increases the volume of urine.
  • Decreases blood plasma volume and cardiac output and lowers blood pressure.
28
Q

Describe statins

A
  • Inhibits an enzyme producing LDLs/cholesterol in liver
  • reducing likelihood of plaque building up - lowering risk of CVD
  • side effects: nausea, diarrhoea and constipation
29
Q

Describe the use of aspirin as an anticoagulant

A
  • Reduces the stickiness of platelets and the likelihood of clot formation.
  • inhibits clotting factors like vitamin K and calcium ions
  • side effects: uncontrolled bleeding
30
Q

Define basal metabolic rate

A

The amount of energy used, per day, whilst at rest.

31
Q

Which two monosaccharides make sucrose?

A

Glucose and fructose.

32
Q

Which two monosaccharides make maltose?

A

Glucose and glucose.

33
Q

Which two monosaccharides make lactose?

A

Glucose and galactose.

34
Q

What is the calculation for the waist-to-hip ratio?

A

Waist circumference divided by hip circumference.

35
Q

Properties of phospholipids

A
  • one of the fatty acids of a triglyceride is substituted by a phosphate-containing group.
  • Phosphate heads are hydrophilic and the tails are hydrophobic
  • phospholipids form a bilayer in the cell membrane as heads face watery environments whereas the tails move away from them.
36
Q

Definition of correlation

A

A measure of the extent to which two variables are related.

37
Q

Definition of a causal relationship

A

When a factor directly causes a specific effect/outcome.

38
Q

Why do large animals have a mass transport system?

A
  • Diffusion alone is insufficient
  • Because they have small surface area : volume ratio
  • Diffusion distances increase
  • Metabolic rate increase
  • Require network of blood vessels to carry oxygen and glucose around body
  • Require high blood pressure from heart and elastic blood vessels
39
Q

Characteristics of arteries

A
  • Carry oxygenated blood to the body tissues (other than the pulmonary artery)
  • Have a small lumen to maintain high blood pressure
  • Smooth inner endothelial lining (less resistance to blood flow)
  • Thick layer of smooth muscle (contract and relax to dilate and constrict blood vessels - controlling their diameter) and elastic fibres (stretch and recoil)
  • Lots of collagen fibres (for strength and support)
40
Q

Characteristics of veins

A
  • Carry deoxygenated blood to the lungs (except the pulmonary vein)
  • Large lumen and smooth endothelium (minimises resistance to flow)
  • Thinner layer of muscle and elastic fibres
  • Reduced collagen fibres
  • Valves (to prevent backflow)
41
Q

Characteristics of capillaries

A
  • Very small (to fit between cells)
  • Narrow Lumen
  • Thin endothelium - one cell thick (to maintain short diffusion distance and fit between cells)
  • Poreus to allow red blood cells to slightly enter to exchange materials
42
Q

What are the four main blood vessels in the heart?

A
  1. Pulmonary vein - carrying oxy-blood to left atrium
  2. Aorta - carrying oxy-blood from left ventricle to body
  3. Vena cava - carrying deoxy-blood to right atrium
  4. Pulmonary artery - carrying deoxy-blood from right ventricle to lungs

A Biology A-level (9 decks)

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