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SNAB A Level Biology > Topic 1: Lifestyle, Health and Risk > Flashcards

Topic 1: Lifestyle, Health and Risk Flashcards

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1
Q

give features of a mass transport system

A

vessels
transport
maintains speed

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2
Q

Define a double circulatory system.

A

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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3
Q

why do some organisms require a mass transport

A

larger animals have a smaller SA:V ratio and a higher metabolic rate.
Diffusion alone is insufficient to supply all cells with the substances they need

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4
Q

what makes water a dipole molecule

A

uneven distribution of charge
O attracts the electron density making it slightly more negative

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5
Q

how is water used in transport

A

water acts as a solvent due to its polar nature, allowing the transport of biological molecules
Other polar substances, as well as ionic and hydrophilic substances, can easily dissolve in water.

The specific heat capacity of water is very high to maintain homeostasis.

Water has a high boiling point due to the hydrogen bonds.

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6
Q

how does a public perception of risk differ from actual risk

A
  • people overestimate risk if something is not under their control / is unfamiliar or has particularly severe consequences
  • people underestimate risk if something only has an effect in the long term
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7
Q

what is the structure of the atria and how does this relate to their function?

A

thin walled + elastic = can stretch when filled with blood

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8
Q

what is the structure of the ventricles and how does this relate to their function?

A

thick muscular walls pump blood under high pressure
the left ventricle is thicker than the right because it has to pump blood all the way around the body

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9
Q

what are the 4 major blood vessels in the heart

A

vena cava
pulmonary artery
pulmonary vein
aorta

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10
Q

what is the function of the vena cava

A

brings deoxygenated blood from the body TO THE HEART

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11
Q

what is the function of the pulmonary artery

A

takes blood from the heart TO THE LUNGS

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12
Q

what is the function of the pulmonary vein

A

brings oxygenated blood from the lungs TO THE HEART

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13
Q

what is the function of the aorta

A

takes blood from the heart AROUND THE BODY

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14
Q

what is the structure of the ARTERIES and how does this relate to their function?

A

thick muscular walls to handle high pressure w/o tearing.
Elastic tissue allows recoil
Narrow lumen to maintain pressure

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15
Q

what is the structure of the VEINS and how does this relate to their function?

A

thin walls due to lower pressure
valves to prevent backflow
less muscular and elastic tissue as they dont have to control blood flow

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16
Q

what is the structure of the CAPILARIES and how does this relate to their function?

A
  • one cell thick walls - short diffusion pathway
  • can form large capillary networks to provide a large surface area
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17
Q

2 main circuits in the mammalian circ system

A

pulmonary - to and from lungs
systemic - to and from rest of body

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18
Q

describe what happens during cardiac diastole

A
  • heart is relaxed
  • blood enters atria , increasing the pressure
  • opens the AV valves
  • blood flows into ventricles
    SL valves remain closed
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19
Q

what happens during atrial systole

A
  • atria contract
  • pushing any remaining blood into the ventricles
  • pressure increases in the ventricles so AV valves close
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20
Q

describe what happens during ventricular systole

A

ventricles contract, pressure increases, AV valves close, SL valves open,
blood flows into the arteries

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21
Q

what causes atherosclerosis

A

endothelium becomes damaged which leads to an inflammatory response and possible blood clotting.
Substances in the blood build up and harden into a plaque (atheroma). The artery loses elasticity, narrows and hardens and raises blood pressure

22
Q

consequences of CVD

A

Narrowed coronary arteries may lead to angina. Heart muscle lacks oxygen and has to respire anaerobically. Arteries blocked and are ischaemic (not enough blood flowing). If muscle cells are starved of oxygen for too long it results in an infarction.

23
Q

why does blood need to clot

A

prevent blood loss
prevent entry of harmful bacteria
provides a framework for repair

24
Q

Describe the clotting cascade reaction.

A
  • platelets release (protein )thromboplastin in response to damage
  • calcium ions (from the plasma) and thromboplastin trigger the conversion of prothrombin into enzyme thrombin
  • thrombin catalyses conversion of soluble protein fibrinogen to the insoluble protein fibrin
  • fibrin forms a network of fibres that traps platelets and blood cells
25
Q

how are blood clots dangerous?

A

may restrict blood flow, therefore, reduces oxygen supply to cells

26
Q

what are some factors that increase the risk of CVD

A

genetics
age
gender (men more likely)
high blood pressure
high cholesterol levels
smoking
obesity

27
Q

what can we use to identify obesity?

A

BMI over 30
waist to hip ratio

28
Q

how to calculate BMI

A

Mass/ height^2

29
Q

3 treatments for CVD

A

Antihypertensives
Statins
Platelet inhibitors

30
Q

benefits and limitations of antihypertensive medication

A

+ reduces risk of kidney failure, lowers blood pressure, increases volume of urine to get rid of excess fluids
- side effects = dizziness, arrhythmia and nausea

31
Q

strengths and limitations of statins

A

+ lower cholesterol, minimal risk of side effects
- side effects that do appear tend to be severe , e.g muscle pain, liver damage, increased risk of diabetes, memory loss

32
Q

strengths and weaknesses of platelet inhibitors

A

+ prevents blood clots to limit narrowing of arteries
- prone to heavy bleeding even from small injuries

33
Q

difference between correlation and causation

A

correlation = where a change in one variable occurs at the same time as a change in another variable
causation = where a change in one variable CAUSES a change in another variable

34
Q

features of a good scientific study

A

clear aim or hypothesis
representative sample
valid and reliable results

35
Q

how to ensure results are valid and reliable

A

control extraneous variables
repeat study using the same method
use a representative sample

36
Q

consequences of energy imbalance

A

more energy burned than consumed = weight loss
more energy consumed than burned = weight gain

37
Q

what do carbohydrates consist of

A

chains of monosaccharides
contains only carbon hydrogen and oxygen

38
Q

difference between disaccharide and polysaccharide

A

di = two monosaccharides
poly = many monosaccharides

39
Q

how are di and polysaccharides formed

A

monosaccharides join through a condensation reaction
glycosidic bonds are formed

40
Q

2 examples of monosaccharides and their functions

A

glucose - main substrate for respiration
ribose - component of DNA and RNA

41
Q

3 examples of disaccharides + their component monosaccharides

A

maltose = two glucose
sucrose = glucose + fructose
lactose = glucose + galactose

42
Q

2 examples of polysaccharides and their function

A

glycogen - energy store in animals
starch - energy store in plants

43
Q

formation of glycogen
(structure)

A

Made up of alpha glucose. Has numerous side branches allowing rapid hydrolysis. 1,4 and 1,6 glycosidic bonds. Stored in liver and muscles. Used by bacteria, fungi and animals as an energy store.

44
Q

relate the structure of glycogen to its function

A

highly branched, molecule can be easily hydrolysed into glucose to release energy quickly

45
Q

how is starch formed?
(structure)

A

Starch is made up of amylose, which is an unbranched chain, 1,4 glycosidic bonds and is coiled into a spiral, and amylopectin, which has side branches and 1,6 glycosidic bonds. Starch is low solubility in water and compact.

46
Q

relate the structure of starch to its function

A

mixture of 2 polysaccharides
amylose - coiled to make molecule compact so large amounts can be stored
amylopectin = highly branched, so energy can be released quickly

47
Q

how is a triglyceride formed

A

one molecule of glycerol forms ester bonds with three fatty acids through condensation reaction

48
Q

what is the difference between unsaturated and saturated fats

A

saturated = no C=C bonds, solid at room temp due to strong intermolecular forces
unsaturated = 1+ C=C bonds, liquid at room temp due to weak intermolecular forces

49
Q

what is meant by HDL + function and structure

A

High density lipoprotein = GOOD
made of triglycerides from unsaturated fats combined with protein.
Reduces blood cholesterol by transporting it to liver to be broken down

50
Q

what is meant by LDL + structure and function

A

low density lipoproteins = BAD
made of triglycerides from saturated fats combined with protein
Blocks receptor sites, reducing cholesterol absorption

51
Q

how do LDLs contribute to risk of CVD

A

high blood cholesterol levels caused by LDLs leads to the formation of atherosclerosis plaques
= causal relationship

SNAB A Level Biology (2 decks)

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