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

Topic 1: Lifestyle, Health and Risk Flashcards

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

Why may larger organisms use more energy

A

they are more complex, so more nutrients, gases and wastes have to be exchanged by diffusion.
They have a higher demand for oxygen in and waste out.

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5
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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6
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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7
Q

how does water act as a solvent

A

water molecules surround the charged particles,
H+ attracted to negative ions
O- attracted to positive ions
The surrounded ions break appart

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8
Q

what is cohesion

A

attraction of water molecules to eachother

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9
Q

what is adhesion

A

water hydrogen bonding to other molecules

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10
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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11
Q

what is the systemic circuit in our circulatory system

A

blood returns to the left side of the heart and oxygenated blood is pumped around the body

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12
Q

what is the pulmonary circuit in our circulatory system

A

right side of the heart pumps deoxygenated bloodto the lungs

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13
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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14
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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15
Q

what are the 4 major blood vessels in the heart

A

vena cava
pulmonary artery
pulmonary vein
aorta

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16
Q

what is the function of the vena cava

A

brings deoxygenated blood from the body TO THE HEART

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17
Q

what is the function of the pulmonary artery

A

takes blood from the heart TO THE LUNGS

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18
Q

what is the function of the pulmonary vein

A

brings oxygenated blood from the lungs TO THE HEART

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19
Q

what is the function of the aorta

A

takes blood from the heart AROUND THE BODY

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20
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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21
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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22
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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23
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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24
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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25
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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26
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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27
Q

what is atherosclerosis

A

the hardening of the arteries

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28
Q

what are the steps involved in athersclerosis

A
  1. damage to the endothelium
  2. an inflammatory response occurs and white blood cells accumulate in the damaged area
  3. lipids and cholesterol clump w the WBC under the endothelium, platelets can also be involved sometimes
  4. this clump of macrophages, cholesterol, lipids and platelets is forms a plaque called an atheroma
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29
Q

what effect does an atheroma have on the blood pressure

A

atheromas narrow the lumen of the artery, reducing and restricting blood flow … therefore increasing BP

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30
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.

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31
Q

why does blood need to clot

A

prevent blood loss
prevent entry of pathogens
provides a framework for repair

32
Q

what is thrombosis

A

the process of blood clotting

33
Q

Describe the process of thrombosis

A
  • platelets release (protein) thromboplastin in response to damage
  • calcium ions (from the plasma) and thromboplastin trigger the conversion of prothrombin(P) 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
34
Q

how are blood clots dangerous?

A

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

35
Q

how does the formation of atheromas and blood clots cause a heart attack

A

blood flow to the heart is restricted
less oxygen reaches cells in heart cells
rate of respiration decreases
cells no longer produce ATP
cells can no longer contract, reducing the force generated by the heart

36
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

37
Q

what can we use to identify obesity?

A

BMI over 30
waist to hip ratio

38
Q

how to calculate BMI

A

Mass/ height^2

39
Q

3 treatments for CVD

A

Antihypertensives
Statins
anticoagulants
Platelet inhibitors

40
Q

how do antihypertensives work?

A

by lowering blood pressure which in turn reduces the risk of arterial endothelia damage

41
Q

examples of antihypertensives

A

beta blockers - prevent heart rate increases
vasodilators - increase diameter of blood vessels
diuretics - reduce blood volume

42
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

43
Q

how do statins work

A

lowering blood cholesterol by blocking an enzyme in the liver which is needed to make cholesterol
which lowers the LDL conc

44
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

45
Q

how do anticoagulants work?

A

reduce blood clotting, therefore decreases the likelihood of thrombosis

46
Q

strengths and weaknesses of anticoagulants

A

+ reduces the formation of new blood clots
- can cause excessive bleeding if injury occurs, including internal bleeding

47
Q

how do platelet inhibitors work?

A

substances which reduce blood clotting
they prevent the clumping together of platelets
e.g aspirin

48
Q

strengths and weaknesses of platelet inhibitors

A

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

49
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

50
Q

features of a good scientific study

A

clear aim or hypothesis
representative sample
valid and reliable results

51
Q

how to ensure results are valid and reliable

A

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

52
Q

consequences of energy imbalance

A

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

53
Q

what do carbohydrates consist of

A

chains of monosaccharides
contains only carbon hydrogen and oxygen

54
Q

what is an example of a monosaccharide

A

glucose - hexose sugar coz 6 carbons

55
Q

on alpha glucose what are the locations of the H and OH groups

A

H = above C1
OH = below C1

56
Q

difference between disaccharide and polysaccharide

A

di = two monosaccharides
poly = many monosaccharides

57
Q

how are di and polysaccharides formed

A

monosaccharides join through a condensation reaction
glycosidic bonds are formed

58
Q

what are the 2 types of glycosidic bonds

A

1,4 and 1,6
1,6 = for branches

59
Q

2 examples of monosaccharides and their functions

A

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

60
Q

3 examples of disaccharides + their component monosaccharides

A

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

61
Q

what is the function of disaccharides

A

provide the body with a quick release source of energy
they are soluble in water

62
Q

properties of polysaccharides that allow them to be good for storage

A

compact
insoluble

63
Q

2 examples of polysaccharides and their function

A

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

64
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.

65
Q

relate the structure of glycogen to its function

A

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

66
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.

67
Q

what are the 2 different polysaccharides that make up starch

A

amylose and amylopectin

68
Q

relate the structure of starch to its function

A

mixture of 2 polysaccharides
amylose -not branched but coiled to make molecule compact so large amounts can be stored
amylopectin = highly branched, so energy can be released quickly

69
Q

how is a triglyceride formed

A

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

70
Q

properties of triglycerides

A

non polar
hydrophobic

71
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
form unbranched linear chains

unsaturated = 1+ C=C bonds, liquid at room temp due to weak intermolecular forces

72
Q

difference between cis-fatty acids and trans-fatty acids

A

cis = H atoms are on the same side of the double bond - can be metabolised by enzymes

trans = H atoms are on opposite sides of the double bond - cannot form enzyme-substrate complexes - not metabolised - linked to CHD

73
Q

what bond do triglycerides have

A

ester bonds formed via condensation reaction, +3H20 molecules

74
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

75
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

76
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 (3 decks)

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