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

Topic 1: Lifestyle, Health and Risk Flashcards

(72 cards)

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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

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
what happens during atrial systole
- atria contract - pushing any remaining blood into the ventricles - pressure increases in the ventricles so AV valves close
26
describe what happens during ventricular systole
ventricles contract, pressure increases, AV valves close, SL valves open, blood flows into the arteries
27
what is atherosclerosis
the hardening of the arteries
28
what are the steps involved in athersclerosis
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
29
what effect does an atheroma have on the blood pressure
atheromas narrow the lumen of the artery, reducing and restricting blood flow … therefore increasing BP
30
consequences of CVD
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 infraction.
31
why does blood need to clot
prevent blood loss prevent entry of pathogens provides a framework for repair
32
what is thrombosis
the process of blood clotting
33
Describe the process of thrombosis
- 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
how are blood clots dangerous?
may restrict blood flow, therefore, reduces oxygen supply to cells
35
how does the formation of atheromas and blood clots cause a heart attack
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
what are some factors that increase the risk of CVD
genetics age gender (men more likely) high blood pressure high cholesterol levels smoking obesity
37
what can we use to identify obesity?
BMI over 30 waist to hip ratio
38
how to calculate BMI
Mass/ height^2
39
4 treatments for CVD
Antihypertensives Statins anticoagulants Platelet inhibitors
40
how do antihypertensives work?
by lowering blood pressure which in turn reduces the risk of arterial endothelia damage
41
examples of antihypertensives
beta blockers - prevent heart rate increases vasodilators - increase diameter of blood vessels diuretics - reduce blood volume
42
how do statins work
lowering blood cholesterol by blocking an enzyme in the liver which is needed to make cholesterol which lowers the LDL conc
43
how do anticoagulants work?
reduce blood clotting, therefore decreases the likelihood of thrombosis
44
how do platelet inhibitors work?
substances which reduce blood clotting they prevent the clumping together of platelets e.g aspirin
45
difference between correlation and causation
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
46
features of a good scientific study
clear aim or hypothesis representative sample valid and reliable results peer review
47
how to ensure results are valid and reliable
control extraneous variables repeat study using the same method use a representative sample
48
consequences of energy imbalance
more energy burned than consumed = weight loss more energy consumed than burned = weight gain
49
what do carbohydrates consist of
chains of monosaccharides contains only carbon hydrogen and oxygen
50
what is an example of a monosaccharide
glucose - hexose sugar coz 6 carbons
51
on alpha glucose what are the locations of the H and OH groups
H = above C1 OH = below C1
52
difference between disaccharide and polysaccharide
di = two monosaccharides poly = many monosaccharides
53
how are di and polysaccharides formed
monosaccharides join through a condensation reaction glycosidic bonds are formed
54
what are the 2 types of glycosidic bonds
1,4 and 1,6 1,6 = for branches
55
2 examples of monosaccharides and their functions
glucose - main substrate for respiration ribose - component of DNA and RNA
56
3 examples of disaccharides + their component monosaccharides
maltose = two glucose sucrose = glucose + fructose lactose = glucose + galactose
57
what is the function of disaccharides
provide the body with a quick release source of energy they are soluble in water
58
properties of polysaccharides that allow them to be good for storage
compact insoluble
59
2 examples of polysaccharides and their function
glycogen - energy store in animals starch - energy store in plants
60
formation of glycogen (structure)
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.
61
relate the structure of glycogen to its function
highly branched, terminal ends can be easily hydrolysed into glucose to release energy quickly
62
how is starch formed? (structure)
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.
63
what are the 2 different polysaccharides that make up starch
amylose and amylopectin
64
relate the structure of starch to its function
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
65
how is a triglyceride formed
one molecule of glycerol forms ester bonds with three fatty acids through condensation reaction
66
properties of triglycerides
non polar hydrophobic
67
what is the difference between unsaturated and saturated fats
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
68
difference between cis-fatty acids and trans-fatty acids
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
69
what bond do triglycerides have
ester bonds formed via condensation reaction, +3H20 molecules
70
what is meant by HDL + function and structure
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
71
what is meant by LDL + structure and function
low density lipoproteins = BAD made of triglycerides from saturated fats combined with protein Blocks receptor sites, reducing cholesterol absorption
72
how do LDLs contribute to risk of CVD
high blood cholesterol levels caused by LDLs leads to the formation of atherosclerosis plaques = causal relationship

SNAB A Level Biology (5 decks)

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