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Biology A level Edexcel > Topic 1 > Flashcards

Topic 1 Flashcards

1
Q

Heart function

A

-To generate pressure to pump blood around the body
-allow mass transport/ mass flow
-To overcome the limitations of diffusion to ensure fast enough delivery of oxygen gas to all body cells

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2
Q

What is the function of the coronary arteries

A

Transports oxygenated blood from the heart into the cardiac muscle

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3
Q

What are the heart walls made of?

A

Cardiac muscle

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4
Q

Define ‘cardiac cycle’

A

The pattern of contraction and relaxation of the heart during one complete heartbeat

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5
Q

Artery structure - outer collagen coat

A

Strong to withstand high blood pressure

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6
Q

Artery structure - Thick smooth muscle layer

A

Muscle contracts to allow vasoconstriction to maintain high blood pressure

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7
Q

Artery structure - Thick elastic fibre layer

A

Allow artery to stretch and recoil to maintain high blood pressure

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8
Q

Artery structure - Smooth endothelium

A

Reduces resistance to blood flow

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9
Q

Artery structure - narrow lumen

A

Maintains high blood pressure

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10
Q

Vein structure - outer collagen coat

A

strength

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11
Q

Vein structure - valves

A

to prevent back flow of blood

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12
Q

Vein structure - thin smooth muscle layer

A

less construction of vein needed

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13
Q

Vein structure - thin elastic fibre layer

A

less elastic recoil needed as blood is moved by contraction of skeletal muscles

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14
Q

Vein structure - smooth endothelium

A

reduces resistance to blood flow

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15
Q

Vein structure - large lumen

A

reduces resistance to blood flow to prevent low blood pressure slowing down

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16
Q

Capillary structure - one cell thick wall

A

reduced diffusion distance speeds up exchange of substances between the blood and tissue cells

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17
Q

Capillary structure - walls have pores

A

to allow the passage of molecules through the wall, aiding formation of tissue fluid

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18
Q

Capillary structure - very narrow lumen

A

decreases the rate of flow of blood to allow more time for exchange of oxygen/ glucose between blood and cells by diffusion

Walls of red blood cells can be in contact with capillary wall, reduction distance for oxygen to diffuse to enter cells

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19
Q

Diffusion

A

The movement of molecules or ions from a region of high concentration to a region of low concentration, down a concentration gradient

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20
Q

Diffusion

A

The movement of molecules or ions from a region of high concentration to a region of low concentration, down a concentration gradient

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21
Q

Open circulatory system

A

There are no blood vessels, instead the blood is held within a body cavity and the organs are bathed in blood. Diffusion takes place between blood and organs. Blood is under low pressure

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22
Q

Closed circulatory system

A

Blood is held within blood vessels and is under high pressure

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23
Q

Single closed circulatory system

A

Blood flows once through the heart during each complete circuit of the body. blood is at low pressure when reaching body capillaries

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24
Q

Double closed circulatory system

A

Blood flows twice through the heart during each complete circuit of the body. Blood is at high pressure when reaching body capillaries

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25
Advantages of double closed circulatory system
-Oxygenated and deoxygenated blood do not mix -blood can be pumped at different pressures -repressurisation
26
Dipolar nature of water
Oxygen is delta negative Hydrogen is delta positive
27
Bonding between water molecules
Hydrogen bonding between delta positive of hydrogen and delta negative of oxygen
28
Properties of water
-good solvent -high latent heat of vaporisation -high specific heat capacity
29
Specific heat capacity
how much energy it takes for 1kg of material by 1 degrees celsius
30
solvent
something other substances can dissolve in
31
Hydrophobic
Repels water (non-polar) molecules eg lipids)
32
Hydrophilic
Attracts water (polar molecules/ions eg glucose)
33
What is blood pressure the measure of?
The hydrostatic force of the blood against the walls of a blood vessel
34
What is elevated pressure known as?
Hypertension
35
What are the units of blood pressure
mmHg
36
What is peripheral resistance?
Contact between blood and the walls of the blood vessels causes friction and this impedes the blood flow
37
When is blood pressure highest in artery blood
during systole - this is called systolic pressure
38
When is blood pressure lowest in artery blood
during diastole - this is called diastolic pressure
39
What is oedema
fluid building up in tissues and causing swelling
40
which type of blood vessel does atherosclerosis usually occur in
arteries
41
Two main risk factors for atherosclerosis
1)high blood pressure 2)high blood cholesterol
42
What is a blood clot also known as
a thrombus
43
platelets in blood clotting
cell fragment releases thromboplastin, found in blood plasma, can change shape
44
thromboplastin in blood clotting
soluble enzyme, catalyses conversion of prothrombin into thrombin, globular
45
prothrombin in blood clotting
soluble plasma protein, globular, present in blood
46
thrombin in blood clotting
soluble enzyme, globular, catalyses the conversion of fibrinogen to fibrin
47
fibrinogen in blood clotting
soluble, plasma protein present in blood, globular
48
fibrin in blood clotting
insoluble protein, fibrous, forms a mesh to trap red blood cells and platelets
49
which artery becomes blocked which leads to a heart attack
coronary
50
what effect does a blocker coronary artery have on the blood flow and oxygen to the heart muscle
reduces flow of oxygenated blood to heart muscle
51
General formula for a monosaccharide
CnH2nOn
52
Two structural differences between a monosaccharide and a disaccharide
-monosaccharide is a single sugar unit, disaccharide is a double sugar unit -A disaccharide has a glycosidic bond, monosaccharide does not
53
condensation reaction definition
joining of monomers or smaller molecules to make a larger molecule water is removed and a bond is formed
54
hydrolysis reaction definition
splitting of polymers or large molecules into smaller molecules water is added and a bond is broken
55
what is a hexose sugar
six carbon sugar
56
function of glucose
-immediate respiration source -joined to form starch or glycogen for energy storage
57
function of galactose
a component of disaccharide lactose
58
fructose function
sweet sugar which attracts animals to eat the fruit and therefore helps seed dispersal
59
how does the structure of glucose relate to its function
-doesn’t need to be hydrolysed as is a single sugar unit -polar with many hydrophilic OH groups making it soluble in water - transport -small so diffuses quickly into blood
60
maltose (glucose+glucose) function
found in germinating seeds (when starch is broken down by enzyme amylase)
61
sucrose (glucose+fructose) function
used for transporting energy in plants (sugar in the phloem)
62
lactose (glucose+galactose) function
sugar in milk - for energy
63
polysaccharide definition
many sugar units joined together by glycosidic bonds formed in condensation reactions
64
starch structure
-alpha glucose -amylose - unbranched, 1,4 glycosidic bonds -amylopectin - branched, 1,4 and 1,6 glycosidic bonds
65
function and properties of starch
-energy storage in plants -rapidly hydrolysed to release glucose quickly due to many branches -insoluble so no osmotic effect -compact - more starch and therefore more glucose can be stored in smaller space
66
glycogen structure
-alpha glucose -branched -1,4 and 1,6 glycosidic bonds
67
glycogen function and properties
-energy storage molecule in animals -rapidly hydrolyses to release glucose quickly due to many branches -insoluble - no osmotic effect -compact - more glycogen and so more glucose can be stored in a smaller space
68
cellulose structure
-beta glucose -unbranched -1,4 glycosidic bonds
69
cellulose function and properties
-provides strength in the plant cell wall
70
Describe the structure of a fatty acid
long straight hydrocarbon chain and a carboxylic acid group.
71
Function of cholesterol
Found in cell membrane, where its function is to regulate fluidity
72
what is a lipoprotein
a molecule made up of cholesterol combined with triglycerides and protein
73
is LDL saturated or unsaturated fatty acid
saturated
74
is HDL saturated or unsaturated fatty acid
Unsaturated
75
Role of LDL in cholesterol transport
Transports cholesterol from liver to body tissues where cholesterol binds to LDL receptors on cell membranes to be taken up into cells
76
Role of HDL in cholesterol transport
Transports cholesterol from body tissues to liver where cholesterol is broken down Important in reducing blood cholesterol levels
77
consequences of increased saturated fats in the diet
Too many LDLs can cause LDL receptors on cells and tissues to overload so LDLs accumulate in blood causing high blood LDL cholesterol
78
does saturated fatty acid have higher or lower H:C ratio?
higher
79
does unsaturated fatty acid have higher or lower H:C ratio?
Lower

Biology A level Edexcel (5 decks)

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