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3B more exchange Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

why is food broken down into smaller molecules during digestion

A

as the large biological molecules are to big to cross cell membranes and be absorbed from the gut into the blood

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2
Q

what are digestive enzymes produced by

A

specialised cells in the digestive system

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3
Q

why do different enzymes needed to catalyse the breakdown of different food molecules

A

as enzymes only work with specific substrate

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4
Q

what are carbohydrates broken down by

A

amylase and membrane bound disaccharide

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5
Q

what does amylase catalyse starch conversion into

A

maltose

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6
Q

where is amylase produced

A

salivary glands- into mouth

pancreas- into small intestine

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7
Q

what are membrane bound disaccharide

A

enzymes which are attached to the cell membranes of epithelial cells lining the ileum

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8
Q

what do membrane bound disaccharide do

A

help break down disaccharide into monosaccharides

involves hydrolysis

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9
Q

what is the ileum

A

final part of small intestine

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10
Q

how can monosaccharides be transported across cell membrane of the ileum epithelium cells

A

via transporter proteins

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11
Q

what are lipids broken down by

A

lipase with the help of bile salts

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12
Q

what does lipase catalyse the breakdown of lipids into

A

monoglycerides and fatty acids

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13
Q

where is lipase made

A

made in pancreas

works in small intestine

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14
Q

where are bile salts produced

A

liver

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15
Q

what does bile slats do

A

emulsifies lipids into small droplets

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16
Q

why are bile salts so important

A

as they emulsify lipid into small droplets which largely increases the surface area and therefore increases the rate of diffusion as there is more area for lipase to work on

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17
Q

once lipids are broken down what do monoglycerides and fatty acids stick to bile salts to form

A

micelles

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18
Q

what are proteins broken down by

A

endopeptidases and exopeptidase

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19
Q

what are endopeptidases

A

they act to hydrolyse peptide bonds within a protein

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20
Q

what are two examples of endopeptidases

and where are they found

A

chymotrypsin and trypsin

both synthesised in pancreases and secreted in small intestine

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21
Q

details on pepsin (another endopeptidase)

A

released into stomach by cells in the stomach lining

only works in acidic conditions- what hydrochloric acid is for in the stomach

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22
Q

what is exopeptidase

A

acts to hydrolyse peptide bonds at the end of protein molecules
removes single amino acid from proteins

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23
Q

what are dipeptidases

A

exopeptidase that only work on dipeptides

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24
Q

how do dipeptidases work

A

they separate the two amino acids which make up the dipeptide by hydrolysing the peptide bond between

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25
Q

where are dipeptidases located

A

found on cell surface membrane of epithelial cells in small intestine

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26
Q

what are the products of digestion absorbed across

A

the ileum epithelium into the blood stream

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27
Q

how is glucose and galactose absorbed

A

by active transport with sodium ions via co transporter proteins

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28
Q

how are monoglycerides and fatty acids absorbed

A

micelles help move them towards epithelium

micelles release them allowing them to be absorbed

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29
Q

why can monoglycerides and fatty acids be absorbed across the epithelial cell membrane

A

as they are lipid soluble

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30
Q

how are amino acids absorbed

A

absorbed via co transport
sodium ions actively transported out of the ileum epithelial cells into the blood
creates sodium conc grad
Sodium ions diffused from lumen of ileum into epithelial cells through sodium dependent transporter proteins carrying amino acids with

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31
Q

How are proteins digested

A

Hydrolysis of peptide bonds
Endopeptidases breaks down polypeptides into smaller peptides
exopeptidases removes terminal Amino acid
Dipeptidase breaks down dipeptides into amino acids

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32
Q

Why is maltose only digested by Maltese

A

Maltase has specific active site shape
Only binds to maltose
To form an enzyme substrate complex

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33
Q

describe haemoglobin

A

large protein with quaternary structure

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34
Q

what does quaternary structure mean

A

made up of more than one polypeptide chain

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35
Q

in haemoglobin what is a haem group and what does it contain

A

each chain has haem group

contains an iron ion giving the red colour

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36
Q

why is haemoglobin described as having a high affinity for oxygen

A

each molecule can carry four oxygen molecules

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37
Q

how and where is oxyhemoglobin formed

A

oxygen joins to haemoglobin in red blood cells forming oxyhemoglobin
this takes place in the lungs

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38
Q

what is the equation of the reversible reaction oxyhaemaglobin to haemoglobin

A

Hb + 4O2 Hb08

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39
Q

what is the partial pressure of oxygen

A

pO2
measure of oxygen concentration
higher conc of dissolved o2 in cells= higher partial pressure

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40
Q

what is the partial pressure of c02

A

pCO2 measure of concentration of carbon dioxide in cell

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41
Q

how does haemoglobin affinity for oxygen depend on the partial pressure of oxygen

A

oxygen loads onto haemoglobin to form oxyhemoglobin where there’s a high po2
oxyhemoglobin unloads its oxygen when there is a low pO2

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42
Q

why does oxygen load onto haemoglobin in the alveoli

A

as The alveoli have a high p02

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43
Q

where does oxyhemoglobin unload its oxygen

A

in respiring cells as they have low pO2

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44
Q

how does pCO2 effect oxygen unloading

A

haemoglobin gives up its oxygen more readily at higher partial pressures of carbon dioxide

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45
Q

explain the bohr effect

A

1- when cells respire they produce co2 which increases pco2

2- this increases rate of oxygen unloading so dissacosiation curve moves to right
more oxygen released

46
Q

what is the circulatory system

A

a mass transport system

47
Q

what is the circualtory system made up of

A

heart and blood vessels

48
Q

what does the heart do in the circulatory system

A

pumps bloood through blood vessels to reach different parts of body

49
Q

what does the blood do in the circulatory system

A

transports respiratory gases, products of digestion,metabolic wastes, hormones around the body

50
Q

what are the two circuits

A

1st- takes blood from heart to lungs

2nd- takes blood around the rest of the body

51
Q

what is the hearts blood supply

A

left and right coronary arteries

52
Q

what do arteries do

A

carry blood from heart to rest of body

53
Q

describe arteries

A

thick muscular and have elastic tissue to stretch and recoil as heart beats

54
Q

what is the inner lining of the artery called

A

endothelium

55
Q

describe endothelium in the artery

A

folded allowing artery to stretch

also helps maintain high pressure

56
Q

what do pulmonary arteries carry

A

deoxygenated blood to the lungs

all other arteries carry oxygenated blood

57
Q

what do arteries divide into

A

aterioles

58
Q

what do aterioles form and what do they do

A

forms network throughout body
blood is directed to areas of demand in body by muscles in aterioles
these muscles contract or relax to allow full blood flow

59
Q

what do veins do

A

take blood back to heart under low pressure

60
Q

describe veins

A

wider lumen , little elastic or muscle tissue

have valves to prevent blood flowing backwards

61
Q

how is bloodflow through veins helped

A

by surrounding body muscle

62
Q

what does the pulmonary vein carry

A

oxgenated blood to heart from lungs

all other veins carry deoxygenated

63
Q

what do aterioles branch into

A

cappilleries

64
Q

how are capilleries adapted for efficient diffusion

A

1) found near cells in exchange tissue so very short difffusion pathway
2) walls are one cell thick so short diffusion pathway
3) large number of cappileries so large SA

65
Q

what is the network of capilleries in tissue called

A

capillary beds

66
Q

what is tissue fluid

A

fluid which surrounds cells in tissues

67
Q

what is tissues fluid made up from

A

made from small molecules that leave the blood plasma like oxygen water and nutrients

68
Q

why cant tissue fluid contain red blood cells or big proteins

A

as too big to be pusshed through capillary wals

69
Q

what do cells take in and release into tissue fluid

A

take in - oxygen and nutrients

release- metabolic waste

70
Q

process of pressure filtration

A

1) (artery)at start of capillary bed, hydrostatic pressure is higher in capilleries than in tissue fluid
2) this difference in pressure means an overall outward pressure forces fluid out of cap into spaces around the cells forming tissue fluid
3) as fluid leaves pressure in reduces in cap so pressure is lowest now at venule end of capillary bed( near vein)
4) due to fluid loss &increasing concentration of plasma proteins -water potential at venue end of cap bed is lower than water potential in tissue fluid
5) this means some water re-enters capillaries from the tissue fluid at venue and by osmosis

71
Q

Where is excess tissue fluid drained

A

Lymphatic system which transports it from tissues and dumps it back into circulatory system

72
Q

what is lymphatic system

A

network of tubes acting like drains

73
Q

what does the right side of heart do

A

Pumps deoxygenated blood to the lungs

74
Q

what does left side of heart do

A

Pumps oxygenated blood to the whole body

75
Q

what are the for blood vessels in the heart and what do they pump

A

Vena cava and pulmonary veins carry blood to the heart

pulmonary artery and aorta carry blood away from her

76
Q

quick heart summmary blood flow

A

Deoxygenated blood pumped through vena cava to right atrium to right ventricle then out of the pulmonary artery

oxygenated blood flows in through the pulmonary vein into the left atrium into right left ventricle out of aorta

77
Q

describe difference between right and left ventricle

A

Left ventricle is thicker more muscular as it needs to contract powerfully to pump blood all around the body

right ventricle only need to get blood lungs

78
Q

why do the ventricles have thicker walls than the atria

A

As they need to push blood out of the heart where as atria just need to push blood a short distance into ventricles

79
Q

what do atrioventricular valves do

A

link atria to ventricles and stop blood flowing back into atria when the ventricles contract

80
Q

what do semi lunar valves do

A

Link the ventricles to the pulmonary artery and aorta

stop blood flowing backwards into heart after ventricles contract

81
Q

what do cords in the heart do

A

attach atrioventricular valves to the ventricles to stop them being forced up into atria when ventricles contract

82
Q

why can blood only flow in one direction in the heart

A

Valves only open one way
if there is pressure behind a valve it’s forced open
but if there is pressure in front of the valve it’s forced shut

83
Q

first step of the cardiac cycle

A

atria contracts, ventricle relaxed

causing higher pressure in the atria so blood moves down the pressure gradient into the ventricles

84
Q

second step of the cardiac cycle

A

atria relax, ventricle contracts
increases pressure in ventricle , forcing AV valve shut( prevents back flow)
presure in ventricle higher than that in aorta and pulmonary artery so forces SL valve open so blood forced out

85
Q

third step of the cardiac cycle

A

atri and ventricle relax

higher pressure in pulmonary artery and aorta now forcing semi lunar valves to close preventing back flow

blood returns and fills atria due to higher pressure in the pulmonary vein and vena cava this increases pressure of atria opening AV valve

86
Q

What is a atheroma

A

Fibrous plaque

87
Q

How is a atheroma formed

A

If damage occurs to endothelial lipids from the blood come together forming fatty streaks overtime this will harden to a atheroma

88
Q

What is a aneurysm and has it formed

A

Atheroma plaques damage the arteries and narrows them
so when blood travels through narrowed artery at high-pressure it can push the inner layers of the artery through the outer elastic layer to form a lballoon like swelling
aneurysm can burst causing haemorrhage

89
Q

What is thrombosis and how is it formed

A

Atheroma plaque can rupture the endothelial and this causes damage
platelets and fibre in accumulate at cited damage forming blood clot this can block an artery

90
Q

What is a myocardial infarction

A

If coronary artery becomes completely blocked area of heart muscle will be cut off from blood supply is receiving no oxygen so can’t respire causing heart attack

91
Q

What are three risk factors of cardiovascular disease

A

High blood cholesterol and poor diet
cigarette smoking
a high blood pressure

92
Q

How does high blood pressure and poor diet lead to cardiovascular disease

A

As cholesterol is one of the main constitutions of fatty deposits that from atheroma is leading to blood clots

93
Q

How does cigarette smoking need to cardiovascular diseases

A

Nicotine increases risk of high blood pressure
carbon monoxide binds the haemoglobin reducing the amount of oxygen in the blood can lead to a heart attack

smoking decreases about antitoxin dents in the bloods

94
Q

How can hide blood pressure need to cardio vascular diseases

A

Increases risk of damage to artery walls increasing risk of atheroma formation

95
Q

what does xylem tissue transport

A

water and mineral ions

96
Q

what does phloem tissue transport

A

sugars

97
Q

describe xylem vessels

A

long tube like made up of dead cells

no end walls making uninterrupted tube so water can pass through easier

98
Q

how does water move up the plant

A

Water evaporates from the leaves at top of xylem

  • creates tension pulling up more water
  • as water is cohesive it pulls up even more water
  • water enter stem from roots
99
Q

whats transpiration

A

1- water evaporates from voice cells and accumulates in spaces between cells in the leaf
2-when stomato open water moves out of leaf down concentration gradient

100
Q

how does light effect transpiration rate

A

more light means faster rate of transpirations as photosynthesis happens more in light

101
Q

how does temperature effect transpiration rate

A

higher temp means faster rate of transpiration as molecules have more energy so can evaporate quicker

102
Q

how does humidity effect transpiration rate

A

lower humidity the faster the transpiration rate as higher concentration gradient

103
Q

how does wind effect the rate of transpiration

A

more windy means faster rate of transpiration as the wind can blow away more water molecules

104
Q

what are seive tube cells and companion cells

A

seive tube elements are living cells which form the phloem tube but they have no nucleus so there is a companion cell for each of them to provide energy needed for active transport

105
Q

what is translocation

A

the movement of solutes in a plant to where they are needed

106
Q

does transloctaion require energy

A

yes

107
Q

how do enzymes maintain the concentration gradient from source to sink

A

by changing (breaking down the solutes) the sloutes at the sink so there is always a lower concentration at the sink

108
Q

what is the first step of mass flow hypothesis

A

1- active transport loads the solutes from companion cells into the sieve tube of p[phloem at the source

2- this lowers water potential inside the sieve tubes so water enters the tubes by osmosis from the companion cells and the xylem

3-this creates high pressure at the source end f the phloem and in the sieve tubes

109
Q

what is the second step of the mass flow hypothesis

A

1- at the sink end solutes are removed from phloem to be used up
2- this increases water potential inside the sieve tubes so water leaves by osmosis
3-this loweres the pressure insed the sieve tubes

110
Q

what is the third step of the mass flow hypothesis

A

1- this results in a pressure gradient from the sink to source end of the phloem

2- the gradient pushes the solutes from the source to sink end of the sieve tubes

3- when the solutes reach the sink they will be used or stored

111
Q

what are two objections to the mass flow hypothesis

A

1- sugar and solutes travel to many different sinks not just the one with the highest water potential

2- the sieve plates would create a barrier to mass flow , a lot of pressure would be needed for solutes to get through at a reasonable rate

112
Q

what are 4 supporting evidences for the mass flow hypothesis

A

1-tree ringing

radioactive tracker

aphids

metabolic inhibitir

BIOLOGY (20 decks)

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