november mocks Flashcards
(125 cards)
1
Q
what is the role of enzymes?
A
biological catalysts in metabolic reactions
2
Q
what happens to the rate of reactions when temperature increases up to the optimum? (enzymes)
A
the enzyme and substrate have more kinetic energy, so they have more frequent successful collisions, so there are more enzyme-substrate complexes formed, so rate of reaction increases
3
Q
what happens to the rate of reaction when temperature increases past the optimum? (enzymes)
A
the active site changes shape so the substrate is no longer complimentary to the enzyme and it cannot fit into the active site anymore, so no enzyme-substrate complexes are formed, so rate of reaction decreases
4
Q
describe the method for how enzyme activity is affected by changes in temperature?
A
- heat starch solution (in a test tube) to 10 degrees using a water bath
- add amylase to the solution then use a pipette to add a drop to the spotting tile
- immediately after, put a drop of iodine to the starch solution
- add another drop after 30 seconds to the next spotting tile and add iodine solution
- repeat every 30 seconds until the iodine solution stays orange
- repeat all 5 steps for 20 30, 40, 50, 60 degrees
5
Q
how do pH levels affect enzyme activity?
A
as the pH increases up to the optimum, the enzyme’s active site becomes more complimentary to it’s substrate, so enzyme activity increases. after it reaches the optimum, the active site changes shape and so the enzyme denatures so enzyme activity decreases/stops
6
Q
what is diffusion?
A
random movement of particles from high concentration to low concentration
7
Q
what is osmosis
A
net diffusion of free water molecules from an area of high water potential to low water potential across a semi-permeable membrane
8
Q
what is active transport?
A
the movement of molecules from an area of low concentration to high concentration using ATP
9
Q
how does SA:V affect the rate of diffusion?
A
the smaller the sa:v is, the higher the rate of diffusion
10
Q
how does distance affect diffusion?
A
the further the distance, the lower the rate of diffusion
11
Q
how does concentration gradient affect diffusion?
A
the higher the concentration gradient, the higher the rate of diffusion
12
Q
how do you investigate osmosis in a living system?
A
- use a cork borer to cut equal cylinders in a potato
- cut the cylinders the same length (about 3cm) - have five
- measure and record the mass of each
- measure out 10cm^3 of 0M, 2.5M, 5M, 7.5M, 1M sucrose solution into 5 different test tubes
- add one potato cylinder (of known mass) into each tube
- leave for 30 minutes
- take out each potato and gently dry them by tapping them with a paper towel then weigh them and record the new mass for each
13
Q
how do you investigate osmosis in a non-living system?
A
connect a visking tube to a capillary tube, and fill the visking tube with sucrose solution and put into a beaker with 20 cm^3 of water. leave for 30 mins, then measure the volume of water. repeat with different concentrations of sucrose solution
14
Q
how do you investigate diffusion in non-living systems?
A
put potassium permanganate crystals in a beaker of water. observe after 15 minutes, then observe after 1 hour
15
Q
what are organelles?
A
small structures in the cell with a specific function
16
Q
what are cells?
A
smallest functional unit of life, contain organelles to carry out specific function
17
Q
what are tissues?
A
a group of similar cells, working together to carry out the same function
18
Q
what are organs?
A
made up of several different tissues working together to carry out a more complex function
19
Q
what are organ systems?
A
made up of several different organs working together to carry out a complex function essential for life
20
Q
what is in an animal cell?
A
a nucleus, mitochondria, cytoplasm, cell membrane, ribosomes
21
Q
what is in a plant cell?
A
a nucleus, mitochondria, cytoplasm, cell membrane, cell wall, ribosomes, chloroplasts, vacuole
22
Q
what is the function of a nucleus?
A
controls the activity of the cell (by making proteins), contains the chromosomes
23
Q
what is the function of a cell membrane?
A
controls what goes in and out of the cell (selectively-permeable)
24
Q
what is the function of the cytoplasm?
A
jelly-like liquid where chemical reactions occurred
25
what is the function of the mitochondria?
site of aerobic respiration
26
what is the function of the ribosomes?
protein synthesis from amino acids
27
what is the function of the chloroplasts?
site of photosynthesis
28
what is the function of cell walls?
keeps the shape of cell, prevents the cell from bursting
29
what is the function of the vacuole?
contains cell sap, stores dissolved sugars, mineral ions, and other substances
30
what is the function of the mouth?
mechanical digestion; increased sa:v, chemical digestion; salivary amylase breaks down starch into maltose, food is shaped into bolus
31
what is the function of the oesophagus?
connects mouth to stomach, peristalsis to push bolus down to stomach (mechanical digestion)
32
what is the function of the stomach?
chemical digestion: pepsin from stomach walls to break down proteins into peptides, mechanical digestion by muscle churning, stomach aid lowers pH for pepsin and sterilises food
33
what is the function of the duodenum?
chemical digestion - contains many enzymes (amylase, lipase, protease)
34
what is the function of the ilieum?
chemical digestion - enzymes break down food
villi and microvilli to absorb nutrients
35
what is the function of the colon?
reabsorbing water to make faeces
36
what is the function of the rectum?
egestion
37
what is the function of the pancreas?
secretes enzymes into the stomach and small intestine
38
what enzymes are there in the mouth and what do they do?
salivary amylase
starch --> maltose
39
what enzymes are there in the stomach and what do they do?
pepsin
proteins --> peptides
40
what enzymes are there in the duodenum and what do they do?
pancreatic amylase
starch --> maltose
trypsin
peptides --> amino acids
pancreatic lipase
lipids ---> fatty acids and glycerol
maltase (from glands in the walls)
maltose ---> glucose
41
what enzymes are produced in the pancreas?
pancreatic amylase, trypsin, pancreatic lipase
41
what kind of enzymes are in the ileum?
maltase
42
where is bile produced?
liver
43
where is bile stored?
gall bladder
44
what is the function of bile?
emulsifies lipids and neutralises stomach acid
45
what is in stomach acid?
hydrochloric acid and pepsin
46
how is the small intestine adapted for absorption?
thin cell walls -> shortens diffusion distance
large surface area to volume ratio from villi and microvilli
large network of capillaries for maintaining the concentration gradient
47
what process produces ATP?
respiration
48
what is the difference between aerobic and anaerobic?
aerobic needs oxygen and produces more ATP
49
what is the word equation for aerobic respiration?
glucose + oxygen --> water + carbon dioxide (+ATP)
50
what is the balanced symbol equation for aerobic respiration?
C6H12O6 + O2 --> H2O + CO2
51
what is the word equation for anaerobic respiration in animals?
glucose --> lactic acid
52
what is the word equation for anaerobic respiration in plants and fungi?
glucose --> ethanol + carbon dioxide
53
what is the method to investigate the evolution of carbon dioxide from respiring seeds (or other organisms)?
1. pour some sodium hydroxide solution into the first conical flask. this is connected to the pipe that allows the inflow of air and removes the carbon dioxide from the air
2. pour some hydrogen carbonate indicator in the second flask. this is connected to the first flask with a delivery tube
3. place the respiring seeds in the third conical flask on some moist cotton. this is connected to the second conical flask
4. pour some hydrogen carbonate indicator in the fourth flask, which is connected to the pipe to allow the outflow of air
5. observe the colour of the hydrogen carbonate indicator
54
what colour does hydrogen carbonate indicator go in carbon dioxide?
yellow
55
what is the method to investigate the evolution of heat from respiring cells (and other organisms)?
1. set up two thermoflasks
2. place the respiring seeds with cotton wool in one of the thermoflasks
3. place the boiled seeds with moist cotton wool in the other thermoflask
4. use a thermometer to measure and record the initial temperature
5. after a certain number of days, measure and record the final temperature and work out the temperature difference
56
what are the ribs?
bone structures that protect internal organs including the lungs
57
what are the intercostal muscles?
muscles between the ribs that move the rib cage during inhalation and exhalation
58
what is the diaphragm?
sheet of muscle at the bottom of the thorax that changed the thoracic volume during inhalation and exhalation
59
what is the trachea?
the windpipe that connects the mouth and nose to the lungs
60
what are the bronchi?
thick tubes that divided into two bronchi inside lungs - one bronchus for each lung
61
what are bronchioles?
bronchi will split to form them and they are connected to the alveoli
62
what are alveoli?
tiny air sacs where gas exchange occurs
63
what is the pleural membrane?
the thin moist membrane lining the outside of the lungs for lubrication to reduce friction, and to stick outside of lungs to chest cavity for lungs to follow chest movement
64
what happens during inhalation?
diaphragm contracts so it moves down and flattens, the intercostal muscles contract, which pulls the ribs up and out
volume of thorax increases, air pressure falls. the air pressure in the thorax is now lower than the atmospheric pressure, so air moves into the lungs
65
what happens during exhalation?
the diaphragm relaxes so it moves up and domes, the intercostal muscles relax, which makes the rib cage move down and in
the volume of the thorax decreases so air pressure rises. air pressure in the thorax is higher than atmospheric pressure so air moves out of the lungs
66
how are alveoli adapted for gas exchange?
they have a large surface area to volume ratio which increases the rate of diffusion
they are surrounded by a network of capillaries which keeps the concentration gradient high
each alveolus is one cell thick which shortens the diffusion distance
67
what is the effect of smoking on the air passages?
- tar in cigarettes destroys cilia (which gets rid of dust and microbes trapped in mucus) so it causes a build up of mucus, and increased risk of bronchitis
- tar in cigs contains carcinogens which increases risk of lung cancer
68
what is the effect of smoking on the alveoli?
tar in cigs breaks down alveoli walls and makes them merge together, so it increases the surface area : volume
insufficient gas exchange will increase the risk of emphysema - shortness of breath due to insufficient oxygen transport in blood
69
what effect does smoking have on the circulatory system?
- nicotine in blood vessels cause the blood vessels to narrow, placing strain on circulatory system and results in increased blood pressure
- narrowing of blood vessels also cause the build up of fat globules, increasing the risk of coronary heart disease (CHD).
- the carbon monoxide from cigarette smoking will bind irreversibly to haemoglobin, reducing the amount of oxygen that can be carried in red blood cells, so it increases risk of emphysema (shortness of breath due to insufficient oxygen transport)
70
what is coronary heart disease?
it is when the lumen of the coronary arteries is blocked with fat, and irritation of the lining of the arteries causes it to harden until lumen is blocked. this means there's less oxygen taken to the heart, so there is more anaerobic respiration, so lactic acid is produced which causes chest pains (angina). this means less atp is formed, so the muscles stop contracting and die, causing a heart attack
71
what is the method to investigate breathing in humans and the release of carbon dioxide?
1. pour lime water into a boiling tube
2. using the straw, breathe into it
3. note the change in limewater
72
what is the method to investigate breathing in humans and the effect of exercise?
1. measure the breathing rate of the person at rest (breaths/minute)
2. carry out a specific exercise, like star jumps, for 1 minute
3. measure the breathing rate immediately after
4. repeat 2-3 for different intensities of exercise (still the same thing though)
73
what is transpiration?
transpiration is the loss of water from plants through the stomata. it is the process of water evaporating then diffusing out of the leaf
74
which humidity is best for transpiration?
low humidity because there is a lower water concentration outside the leaf
75
what wind speed is best for transpiration?
high wind speed because there is a lower concentration of water outside
76
what temperature is best for transpiration?
high temperatures because the leaf has more kinetic energy
77
what light intensity is best for transpiration?
high because there is more photosynthesis so the stomata open because carbon dioxide is diffusing in so water can also diffuse out
78
what is the method to investigate how the rate of transpiration is affected by different environmental factors?
1. set up a potometer
2. cut leafy shoot under water to prevent xylem closing
3. use vaseline at the joints of potometer to reduce water loss
4. set up the necessary environmental factors (temp=temp controlled room/water bath, humidity = wrap in plastic bags with different concentrations of water, windspeed = fan, light intensity = lamp at different distances)
5. record starting place of air bubble on scale
6. leave it for 1 hour
7. record the final position of air bubble, work out distance moved, work out water absorbed
79
how does a poor diet affect the risk of developing CHD?
diets which have saturated fats, alcohol, and salts increase the presence of cholesterol in the diet, which increases the the risk of fatty deposits which increases the risk of CHD
80
how does smoking increase the risk of chd?
increases blood pressure and increases the risk of fatty deposits forming
81
how does high blood pressure increase the risk of developing CHD?
high bp damages the artery linings and increases the risk of fatty deposits forming
82
how does obesity increase the risk of developing CHD?
causes high blood pressure and may be linked to poor diet
83
how does lack of exercise increase the risk of developing CHD?
increases blood pressure
84
what is the structure and function of arteries?
thick outer layer so it can transport blood at high pressures without bursting
thick layer of elastic tissue to allow the artery to stretch and recoil to maintain high blood pressure
thick layer of muscle tissue to help control the flow of blood by widening (dilating) and narrowing (constricting)
85
what is the structure and function of veins?
thin outer wall because blood is not at very high pressure so it won't burst
thin layer of muscle and elastic tissue so the wall can contract to keep the blood flowing
semilunar valves to prevent blood flowing backwards
86
what is the structure and function of capillaries?
wall is one cell thick for short diffusion distances from blood to tissue
87
what chemical elements are present in carbohydrates?
CHO
carbon, hydrogen, oxygen
88
what chemical elements are present in proteins?
CHON
carbon, hydrogen, oxygen, nitrogen
89
what chemical elements are present in lipids?
CHO
carbon, hydrogen, oxygen
90
what is the monomer of carbohydrates?
glucose/ simple sugars
91
what is the monomer of proteins?
amino acids
92
what are the monomers of lipids
fatty acids and glycerol
93
how an selective breeding develop plants with desired characteristics?
select plants with the desired characteristic and cross pollinate them. take the offspring and continue to cross pollinate them with plants that have the desired characteristic over many generations
94
how can selective breeding develop animals with desired characteristics?
select animals that show that characteristic and breed them together
the gene for it will be passed down to offspring
then select the offspring that best shows the characteristic and breed it with another animal that shows that characteristic and repeat this over many generations
95
what does lactobacillus do in yoghurt production?
ferments lactose into lactic acid which denatures proteins to make the texture gloopy, and gives it the acidic taste
it ferments to produce lactic acid (anaerobic respiration glucose --> lactic acid)
96
what is the method to make yoghurt using lactobacillus?
- equipment is sterilised
- milk is pasteurised (at 85-95 degrees) to kill harmful bacteria
- then milk is homogenised to emulsify fat droplets
- milk is left to cool (at 46 degrees) for four hours to allow the Lactobacillus to grow at optimum temp
- then it is fermented to break down fat droplets into lactic acid
- flavours added and yoghurt packaged
97
what are the biological consequences of pollution of air by sulphur dioxide (and nitrogen dioxide)?
- reacts with water vapour in atmosphere to form dilute acids
- the acid lowers the pH of lakes and rivers which can damage/denature the marine life's enzymes which can cause them to die
- acid rain can also damage trees and plants
- and acid rain can increase the dissolution of metal ions in the soil like aluminium which can then run off into lakes and rivers and poison the fish
98
what are the biological consequences of pollution of air by carbon monoxide?
- when something is burned and there is not enough oxygen (incomplete combustion) carbon monoxide is produced
- carbon monoxide bonds more strongly to haemoglobin than oxygen does, so when a person breathes in carbon monoxide they are not able to get oxygen to respire so they can pass out and die because there is not enough aerobic respiration
99
where are sulphur dioxide, nitrogen dioxide, and carbon monoxide released from?
cars and factories
100
what are five examples of greenhouse gasses?
water vapour, carbon dioxide, nitrous oxide, methane, and CFCs
101
what is sexual reproduction?
- two parents
- two gametes
- meiosis
- forms a zygote which will become a non-identical offspring
102
what are the advantages of sexual reproduction?
- increasing variation
- offspring can adapt to a new environment
- less susceptible to diseases due to variation
103
what are the disadvantages of sexual reproduction?
- time consuming to find a mating partner
- not possible for isolated members
104
what is asexual reproduction?
- one parent
- genetically identical offspring
- produced by mitosis
105
what are the advantages of asexual reproduction?
- rapid increase of population
- thrive in suitable environment
106
what are the disadvantages of asexual reproduction?
- decreases variation
- vulnerable to change in environment due to in-adaptability
- more susceptible to disease as there is less variation
107
what are alleles?
alternative forms of genes that code for a specific characteristic
108
what is the structure of an insect-pollinated flower?
its stamens and the stigma are enclosed within the flower
the petals are large and brightly coloured
the nectaries are present to produce sugary fluid to attract insects
109
what is the structure of wind-pollinated flowers?
the stames are exposed outside of the petals
the stigma is exposed out of the petals and is usually feathery
the petals are small and usually green
there are no nectaries
110
what are three examples of natural asexual reproduction in plants?
runners (eg strawberries), tubers (eg potatoes), bulbs (eg onions)
111
how do runners reproduce?
a new plant is produced where the runner touches the ground
112
how do tubers reproduce?
they are swollen underground stems containing lots of stored food. a plant can produce many tubers which each grow many shoots which form new plants
113
how do bulbs reproduce?
they are underground buds with thick fleshy leaves containing stored food. a main shoot will grow out of the parent bulb, and another will grow out of the side of the 'daughter' bulb, forming two plants
114
what is an artificial method of asexual reproduction?
cuttings
115
how are cuttings used to reproduce artificially?
a piece of a plant's stem, with a few leaves attatched is cut from a healthy plat. this is planted in damp compost, where it will grow roots and develop into a new plant
116
what is the role of oestrogen in the menstrual cycle?
- it thickens the lining of the uterus
- it inhibits FSH production to stop another ovum being matured
- stimulates LH production
117
what is the role of progesterone in the menstrual cycle?
FSH and LH are inhibited to stop another ovum being matured or released
thickness of the uterine lining maintained
118
what is the role of FSH in the menstrual lining?
- follicle and ovum mature
- stimulates oestrogen production
119
what is the role of LH?
- ovulation - follicle on ovary releases mature ovum into oviduct (fallopian tubes)
- remnant of follicle (on ovary) becomes corpus luteum
120
what is the role of the placenta in the nutrition of the developing embryo?
- allows nutriend (eg glucose, amino acids, and salts) and oxygen to move from the mother to the embryo
- allows metabolic wastes (carbon and urea) to move from the embryo to the mother
121
how does the amniotic fluid protect the developing embryo?
it protects the baby against jolts and bumbs (mechanical shocks), drying out, and temperature fluctuations (due to waters high specific heat capacity)
122
how does human activity contribute to greenhouse gasses?
carbon dioxide - burning fossil feuls, slash and burn forest clearance
methane - generated by bacteria in anaerobic conditions, eg. ruminants suchas cattle produce large volumes of methane from the anaerobic activity of bacteria in their gut, which largely comes out from their mouths, and bacteria in waterlogged paddy fields for rice cultivation give off methane
nitrous oxides - burning fossil fuels
CFCs - until the 1990s they were used in aerosols like deodorants, and were used in fridges and freezers. CFCs were also blamed for the hole in the ozone layer
123
what is enhanced greenhouse effect?
there are more greenhouse gasses in the atmosphere so there is more greenhouse effect. the greenhouse effect is that some IR radiation passes through the atmosphere but some gasses absorb the radiation which prevents it from escaping back to space. this leads to more energy being held by the atmosphere, which heats it. too muh greenhouse effect contributes to global warming
124
what are the potential effects of global warming
- melting of polar ice caps -> causes flooding and rise in sea levels
- destruction of habitat -> could lead to extinction of species
- drought and desertification -> can lead to crop failure and food shortages/famines
- increased extreme weather events
- spread of disease -> disease carrying organisms (eg mosquitos) will survive in a wider range of countries so those diseases can become more common
- change in crops
- increased heat related illness and deaths -> increases death rates in the elderly related to heat waves in recent years
