Biology paper 2 Flashcards
1
Q
What is the balanced equation for photosynthesis?
A
6CO2+6H2O—>C6H12O6+6O2
2
Q
Word equation for photosynthesis?
A
carbon dioxide+ water
–>glucose+oxygen
3
Q
How do you test for how light can effect photosynthesis?
A
1)set up apparatus, empty gas syringe and add sodium hydrgen carbonate to esnure the plant has enough CO2, a source of white light is placed at a specific distance from the plant, leave for a set amount of time for photosynthesis to take place, see how far the gas syirnge has moved, then change the distance to closer and furtehr away to get more results, make sure you leave for the same amount of time and have the same temperature.
4
Q
When light intensity increase will rate of photosyntheiss also increase?
A
they will both increase together up untill a certain point where light intensity will no longer effect the rate of photosynthesis.
5
Q
what factors effect photosynthesis?
A
the amount of Carbo dioxide as too little will slow the reaction down, and temeprature also effects it as if to cold enzymes take longer to work and if too hot the enzymes will denature.
6
Q
What is the role of root hairs in plants?
A
they take in minerals and water from the soil, there are million microscopic ones meaning there is a large surface area
7
Q
What is the role of phloem tubes in plants?
A
they transport the food, they are made from elongated cells
8
Q
What is the role of xylem tubes in plants?
A
they take water up, made from dead cells, carry the water and minerals from the roots to stems and leaves
9
Q
What is the process of transpiration?
A
transpiration is caused by evaporation and diffusion, mainly in the leaves, , thsi creates water loss so the xylem brings up more water, this means tehre is a cosntant water transport and carry of minerals which are in the water
10
Q
What are and what do are stomota needed for?
A
Stomato are tiny pores on the surfaces of plants and they are needed for gas exchange, the allow oxygen abd carbon dioxide to diffuse directly into the leaves, as well as for water vapour to leave during transpiration.
11
Q
What environmental factors affect transpiration rate?
A
light intesnity brighter light means greater transpiration rate, temperature the warmer it is the fats it occurs and air flow better air flow also increases transpiration rate,
12
Q
What is in a leaf?
A
The wacy cuticle, xylem and phloem, upper epidermis, stomata, guard cells, lower epidermis, air space, spongy mesophyll tissue, palisade mesophyll tissue.
13
Q
what does the palisade layer in a plant do?
A
contains lots of chloroplasts
14
Q
what does the upper epidermis do?
A
it is transparent so light can pass through and go to the palisade layer.
15
Q
what are some adaptions plants have for harsh environments?
A
small leaves or spines - reduces surface area for water loss by evapouration, spine salso prevent animals eatng the plant. curled leaves or hairs reduce airflow. thick waxy cuticles, reduce water lost by evapouration. thick fleshy stems store water, fewer stomata or stomata that open at night reduce water loss by evapouration
16
Q
what are and what do auxins do?
A
they are plant growth hormones, they grow at tips of shoots and roots encourage shoot growth but not root growth. they also make the plant change shape to bend towards sunlight.
17
Q
What are 6 ways that plant hormones can be used for commercial use?
A
selective weed killers, growing from cuttings with rooting powder, controlling flower and fruit formation, producing seedless fruits, controlling the ripening of fruits, controlling seed germination
18
Q
What is the pituitary gland where is it and what does it do?
A
it is located in the brain, called the master gland and produces hormones to regulate body conditions.
19
Q
What is the thyroid gland where is it and what does it do?
A
it is in the neck, produces thyroxine which is used to regulate metabolism rate, heart rate and temperature,
20
Q
What is the adrenal glands where is it and what does it do?
A
produces adrenaline near pancrease, kicks in the fight or flight response
21
Q
What is the testes where is it and what does it do?
A
in the testicals, produces testosterone, controls puberty and sperm production,
22
Q
What is the ovaries where is it and what does it do?
A
produces oestrogen involved in menstrual cycles
23
Q
What is the pancreas where is it and what does it do?
A
produces insulin to regulate blood glucose levels.
24
Q
How does adrenaline work?
A
binds to sepcific receptors in the heart meaning it contracts more frequently and with more force, increasing heart rate and blood pressure, increasing oxygen and glucose going to the muscles, also binds to receptors in liver making glycogen break into glucose, increase blood glucose levels.
25
How does the body control hormone levels.
It uses negative feedback which helps detect when a substance is too high or low allowing the body to recat and bring the level back to normal.
26
How does negative feedback keep the right thyroxine level?
when lower then normal the hypothalamus is stimulated to release TRH, this makes the pituitary gland release TSH, which makes the thyroid gland release thyroxine when higher TRH production inhibited so amount of TSH decrease so less thyroxine is released.
27
how many stages are in a mnestrual cycle and what are they?
4 stages,
stage 1 menstruation starts
stage 2 uterus lining is repaired,
stage 3 an egg develops and is released
stage 4 lining is maintained
28
what are the 4 hormones used during menstruation?
FSH - released by pituartity gland and causes a follicle to mature in one of the ovaries this stimulates oestrogn production
Oestrogen - released by ovaries this causes the uterus to thicken and grow, and a high level stimulates LH surge.
LH - released by pituitary gland, the surge causes the egg to release,, stimulates the remains of the follicle to develop into a structure called a corpus luteum, this secretes progesterone.
progesterone - released by the corpeus luteum after ovulation, maintains uterus lining and inhibits FSH and LH, when progesterone level falls the uterus lining breaks down, this allows FSH to increae and restart the cycle
29
what are the different steps during a menstrual cycle?
day 1- 4 lining of uterus breaks
day 4-14 lining of uterus builds up.
day 14-28 lining of uterus is maintained
day 28-1 lining begins to deteriorate
30
What is chlomifene?
It is a therapy that involves giving them the drug so that they can have an increase in FSH and LH so that they ovulate more regularly and encourage egg maturation. by knowing when the women will ovulate the couple can have intercourse during this period
31
what is IVF?
collecting eggs from womens ovaries and fertilising them in a lab using the mans spem. these get grown into embryos once they become tiny balls of cells on or two are transferred into the womens uterus to improve chance of pregnancy.
32
What types of contraceptions can be used to prevent pregancy?
Hormones - oestrogen can prevent release of egg as if high level kept egg won't release, progesterone reduces fertility, produces thick mucus preventing sperm to reach egg this can be done by a pill. or a condom can be used so that a barrier prevents the sperm and egg from ever meeting.
33
What is homeostatis?
the maintaining of a constant internal environemnt - conditions in body neeed to be steady as your cells need the right conditions to work properly, can be dangerous once conditions vary too much.
34
What are 3 examples of homeostatis action?
Osmoregulation - keep a balance between water you drink and water you pee, sweat and breathe out,
thermoregulation - reduce your body temperature when you are hot but increase when cold
blood glucose regulation - need to make sure amount of glucose in blood doesn't get too high or too low.
35
What happens when blood glucose is too high?
Insulin gets added either by injection if you have diabetes or is secreted from pancreas, the blood with too much glucose and insulin enters the liver where the insulin converts the glucose into glycogen
36
What happens when blood sugar levels are too low?
blood with too little glucose is detected by pancreas, this time it secrets glucagon, this goes round the blood strem to the liver, the glucagon and too little glucose blood enters the pancreas where it converts the glycagon in the liver to glucose which is the secretd out.
37
What is type 1 diabetes caused by?
A lack of insulin, this is because the pancreas secrets little to no insulin meaning a person glucose levels can rise to a level it could kill them, so they inject insulin into their blood stream (mealtimes) so glucose can be quickly removed from blood once food has been consumed. as well as this they alo need to be careful of foods rich in simple carbs like sugar and regularly exercise
38
what is type 2 diabetes caused by?
When a person is resistant to insulin, pancreas doesn't produce enough or the person becomes resistant to insulin, tehre is a correlatin between obesity and type 2 diabetes.
39
What BMI do you need to be classified as obese?
over 30
40
how do you work out BMI?
Weight (kg)/height (m^2)
41
What is the normal body temperature and what controls the body's temperature?
37 degrees celsius, the hypothalamus controls the body tmeeprature.
42
What happens when your body is too hot?
the erector muscles will relax meaning hairs on your body will relax, you will sweat lots (cotaining water and salts) produced from sweat glands, sweat gets released onto the skin through pores, when sweat evapourates it transfers energy from skin to environment cooling you down, blood vessels close to the skins surface will dilate, allwoing more blood flow close to te sruface so more energy is transferred to surroundings cooling you down.
43
What happens when your body is too cold?
erector muscles contract, this makes your hairs stand up, this traps and isnulating layer of air near the skins surface to keep you warm, verry little sweat is produced, blood vessels will constrict so less blood flows near surface so less energy is transferred to surroundings. when your cold you also shiver, increasing respiration rate which transfers more energy to warm the body
44
Why do we need to regulate water content?
so we can keep cells funtioning normally as if water in blood is too high then water will move into the body cells by osmosis and the cells may burst when there is too much water, if there is too little water the cells will shrink
45
what role does the kidney have in the urinary system?
removal of urea from the blood, urea is produced in the liver from the breakdown of excess amino acids.
they help adjust ion levels in the blood
they adjust water content in the blood too
this is done by filtering stuff out of blood by high pressure and then re absorbing the suefull things, the end product creates urine.
46
what do nephrons do in the kidneys?
They are filtration units,
47
how does the negative feedback system control water content?
The brain monitors the water content in blood and instructs the pituitary gland to relase ADH into the blood depedning on how much is required, the ADH makes the nephrons more premable so that more water is reabsorbed, stopping the body from becoming dehydrated. if the person is dehydrated the brain release more ADH making the kidney reabsorb more water
48
How does dialysis work?
patients who have kidney failure can not filter their blood properly so they need a dialysis, it has to be done regularly to keep dissolved substances at the right concentrations and to remove waste, dialysis fluid has the same concentration of glucose and salts as blood plasma meaning they won't be removed from the blood.
49
How can we cure kidney disease?
At the moment only with a kidney transplant, normally transplanted when a person sudenley dies and they have a healthy kidney and if they are down to donate organs or carry and organ card howveer the persons body may reject the kidney as the immune system may treat the kidney as a foreigner and attack it with antibodies, the donors tissues need to match up with the recievers and the patient will be treated with drugs to try and supress the immune system so that it won't attack the transplanted kidney.
50
How does diffusion occur in single celled organisms?
gases and disolved substanes can diffuse directly into the cell across the cell membrane, this is because they have a large surface area compard to the volume
51
How does diffusion occur in multicellular organisms?
smaller surface area to volume s need an exchange surface and a mass trasnport system. to move substanxes between the exchange surface and rest of the body
52
what does rate of diffusion depend on?
distance- diffuses more quicker over shorter distances
concentration - diffuse faster when there is a big difference in concentration from where they are going to and where they have come from
surface area- the more surface area there is available to move across the faster they move.
53
What is ficks law?
The rate of diffusion = surface area*concentration difference/thickness of membrane
54
How does gas exchange occur in mammals?
1)lungs transfer oxygen to the blood and to rmeove carbon dioxide, to do this lungs contain millions of little air sacs called alveoli where gas exchange occurs. blood arrives at the alveoli with lots of carbon dioxide and little oxygen maximising diffusion for both gases. then oxygen diffuse out the air in the alveoli and into the blood, carbon dioxide does the opposite and gets breathed out.
55
What do red blood cells do?
They transport oxygen around the body and take carbon dioxi to the lungs to be breathed out. no nucleus so have more room of oxygen and are biconcve to have a larger surface area.
56
what do white blood cells do?
They protect against infection, phagocytes are white blood cells tha can change shape to engluf unwanted microorganism
lymphoctes are white blood cells that produce antibodies against microorganisms, some produce anti toxins to neatralise any toxns in the microorganisms. when you have an infection these multiplu to fight it off so you blood will have a high white blood cell count
57
What do we use platelets for?
They help clot the blood, they are small cell fragments with no nucleus, they jelp clot wounds so your blood doesn't pour out. a lack of these can cause excessive bleeding and bruising.
58
what does plasma do?
it is a plae straw-coloured liquid that carries everything, it carries your: red and white blood cells, platelets, glucose and amino acids, carbon dioxie, urea, hormones and proteins
59
Whar are the three types of blood vessels?
arteries - they carry blood from the heart
capillaries - these are involved in the exchange of materials at tissues
veins- these carry the blood to the heart
60
What are arteries like ?
They carry blood away from the heart, they walls are strong and elastic due to the high pressure pumping from the heart, walls are thick compared to hole size,
61
what are capillaries like?
thin wall on cell thick, very narro so can squeeze in the gaps between cells, carry blood close to cells so can exchange substances, permeable walls to allow diffusion supply food and oxygen and remove carbon dioxide
62
what are veins like?
They take blood back to the heart, low pressure so walls aren't as thick, larger lumen to keep blood flow, have valves so blood flows in right direction
63
What type of circulatort systems do mammals have?
They have a double circulatory system, heart pumps deoxygenated blood to lungs and then once the oxygenated blood returns that gets pumped round the body
64
Whats the differences between a humans circulatory system and a fishes?
humans have a double cirulatory system, fish have a single, fish have 2 chambered hearts humans have 4, fish goes round once human goes round twice.
65
what is the journey of blood around the cirulatory system?
the right atrium recieves deoxygeneted blood (vena cava), then it eneters the right ventricle where it is pumped to the lungs by the pulmonary artery, the newly oxygenated blood returns to the heart and enters the left atrium from the pulmonary vein, it enters the rleft ventricle which pumps it round the rest of the body using the aorta
66
How do you calculate how much blood is pumped every minute?
heart rate*stroke volume
67
What are the two types of respiration?
aerobic and anaerobic
68
What is respiration?
Respiration is the process of trasnferring energy from the breakdown of irganic compounds its an exothermic reaction.
69
What is the equation for aerobic resperation?
glucose + oxygen ----> carbon dioxide + water
C6H12O6 +6O2 ----> 6CO2 +6H2O
70
What are the equations for anaerobic respiration?
in plants - glucose ---> ethanol + carbon dioxide
not in plants ---> glucose ---> lactic acid
71
What What is the difference between aerobic an anaerobic respiration?
aerobic uses xygen anaerobic doesn't, anaerobic in humans happens when you are exercising and your body can not provide enough oxygen to your muscles
72
Explain the steps for the respiration practicle?
Add sine sida lime granules to two test tubes, these will absorbs the carbon dioxide produced by the woodlice in the practical, place cotton wool above the soda lime, then in ne test tube put woodlice in one and glass beeds in another, set up the respirometer, the syringe will be used to set the fluid in the manometer to a known level, leave the apparatus for s et time in a water bath of 15 degrees celsius, over time the volue f air in the test tube with the woodlice will decrease, as the woodlice will use oxygen to respire, the volume decreasing means the pressure in the tube also decerases so the colour liquid will move closer to the tube with woodlice. the distance that the liquid moves in the time is measured, this can be sued to work out how much oxygen the woodlice took in every minute giving you the rate of respiration. repeat the steps but change the temperature of the water bath.
73
What are the four different levels in an ecosystem?
Individual - single organism
population
population- all organisms of a species in a habitat
community - all organism of different sepcies living in a habitat
ecosystem - a communit of organisms along with non living things
74
What is mutualism?
Is a relationship between two organisms which both benefit, likes bees and flowers
75
What do parasites do?
They live closely with a host species take what they need from host to survive but this doesn't benefit the host
76
What are the abiotic factors that affect communities?
temperature -different temperatures in areas depend on whether animals can live there or not as the place could be too cold or too warm.
Amount of water/rainfall - as different plants need different amount of water in order to survive like cactuses in deserts don't need too much water hence why they grow in desert not rainforests
light intensity - some vegetation deal better with low intensity so deal well with shaded areas
pollution levels - if level is too high they can't survive for example lichen unable to survive if sulfur dioxide concentration is too high
77
Biotic factors affecting communities?
competition - if predators outumber prey large competition increase to get food,
predation - if number of predators decrease number of prey could increase as less are getting hunted and eaten
78
What are pyramids of biomass?
They show weight of a species if you put all of the creatures at each level of a food chain together. it decreases as it goes up as the amount gets less and less (typically)
79
Pyramid of biomass draw info
fist level producer, second primary consumer, third secondary consumer and so on
5 small squares on a grid = 1kg
80
efficiency equation?
energy transferred to next level
----------------------------------------------- *100
energy available at previous level
81
What is eutrophication?
It is when nitrates are put into fields as fertilisers, if there is too much applied and it the rains afterwards the nitrates can easily find their ways to rivers and lakes, this can kill many species in the water and reduce biodiversity.
82
What are 6 benefits of maintaining biodiversity?
1) protects the human food supply so that there is enough for future generations
2) ensures minimal damage to food chain
3) future medicines can be discovered as lots of medicines come from plants undiscovered plants could get destroyed and go extinct
4)cultural aspects species important to a countries nature or heritage can survive
5)ecotourism - draws people to these places and the money earnt goes back into investing in protecting areas
6)provides jobs, ecotourism and conservation schemes and reforestation schemes
83
What is the process for the carbon cycle?
1)Plants photosynthesis to make carbs, fats and proteins
2)eating passes carbon compounds in the pant along animals in the food chain
3)both plants and animals respire while alive this releases carbon dioxide back into air
4)when plants and animals die and decompose or get killed to turn into useful products
5)when plants and animals decompose they get broken down by micro organisms like bacteria and fungi, this release carbon dioxide back into the air by respiration as they break down the material,
6)so useful plant and animal products release carbon dioxide back into the air
7)decomposition of materials means that habitats can be maintained f organisms that live there.
84
What is the process of water cycle?
1)energy from the sun makes water evaporate by turning water into water vapour, 2)the warm water vapour gets carried upwards when it gets higher it cools and condenses to form clouds.3) water falls as precipitation onto land and some into sea where the process then repeats again
85
when do droughts occur?
Droughts cause big problems, partly because we rely on the precipitation to get fresh water,
86
What is desalination?
It is the removal of salts from salt water, there are a few different methods, thermal which is where it is boiled in an enclosed vessel, steam rises salt stays.
87
What is reverse osmosis?
osmosis is the reverse net movement of water across a partially permeable membrane high concentration to low concentration, high salt concentration=lower salt concentration. reverse osmosis gts rid of impurities in water
88
What is the nitrogen cycle?
1)atmosphere has 78% nitrogen gas, decomposer break down proteins in rotting plants and animals and urea un animal waste, this returns nitrogen to soil so nitrogen is recycled, nitrogen fixation is turning N2 into nitrogen contain ions in soil for plants to use. lightning has so much energy it can create nitrates, nitrogen fixing bacteria in roots and soil.
what 4 types of bacteria are found in the nitrogen cycle - decomposers, nitrifying bacteria - turns ammonium into nitrites then nitrates
nitrogen fixing bacteria - atmospheric N2 to ammonia to ammonium ion.
denitrifying bacteria - nitrates into N2 gas.
89
What two ways can farmers increase the amount of nitrates in soil?
crop rotation - growing crops in a cycle not the same on each year in the same spot (usually has a nitrogen fixing crop which helps but nitrates back into the soil for the next crop.
fertiliser - spreading animal manure or composts on fields recycles the nutrients left in the plant or animal waste and the nitrates go back into the soil via decomposition.
90
What can indicator species show the level of?
water and air pollution
91
How do indicator species show water pollution level?
raw sewage or fertilizers containing nitrates get released into rivers the microorganisms use up oxygen. so invertebrate animals like stonefly lava and freshwater shrimp are good water pollutant indicators due to sensitivity of the concentration of dissolved oxygen in water if you find either water is clean, but if you find blood or sludge worms there is a very high water pollutant level.
92
How do indicator species show air pollution level?
lichen is the main example as they are sensitive to sulfur dioxide concentration, the number of lichen and type tells you how clean the air is, if there is a lot of lichen the air is clean, black spot fungus on rose leaves indicate clean air.
93
What are flaws with indicator species?
Counting the number of times an indicator occurs gives a numerical value but this is only roughly how un polluted the area is. a simple survey could be done but this isn't good for telling how polluted the area is but isn't a good way for telling how polluted an area is
94
What three things are need for something to decompose?
temperature - warm temperature speeds up rate of enzyme controlled reactions, decay happens faster this way, however if gets too hot enzymes denature
water content - decay takes place faster in moist environments because the organisms involved in decay need water to survive and carry out biological processes.
oxygen availability - decomposure is faster where there is plenty of oxygen available. many microorganisms need oxygen for aerobic respiration.
95
What are ways to preserve foods?
storing foods in a fridge or freezer lowers food temp slowing down decomposers rate of reproduction.
put it in airtight cans stops microorganisms getting in, once food is in and sealed and sterilised microorganisms are killed
drying foods removes water that the microorganisms use to survive and reproduce, same for adding salt or sugar which causes microorganisms to lose water by osmosis.
96
what conditions are needed to make compost?
it produced quickest in warm, damp, moist conditions with lots of conditions. like compost bins create ideal conditions and bring decomposers, some have mesh sides to increase oxygen availability, decomposing material is moist and heat because of decomposers, some compost bins are also insulate to increase temperature further
