Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

freakology > things idk from the spec > Flashcards

things idk from the spec Flashcards

1
Q

what is a pathogenic example of a Protoctista

A

plasmodium and it is responsible for causing malaria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are 2 examples of a bacteria

A
  • lactobacillus bulgaricus -> a rod shaped bacterium used in the production of yogurt from milk
  • pneumococcus -> a spherical bacterium that acts as the pathogen causing pneumonia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are some examples of viruses

A
  • tobacco mosaic virus which causes the discolouring of the leaves of tobacco plants by preventing the formation of chloroplasts
  • the influenza virus which causes the flu
  • the HIV virus which causes AIDS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

describe what tissue is

A

a group of similar cells that work together to carry out a particular function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

describe what an organ is

A

a group of different tissues that work together to perform a function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

describe what an organ system is

A

organs work together to perform an organ system, each system does a different job

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

describe what an organelle is

A

a subcellular structure that has one or more specific jobs to perform in the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

describe what a cell is

A

the fundamental unit that makes up living things

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is the function of the nucleus

A

an organelle which contains the genetic material that controls the cells activities, it is surrounded by its own membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the function of the cytoplasm

A

a gel like substance where most of the cells chemical reactions happen, it contains enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is the function of the cell wall in a plant

A

a rigid structure made of cellulose which surrounds the cell membrane, it supports and strengthens it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is the function of mitochondria

A
  • small organelles where most of the reaction for aerobic respiration take place, respirations transfers energy that the cell needs to work
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is the function of chloroplasts

A
  • photosynthesis which makes food for the plant happens here, chloroplasts contain a green substance called chlorophyll which is used in photosynthesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is the function of ribosomes

A
  • small organelles where proteins are made in the cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is the function of the vacuole

A

a large organelle that contains cell sap, it helps support the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is the difference between a plant and animal cell

A
  • plant cells have everything that animals have plus chloroplasts, cell wall and a vacuole
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what are the chemical elements present in carbohydrates

A
  • carbohydrate molecules contain the elements carbon, hydrogen and oxygen
  • starch and glycogen are large, complex carbohydrates, which are made up of many smaller units such as glucose and maltose which are joined together by a long chain
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what are the chemical elements present in proteins

A
  • proteins are made up of long chains of amino acids
  • they all contain carbon, nitrogen, hydrogen and oxygen atoms
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what are the chemical elements present in lipids

A
  • lipids are built from fatty acids and glycerol
  • lipids contain carbon, hydrogen and oxygen atoms
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

how do you make a food sample

A
  • get a piece of food and break it up using a pestle and mortar
  • transfer the ground up food to a beaker and add some distilled water
  • give the mixture a good stir with a glass rod to dissolve some of the food
  • filter the solution using a funnel lined with filter paper to get rid of the solid bits of food
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

describe the benedict’s test

A
  • test for glucose
  • prepare a food sample and transfer 5cm3 to a test tube
  • prepare a water bath so that its set to 75 deg
  • add 10 drops of benedict’s solution to the test tube using a pipette
  • place the test tube in the water bath using a test tube holder and leave it in there for 5 mins, make sure the tube is pointing away from you
  • if glucose is present it will turn from blue to brick red
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

describe the iodine test

A
  • test for starch
  • make food sample and transfer 5cm3 of your sample to a test tube
  • add a few drops of iodine solution and gently shake the tube to mix the contents
  • if starch is present it will turn from orange to blue black
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

describe the biuret test

A
  • test for protein
  • prepare a food sample and transfer 2cm3 of your sample to a test tube
  • add 2cm3 of biuret solution to the sample and mix the contents by shaking it gently
  • if the food sample contains protein the solution will change from blue to purple
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

describe the emulsion test

A
  • test for lipids
  • place food sample in a test tube
  • add a small volume of absolute ethanol and shake to dissolve any lipid in the alcohol
  • add an equal volume of water
  • a cloudy white colour caused by an emulsion forming indicated the presence of lipids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what is the definition of active transport

A
  • the movement of particles against a concentration gradient, from an area of low concentration to an area of high concentration using energy released from respiration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

describe the practical for how to investigate osmosis using a living system

A
  • cut up a potato into identical cylinders and get some beakers with different sugar solutions in them
  • one should be pure water and the other a very concentrated sugar solution
  • then you have others with concentrations in-between
  • measure the length of the cylinders then leave a few in each beaker for an hour
  • take them out and measure them again
  • if the cylinders have drawn in water via osmosis they will be longer, if water has been drawn out they will have shrunk a bit
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

describe the practical for how to investigate osmosis using a non-living system

A
  • fix some Visking tubing over the end of the thistle funnel, then pour some sucrose solution down the glass tube and into the thistle funnel
  • put the thistle funnel into a beaker of pure water- measure where the sucrose solution comes up to on the glass tube
  • leave the apparatus overnight, then measure where the solution is in the glass tube. water should be drawn through the Visking tubing via osmosis and this will force the solution up the glass tube
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what is the balanced symbol and word equation for photosynthesis

A
  • carbon dioxide + water —> glucose + oxygen
  • 6co2 + 6h20 —> c6h12o6 + 6o2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

how can varying co2 concentrations affect the rate of photosynthesis

A
  • increasing the concentration of co2 will only increase the rate of photosynthesis up to a certain point
  • after this the graph will flatten out showing that co2 is no longer the limiting factor
  • it will either be light intensity or temperature which is the limiting factor
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

how can varying light intensity affect the rate of photosynthesis

A
  • if the light intensity is increased then the rate o photosynthesis will increase steadily, but only up to a certain point
  • beyond that it wont make any difference because it will either be co2 concentration or temperature which is the limiting factor
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

how can varying temperature affect the rate of photosynthesis

A
  • as the temperature increases, so does the rate of photosynthesis, up to a point
  • if the temp is to high then the plants enzymes will denature so the substrate will no longer be complimentary, so the rate of photosynthesis decreases rapidly
  • usually though, if temperature is the limiting factor it is because it is too low
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

describe the 6 ways that the structure of a leaf is adapted for photosynthesis

A
  • leaves are broad so there’s a large surface area exposed to light
  • most of the chloroplasts are found in the palisade layer, this is so that they are near the top of the leaf where they get the most light
  • upper epidermis is transparent so light can pass through to the palisade layer
  • leaves have networks of vascular bundles- these are the transparent xylem and phloem, they deliver water and other nutrients to every part of the leaf and take away the glucose produced by photosynthesis
  • the waxy cuticle helps reduce water loss via evaporation
  • the adaptations of leaves for efficient gas exchange also make photosynthesis more efficient, the lower surface is full of stomata which allow co2 to diffuse directly into the leaf
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

why do plants require nitrates

A
  • contain nitrogen for making amino acids and proteins
  • these are needed for cell growth
  • if a plant cant get enough nitrates it will be stunted and older leaves will turn yellow
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

why do plants require phosphates

A
  • contain phosphorous for making DNA and cell membranes and their needed for respiration and growth
  • plats without enough phosphate have poor root growth and their older leaves are purple
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

why do plants require potassium

A
  • it helps the enzymes needed for photosynthesis and respiration
  • if there’s not enough potassium in the soil, plants have poor flower and fruit growth and discoloured leaves
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

why do plants require magnesium in small amounts

A
  • magnesium is one of the most significant because its needed for making chlorophyll which is needed for photosynthesis
  • plants without enough magnesium have yellow leaves
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

how can you test for starch to investigate photosynthesis

A
  • start by duking the leaf in boiling water ( hold with forceps) this stops any chemical reactions happening in the leaf
  • put the leaf in a boiling tube with some ethanol and heat it in an electronic water bath until it boils - this gets rid of any chlorophyll and makes the leaf a white ish colour
  • rinse the leaf in cold water and add a few drops of iodine solution- if starch is present the leaf will turn blue black
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

how can you show that chlorophyll is needed for photosynthesis

A
  • take a variegated leaf from a plant that has been exposed to light for a bit, make sure you record which bits are green and which are not
  • test the leaf for starch, you will see that only the bits that were green turn blue black
  • this suggests that only the parts of the leaf that contained chlorophyll are able to photosynthesize and produce starch
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

how can you show that co2 is needed for photosynthesis

A
  • you will need a sealed bell jar, soda lime, a light and a plant
  • the soda lime will absorb co2 out of the air in the jar
  • if you leave the plant in the jar for a while and then test a leaf for starch, it wont turn blue black
  • this shows that no starch has been made in the leaf, which means that co2 is needed for photosynthesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

how can you show that light is required for photosynthesis

A
  • you need a plant that’s been grown without any light, e.g in a cupboard for 48 hrs, this will mean that its used up its starch stores
  • cut a leaf from the plant and test it for starch using iodine solution, the leaf wont turn blue black
  • this shows that light is needed for photosynthesis, as no starch has been made
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

describe the practical of oxygen production showing the rate of photosynthesis

A
  • set up the apparatus, including a ruler, light source, syringe, 2nd ruler, clamp, clamp stand, capillary tube,gas syringe
  • gas syringe should be empty to start of with, sodium hydrogen carbonate may be added to the water to ensure the plant has enough co2
  • a source of white light is placed at a specific distance from the pondweed
  • the pondweed is left to photosynthesise for a specific amount of time, as it photosynthesises the oxygen released will collect in the capillary tube
  • at the end of the experiment, the syringe is used to draw the gas bubble in the tube up along side a ruler and the length of the gas bubble is measured, this is proportional to the amount of o2 produced
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

what is vitamin A found in and what is its function

A
  • found in liver/ organ meats
  • helps prevent night blindness and keep your skin and hair healthy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

what is vitamin b found in and what is its function

A
  • found in fruit
  • prevents scurvy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

what is vitamin c found in and what is its function

A
  • found in eggs
  • needed for calcium absorption
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

where are mineral irons like iron found and what is its function

A
  • found in red meat
  • needed to make haemoglobin for healthy blood
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

where is dietary fibre found and what’s its function

A
  • found in wholemeal bread
  • aids the movement of food through the gut
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

describe how food is moved through the gut via peristalsis

A
  • there’s muscular tissue all the way down the alimentary canal
  • its job is to squeeze balls of food ( called boluses) through your gut, otherwise it would get clogged up with old food
  • this squeezing action, which is waves of circular contractions is called peristalsis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

what is the function of the mouth in the human alimentary canal

A
  • salivary glands in the mouth produce amylase enzyme in the saliva
  • teeth break down food
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

what is the function of the oesophagus in the human alimentary canal

A
  • the muscular tube that connects the mouth ad stomach
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

what is the function of the liver in the human alimentary canal

A

where bile is produced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

what is the function of the gall bladder in the human alimentary canal

A

where bile is stored

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

what is the function of the large intestine in the human alimentary canal

A
  • also called the colon
  • where excess water is absorbed from the food
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

what is the function of the rectum in the human alimentary canal

A
  • the last part of the large intestine
  • where the faeces ( made up of mainly indigestible food) are stored
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

what is the function of the stomach in the human alimentary canal

A
  • it pummels the food with its muscular walls
  • it produces the protease enzyme, pepsin
  • it produces hydrochloric acid for 2 reasons
    . to kill bacteria
    . to give the optimum PH for the protease enzyme to work
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

what is the function of the pancreas in the human alimentary canal

A
  • produces protease, amylase and lipase enzymes
  • it releases these into the small intestine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

what is the function of the small intestine in the human alimentary canal

A
  • produces protease, amylase and lipase enzymes to complete digestion
  • this is also where the nutrients are absorbed out of the alimentary canal into the body
  • the first part is the duodenum and the last part is the ileum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

how do villi in the small intestine help with absorption

A
  • the small intestine is adapted for absorption of food
  • its very long so there is time to break down and absorb all the food before it reaches the end
  • there’s a really big surface area for absorption, because the walls of the small intestine are covered in millions of tiny projections called villi
  • each cell on the surface of a villus also has its own microvilli -> little projections that increase the surface area even more
  • villi have a single permeable layer of surface cells and a very good blood supply to assist quick absorption
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

what is the role of bile

A
  • produced in the liver and stored in the gall bladder before its released into the small intestine
  • the hydrochloric acid in the stomach makes the PH too acidic for the enzymes in the small intestine to work properly.
  • bile is alkaline- it neutralises the acid and makes conditions alkaline, the enzymes in the small intestine work best in these alkaline conditions
  • bile also emulsifies fats, which breaks the fat into tiny droplets, this gives a much bigger surface area of fat for the enzyme lipase to work on - which makes digestion faster
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

what digestive enzyme converts starch to maltose

A

amylase enzyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

what digestive enzyme converts maltose to glucose

A

maltase enzyme

61
Q

what digestive enzyme converts proteins to amino acids

A

protease enzyme

62
Q

what digestive enzyme converts lipids into glycerol and 3 fatty acids

A

lipase enzyme

63
Q

how does the process of respiration produce ATP in living organisms

A
  • respiration is the process of transferring energy from glucose
  • some of the energy is transferred by heat
  • the energy is transferred by respiration cant be used directly in cells- so its used to make a substance called ATP. ATP stores the energy needed for many cell processes
  • when a cell needs energy, ATP molecules are broken down and energy is released
  • there are two types of respiration aerobic and anaerobic
64
Q

give the work equation and balanced symbol equation for aerobic respiration

A

glucose + oxygen –> carbon dioxide + water (+ energy)

c6h12o6 + 6o2 –> 6co2 + 6h2o

65
Q

give the work equation for anaerobic respiration

A

glucose –> lactic acid (+ energy)

66
Q

what is the word equation for anaerobic respiration in plants

A

glucose –>ethanol + carbon dioxide (+ energy)

67
Q

what happens when breathing in

A
  • intercostal muscles and diaphragm contract
  • thorax volume increases
  • this decreases the pressure, drawing air in
68
Q

what happens when breathing out

A
  • intercostal muscles and diaphragm relax
  • thorax volume relaxes
  • air is forced out
69
Q

describe the experiment to investigate the release of co2 in your breath

A
  • set up 2 boiling tubes, put the same amount of limewater in each
  • put your mouth around the mouthpiece and breath in and out several times
  • as you breath in air is drawn in through the opposite boiling tube, this contains very little co2 so the limewater will remain colourless
  • when you breath out, the air you exhale bubbles through the limewater in the boiling tube, this air contains co2 produced during respiration so the limewater turns cloudy
70
Q

what are the biological consequences of smoking

A
  • smoking damages the walls inside the alveoli, reducing the surface area for gas exchange and leading to diseases like emphysema
  • the tar is cigarettes damages the cilia in your lungs and trachea, the cilia along with mucus catch a load of dust and bacteria before they reach the lungs , the cilia also help to keep the trachea clear by sweeping mucus back towards the mouth
  • tar also irritates the bronchi and bronchioles, encouraging mucus to be produced which cant be cleared by damaged cilia, this causes bronchitis and smokers cough
  • carbon monoxide reduces the amount of oxygen the blood can carry, to make up for this the heart rate increases which leads to an increased blood pressure, high BP damages artery walls, making blood clots more likely, increases risk of CHD
  • tobacco also contains carcinogens that lead to cancer
71
Q

what are the 5 reasons that alveoli are specialised for gas exchange

A
  • huge number of alveoli gives an enormous surface area
  • there’s a moist lining for gases to dissolve in
  • the alveoli have very thin walls - 1 cell thick, so a short diffusion distance
  • they have a great blood supply to maintain a high concentration gradient
  • the walls are permeable so gases can diffuse across easily
72
Q

describe the structure of the phloem

A
  • made of living cells
  • have pore in its end walls
  • contains cytoplasm
  • doesn’t contain lignin
  • tubular
  • made from cells
73
Q

describe the structure of the xylem

A
  • made from dead cells
  • do not have pores in their end walls
  • hollow
  • contains lignin
  • tubular
  • made of cells
74
Q

describe the role of the xylem

A
  • transports mineral salts and water from the root to the shoot of the leaves in the transpiration stream
75
Q

describe the role of the phloem

A
  • transports sugars like sucrose and amino acids from where there made in the leaves to other parts of the plant
  • the movement of food substances around the plant is known as translocation
76
Q

what is plasma

A
  • pale yellow liquid which carries everything around the body including:
  • red and white blood cells and platelets
  • digested food products from the gut to all body cells
  • carbon dioxide from body cells to the lungs
  • urea from the liver to kidneys
  • hormones which act as chemical messengers
  • heat energy
77
Q

what are platelets

A
  • when you damage a blood vessel, platelets clump together to plug the damaged area
  • the is known as blood clotting, blood clots stop you losing to much blood and prevent microorganisms from entering your wound
  • in a clot, platelets are held together by a mesh of protein called fibrin
78
Q

what is the structure of a red blood cell

A
  • small and have a biconcave shape to give a large surface area for absorbing and releasing oxygen
  • don’t have a nucleus which frees up space for more haemoglobin, so they can carry more oxygen
79
Q

how does the hormonal system help to control heart rate

A
  • when an organism is threatened, the adrenal glands release adrenaline
  • adrenaline binds to specific receptors in the heart, this causes the cardiac muscles to contract more frequently and with more force, so heart rate increases and the heart pumps more blood
  • this increases oxygen supply to the tissues, getting the body ready for action
80
Q

describe how exercise increases the heart rate

A
  • when you exercise your muscles need more energy, so you respire more
  • you need to get more oxygen into the cells and remove more carbon dioxide, for this to happen the blood has to flow faster, so your heart rate increases
  • exercise increases the amount of co2 in the blood
  • high levels of blood co2 are detected by receptors in the aorta and the carotid artery
  • these receptors send signals to the brain
  • the brain sends signals to the hear causing it to contract more frequently with more force
81
Q

what does pulmonary mean

A

to do with the lungs

82
Q

what does renal mean

A

to do the the kidneys

83
Q

what does hepatic mean

A

to do with the liver

84
Q

describe the ole of phagocytes

A
  • phagocytes recognise pathogen
  • phagocyte engulfs pathogen in a process called phagocytosis
  • the lysozymes containing enzymes move towards the pathogen
  • enzymes break down pathogen
  • useful materials are absorbed
  • waste products are removed from the phagocyte
85
Q

describe what auxins are

A
  • auxins are plant hormones which control growth at the tips of shoots and roots, they move through the plant in solution
  • auxins are produced in the tips and diffuse backwards to stimulate the cell elongation process
  • promotes growth in the shoot but inhibits growth in the root
86
Q

what is the role of synapses

A
  • the connection between 2 neurones is called a synapse
  • the nerve signal is transferred by chemicals called neurotransmitters which diffuse across the gap
  • these chemicals then set of a new electrical signal in the next neurone
87
Q

describe what happens in the eye when adjusting for bright and dim light

A
  • very bright light triggers a reflex that makes the pupil smaller and the circular muscles contact, allowing les light in
  • the opposite happens in dim light a the radial muscles contract which makes the pupil bigger, it dilates
88
Q

describe what happens in the eye when focussing on a distant object ( accommodation)

A
  • the ciliary muscles relax which allows the suspensory ligaments to pull tight
  • this makes the lens go thin ( less curved )
  • so it refracts less light
89
Q

describe what happens in the eye when focussing on a near object ( accommodation)

A
  • the ciliary muscles contract, which slackens the suspensory ligaments
  • the lens becomes more curved
  • this increases how much light it refracts
90
Q

where is insulin produced and what’s its role and effect

A
  • produced in the pancreas
  • helps control blood sugar level
  • stimulates the liver to turn glucose into glycogen for storage
91
Q

where is progesterone produced and what’s its role and effect

A
  • produced in the ovaries
  • supports pregnancy
  • maintains the lining of the uterus
92
Q

describe the steps of mitosis

A
  • the cell grows
  • prophase: the DNA replicates to form two copies of each chromosome, these chromatids are joined together at the centromere
  • metaphase: the nuclear membrane breaks down, the chromosomes line up across the centre of the cell, attached to spindle fibres
  • anaphase: the chromatids are pulled apart and move to opposite ends of the cell
  • telophase: the cytoplasm and cell membrane divides to form two identical cells
93
Q

describe the steps of meiosis

A
  • the parent cell grows
  • the DNA replicates to form 2 copies of each chromosome, these chromatids are joined together at the centromere
  • the nuclear membrane breaks down, the homologous pairs of chromosomes join together
  • the homologous pairs of chromosomes exchange sections of DNA, they then attach to the spindle fibres in pairs, at the centre of the cell
  • the homologous pairs of chromosomes are pulled apart and moved to opposite ends of the cell, the cell divides
  • the chromosomes line up along the centre of the cell, attached to the spindle fibres. the chromatids separate and move to opposite ends of the cell, each cell divides again
94
Q

describe the 7 stages of sexual reproduction

A
  • 1) sexual reproduction is where genetic information from 2 organisms is combined to produce genetically different offspring
  • in sexual reproduction the mother and father produce gametes
  • gametes are haploid so 23 chromosomes each
  • at fertilisation the male gamete fuses with the female gamete to form a zygote , the zygote has all 46 chromosomes
  • the zygote then undergoes mitosis and develops into an embryo
  • the embryo inherits features from both parents, mixture of chromosomes
  • the fertilisation of gametes is randoms, this produces genetic variation in offspring
95
Q

how are some plants adapted for insect pollination

A
  • they have brightly coloured petals to attract insects
  • they have scented flowers and nectaries to attract insects
  • they make big, sticky pollen grains- the grains stick to insects as they go from plant to plant
  • the stigma is sticky so that any pollen picked up by insects on other plants will stick to the stigma
96
Q

describe how some plants are adapted for wind polination

A
  • small, dull petals on the flower as they don’t need to attract insects
  • no nectaries or strong scents
  • a lot of pollen grains - they’re small and light so that they can easily be carried by the wind
  • long filaments that hang the anthers outside the flowers, so that a lot of pollen gets blown away by the wind
  • large and feathery stigma to catch pollen as its carried past by the wind, the stigma often hangs outside of the flower to
97
Q

describe the process of fertilisation in plants

A
  • a pollen grain lands on the stigma of a flower, usually with help from insects and the wind
  • a pollen tube grows out of the pollen grain and down through the style to the ovary and ovule
  • a nucleus from the male gamete moves down the tube to join with the female gamete in the ovule. fertilisation is when 2 nuclei fuse together and form a zygote, this divides by mitosis to form an embryo
  • each fertilised female gamete forms a seed, the ovary develops into a fruit around the seed
98
Q

describe what germination is

A
  • a seed will lie dormant until the conditions are right for germination
  • they need water and oxygen and temperature
  • water is needed to activate the enzymes that break down the food reserved in the seed
  • oxygen is needed for respiration which transfers the energy from food for growth
  • a suitable temp is needed for the enzymes inside the seed to work
99
Q

describe how germinating seeds get energy from food stores

A
  • a developed seed contains an embryo and a store of food reserved, wrapped in a hard seed coat
  • when a seed starts to germinate, it gets glucose for respiration from its own food store, this transfers the energy it needs to grow
  • once the plant has grown enough to produce green leaves it can get its own energy from photosynthesis
100
Q

what is the stamen in a plant

A
  • the male reproductive part
  • consists of the anther and the filament
  • the anther contains the pollen grains, these produce the male gamete (sperm)
  • the filament is the stalk that supports the anther
101
Q

what is the carpel in the plant

A
  • the female reproductive part
  • the carpel consists of the ovary, style and stigma
  • the stigma is the end bit that the pollen grains attach to
  • the style is the rod like section that supports the stigma
  • the ovary contains the female gametes (eggs) inside ovules
102
Q

describe what pollination is

A
  • the transfer of pollen from the anther to the stigma, so that the male gametes can fertilise the female gametes in sexual reproduction
103
Q

describe the practical to investigate the conditions needed for germination

A
  • take 4 boiling tubes and put cotton wool at the bottom of each one
  • put 10 seeds on top of the cotton wool in each boiling tube
  • set up one tube as a control with all conditions, another tube with all the conditions apart from water, another with all the conditions but is in the fridge, another has a layer of oil to prevent oxygen entering
  • leave the tubes for 7 days and then observe what has happened
104
Q

how do you interpret your observations for the conditions needed for germination in plants

A
  • you should only see germination happening in tube 1
  • this is because all of the conditions needed for germination are present
  • the seeds in the other boiling tubes wont germinate, this shows that water, oxygen and a suitable temp is needed for germination
105
Q

describe how plants can reproduce asexually using natural methods like runners

A
  • the parent plant sends out runners which are fast growing stems that grow out sideways, just above the ground
  • the runners take root at various points a short distance away and new plants start to grow
  • the new plants are clones of the parent plant, so there is no genetic variation between them
106
Q

describe how plants can reproduce asexually using artificial methods such as cuttings

A
  • gardeners can take cuttings from good parent plants and then plant them to produce clones of the parent plant
  • these plants can be produced quickly and cheaply
107
Q

describe how the male reproductive system creates sperm

A
  • sperm are male gametes, they’re made in the testes all the time after puberty
  • sperm mix with a liquid to make semen, which is ejaculated from the penis into the vagina during sexual intercourse
108
Q

describe how the female reproductive system makes ova (eggs)

A
  • ova are female gametes, an ovum is produced every 28 days from 1 of the 2 ovaries
  • it then passes through the fallopian tube, this is where it would meet sperm
  • if it isn’t fertilised by sperm, the ovum will break up and pass out of the vagina
  • if it is fertilised, the ovum starts to divide, the new cells will travel down the fallopian tube to the uterus and attach to the endometrium, a fertilised ovum develops into an embryo
109
Q

describe the role of oestrogen

A
  • produced in the ovaries
  • causes the uterus lining to grow
  • stimulates the release of LH
110
Q

describe the role of progesterone

A
  • produced in the ovaries
  • maintains the lining of the uterus during the 2nd half of the cycle, when the level of progesterone drops the lining breaks down
  • inhibits the release of LH and FSH
111
Q

describe the role of placenta in the nutrition of the developing embryo

A
  • once the embryo has implanted, the placenta develops
  • this lets the blood of the embryo and mother get very close to allow the exchange of food, oxygen and waste, short diffusion distance
  • villi provide a large surface area for diffusion/active transport
  • blood supply/cappilaries brings nutrients and removes waste
112
Q

how is the developing embryo protected by amniotic fluid

A
  • an amnion membrane forms
  • this surrounds the embryo and is full of amniotic fluid
  • amniotic fluid protects the embryo against knocks and bumps as it provides a cushion between the foetus and umbilical cord
113
Q

what are the chromosomes in females

A

xx female

114
Q

what are the chromosomes in males

A

xy male

115
Q

how many cells does mitosis produce

A

2 identical sets of chromosomes

116
Q

what is the role of mitosis

A

growth and repair, cloning and asexual reproduction

117
Q

what is the definition of an ecosytsem

A

all the organisms living in a particular area

118
Q

why is only 10% of energy transferred from one trophic level to another

A
  • plants use energy from the sun to make food via photosynthesis, tis energy makes its way through the food chain as animals eat the plants and each other
  • some parts of food e.g roots and bones aren’t eaten so the energy isn’t taken in, some parts of the food are indigestible like fibre, so pass through organisms and come out as waste
  • a lot of the energy is used for staying alive like in respiration
  • most of this energy is eventually transferred to the surroundings as heat
  • only 10% of the total energy available becomes biomass
119
Q

describe what eutrophication is

A
  • fertilisers enter the water, adding extra nutrients
  • the extra nutrients cause algae to grow fast and block out the light (algal bloom)
  • plants cant photosynthesise due to lack of light and start to die
  • with more food available microorganisms that feed on dead plants increases in number and deplete the oxygen levels in water
  • organisms that need water (fish) die
120
Q

how do glasshouses/polythene tunnels increases crop yield

A
  • keeping plants enclosed helps to keep them free from pests and diseases
  • it also helps the farmers to control the water supplied to their crops
  • commercial farmers use artificial light after the sun goes down to give their plants more time to photosynthesise
  • glasshouses trap the suns heat to keep the plants warm, in the winter the farmer might use a heater to maintain an optimum temp
121
Q

what is the effect of increases in co2 and temperature in glasshouses on crop yield

A
  • glasshouses trap the suns heat to keep the plants warm, in winter a farmer might use a heater to keep the temp ideal
  • farmers also increase the level of co2 in glasshouses by using paraffin heaters to heat the place, as it burns it makes co2 as a bi product
  • by increasing the co2 and temperature concentrations, a farmer can increase the rate of photosynthesis for their plants
122
Q

how do fertilisers ensure the crops have enough minerals and increase crop yield

A
  • plants need certain minerals like nitrogen, potassium and phosphorus so they can make important compounds like proteins
  • if plants don’t get enough of these minerals their growth and life process is affected
  • sometimes these minerals are missing from the soil because they’ve been used up by a previous crop
  • farmers use fertilisers to replace these missing minerals or provide more of them
123
Q

how can pest control stop pests from eating crops

A
  • pesticides are a form of chemical pest control, often poisonous to humans so must be used in consideration
  • biological control is an alternative to using pesticides, it means using other organisms to reduce the numbers of pests, by encouraging wild organisms or adding new ones
  • the helpful organisms be predators, parasites or disease causing
  • biological control can have longer lasting effect than spraying on pesticides and can be less harmful to wildlife , they can cause problems however as they can become a pest themselves
124
Q

how is yeast used when making bread

A
  • a bread dough is made by mixing yeast with flower, water and a bit of sugar
  • the dough is left in a warm place to rise
  • enzymes break down the carbohydrates in the flour into sugars
  • yeast then uses these sugars in aerobic respiration producing co2
  • when the oxygen runs out the yeast uses anaerobic respiration, this is known as fermentation and produces co2 and ethanol
  • the co2 produced is trapped in bubbles in the dough
  • these pockets of gas expand and the dough begins to rise
  • the dough is then baked in the oven where the yeast continues to ferment until the temp of the dough rises enough to kill the yeast, any alcohol is bubbled away
  • as the yeast dies, the bread stops rising but the pockets are left in the bread where the co2 was trapped
125
Q

how is bacteria used to make yogurt

A
  • the equipment is sterilised to kill of any unwanted organisms
  • the milk is pasteurised ( heated to 72 c for 15s) again to kill any harmful microorganisms, then the milk is cooled
  • lactobacillus bacteria are added, and the mixture is incubated in a fermenter
  • the bacteria ferment the lactose sugar in the milk anaerobically to form lactic acid
  • lactic acid causes the milk to clot and solidify into yoghurt
126
Q

describe the practical to investigate the respiration rate of yeast depending on its conditions

A
  • mix together some sugar, yeast and distilled water, then add the mixture to a test tube
  • attach a bung with a tube leading to the next test tube of water
  • sealing the 2 tubes with bungs stops oxygen from entering, so the yeast has to start respiring anaerobically
  • place the test tube containing the yeast mixture in a water bath at a certain temp
  • leave the tube to warm up a bit and then count how many bubbles are produced per minute
  • calculate the rate of co2 produced, this gives an indication of respiration rate
  • repeat this with the water bath at different temperatures
  • respiration is controlled by enzymes, so as temp increases so should rate of respiration
127
Q

how can selective breeding create animals with desired characteristics

A
  • cows can be selectively bred to produce offspring with a high meet yield
  • first, the animals with characteristics that will increase meet yield are selected and bred together
  • next the offspring with the best characteristics are selected and bred together
  • if this is continued over several generations, cows with very large meet yields can be produced
  • mating cows and bulls naturally can be difficult, so artificial insemination is often used. its safer for the cow, and its much quicker and cheaper to transport semen than bulls, the semen can also be used to inseminate multiple cows and be stored after the bull has died
128
Q

how can selective breeding develop plants with desired characteristics

A
  • selective breeding can be used to combine two different desirable characteristics
  • tall wheat plants have a good grain yield but are easily damaged by wind and rain. dwarf wheat plants can resist wind and rain but have a lower grain yield
  • these two types of wheat plant cab be cross-bred, and the best resulting wheat plants were cross-bred again
  • this resulted in a new variety of wheat combining the good characteristics- dwarf wheat plants which could resist bad weather and had a high grain yield
129
Q

how can enzymes be used to cut DNA or join DNA pieces together

A
  • restriction enzymes recognise specific sequences of DNA and cur the DNA at these points
  • ligase enzymes are used to join two pieces of DNA together
  • two different bits of DNA stuck together are known as recombinant DNA
130
Q

what is a vector

A

something that’s used to transfer DNA into a cell, there are 2 sorts , plasmids and viruses

131
Q

what are plasmids that act as vectors

A

small circular molecules of DNA that can be transferred between bacteria

132
Q

what are viruses that act as vectors

A
  • viruses insert DNA into the organisms they infect
133
Q

what does transgenic mean

A
  • the transfer of genetic material from one species to a different species
134
Q

how does genetic engineering work

A
  • the DNA that you want to insert ( the gene for human insulin) is cut out with a restriction enzyme, the vector DNA is then cut open using the same restriction enzyme
  • the vector DNA and the DNA your inserting are mixed together with ligase enzymes
  • the ligases join the 2 pieces of DNA together to produce recombinant DNA
  • the recombinant DNA is inserted into other cells e.g bacteria
  • these cells can now use the gene you inserted to make the protein you want e.g bacteria for human insulin can be grown in huge numbers in a fermenter to produce insulin for people with diabetes
  • bacteria that contain the gene for human insulin are transgenic -this mean they contain genes transferred from another species
135
Q

how can genetically modified plants improve food production

A
  • crops can be genetically modified to increase food production, e.g making them resistant
    tant to insects or resistant to herbicides
  • making crops insect resistant means farmers don’t have to spray as many pesticides, so wildlife that don’t eat the crop isn’t harmed, also increases crop yield producing more food
  • making crops herbicide resistant means farmers can spray their crops to kill weeds, without affecting the crop itself, this will increase crop yield
  • there are concerns about growing GM crops, transplanted genes may get into the environment, for example a herbicide resistance gene may be picked up by weeds, another concern is that GM crops wood adversely affect food chains, or even human health
  • some people are against genetic engineering altogether, they worry that changing an organisms genes might create unforeseen problems, which could get passed to future generations
136
Q

what effect does temperature have on transpiration

A
  • on a hot day, water will evaporate quickly from the leaves of a plant as the water molecules have more kinetic energy
  • transpiration therefore increases as temperature increases
137
Q

what effect does light intensity have on transpiration

A
  • light itself does not affect evaporation, but in daylight the stomata of leaves are open to supply co2 for photosynthesis
  • this allows more water to diffuse out of the leaves and into the atmosphere
138
Q

what effect does humidity have on transpiration

A
  • very humid air contains a great deal of water vapour - there is a smaller concentration gradient, so transpiration slows down
  • in dry air the diffusion of water vapour from the leaf to the atmosphere will be rapid
  • transpiration therefore increases as humidity decreases
139
Q

what effect does wind speed have on transpiration

A
  • in still air, the region around a transpiring leaf will become saturated with water vapour so that no more can escape the leaf, causing transpiration to slow down
  • in moving air, the water vapour will be blown away from the leaf as fast as it diffuses out, this will speed up transpiration
  • transpiration therefore increases as wind speed increases
140
Q

what effect does water supply have on transpiration

A
  • if water supply is in short supply, and the plant is losing water by transpiration faster than its being taken up by roots
  • the plant may start to wilt
  • before this happens the guard cells will become flaccid and stomata start to close, therefore reducing transpiration and delaying wilting
141
Q

describe the potometer experiment to find transpiration rates

A
  • the potometer must be set up under water - this prevents any air bubbles from entering the system and blocking the xylem
  • cut the stem of a shoot
  • put the shoot stem into the bung, grease the joint with plenty of petroleum jelly - this prevents water loss and air entry
  • put the bung into the potometer
  • make sure the tap is closed and it is full of water (no bubbles), then lift the potometer out of the water
  • leave the end of the capillary tube out of the water until an air bubble forms then put the end into a beaker of water
  • you can measure the transpiration rate as distance the bubble travels in 5 minutes, take a number of readings to find a mean rate
142
Q

definition of active transport

A

the movement of molecules from an area of low concentration to an area of high concentration using ATP

143
Q

definition of osmosis

A

net diffusion of free water molecules from an area of high wate concentration to an areas of low water concentration across a partially permeable membrane

144
Q

definition of diffusion

A

random movement of molecules from an area of high concentration to an area of low concentration

145
Q

what is the name of the type of genetic control where many genes control 1 phenotype

A

polygenetic

146
Q

describe an experiment to show how different concentrations of sodium chloride solution affect the appearance of plant cells

A
  • immerse onion epidermis in sodium chloride
    solution
  • have a control variable wit just water and take a photo
  • use the same volume of solutions
  • 3 of more concentrations of sodium chloride solution
  • leaf cells for 2 hours
  • observe using a microscope and take a photo
147
Q

what enzyme converts protein to peptide

A

pepsin or trypsin

148
Q

what enzyme converts peptide to amino acids

A

peptidase

149
Q

why do plants not gain 100% of the energy from the sun

A
  • some light is reflected
  • not all of the plant has chloroplasts

freakology (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions