b1 chemistry

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  • Created by: elliesp
  • Created on: 07-05-16 14:42
what are the 5 food groups?
vitamins and minerals, fibre, proteins, fats, carbohydrates
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why is it important to eat vitamins and minerals?
to keep healthy function in the body and prevent deficiency disease, they are also used for various chemical reactions in the body.
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why is it important to eat fibre?
prevent constipation, it allows the gut to push food along efficiently.
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why is it important to eat proteins?
growth, cell repairing and cell replacement
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why is it useful to eat fats?
provide energy, to provide insulation, protection of internal organs and to produce components of cells like cell membranes.
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why is it useful to eat carbohydrates?
provide energy
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Why do we need a balanced diet?
to stop malnutrition, as this can lead to being overweight or underweight- also, in order to keep our bodies in a healthy condition.
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why is it vital that water is a part of our daily diet?
we need water because all chemical reactions happen in a watery environment.
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what is metabolic rate?
metabolism is the rate of chemical reactions that are happening in your body
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how is metabolic rate affected?
genes inherited, your ratio of muscle to fat, sex, age
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why do females usually have a lower metabolic rate than men?
females tend to have slower metabolic rate as they have a higher muscle to fat ratio in their body and fat requires less energy to be stored than muscle,
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what is cholesterol?
a type of fat found in the blood required to make cell membranes in cells
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what can too much cholesterol lead to?
too much cholesterol can block arteries, and can cause heart attacks and heart disease.
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what is type 2 diabetes?
it is a condition that is linked to being overweight. in type 2 diabetes insulin isn't recognised by the cells in the body to take sutra out of the blood
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what are the micro-organisms that cause disease?
pathogens
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what are non infectious diseases caused by? infectious?
NON infectious: lifestyle (smoking etc), genes, ageing INFECTIOUS: pathogens (bacteria and viruses)
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what do pathogens do?
they produce toxins that harm the body
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what are the main pathogens?
bacteria and viruses
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how do viruses work?
viruses infect a body cell and reproduce; the cell will then break open and be permanently damaged
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in what ways can the body defend itself?
whiteblood cells can identify pathogens & then: 1) ingest them, produce antibodies or produce antitoxins.
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how does a white blood cell ingest pathogens?
if a pathogen infects the body, the white blood cell will move towards it and engulf it. Once the pathogen is inside of it, it will release enzymes which break down and digest the pathogen.
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what happens when a white blood cell produces antibodies?
on the surface of any pathogen are antigens, so when a white blood cell produces antibodies they are designed to fit the antigens exactly and so antibodies attach to the antigen of the pathogen & slowly destroy it.
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what happens when a white blood cell produces antitoxins?
antitoxins latch on to toxins produced by pathogens and viruses and neutralise them to make them harmless.
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what is a vaccine?
a dead pathogen injected into someone's body to prevent them getting a specific disease?
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how do vaccinations work?
a dead pathogen is injected into someone's body (harmless) so that the white blood cells in the body can produce antibodies that fit the pathogen's antigens, so that when a live version of the pathogen enters the body, it will be destroy it quickly
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What is an MMR vaccination for? what was thought to be linked to this?
Measles, Mumps and Rubella... it was thought that this vaccine had a link with getting autism.
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what did Semmelweiss discover? what did he do?
he discovered that doctors were not washing their hands in-between handling dead bodies and delivering babies, causing many mothers to die in childbirth as infection was passed on. He told doctors to wash their hands &childbirth death rate decreased
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what are antibiotics? what are the 2 types?
medicines that kill (bactericidal) or slow growth (bacteriostatic) in bacteria inside the body.
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How do bacteria static antibiotics work?
bacteriastatic antiobiotics slow the growth of bacteria by interfering with the processes bacteria need to multiply, e,g DNA replication and protein production.
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how do bactericidal antibiotics work?
they kill bacteria by preventing them from creating a cell wall/
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what are the steps of antibiotic resistance?
bacteria exists in large numbers& so there is variation, some bacteria are naturally resistant to antibiotics (chance mutation or genes), so they'll survive longer &reproduce. Soon a population of resistant bacteria will be made
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how does not taking your full dosage of antibiotics increase resistance?
when you first take your antibiotics the least resistant bacteria die first, when the population of bacteria falls below the symptoms level many stop taking the antibiotics, however this allows the most resistant bacteria left to survive & reproduce.
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how does over prescribing antibiotics cause resistance?
the pathogens gets lot of exposure to this type of antibiotic and some of the pathogens become resistant to them due to mutation, and reproduce & pass their genes on making a super resistant population of pathogens due to natural selection.
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what is a mutation?
a permanent spontaneous change in the dna
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why don't antibiotics work on viruses?
viruses use a host cell in the body in order to multiply, so antibiotics can't be used to kill the virus as you would damage body cells. also, viruses don't have a cell wall so bactericidal viruses can't be used against them anyway
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what are broad and narrow spectrum antibiotics? which is better?
broad = effective against a rage of bacteria, narrow - effective against only a few bacteria. Narrow is probably better as is targeted at specific bacteria rather than destroying bacteria that could be useful to us
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what are the two types of mutation?
hereditary mutations and acquired mutations
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how may acquired mutations be caused?
environmental factors, or can occur if a mistake is made as DNA copes itself during cell division
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what is an epidemic?
a wide spread outbreak of disease
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what is a pandemic?
an outbreak of disease across continents
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in what case could an epidemic occur?
if a mutation occurs amongst bacteria and makes the vaccine ineffective, and a new vaccine isn't developed quickly the disease may spread very quickly.
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what do pain killers do?
releives the symptoms of pathogens
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what is the job of the nervous system?
to detect stimuli and react to them by sending information to the central nervous system (brain and spinal cord)
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what are the different receptors in the body?
light receptors (eyes), chemical receptors (nose and mouth) and sound and position receptors (ears)
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list the order of the nervous system?
stimulus, receptor, sensory neurone, relay neurone, motor neurone, effector
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what is a synapse?
a synapse is a junction between two neurones, when a nerve impulse reaches a synapse, a transmitter chemical is released. This diffuses across the gap and sets up an impulse in the next neurone.
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what are reflexes?
the quick response in reaction to stimuli
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why is the brain not involved in a reflex?
it would take too long to respond and cause a delay in reaction
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what is an effector?
a part of the body that produces the response to stimuli
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what is a receptor?
receptors are groups of specialised cells that can detect stimuli and turn them into electrical impulses carried to the sensory neurone
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what is homeostatis? what is involved?
controlling conditions in the body and keeping them constant such as water,blood sugar, ions and temperature
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how is homeostatis achieved?
1) change is detected by receptor cells, usually in the central nervous system, the change is reversed, the change is monitored and the mechanisms are switched off when no longer needed.
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how can you ensure water is in your body? how does it get out of your body?
in= food and drink out = urine, breathing, sweating, faeces
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how can your blood sugar levels go up? go down?
up = food and drink down =excercise, insulin
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what is insulin?
a hormone that reduces blood sugar levels when it's too high
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how are ions lost?
sweating, diarrhoea, urine,
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why is important to control body temp?
human enzymes work best at 37 degrees, so this needs to be maintained as enzymes keep chemical reactions in the body happening at a fast rate and keep us alive
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how does the body reduce temp? increase?
reduce = sweat, blood flows to surface of skin increase = shivering
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what is the menstrual cycle?
the menstrual cycle is a reproductive process that takes place very month in woman, where an egg is developed in the ovaries, and if not fertilised - released in ovulation
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what are hormones? how do they travel?
compounds secreted by glands such as the ovaries, testes and pituitary gland - and they always travel in the blood.
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what are the main hormones in the menstrual cycle?
FSH, Oestrogen, LH,
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Where is FSH made? what is its function and what does it stimulate?
FSH is made in the puitary gland, it matures eggs and stimulates oestrogen
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Where is oestrogen made? what is its function and what does it stimulate/inhbit?
made in the ovaries, thickens the lining of the uterus, inhibits FSH so not more than one egg is matured, but stimulates LH
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Where is LH made? what is its function?
LH is made in the puitary gland, its job is to release the egg (causes ovulation)
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Where is progesterone made? what is its function?
made in ovaries, job is to maintain lining of uterus during middle part of menstrual cycle and during pregnancy
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state the process of the menstrual cycle and what happens on certain days.
day 1-4: period starts&lining of uterus breaks down, lining of uterus builds up to accept fertilised egg, egg released (ovulation), lining of uterus maintained for 14 days.
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what hormones does the contraceptive pill contain?
oestrogen and progesterone (inhibit production of FSH which means an egg can't be matured and released).
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What hormones are used in IVF?
woman is given FSH causing more eggs to be matured than usual and LH to release the egg.
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what is the purpose of IVF?
to increase chances of fertility for women who don't produce enough FSH to mature an egg.
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Explain the process of IVF.
eggs are removed from the uterus and are placed in a petri dish. These eggs are then fertilised by the father's sperm and will then develop into embryos and the healthiest ones are then placed back into the womb of the mother.
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what are the stages of testing a drug?
tested on animals, and if successful tested in clinical trials on healthy human volunteers, then blind or double blind trials are carried out.
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what is the placebo affect?
if a person thinks that they've been given an active drug they may feel better even if they've had nothing of significance to them
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what is a blind trial?
Blind trials are used to get rid of the placebo affect; so some patients are given the drug and the others are given a placebo drug, this allows the doctor to analyse whether the drug is effective or not by comparing the results of both groups
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what is a double blind trial?
as some people can tell whether theyv been given a placebo drug or not through the doctor's actions, a double blind trial is set up so that neither the doctor or the patient know who's being given a placebo drug or not.
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what was thalidomide originally used for? what did it do? used for now?
a sedative and to cure morning sickness, however it caused the children born to have stunted the growth of their limbs. Its now used as a treatment to leprocy and bone cancer
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why do people take recreational drugs?
happiness, relaxation, social reasons
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how do people become addicted to smoking?
nicotine is an addictive substance that is found in tobacco, it reaches the brain quickly and creates a dependency so that smokers become addicted.
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why do smokers have an increased risk of heart disease and strokes?
the carbon monoxide combines with haemoglobin in red blood cells and reduces the ability of blood to carry oxygen. This causes heart rate to increase to compensate for lack of oxygen in circulatory system and can cause heart disease and strokes
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why is it dangerous to smoke when pregnant?
the carbon monoxide in cigarettes combines with haemoglobin in red blood cells and so reduces the ability of blood to carry oxygen; this means oxygen supply to a growing baby is limited and can lead to miscarriage or low weight of babies at birth.
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why does smoking cause cancer?
tar contains carcinogens that react with the DNA in epithelial cells and cause mutations which can lead to tumours.
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what does alcohol contain? what are it's effects?
ethanol, it is a depressant and slows down signals in the nerves and brain
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what are the types of performance enhancing drugs?
anabolic steroids (build muscle quickly) and stimulants (increase heart rate which improves stamina)
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what is a phototropism? negative phototropism?
phototropism =a plant grows towards light, negative phototropism = plant grows away from light
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what effect do auxins have in shoots?
encourage growth
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what effect do auxins have in roots?
slow growth
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how does a phototropism happen?
auxins flow down the stem of a plant evenly so shoot grows up, when light is shone on the plant in one direction, auxins move to other side. As auxin encourages growth, the further side will grow quicker & plant bends toward light
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what is a geotropism? negative geotropism?
a geotropism is when the door grows towards the force of gravity. a negative geotropism is when the root grows against force of gravity
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Explain how a geotropism happens?
in roots the auxin will first accumulate on the lower side of the root, so the lower side will grow slower, making the root grow downward
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how are plant hormones used by humans?
humans use rotting compound for cuttings before putting it in soil to clone plants. This encourages the growth of roots. They also use weedkiller which has a high dose of auxins in it, leading to massively accelerated growth &the death of the plant
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what do plants compete for?
water, light, minerals, space
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what do animals compete for?
food, territory, mates,
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what are extremophiles?
beings which have the ability to live in extreme conditions such as high salt concentrated areas, extreme heat and high pressure
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how can animals adapt to cold conditions?
thick fur which traps in air which is a good insulator, thick layer of fat which is a good insulator, small surface area (less area in contact with air the less heat lost), white coat for camouflage
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how do animals adapt to hot conditions?
large surface to increase the surface exposed to air so more heat lost, veins near skin surface so cooled by air,
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how do plants adapt to dry conditions?
fleshy stem to store water, widespread roots near the surface that absorb any rainfall (rain evaporates quickly), small leaves (less water lost)
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what non living factors affect the population size of living things in an area?
temp, rainfall, pollution, amount of nutrients
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what living factors affect the population size of living things in an area?
prey, predators, competition, disease
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what is global warming?
in the atmosphere, gases such as carbon dioxide and methane act together so that sunlight can pass through the atmosphere, but heat can't get out.
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what are the effects of global warming?
rising sea levels as glaciers melt, high temps could mean more evaporation so more clouds and a change in rainfall, more rainfall and rising sea levels could mean flooding
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what are the indicators of air pollution? how?
lichens - they are sensitive to sulphur dioxide so they aren't present in an area it probably means it is polluted with sulphur dioxide
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what type of lichens are there? what conditions do they grow best in?
bushy = clean air leafy = small amount of pollution crusty = more polluted air
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what can be used as an indicator for water pollution? how?
invertibrates, as they can't survive in polluted water so if they're not present it is likely the water is heavily polluted
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what are invertebrates?
animals who have their skeleton outside their bodies.
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what does biomass mean?
the mass of living material at each stage in a food chain
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why does biomass become less as you move down the food chain?
because energy is wasted at each stage through respiration and faeces etc
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how does decay occur?
decay occurs because bacteria & fungi land on dead material &release enzymes that break down compounds &are absorbed by decomposers' cells. Mineral ions (phosphate&nitrate) etc that bacteria don't need released into soil & essential for plant growth.
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what conditions are needed for decay?
aerobic, moist and warm
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LEARN CARBON CYCLE NOW!!!!!!!
!!!!!
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what are the two types of variation?
inherited and environmental
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what are some factors that could contribute to environmental variation?
diet, climate, accidents, culture... e.g if you eat too much you'll become heavier, and a plant in the shade will grow taller to reach light
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what is sexual reproduction?
Sexual reproduction requires a male and female gamete, and they must fuse together. -In sexual reproduction there is variation, as the offspring are not clones of the parent, genes are shared/mixed from the male and female gamete.
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what is asexual reproduction?
asexual reproduction involves 1 parent, so all the offspring are clones of the parent as there is no variation in genes
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explain cuttings.
a branch from a parent plant is cut off, the leaves at the bottom of it are stripped off. It is then dipped in rooting powder and placed in soil. After a few weeks the roots develop and it will grow into a clone of the plant
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explain tissue culture.
some cells are taken from the parent plant and placed in agar w/ nutrients and auxins. The cells will multiply and eventually develop into plantlets so they can be removed from agar and planted into soil to develop into a clone of the parent.
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what conditions must tissue culture take place in? why?
sterile, so the cells aren't destroyed
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disadvs of tissue culture? advs?
more expensive and time consuming than cuttings, but can produce loads of clones of the plant
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explain embryo transplants?
a sperm and an egg cell fuse together to make a fertilised egg which then develops into an embryo. This embryo can be split into smaller embryos which can then be placed into the wombs of surrogate mothers, so all the embryos will develop into clones
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explain adult cell cloning?
cell is taken from animal with desired genes (animal A) & nucleus is removed, then a cell is taken from another animal & nucleus removed (animal b) &discarded. Animal A's nucleus is implanted into animal B's cell &the new cell is put in host mother.
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in adult cell cloning, which animal will the offspring be a clone of?
the one with the desired characteristics, whose nucleus was used (animal A)
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what is the nucleus?
the nucleus is the control centre of the cell, containing DNA
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what are chromosomes?
DNA coiled into long x shape structures
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what are genes?
instructions that control the way an organism grows and develops. They are regions of DNA.
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how many chromosomes do humans have?
46 (23 pairs)
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explain the genetic engineering of insulin.
chromosome taken from nucleus of cell in pancreas& a gene that produces insulin is cut from chromosome by enzymes. then a bacterium's dna removed& an enzyme cuts out a part of dna, which is discarded &then insulin gene put in DNA &back in bacterium.
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What are genetically modified crops?
-a cell is taken out from the plant and one of it’s chromosomes is removed. -then a gene is found that offers insect resistance and it can be inserted into the chromosome using enzymes and then placed back into the plant cell.
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disadvs of genetic engineering?
-unorganic -expensive -fear it may be harmful to people
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advs of genetic engineering?
-can choose the desired features for crops -the crop yield will be larger as less damage by insects etc.
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why didn't people believe darwin's theory?
-Strong religious beliefs. -Not enough evidence. -No explanation about variation and inheritence etc.
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explain natural selection
in every living species there is variation, & some have genes that are advantageous -this means they can live longer & reproduce, to pass their genes on. soon, all the species become adapted to have this gene that increases their chance of survival
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what was lamarck's theory?
A characteristic which is used more and more by an organism becomes bigger and stronger, and one that is not used eventually disappears. Any feature of an organism that is improved through use is passed to its offspring.
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why is it not true?
His theory is not true because a feature that is improved over your lifetime cannot be inherited by offspring as it is not a gene, it is something that you have changed yourself.
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What is the result of being undernourished?
it can lead to you being less resistant to infection and can stop children growing and developing normally.
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how does exercise make you lose weight?
increases the amount of energy expended by your body, and the only way to lose weight is to reduce the input of energy content in your body (diet) and increase the output balance in your body.
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how are symptoms of disease caused?
bacteria and viruses produce toxins to interfere with the normal functioning of our body, and viruses damage our cells when they burst out.
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what are pain killers like paracetamol used for?
to relieve symptons, but they won't get rid of the bacteria or disease.
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what is the job of the immune system?
the job of the immune system is to recognise any foreign pathogens and to produce white blood cells to destroy them.
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what are the key features of a reflex?
they're fast, they are automatic (not controlled by brain) and the same stimulus always leads to the same response.
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what is the job of the sensory neurone?
carry signals from receptors to the CNS
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what is the job of relay neurones?
carry messages from one part of the CNS to another
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what is the job of motor neurones?
carry signals from the CNS to effectors
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explain the process of control of water balance when you're dehydrated
pituitary gland secretes more ADH, kidneys reabsorb more water back into the blood, less water is lost through urine
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explain the process of control of water balance when you're over hydrated
puitary gland secretes less ADH, kidneys reabsorb less water back into the blood, more water is lost in urine.
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what is water balanced carried out by?
the kidneys
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what do important ions include? what are they usually called and where do we get them from?
sodium and chloride, potassium, calcium - these ions are called salts and electrolytes. We get them in our diet and the kidneys remove the excess.
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where does most of our glucose come from? what can we store glucose as and where?
the digestion of carbohydrates such as starch - we can store glucose as glycogen, mainly in the liver
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why do blood sugar levels need to be kept constant?
to provide cells with a constant supply of energy
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what do people who cannot control their blood sugar levels suffer with
diabetes
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how is blood sugar controlled?
glucose is stored when we have too much, and releasing it when there is not enough
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what are the basic requirements of a plant?
light, water, co2, minerals (such as nitrate and phosphate) and a little warmth
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what are plant responses called?
tropisms
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why is plant movement slow?
because it is brought about by cell division and elongation
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what is oxygen measured by? temperature? rain fall?
oxygen meter, maximum-miniumum thermometer, rain gauge/pluviometer
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which type of invertebrates indicate that the water is clean?
fresh water shrimp, mayfly nymph
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which type of invertebrates indicate that the water is polluted?
rat tailed maggot, chrinonomid midge lava
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which gases in our atmosphere add to global warming?
carbon dioxide and methane prevent heat escaping the atmosphere
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why is cutting down trees/deforrestation a problem?
because a lot of carbon is locked up in wood so when we cut down and burn trees more co2 is released and there is fewer trees to remove co2 from the atmosphere through photosynthesis
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what are plants usually known as in a food chain?
producers
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what is the process of a food chain?
producers --> primary consumers --> secondary consumers
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why are phosphate and nitrate essential for plant growth?
nitrate makes protein which helps growth, and nitrate makes chlorophyll which is essential in photosynthesis
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