Extension Science Flashcards
What in the human brain regulates things over 24 hours?
Biological clock
The biological clock relies on what?
Light exposure
What is photoperiodism?
Plants response to changing day length
Name 2 things which photoperiodism affects in plants
Germination and flowering
What do young lupine produce that are poisonous?
Alkaloids
What are alkaloids poisonous to?
Insects or pests
Where is digoxin found and what is it used for?
Foxgloves, to treat heart disorders
Where is quinine found and what is it used for?
Cinchona trees, to treat malaria
Where is aspirin found and what it is it used for?
Willow trees, to treat pain and fever
What did Louis Pasteur do?
He showed that microorganism a were responsible for food going off
What is an antiseptic technique?
A method of keeping microbes away from people and food
What is pasteurisation?
When food is heated before stored to kill microbes
How did Edward Jenner develop smallpox vaccines?
He rubbed the pus from a cowpox blister onto a boy and after he was infected and healed, he did the same with the smallpox blister and the boy was unaffected
How do vaccines work?
1) weakened antibody is injected into the body
2) lymphocyte with matching antibody for the antigen is released
3) lymphocyte undergoes division
4) lymphocytes release antibody to destroy pathogen and memory lymphocytes remain
Name the disadvantages of vaccines
Swelling and redness around the vaccination
Children can get a mild disease
Some get allergic reactions
Name advantages of vaccines
Immunity without being infected
Chances of long lasting harm is small
If enough people get vaccinated it becomes rare so that even unvaccinated individuals aren’t likely to get it
What is a primary response?
The way in which our immune system responds on first occasion that a particular pathogen enters the body
What is a secondary response?
The way in which our body responds to the second occasion that a pathogen enters the body
What are monoclonal antibodies
Many identical antibodies
What is a b lymphocyte?
A lymphocyte that can no longer divide due to production of antibodies
What is a hybridoma cell?
A fusion of b lymphocytes and cancer cells so that they can divide
How are monoclonal antibodies used in pregnancy tests?
They are used to detect HGH which sticks to dipstick and causes colour change
How are monoclonal antibodies used to detect cancer
They are stuck to cancer drugs as they target the cancerous cells only
What is a metabolic reaction?
A reaction in the body
What are the waste products of metabolic reactions?
Co2 and urea
What’s the difference between the renal vein and the renal artery?
Renal vein carries blood to the body
Renal artery carries blood to kidneys for filtration
What do the kidneys do?
The remove waste from the blood to form urine
What is the function of the ureters
They carry urine to the bladder
What does the bladder do
Stores urine
What does the urethra do
It releases urine from bladder to outside the body
What causes rejection of transplanted organs?
The body recognises the antigens on the tissue as foreign and then tries to destroy it
How do dialysis machines work?
They remove waste products from the blood. They need to be connected to the patient for server all hours, several times a week
What is a nephron?
The place where filtration occurs in the kidneys
What is the glomerus?
The network of blood capillaries in the nephrons
What happens in the first phase of filtration?
The blood flows through the glomerus and to the bowman’s capsule where it allows water, glucose and urea into the nephron
Describe the process of selective reabsorption
Useful substances such as glucose are absorbed back into the blood at the convoluted tubes
Describe the last process of reabsorption (in the nephrons)
Depending on how much ADH is present the pituitary gland will cause the nephron to absorb more/less water
What does more ADH cause
More concentrated urine
What is ovulation
When the egg is released from the ovary
Ovulation causes what?
Thickening of the uterus lining
What is it called when the lining breaks down and the egg lost?
Menstruation
What does the initial low level of progesterone cause?
FSH release
What does FSH do?
It triggers maturation of follicles
What does the maturing of follicles cause?
Release of oestrogen
What does the oestrogen cause?
Thickening of uterus lining and LH release
What does LH cause
Ovulation
When ovulation occurs, what happens to the follicle?
It becomes a corpus luteum
What does the corpus luteum cause?
An increase in progesterone
What does increase in progesterone cause?
It inhibits FSH and LH
Falling levels of progesterone and oestrogen lead to what?
Menstruation
What is the name of a rhythm that occurs over a period of 24 hours?
Circadian rhythm
What does the cytoplasm of an egg cell contain?
Lipid droplets (yellow spots)
What does the acrosome of a sperm cell contain?
Enzymes for digesting a way into the egg
What does the middle section of a sperm cell contain?
Mitochondria
What happens regarding the egg cell once a sperm has entered to ensure no other sperm gets in?
The membrane quickly changes
How does IVF work?
Some of the women’s egg cells are taken from her ovaries and fertilised in a Petri dish before being implanted back into the uterus
What are some problems with IVF?
The babies tend to be born premature which may cause problems in birth or later development
How does egg donation work?
Hormones are given to the donor to release eggs and then IVF is carried out
What is a problem with egg donation?
Some women react badly to the high levels of hormones given to them
When is surrogacy an option for a couple?
If the women is unable to grow an embryo in her uterus
How does surrogacy work?
The egg and sperm are fertilised through IVF and then implanted into the surrogate mother’s uterus
What is the problem with surrogacy?
Sometimes the surrogate grows a strong bond with the baby and doesn’t want to give it up
How does hormone treatment work to conceive a child?
Hormones are given to the woman to help her produce more eggs
What is the problem with hormone treatment?
Increases the chance of multiple births and the babies tend to be born premature
What is haemophilia and example of?
A sex-linked genetic disorder
Why are sex-linked genetic disorders mainly found in boys?
Because some genes are only found on the X chromosome so the boy only has one copy
Is the gene for red-green colour blindness on the X or Y chromosome?
X
Define the term behaviour
The ways in which animals respond to a stimuli
A mate that is healthy and well adapted is of what quality?
Good reproductive quality
What helps with finding a mate?
Elaborate courtship behaviour such as when a male displays to a female to show that he is high quality
Describe the 3 kinds of mate
Mate for life
Mate for season
Multiple mates a season
Describe how mating tends to work in dear, lions and apes
Groups of females will all breed with one ‘dominant’ male which will remain for years
Describe a parental instinct over their young
That they will risk their own life in order to ensure the survival of their young
What is innate behaviour?
Behaviour that is ‘hardwired’ into our brain and is with us from when we are born
Animals who use innate behaviour are more likely to what?
Survive
What innate behaviour did Tinbergen show in herring gulls?
That the young would peck at the spot on their parents beak when they wanted food
What is imprinting?
It is a kind of simple learning where an animal believes the first thing it sees to be its mother
Why is imprinting important for animals?
As it ensures the young are protected and can learn from their mother how to find food
What is habituation?
A process in which an animal learns not to respond to a repeated stimulus
What is classical conditioning?
A process in which learning causes a reflex action to happen in response to a new stimulus (such as a dog salivating at the sound of a bell as they associate it with food)
What is operant conditioning?
A process in which an animal changes its behaviours as a result of experiencing rewards or unpleasant consequences
Give two examples in which police use operant conditioning and habituation
Sniffer dogs
Horses that learn not to be afraid of smoke
How are dolphins trained to be useful?
They are trained to locate mines so that they can be cleared
Name the three methods that organisms use to communicate
Visual signals, sound and chemical substances
In what way do organisms use visual signals to communicate their mood?
Mammals often use gestures, facial expressions and body language
Describe how sound is used to communicate
Many birds use singing to keep others out of their territory and male grasshoppers rub their legs against their wing cases to attract females
What chemical substances do many animals produce to influence the behaviour of others?
Pheromones
What is social behaviour?
Behaviour between members of the same species
Describe the role of Fossey in understanding gorillas
She studied them through imitating their behaviour and therefore became accepted into the group and could study the family relationships which she discovered weren’t violent. She also learnt the meaning of their calls
Describe the role of Goodall in understanding chimpanzees
She worked closely with the chimpanzees and discovered that they use tools to help them obtain food
How do plants attract animals for pollination?
Through brightly coloured fruits and flowers
How does the Labrador tea plant prevent insects from landing on its leaves?
By producing poisonous chemicals in its leaves which then diffuses into the air
Describe the role of ethene in acacia trees
When an acacia tree is eaten it produces distasteful chemicals as well as ethene which causes the other acacia trees to produce the distasteful chemicals
What is co-evolution?
When two species change together over time
What do orchids do to attract wasps?
They smell like a female wasp so when the wasp tries to mate with it the wasp receives a pack of pollen which is then carried to the next flower for pollination
What are grey kangaroos able to do?
Eat the leaves of bushes which contain a poison called fluoroacetate
Describe the features of ardi who was estimated to have lived 4.4 million years ago
120cm, 50kg, Walked upright, Long arms, brain size - 350cm^3
Describe the features of Lucy and when she lived?
3.2 million years ago, 1.07m tall, long arms, didn’t walk completely upright, brain - 400cm^3
Describe the features of homo habilis
2.4 - 1.4 million years ago, walked upright, quite short with long arms, brain size 500-600cm^3
Describe the features of homo erectus
1.8 - 0.5 million years ago, 1.79m, brain - 850cm^3
How can stone tools be used to support evolution?
Because over time the tools have become more sophisticated
How are stone tools dated?
By dating the layers of sediment that they were found in
Around 60,000 years ago there was a glacial period, what did this allow for people living at the time to do?
Cross from Africa to Yemen due to the sea level being much lower
Why did these people 60,000 years ago migrate?
To hunt and gather food
About 25,000 years ago, another land bridge was formed, where was it and what did it allow?
It was between Siberia and North America and allowed people to spread from Asia into North America
What do mitochondria have of their own?
DNA
What is the difference between where nuclear and mitochondrial DNA comes from?
Nuclear DNA comes from both mother and father whereas mitochondrial DNA comes only from the mother
How much faster than nuclear DNA does mitochondrial DNA mutate?
100-1000 times
Why is mitochondrial DNA more likely to be found?
Because it is in a greater abundance than nuclear DNA
Who is African eve?
A woman who lived between 130000 and 200000 years ago who has an unbroken female-female chain of mitochondrial DNA
What does the evidence from African eve mean?
That humans spread out of Africa and populated the rest of the world
What is biotechnology?
The alteration of natural biomolecules using science and engineering to provide goods and services
What is a biomolecule?
A substance made by living organisms
What is a fermenter?
A vessel used to cultivate microorganism a for the production of biomolecules on a large scales
How are fermenters sterilised?
By using high pressure steam
What does the term aseptic precaution mean?
Any method to ensure that living organisms do not come into contact with something
What do the microorganisms in a fermenter need to be provided with?
Nutrients such as sugar and ammonium as sources of carbohydrates and nitrogen
Why is an optimum temperature required in a fermenter?
To ensure the microorganisms work at a fast rate but don’t get denatured
What is an optimum pH required for in a fermenter?
To ensure the enzymes work efficiently
Why is oxygen provided to the microorganisms in a fermenter?
So they can respire aerobically
Why is agitation applied to the microorganisms in the fermenter?
To mix all of the oxygen and nutrients into the liquid
What fungus is mycoprotein made from?
Fusarium
Why is there no stirrer in the fermenter for mycoprotein?
Because fusarium is made up of tiny fibres called hyphae which would tangle and break
Name 4 things provided to the fusarium in the fermenter
Ammonia, air, glucose syrup and minerals
What happens to the hyphae once it is collected from the fermenter?
They are heat treated and then dried and pressed to form a fibrous substance which is similar to the texture of meat
What are the 4 advantages of food from microorganisms over growing crops and keeping animals
Populations can double extremely quickly
Microbes are easy to handle and manipulate
Doesn’t rely on climate
Can be grown from waste products
What does mycoprotein not contain that makes it healthier than meat?
Saturated fats
Why is the high fibre content in mycoprotein beneficial in terms of insulin secretion?
Because it slows the rate of glucose absorption which means insulin isn’t secreted in such large amounts
How is invertase produced?
By cultivating a yeast called saccharomyces cerevisae in fermenters
What does invertase do which is beneficial for making sweets?
Breaks down sucrose to glucose and fructose which is sweeter than sucrose so less is needed
Why are proteases and lipases used in washing powders?
To help remove stains that the detergent cannot remove by itself
What is chymosin used for?
To form curds in milk to produce cheese
Why did scientists begin to genetically modify bacteria to produce chymosin?
Because it typically comes from calves stomachs so it is therefore easier and cheaper and also suitable for vegetarians
What does making genetically modified organisms use?
Recombinant DNA technology
What kind of enzymes ‘cut’ the DNA, leaving sticky ends?
Restriction enzymes
What are restriction enzymes used to cut from the bacteria?
The plasmid DNA
What happens when the DNA strand and the plasmids are mixed?
The sticky end base pairs link up
What does ligase do after the sticky ends have paired?
Links e DNA back into a continuous circle
What happens to the recombinant plasmids after they have been joined up?
They are now inserted back into the bacteria
What is the ‘global food security crisis’?
That as the population begins to grow, people in certain places don’t get enough food
Describe what conventional breeding is
Producing offspring using the natural technique of cross breeding to produce a high quality and high yielding product
What is integrated pest management?
Reducing the populations of insects and pests by a co-ordinated treatment of different pest control strategies
How is crop rotation a form of pest control?
Because it helps to prevent a build up of soil pests for each of the different crops
How has conventional breeding helped to manage raspberry pests?
Because it has developed raspberry varieties that are resistant to aphids
How are raspberry beetles lured into traps where they drown?
Chemicals produced by raspberry plants are places in the traps
When are pesticides used on raspberries?
Only when the traps show that a large number of beetles are present
What is a biofuel?
A fuel made by/from living organisms such as maize or oil palms
Why are biofuels better than petrol or diesel?
Because they are renewable
What are biofuels said to be?
Carbon neutral
What is a disadvantage of biofuels?
The plants take up land which could be used for growing food
