Extension Science Flashcards
1
Q
What in the human brain regulates things over 24 hours?
A
Biological clock
2
Q
The biological clock relies on what?
A
Light exposure
3
Q
What is photoperiodism?
A
Plants response to changing day length
4
Q
Name 2 things which photoperiodism affects in plants
A
Germination and flowering
5
Q
What do young lupine produce that are poisonous?
A
Alkaloids
6
Q
What are alkaloids poisonous to?
A
Insects or pests
7
Q
Where is digoxin found and what is it used for?
A
Foxgloves, to treat heart disorders
8
Q
Where is quinine found and what is it used for?
A
Cinchona trees, to treat malaria
9
Q
Where is aspirin found and what it is it used for?
A
Willow trees, to treat pain and fever
10
Q
What did Louis Pasteur do?
A
He showed that microorganism a were responsible for food going off
11
Q
What is an antiseptic technique?
A
A method of keeping microbes away from people and food
12
Q
What is pasteurisation?
A
When food is heated before stored to kill microbes
13
Q
How did Edward Jenner develop smallpox vaccines?
A
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
14
Q
How do vaccines work?
A
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
15
Q
Name the disadvantages of vaccines
A
Swelling and redness around the vaccination
Children can get a mild disease
Some get allergic reactions
16
Q
Name advantages of vaccines
A
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
17
Q
What is a primary response?
A
The way in which our immune system responds on first occasion that a particular pathogen enters the body
18
Q
What is a secondary response?
A
The way in which our body responds to the second occasion that a pathogen enters the body
19
Q
What are monoclonal antibodies
A
Many identical antibodies
20
Q
What is a b lymphocyte?
A
A lymphocyte that can no longer divide due to production of antibodies
21
Q
What is a hybridoma cell?
A
A fusion of b lymphocytes and cancer cells so that they can divide
22
Q
How are monoclonal antibodies used in pregnancy tests?
A
They are used to detect HGH which sticks to dipstick and causes colour change
23
Q
How are monoclonal antibodies used to detect cancer
A
They are stuck to cancer drugs as they target the cancerous cells only
24
Q
What is a metabolic reaction?
A
A reaction in the body
25
What are the waste products of metabolic reactions?
Co2 and urea
26
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
27
What do the kidneys do?
The remove waste from the blood to form urine
28
What is the function of the ureters
They carry urine to the bladder
29
What does the bladder do
Stores urine
30
What does the urethra do
It releases urine from bladder to outside the body
31
What causes rejection of transplanted organs?
The body recognises the antigens on the tissue as foreign and then tries to destroy it
32
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
33
What is a nephron?
The place where filtration occurs in the kidneys
34
What is the glomerus?
The network of blood capillaries in the nephrons
35
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
36
Describe the process of selective reabsorption
Useful substances such as glucose are absorbed back into the blood at the convoluted tubes
37
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
38
What does more ADH cause
More concentrated urine
39
What is ovulation
When the egg is released from the ovary
40
Ovulation causes what?
Thickening of the uterus lining
41
What is it called when the lining breaks down and the egg lost?
Menstruation
42
What does the initial low level of progesterone cause?
FSH release
43
What does FSH do?
It triggers maturation of follicles
44
What does the maturing of follicles cause?
Release of oestrogen
45
What does the oestrogen cause?
Thickening of uterus lining and LH release
46
What does LH cause
Ovulation
47
When ovulation occurs, what happens to the follicle?
It becomes a corpus luteum
48
What does the corpus luteum cause?
An increase in progesterone
49
What does increase in progesterone cause?
It inhibits FSH and LH
50
Falling levels of progesterone and oestrogen lead to what?
Menstruation
51
What is the name of a rhythm that occurs over a period of 24 hours?
Circadian rhythm
52
What does the cytoplasm of an egg cell contain?
Lipid droplets (yellow spots)
53
What does the acrosome of a sperm cell contain?
Enzymes for digesting a way into the egg
54
What does the middle section of a sperm cell contain?
Mitochondria
55
What happens regarding the egg cell once a sperm has entered to ensure no other sperm gets in?
The membrane quickly changes
56
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
57
What are some problems with IVF?
The babies tend to be born premature which may cause problems in birth or later development
58
How does egg donation work?
Hormones are given to the donor to release eggs and then IVF is carried out
59
What is a problem with egg donation?
Some women react badly to the high levels of hormones given to them
60
When is surrogacy an option for a couple?
If the women is unable to grow an embryo in her uterus
61
How does surrogacy work?
The egg and sperm are fertilised through IVF and then implanted into the surrogate mother's uterus
62
What is the problem with surrogacy?
Sometimes the surrogate grows a strong bond with the baby and doesn't want to give it up
63
How does hormone treatment work to conceive a child?
Hormones are given to the woman to help her produce more eggs
64
What is the problem with hormone treatment?
Increases the chance of multiple births and the babies tend to be born premature
65
What is haemophilia and example of?
A sex-linked genetic disorder
66
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
67
Is the gene for red-green colour blindness on the X or Y chromosome?
X
68
Define the term behaviour
The ways in which animals respond to a stimuli
69
A mate that is healthy and well adapted is of what quality?
Good reproductive quality
70
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
71
Describe the 3 kinds of mate
Mate for life
Mate for season
Multiple mates a season
72
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
73
Describe a parental instinct over their young
That they will risk their own life in order to ensure the survival of their young
74
What is innate behaviour?
Behaviour that is 'hardwired' into our brain and is with us from when we are born
75
Animals who use innate behaviour are more likely to what?
Survive
76
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
77
What is imprinting?
It is a kind of simple learning where an animal believes the first thing it sees to be its mother
78
Why is imprinting important for animals?
As it ensures the young are protected and can learn from their mother how to find food
79
What is habituation?
A process in which an animal learns not to respond to a repeated stimulus
80
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)
81
What is operant conditioning?
A process in which an animal changes its behaviours as a result of experiencing rewards or unpleasant consequences
82
Give two examples in which police use operant conditioning and habituation
Sniffer dogs
| Horses that learn not to be afraid of smoke
83
How are dolphins trained to be useful?
They are trained to locate mines so that they can be cleared
84
Name the three methods that organisms use to communicate
Visual signals, sound and chemical substances
85
In what way do organisms use visual signals to communicate their mood?
Mammals often use gestures, facial expressions and body language
86
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
87
What chemical substances do many animals produce to influence the behaviour of others?
Pheromones
88
What is social behaviour?
Behaviour between members of the same species
89
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
90
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
91
How do plants attract animals for pollination?
Through brightly coloured fruits and flowers
92
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
93
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
94
What is co-evolution?
When two species change together over time
95
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
96
What are grey kangaroos able to do?
Eat the leaves of bushes which contain a poison called fluoroacetate
97
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
98
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
99
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
100
Describe the features of homo erectus
1.8 - 0.5 million years ago, 1.79m, brain - 850cm^3
101
How can stone tools be used to support evolution?
Because over time the tools have become more sophisticated
102
How are stone tools dated?
By dating the layers of sediment that they were found in
103
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
104
Why did these people 60,000 years ago migrate?
To hunt and gather food
105
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
106
What do mitochondria have of their own?
DNA
107
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
108
How much faster than nuclear DNA does mitochondrial DNA mutate?
100-1000 times
109
Why is mitochondrial DNA more likely to be found?
Because it is in a greater abundance than nuclear DNA
110
Who is African eve?
A woman who lived between 130000 and 200000 years ago who has an unbroken female-female chain of mitochondrial DNA
111
What does the evidence from African eve mean?
That humans spread out of Africa and populated the rest of the world
112
What is biotechnology?
The alteration of natural biomolecules using science and engineering to provide goods and services
113
What is a biomolecule?
A substance made by living organisms
114
What is a fermenter?
A vessel used to cultivate microorganism a for the production of biomolecules on a large scales
115
How are fermenters sterilised?
By using high pressure steam
116
What does the term aseptic precaution mean?
Any method to ensure that living organisms do not come into contact with something
117
What do the microorganisms in a fermenter need to be provided with?
Nutrients such as sugar and ammonium as sources of carbohydrates and nitrogen
118
Why is an optimum temperature required in a fermenter?
To ensure the microorganisms work at a fast rate but don't get denatured
119
What is an optimum pH required for in a fermenter?
To ensure the enzymes work efficiently
120
Why is oxygen provided to the microorganisms in a fermenter?
So they can respire aerobically
121
Why is agitation applied to the microorganisms in the fermenter?
To mix all of the oxygen and nutrients into the liquid
122
What fungus is mycoprotein made from?
Fusarium
123
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
124
Name 4 things provided to the fusarium in the fermenter
Ammonia, air, glucose syrup and minerals
125
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
126
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
127
What does mycoprotein not contain that makes it healthier than meat?
Saturated fats
128
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
129
How is invertase produced?
By cultivating a yeast called saccharomyces cerevisae in fermenters
130
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
131
Why are proteases and lipases used in washing powders?
To help remove stains that the detergent cannot remove by itself
132
What is chymosin used for?
To form curds in milk to produce cheese
133
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
134
What does making genetically modified organisms use?
Recombinant DNA technology
135
What kind of enzymes 'cut' the DNA, leaving sticky ends?
Restriction enzymes
136
What are restriction enzymes used to cut from the bacteria?
The plasmid DNA
137
What happens when the DNA strand and the plasmids are mixed?
The sticky end base pairs link up
138
What does ligase do after the sticky ends have paired?
Links e DNA back into a continuous circle
139
What happens to the recombinant plasmids after they have been joined up?
They are now inserted back into the bacteria
140
What is the 'global food security crisis'?
That as the population begins to grow, people in certain places don't get enough food
141
Describe what conventional breeding is
Producing offspring using the natural technique of cross breeding to produce a high quality and high yielding product
142
What is integrated pest management?
Reducing the populations of insects and pests by a co-ordinated treatment of different pest control strategies
143
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
144
How has conventional breeding helped to manage raspberry pests?
Because it has developed raspberry varieties that are resistant to aphids
145
How are raspberry beetles lured into traps where they drown?
Chemicals produced by raspberry plants are places in the traps
146
When are pesticides used on raspberries?
Only when the traps show that a large number of beetles are present
147
What is a biofuel?
A fuel made by/from living organisms such as maize or oil palms
148
Why are biofuels better than petrol or diesel?
Because they are renewable
149
What are biofuels said to be?
Carbon neutral
150
What is a disadvantage of biofuels?
The plants take up land which could be used for growing food
