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B3 Flashcards

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1
Q

What are the 3 roles Kidneys perform?

A
  1. Removal of urea from the blood
  2. Adjustment of ion levels in the blood
  3. Adjustment of water content of the blood
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2
Q

Where is urea produced?

A

In the liver from the breakdown of excess amino acids

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3
Q

How do kidneys perform these roles

A

By filtering stuff out of the blood under high pressure and then reabsorbing the useful things. The end product is urine

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4
Q

What are nephrons

A

They are the filtration units in the kidneys

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5
Q

Describe ultrafiltration

A
  1. A high pressure is built up which squeezes water, urea, ions and glucose out of the blood and into the Bowman’s capsule
  2. The glomerulus and the Bowman’s capsule act like filters, so big molecules like proteins and blood cells are not squeezed out. They stay in the blood
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6
Q

What happens in reabsorption

A
  1. All the glucose is selectively reabsorbed- it’s moved out of the nephron back into the blood against the concentration gradient.
  2. Sufficient water is reabsorbed, according to the level of the hormone ADH. The process of maintaining the right water content in the body is called osmoregulation
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7
Q

Release of wastes

A

Urea and excess water are not reabsorbed

They continue out of the nephron, into the ureter and down to the bladder as urine. Urine is released through the urethra.

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8
Q

How is water content regulated in the kidneys?

A

By a negative feedback system

The amount of water reabsorbed in the kidney nephron is controlled by Anti diuretic hormone

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9
Q

Describe the negative feedback system that regulates water content

A

The brain monitors the water content of the blood and instructs the pituitary gland to release ADH into the blood according to how much is needed

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10
Q

Negative feedback

A

Where changes in the environment trigger a response that counteracts the changes. This means that the internal environment tends to stay around a norm, the level at which the cells work best.

If the water content gets too high or low, negative feedback brings it back to normal

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11
Q

When there is too much water…

A

Pituitary gland releases less ADH

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12
Q

When there is too little water…

A

Pituitary gland releases more ADH

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13
Q

More ADH makes

A

The Kidney absorb more water

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14
Q

What is dialysis

A

Patients who have kidney failure can’t filter their blood properly so a dialysis machine does it for them
Dialysis has to be done regularly
Dialysis fluid has the same concentration of salts and glucose as blood plasma

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15
Q

Cell metabolism produces what?

A

Waste products like urea and carbon dioxide

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16
Q

How are egg cells specialised for reproduction

A
  • contain nutrients in the cytoplasm to feed the embryo
  • Straight after fertilisation the membrane changes to stop any more sperm getting in
  • the egg contains a haploid nucleus
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17
Q

What is the main function of the egg

A

To carry the female DNA and to nourish the developing embryo in the early stages

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18
Q

What is the function of the sperm cell

A

To transport the males DNA to the female egg

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19
Q

How is the sperm cell specialised for reproduction

A
  • small and have long tails to swim
  • have lots of mitochondria in their middle section to provide energy to swim the distance
  • acrosome at the front where enzymes they need to digest through egg membrane are stored
  • contains haploid nucleus
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20
Q

Menstrual cycle

A

Day 1- uterus lining breaks down
Day 4 -14 - lining of the uterus builds up again
Day 14- egg is released from ovary
Day 28- if no egg is fertilised the lining breaks down again

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21
Q

FSH

A

Causes a follicle to mature in one of the ovaries

Stimulates oestrogen

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22
Q

Oestrogen

A

Causes the lining of the uterus to thicken and grow

High level stimulates an LH surge

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23
Q

LH

A

Stimulates ovulation at day 14, the follicle ruptures and the egg is released

Stimulates the remains of the follicle to develop into a corpus luteum which secrets progesterone

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24
Q

Progesterone

A

Maintains the lining of the uterus
Inhibits FSH and LH

When level falls, and there’s a low oestrogen level the uterus lining breaks down
A low progesterone level allows FSH to increase

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25
Q

Placenta

A

Supplies the baby with oxygen, glucose and nutrients

Removes waste products

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26
Q

What was pasteurs experiment

A

Pasteur heated broth in two flasks, left them open
One had a curved neck so that the bacteria settled in the loop and couldn’t get through
One stayed fresh but the other didn’t, showing it was the microbes not the air causing it to go off

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27
Q

How do B- lymphocytes respond to invading microorganisms

A

When the B-Lymphocytes come across a foreign antigen, they produce proteins called antibodies which bind to and kill the new invading cells
The antibodies produced are specific to that antigen
Antibodies are produced rapidly and flow all around the body to kill all similar bacteria or viruses

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28
Q

Monoclonal antibodies

A

Hybridoma cells divide quickly to produce lots of identical antibodies called monoclonal antibodies

You can make ones that bind to any specific antigen- only targets one cell

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29
Q

How are monoclonal antibodies used in pregnancy tests

A

The first window has antibodies with blue beads attached, the test strip has antibodies that are stuck down
If you are pregnant then the antibodies bind to the hormone and are moved up the stick
The beads with the hormone bind to the antibodies on the strip turning that section blue

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30
Q

How are monoclonal antibodies used to detect cancer

A

Cancer cells have special cells called Tumour markers
The antibodies are labelled with a radioactive element, given through a drip into the blood
They bind to the tumour markers and are detected with a special camera

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31
Q

How are antibodies used to kill cancer cells

A

Drug kills the cancer cells but not any other cells near it

Less side effects

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32
Q

How can antibodies be used to find blood clots

A

When blood clots, proteins in the blood join together to form a solid mesh
Monoclonal antibodies bind to these proteins with a radioactive element

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33
Q

Germination of Arctic plants

A

When the days are long so they know it’s summer

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34
Q

Long day plants

A

Only flower when the day is at least a certain length

Eg spinach

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35
Q

Short day plants

A

Only flower when the days are less than a certain length so they flower in early spring or autumn

Eg primroses

To ensure they only flower when the right insects are about

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36
Q

Sleep patterns

A

When it gets dark your body produces more melatonin which makes you sleepy
Having regular sleep patterns is good for your health and ensures you feel awake at the right time

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37
Q

Urine production

A

At night ADH levels increase which reduces urine production

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38
Q

Stomata opening

A

During the day photosynthesis occurs, the stomata open to let in CO2 and O2 in and out
At night photosynthesis stops so stomata can close to reduce water loss

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39
Q

Flower opening

A

Flowers only need to be open when the creatures that pollinate them are active

Tobacco flowers-pollinated by moths only open at night

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40
Q

Classical conditioning

A

When an animal learns passively to associate a neutral stimulus with an important one, the response is automatic and reinforced with repetition

Eg Ivan Pavlov- classical conditioning in dogs

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41
Q

Operant conditioning

A

Where an animal learns actively to associate an action with a reward or punishment

Eg Burrhus skinner- Operant behaviour in pigeons and rats

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42
Q

Animal training using operant conditioning

A

Training guide dogs to stop at a roadside and wait for a command
Training police sniffer dogs to retrieve drugs
Training police horses to only respond to commands from their riders

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43
Q

When is classical conditioning used in combination with operant conditioning

A

When a reward can’t be given at the exact time the act is carried out
For example in Dolphins, the fish cannot be given at the exact time the dolphin does the jump so a whistle is blown instead.
The whistle shows the dolphin it will get the fish

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44
Q

Why do plants release chemicals

A

Attract pollinators
Attract insect predators
Warn other plants

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45
Q

How do plants attract pollinators

A

Lots of flowers release scented chemicals which attract pollinators who are looking for nectar. While they are there some pollen gets stuck to them

46
Q

How do plants attract insect predators

A

Some plants release chemicals into the air when a pest is eating them
These attract a predator insect which feeds on the pest but not the plant

47
Q

How do plants warn other plants

A

Some plants have leaves that can release chemicals into the air if they are being eaten
When another leaf detects them it makes chemicals that make the leaf harder to digest
Another plant nearby detects the signal and they prepare themselves in the same way

48
Q

Why have plants and their pollinators co evolved

A

It’s an advantage for both as the insect has less competition and the insect is more likely to visit other flowers of that type

Eg orchids and moths- deep nectar store

49
Q

Why do plants and their pests co evolve

A

Some plants produce nasty chemicals so most insects can’t eat them
Some insects can eat poisonous plants so less competition
Eg caterpillars of the cinnabar moth eat ragwort

50
Q

How did settlers on the coast of the near East and Asia change

A

Started to eat shellfish and seafood

New stone tools to get them out of their shells

51
Q

How did settlers in Australia change

A

Rainforest so eating fruit that grew in trees

New tools to reach it- long sticks

52
Q

How did settlers in Europe change

A 
Changed their diet 
Larger animals so new methods of hunting so they could hunt in groups
New tools like knives and saws 
Colder climate so more shelters 
Animal skins to make warm clothes
53
Q

How humans adjusted to the ice age

A 
More shelters 
Fire
Warm clothing made of skins and fur 
Hunting increased 
Make and use more tools 
Cooperation and communication increased 
Language developed
54
Q

Mycoprotein

A

Meat substitutes for vegetarians
Fungus fusarium is grown in fermenters using glucose syrup as food
Respires aerobically so needs oxygen
More protein, fibre, less fat than meat

55
Q

Producing yoghurt

A

Equipment sterilised
Milks pasteurised then cooled
Lactobacillus bacteria is added and the mixture is incubated in a fermenter
Bacteria ferment the lactose sugar to form lactic acid
This causes the milk to clot and solidify into yoghurt

56
Q

Advantages of using microorganisms for food production

A 
Grow quickly 
Easy to look after 
Not affected by climate 
Use waste products from agriculture and industry as food 
Cheaper
57
Q

What enzymes can be used in food production

A

Chymosin

Invertase

58
Q

How is chymosin used in food production

A

Cheese is made using rennet
Rennet is obtained from calfs stomach lining containing the enzyme chymosin which clots the milk
Genes for chymosin were isolated from the stomach cells and put into yeast cells

59
Q

How is invertase used in food production

A

Used to manufacture sweets and other foods
Converts sucrose into glucose and fructose which are sweeter so less sugar is needed for the same sweetness
Cheaper, lower calorie
Naturally produced by the yeast saccharomyces cerevisiae

60
Q

Non biological washing powders

A

Contain chemicals which break up the stains

61
Q

Biological washing powders

A

Contain the same chemicals as non-biological but with enzymes which break down the starch proteins and fats
More effective at low temperatures
Work best at pH 7

62
Q

Immobilised enzymes

A

Enzymes attached to an insoluble material or encapsulated in alginate beads so they don’t dissolve into the mixture
Can be easily separated and re used

63
Q

Immobilised enzymes in lactose free milk

A

Mix sodium alginate and lactose together in a syringe
Add the mixture one drop at a time into calcium chloride
They should form beads
Put nylon gauze in a syringe and add the beads into it
Slowly add the milk to the syringe, collect the treated milk in a beaker
Test for glucose

64
Q

Why make lactose free milk

A

The sugar lactose is naturally found in milk, it’s broken down by lactase to form glucose and galactose which are absorbed into the blood

Some people lack lactase so the lactose isn’t broken down and causes abdominal pain, wind and diarrhoea

65
Q

Pectinase

A

Used in fruit juice extraction. It breaks down pectin (a part of the cell wall) causing the cell to release its juice

66
Q

How do u use pectinase in the lab

A
  1. Chop up an apple into small chunks and divide it into two beakers
  2. Add pectinase solution to one of the beakers, and add the same volume of water to the other, then stir
  3. Incubate the beakers at 40*C for 15 mins
    4 filter out the contents and record the volume of juice you get from each
67
Q

How do restriction enzymes work

A

They recognise the specific sequence of DNA and cut the DNA at these points
The cut leave some of the DNA strands with unpaired bases- called a sticky end

68
Q

Transgenic

A

When something contains a gene transferred from another species

69
Q

How is human insulin made

A
  1. Plasmid removed from the bacterium
  2. Insulin gene is cut out of a human chromosome using a restriction enzyme
  3. The plasmid is cut open using the same restriction enzyme leaving the same sticky ends
  4. The plasmid and human gene are mixed together and ligase is added to join the sticky ends and produce recombinant DNA
  5. Inserted into bacteria, the bacteria is grown in a fermenter
70
Q

What’s agrobacterium tumefaciens?

A

Pathogen that invades plant cells and inserts its genes into the plants DNA
Used as a vector

71
Q

How are herbicide resistant plants made

A
  1. Get a plant that already has resistance and cut out the gene from one of the cells
  2. Remove the circular loop of DNA from the bacterium and insert the gene
  3. Allow bacteria to ‘infect’ the cells of the target plant, they will insert their genes into the plant DNA
  4. Cells are grown on a medium containing herbicide- ones that grow must contain the herbicide resistant gene
72
Q

How to increase food production

A

Reducing pest numbers
Selective breeding programs
GM plants

73
Q

Reducing pest numbers

A

This can be done using

  • Insecticides
  • GM crops to kill pests
  • Crop rotation to stop pests building up
  • Biological control- pest predators
74
Q

Selective breeding programs

A

Parent plant with the best characteristics are selected and bred with each other
The best of the offspring are selected and bred
Repeated over several generations to develop the desired traits

75
Q

Biogas

A
  • Microorganisms decompose waste material to produce biogas
  • 70% Methane and 30% carbon dioxide
  • Burned to power a turbine
  • Fuel for cars and buses
76
Q

Biodiesel

A
  • An alternative fuel similar to diesel which can be used in vehicles
  • Doesn’t take much alteration
  • Made from vegetable oils, animal fats or waste cooking oil
77
Q

Ethanol

A
  • Can be burnt as a fuel
  • Cleaner than petrol or diesel producing fewer pollutants
  • Produced by using yeast to ferment glucose
  • Cars can be adapted to run on a mixture of ethanol and petrol known as gasohol
78
Q

Advantages and disadvantages to biofuels

A
  • Sustainable, replaced quickly
  • Carbon neutral
  • Fairly clean- less particulates
  • Not much sulphur dioxide produced
  • Takes up land
  • Power stations and vehicles need to be adapted which takes time and money
79
Q

How can u make crops resistant to pests

A
  • Bacillus Thuringiensis produces a toxin that kills many of the insect larvae that are harmful
  • Gene for the Bt toxin is inserted into crops which produce the toxin in their stems and leaves
  • Harmless to humans, and animals but long term effects of exposure are unknown
  • There’s a danger they’ll develop resistance
80
Q

How to farmers reduce pest resistance to the Bt toxin

A

By using other insecticides too

81
Q

How can biotechnology help provide food to developing countries

A
  • GM pest resistant- crop yields
  • GM grow in drought conditions- crop yields
  • GM deficiency diseases
  • Some people say it’s because they can’t afford food not because there is none
  • Fears countries may become dependent on companies that sell GM seeds
  • Doesn’t tackle the problem of poor soil
82
Q

Aspirin

A
  • Treat pain and lower fever

- Developed from a chemical found in the leaves and bark of the willow tree

83
Q

Taxol

A
  • Anti-cancer drug
  • Comes from the bark of the Pacific Yew tree
  • Discovered when scientists were screening loads of plants looking for potential treatments
84
Q

Quinine

A
  • South American cinchona tree

- For years it was the main treatment against malaria

85
Q

How do pests reduce crop yields

A
  • Fruit flies feed on fruit and ruin entire crops
  • Weeds that grow near compete for nutrients in the soil, crop yield is lower
  • If a plant is infected with a pathogen, some of its energy is taken by the pathogen or try and replace dead parts
  • Add to the cost of producing food- money for pesticides
  • Low crop yield mean high prices for customers
86
Q

Pros of immunisation

A
  • Epidemics can be prevented if a large percentage of the population are immunised, even the people that aren’t immunised are less likely to catch it
  • Some diseases have been virtually wiped out by immunisation
87
Q

Immunisation cons

A
  • Doesn’t always work

- Can have a bad reaction to the vaccine, but these are rare

88
Q

Hormones for fertility

A

Some women have low levels of FSH which means no eggs are released and the women can’t get pregnant, so it can be injected
- Helps people the get pregnant when they couldn’t

  • Doesn’t always work
  • Too many eggs stimulated resulting in twins etc.
89
Q

IVF

A

In vitro fertilisation involves collecting the eggs and fertilising them in the lab using the sperm,
when the Embryos are a ball of cells one or two are transferred to the uterus
FSH and LH are given before collection to stimulate egg production

90
Q

Pros and cons of IVF

A

-Gives infertile couple a child

  • Some women have a strong reaction to the hormones
  • Reports of an increased risk of cancer
  • Multiple births which can be risky for the mother and baby (higher chance of miscarriage)
91
Q

IVF with donated eggs pros and cons

A
  • Allows woman who can’t produce eggs to have a baby
  • Can prevent risk of genetic disorder

-Emotionally difficult - different genetic mother

92
Q

Surrogate mother pros and cons

A
  • Allows couple to have a child if she can’t become pregnant or it’s risky for her to give birth
  • Surrogate mother has the right to keep the child as she is legally the mother until it is adopted by the intended couple
93
Q

Ardi

A
  • Ardipithicus ramidus
  • Ethiopia
  • 4.4 million years
  • Climbed trees- structure of feet
  • Long arms and short legs- More ape than human
  • Brain size same as chimpanzee
  • Walked upright
94
Q

Lucy

A
  • Australopithecus afarensis
  • Ethiopia
  • 3.2 million years old
  • Arched feet more adapted to walking
  • Moderate size of arms and legs
  • Brain larger than Ardi’s but similar to chimps
  • Walked more efficiently than ardi
95
Q

Turkana Boy

A
  • Homo erectus
  • 1.6 million years
  • Short arms and long legs much more human
  • Brain size is much larger- similar to humans
  • Even better adapted to walking upright
96
Q

Mitochondrial DNA

A
  • Inherited from the mother
  • High mutation rate
  • Lots of copies of Mitochondrial DNA
  • Less likely to degrade over time
97
Q

Using mitochondrial DNA as evidence for human evolution

A
  • The more different two samples are the further back they shared a common ancestor
  • Everyone on the planet has similar mitochondrial DNA
  • Everyone is descended from one woman who lived in Africa 200,000 years ago
98
Q

How to date a rock (not THE rock lol good luck with that)

A
  • Stratigraphy
  • Dating any fossils found with the tools
  • Using carbon-14 dating to date any materials made from carbon
99
Q

Behaviour

A

An organisms response to changes in its environment

100
Q

Innate behaviour

A
  • Inherited behaviour, reflexes

- Protect us from dangerous stimuli

101
Q

Examples of reflexes

A
  • Earthworms show negative phototaxis- move away from light

- Sea anemones wave their tentacles when stimulated by chemicals emitted by their prey

102
Q

Learned behaviour

A

Let’s animals respond to changing conditions

103
Q

Habituation

A

If you keep giving an animal a stimulus that isn’t beneficial or harmful they learn not to respond

By ignoring non-threatening and non rewarding stimuli, animals can use their energy more effectively

104
Q

Imprinting

A
  • Combination of learned and innate
  • The animal learns to recognise its parents and instinctively follows them.
  • Occurs in species that can move soon after they’re born
  • Has an instinct to follow the first thing it sees but has to learn what this is
105
Q

Why do animals communicate

A
  • Help keep the group together
  • Warn others about predators
  • Communication of mood can avoid unnecessary fighting
  • Baby animals can communicate needs to parents
  • Allows predators in a group to coordinate attack
106
Q

How can animals communicate

A
  • Sound
  • Chemicals
  • Visual signs
107
Q

How do animals use sound to communicate

A
  • Humans through language
  • Wales and dolphins through infrasound
  • Birds calls declare territory, attract mates of warn others from predators
108
Q

How can animals use chemicals to communicate

A

Chemicals called pheromones can be released to tell others where it is or has been

  • Many use chemical scents to mark territory
  • Some are for sexual attractants- in some moths the male can detect the females pheromone from several kilometres
109
Q

Examples of visual signals

A
  • Honey bee waggle dance when they return to the hive to tell the others they’ve found food
  • Body language and posture
  • Use behaviour to intimidate others and avoid an actual fight
  • To admit defeat or attract a mate
  • Facial expressions
110
Q

Ethologyst

A

Study animal behaviour

Biology (8 decks)

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