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Biology > Paper 1 - Is Assessed > Flashcards

Paper 1 - Is Assessed Flashcards

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1
Q

Describe the functions of the Cerebellum

A

Responsible for muscle coordination and balance

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2
Q

Describe the function of the Medulla Oblongata

A

Controls unconcious activities like breathing and heart rate

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3
Q

Describe the division of the Cerebrum

A

Divided into two halves = cerebral hemispheres = right side controls muscles on left side of the body

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4
Q

Describe the function of the Cerebrum

A

Movement, Intelligence, Memory, Language, Vision

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5
Q

State the largest part of the brain

A

Cerebrum

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6
Q

State what is used in a CT scanner to produce an image of the brain

A

X-rays

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7
Q

State what is used in a PET scanner to produce an image of the brain

A

Radioactive chemicals

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8
Q

Describe what the spinal cord is

A

A long column of neurones that run from the base of the brain down the spine

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9
Q

State the job of the spinal cord

A

To relay information between the brain and the rest of the body

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10
Q

Describe what a CT scan shows

A

The main structures in the brain, but not the functions of them

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11
Q

Describe what a PET scan shows

A

Detailed image used to investigate structure AND function of the brain in real time

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12
Q

Explain how a CT scan can determine the function of parts of the brain

A
  • CT scan shows diseased or damaged brain structure
  • If the patient has lost some function, then the function of that part of the brain can be worked out
    EG. If a patient can’t see and has damaged structure, that part is involved in vision
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13
Q

Explain how a PET scan can help discover brain disorders

A
  • PET scan shows if brain is unusually inactive or active

- So they are useful for studying disorders that change the brain’s activity

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14
Q

Explain how a PET scan can discover Alzheimer’s disease

A
  • shows activity in certain areas of the brain is reduced

- PET scan shows this reduction compared to a normal brain

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15
Q

Explain why it’s hard to repair damage to the nervous system

A

Neurones in the CNS don’t readily repair themselves, and scientists haven’t developed a way to repair damaged nervous tissue

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16
Q

Explain why treating problems with the CNS can be tricky

A

CNS isn’t all easy to access, so it can be hard to treat (eg. Impossible to surgically remove tumours in certain parts of the brain)

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17
Q

Explain why the treatment for problems in the CNS may cause further issues

A

Treatments may cause permanent damage (eg. may be damaged further in surgery)

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18
Q

State what a cataract is

A

A cloudy patch on the lens, which stops light being able to enter the eye normally

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19
Q

What are the consequences of a cataract

A

Blurred vision, colours are less vivid, difficulty seeing in bright light

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20
Q

Explain how a cataract can be treated

A

By replacing the faulty lens with an artificial one

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21
Q

Describe what causes red-green colour-blindness

A

When red or green cones in the retina aren’t working properly

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22
Q

Explain why there is no cure for colour-blindness

A

Cone cells can’t be replaced

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23
Q

State what is long-sightedness and how can it be corrected

A

Unable to focus on near objects - correct with convex lens

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24
Q

What causes long-sightedness

A

The lens is the wrong shape, and doesn’t bend the light enough OR the eyeball is too short = light from near objects is brought into focus behind the retina

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25
Q

What causes short-sightedness

A

The lens is the wrong shape and bends light too much OR the eyeball is too long = light from distant objects is brought into focus in front of retina

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26
Q

State what is short-sightedness and how can it be corrected

A

Unable to focus on distant objects - correct with concave lens

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27
Q

Explain how the eye sees distant objects

A
  • ciliary muscle relaxes
  • this pulls suspensory ligaments tight
  • this pulls the lens less rounded
  • so less light is refracted
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28
Q

Explain how the eye sees close objects

A
  • ciliary muscle contracts
  • which slackens suspensory ligaments
  • so the lens becomes more rounded
  • so more light is refracted
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29
Q

State the function of the cornea

A

Cornea refracts light into the eye

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30
Q

State the function of the iris

A

Controls how much light enters the pupil (hole in middle)

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31
Q

State the function of the lens

A

Refracts light, focusing it onto the retina

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32
Q

State the function of the retina

A

The light sensitive parts - covered in rods and cones

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33
Q

State the function of rods

A

Sensitive to dim light

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34
Q

State the function of cones

A

Sensitive to colours

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35
Q

How is information from light taken to the brain

A
  • converted into electrical impulses

- optic nerve carries impulses from receptors to the brain

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36
Q

What is the optic nerve?

A

A sensory neurone which relays information from the eyes to the brain

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37
Q

Describe the path from a stimulus to a reaction

A

Stimulus - Receptor- Info converted to electrical impulse - Sensory Neurone - CNS coordinates response - Motor Neurone - Effector (muscle/gland) - Response

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38
Q

Go to Photo 1 and state the labels

A

A - Cerebrum
B - Cerebellum
C - Medulla Oblongata

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39
Q

All neurones have a…

A

cell body and nucleus

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40
Q

What do dendrons / dendrities do?

A

Carry nerve impules towards the cell body

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41
Q

What do axons do?

A

Carry a nerve impulse away from the cell body

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42
Q

What do myelin sheaths do?

A

Act as an insulator, speeding up the conductance of the impulse

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43
Q

What sends a faster impulse: one long neurone or many short ones?

A

One long one because connecting many slows down the impulse

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44
Q

What is the structure of a sensory neurone? Photo 2

A

From left to right: receptor cells - one long dendron - cell body - axon - dendrites

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45
Q

Explain how a sensory neurone functions

A
  • 1 long dendron carries nerve impulses from receptor cells to the cell body
  • which is located in the middle of the neurone
    - 1 short axon carries nerve impulses from the cell body to the CNS
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46
Q

Explain how a motor neurone functions

A
  • many short dendrites Carry nerve impulses from the CNS to the cell body
  • 1 long axon carries nerve impulses from the cell body to effector cells
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47
Q

Explain how relay neurones function

A
  • many short dendrites carry nerve impulses from sensory neurones to the cell body
  • an axon carries nerve impulses from the cell body to motor neurones
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48
Q

What is the structure of a motor neurone? Photo 3

A

From left to right: dendrites - cell body - axon (myelin sheath) - effector cells

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49
Q

What is the structure of a relay neurone? Photo 4

A

From left to right: dendrites - cell body - axon

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50
Q

State the name for the connection between two neurones

A

Synapse

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51
Q

Explain how an electrical signal moves across synapses

A
  • neurotransmitters diffuse across the gap between neurones

- The neurotransmitters then set off a new electrical signal in the next neurone

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52
Q

Describe why the transmission of nervous impulses can be slowed

A

It is slowsd down at the synapse because the diffusion of neurotransmitters across the gap takes time

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53
Q

Define a communicable disease

A

Diseases that spread between individuals

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54
Q

Define non-communicable diseases

A

Can’t be transmitted between indivuals

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55
Q

Explain why the presence of one disease can lead to a higher susceptibility to another

A

If you are affected by one disease, your body may become weakened, so is less likely to fight off ofhers

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56
Q

Define a pathogen

A

Organisms such as viruses, bacteria, fungi, protists that cause communicable diseases

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57
Q

What causes cholera, and what are its symptoms?

A

A bacteria called Vibrio cholerae - diarrhoea

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58
Q

What causes TB, and what are its symptoms?

A

A bacterium called Mycobacterium tuberculosis - coughing and lung damage

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59
Q

What causes Malaria and what are its symptoms?

A

A protist - damage to red blood cells, and in severe cases the liver

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60
Q

What causes stomach ulcers, and what are its symptoms?

A

A bacterium called Heliobacter pylori- stomach pain, nausea, vomiting

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61
Q

What causes Ebola and what are its symptoms?

A

Ebola virus - haemorrhagic fever (a fever with bleeding)

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62
Q

What causes chalara ash dieback and what are its symptoms?

A

A fungus - leaf loss, bark lesions

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63
Q

How does cholera spread, and how do you reduce it?

A

Via contaminated water - clean water supplies

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64
Q

How does TB spread and how can it be reduced?

A

Through the air - avoid crowded spaces, practise good hygiene, ventilation, sleep alone

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65
Q

How does malaria spread and how can it be reduced?

A

Mosquitoes act as vectors - nets, insect repellents to prevent biting

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66
Q

How are stomach ulcers causes and how can it be reduced?

A

Oral transmission eg. Eating contaminated food - clean water/hygienic living conditions

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67
Q

How does Ebola spread and how can it be reduced?

A

Via bodily fluids - by isolating infected individuals and sterilising any areas it may be

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68
Q

How does chalara ash dieback spread and how can it be reduced?

A

Carried through air by wind or when trees are moved between areas - removing young infected trees or restricting import of trees

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69
Q

What is HIV?

A

Kills white blood cells, leading to AIDS

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70
Q

What does HIV stand for?

A

Human Immunodeficiency Virus

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71
Q

What does AIDS stand for?

A

Acquired Immune Deficiency Syndrome

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72
Q

What is AIDS?

A

When the infected person’s immune system deteriorated and eventually fails - because of this the person is more vulnerable to other pathogens

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73
Q

How is HIV spread?

A

Via infected bodily fluids

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74
Q

How can HIV be prevented?

A

condoms / avoid sharing needles / medication / screening and proper treatment

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75
Q

What is Chlamydia?

A

A kind of bacterium, that behaves in a similar way to a virus as it can only reproduce inside host cells

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76
Q

What are Chlamydia’s symptoms?

A

It doesn’t always have them, but it can cause infertility

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77
Q

How can Chlamydia be prevented?

A

Wearing a condom / screening individual so they can be treated / avoiding sexual contact

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78
Q

What are chromosomes?

A

Coiled up lengths of DNA molecules

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79
Q

How is diploid represented?

A

2n

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80
Q

What happens during interphase?

A
  • grows amount of sub cellular structures eg. Mitochondria
  • duplicates it’s DNA
  • forms X-shaped chromosomes with duplicates
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81
Q

What happens during prophase?

A
  • chromosomes condense getting shorter and fatter
  • membrane around nuclear breaks down
  • chromosomes lie free in the cytoplasm
82
Q

What happens in metaphase?

A

The chromosomes line up at the centre of the cell

83
Q

What happens in anaphase?

A
  • spindle fibres pull the chromosomes apart

- chromatids are pulled to opposite ends of the vell

84
Q

What happens in telophase?

A
  • membranes form around each of the sets of chromosomes

- these become the nuclei of the two new cells = nucleus has divided

85
Q

What is cytokinesis?

A

Before telophase ends, the cytoplasm cell membrane divide to form two separate cells

86
Q

What is the longest part of mitosis?

A

Interohas

87
Q

What are the products of mitosis?

A
  • 2 new daughter cells
  • genetically identical diploid cells
  • identical sets of chromosomes to parent cell
88
Q

What do multicellular organisms use mitosis for?

A

To grow or replace cells that have been damaged

89
Q

Give an example of mitosis being used to asexually reproduce

A

Strawberry plants form runners by mitosis, which become new plants

90
Q

What is chromatin?

A

Unpackaged / uncoiled chromosomes

91
Q

What controls the rate at which cells divide by mitosis?

A

Genes in an organism’s DNA

92
Q

What causes cancer?

A
  • cells dividing uncontrollably due to a change in genes that control division
  • a mass of abnormal cells = tumour
  • tumour invades and destroys surrounding tissue
93
Q

Define cell differentiation

A

The process by which a cell changes to become specialised for its job

94
Q

How does cell differentiation improve the body?

A

Specialised cells allows multicellular organism to work more efficiently

95
Q

What is another name for cell division

A

Mitosis

96
Q

What is cell elongation?

A

Where a plant cell expands, making the cell bigger and so making the plant grow

97
Q

When do animals tend to grow?

A

At a young age, then they reach full growth and stop

98
Q

When you’re a young animal, how fast are your cells diving?

A

At a fast rate

99
Q

Why do cells divide once an animal is fully grown?

A

Cells divide to repair and replace old or damaged cells, meaning for animals cell differentiation is lost at a young age

100
Q

Where does cell division happen in plants?

A

Mostly at the tips of the roots and shoots (meristems) m

101
Q

How long do plants grow for?

A

Continuously, so plants continue to differentiate to develop new parts

102
Q

What is the passage of information in a reflex called?

A

A reflex arc

103
Q

Where do the neurones in reflex arcs go through?

A

The spinal cord or unconscious part of the brain

104
Q

Step 1 of a reflex arc -

What happens when a stimulus is detected by receptors?

A

Impulses are sent along a sensory neurone to a relay neurone in the CNS

105
Q

Step 2 of a reflex arc -

What happens when the impulse reaches a synapse between sensory and relay neurone?

A

They trigger neurotransmitters to be released, carrying the impulse along to relay neurones

106
Q

Step 3 of reflex arc -

What happens when an impulse reaches a synapse between a relay and motor neurone?

A

Neurotransmitters are released and cause an impulse to be sent along the relay neurone

107
Q

Step 4 of a reflex arc -

What happens to the impulses that travel along the motor neurone?

A

They reach the effector (this could be a muscle or gland)

108
Q

Step 5 of a reflex arc -

What happens when the impulse has reached the effector?

A

The muscle contracts and responds

109
Q

What are the advantages of asexual reproduction?

A
  • produce many offspring very quickly

- only one parent is needed

110
Q

What are the disadvantages of asexual reproduction?

A
  • no genetic variation in offspring

- so if environment conditions become unfavourable, the whole population may be affected

111
Q

What are the advantages of sexual reproduction?

A
  • genetic variation = different characteristics

- more likely for population to survive if environmental conditions change

112
Q

What are the disadvantages of sexual reproduction?

A
  • more time and energy
  • produces fewer offspring
  • two parents are needed, so must find a mage
113
Q

What is the outcome of meiosis?

A
  • 4 daughter cells
  • genetically different
  • each gamete has a single set of chromosomes = haploid
114
Q

In humans, where does meiosis happen?

A

In the reproductive organs

115
Q

Define DNA

A

Polymers made up of repeating units called nucleotides

116
Q

What does a nucleotide consist of?

A 
A sugar (pentagon) 
A phosphate group (round)
A base (square)
117
Q

What forms a backbone to DNA strands?

A

The sugar and the phosphate group in the nucleotide - these alternate

118
Q

What are the 2 complementary base pairs?

A 
A = T
C = G
119
Q

What is the shape of a DNA molecule?

A

Two strands coiled together in the shape of a double helix

120
Q

How do the bases join on strands of DNA?

A

Each base links to a base on the opposite strand of the helix

121
Q

How are the complementary base pairs joined up?

A

By weak hydrogen bonds

122
Q

Define a gene

A

A section of DNA on a chromosome that codes for a particular protein

123
Q

What is a genome?

A

All of an organism’s DNA

124
Q

How do you extract DNA from fruit?

A
  • mash strawberries and put them in a beaker with a solution of detergent and salt
  • filter the mixture to get the froth and big insoluble bits of cell out
  • gently add some ice-cold ethanol
  • the DNA will start to come out of solution as it’s not soluble in cold alcohol
  • it will appear as a stringy white precipitate that can be carefully fished out with a glass rod
125
Q

Why do you use detergent in the solution when extracting DNA?

A

The detergent will break down the cell membranes to release the DNA

126
Q

Why do you use the salt in the solution when extracting DNA?

A

The salt will make the DNA stick together

127
Q

How do new alleles arise?

A

Through mutations

128
Q

Give examples of selection pressures that affect and organisms chance of surging

A

Predation, competition (biotic factors)

129
Q

What happens to beneficial characteristics over time?

A

They become more common as they’re more likely to survive

130
Q

How are mutations helpful to bacteria?

A
  • A random mutation = resistance
  • more likely to survive antibiotics
  • live longer
  • more chance to reproduce
  • resistance is passed on
131
Q

How do bacteria provide evidence for evolution?

A

bacteria become better adapted to their environment

132
Q

What is a fossil?

A

Any trace of an animal or plant that lived over a thousand years ago

133
Q

How can we observe gradual changes in organisms over time?

A

By arranging fossils in chronological order to see how they’ve developed

134
Q

Who came up with the theory of evolution by natural selection?

A

Charles Darwin

135
Q

What did Charles Darwin spend 5 years doing?

A

On a voyage around the world studying plants and animals on a ship called HMS Beagle

136
Q

What 3 things did Darwin notice on his travels?

A
  • variation in members of same species
  • characteristics suited to environment = more likely to survive
  • characteristics are passed on
137
Q

Who else published papers on evolution with Darwin?

A

Alfred Russel Wallace

138
Q

What did Wallace write about?

A

How warning colours are used by some species (eg butterflies) to deter predators - a beneficial characteristic

139
Q

What book did Darwin write and when?

A

On the Origin of Species - 1859

140
Q

What does Darwin’s theory of evolution suggest about where we came from?

A

We have all descended from a common ancestor

141
Q

What is classification?

A

Organisms are classified into groups based on how closely they are related

142
Q

Why do it we always finish a course of drugs?

A

To prevent resistant bacteria spreading

143
Q

Why is conservation so important?

A

Must maintain genetic diversity and how it helps populations adapt to changing environment

144
Q

How do antibiotics work?

A

By inhibiting processes in bacterial cells, but not in the host organism, so the bacteria can’t reproduce

145
Q

Why is it hard to develop drugs to kill viruses?

A
  • viruses reproduce using your body’s cells

- any drug would kill the body’s cells as well as the viruses

146
Q

How do you calculate the cross-sectional areas of bacterial cultures and clear agar jelly?

A

Pi r squared

147
Q

How can an autoclave be used to get aseptic conditions?

A

Uses steam at a high pressure and temperature to kill any microorganisms present

147
Q

How can an inoculating loop (used fo transfer bacteria) be sterilised?

A

Passing it through a hot flame

147
Q

Why should the lid always be kept on a petri dish?

A

To prevent any other microbes getting in

147
Q

After transferring bacteria, why should a Petri dish lid be lightly tapped on?

A

To stop microorganisms from the air getting in

147
Q

How should you investigate the effect of substances on bacteria growth?

A
  • place paper discs soaked in different antibiotics on an agar plate that has an even covering of bacteria
  • antibiotic should diffuse into the agar
  • non-resistant bacteria will die
  • a clear area will be left where the bacteria have died
148
Q

What is the clear area called where bacteria have died in an agar plate?

A

The inhibition zone

149
Q

Why should a control be used?

A

To ensure the inhibition zone is due to solely the effect of the antibiotic

149
Q

The more effective the antibiotic is against bacteria….

A

The larger the inhibition zone

149
Q

Where do antibiotics kill bacteria?

A

Inside the body

149
Q

Where do antiseptics kill bacteria?

A

Outside the body

150
Q

In preclinical testing, what are the first two things the drug is tested on?

A
  • first human cells and tissues in a lab

- test on live animals

151
Q

Why do we test new drugs on live animals?

A
  • to check it works
  • to see if it is toxic
  • to find the best dosage
152
Q

What happens once a new drug passes the tests on animals?

A

It’s tested on human volunteers in a clinical trial

153
Q

In what order are humans tested with the new drug?

A
  • healthy volunteers

- then ill people where the optimum dosage is found

153
Q

What is the placebo effect when testing new drugs?

A
  • patients are put in two groups
  • one group is given the drug
  • one group is given the placebo
  • neither know what they have
  • to get reliable, unbias results
153
Q

What was Ardi’s feet structure and what does this suggest?

A

Ape-like big toe to grasp branches and climb trees

153
Q

What was Ardi’s height and what does this suggest?

A

Long arms, short legs suggest she walked upright and didn’t use her hands

154
Q

What was Ardi’s brain size?

A

About the same size as a chimpanzee

154
Q

Where and when was Ardi discovered?

A

In Ethiopia and is 4.4 million years old

155
Q

When and where was Lucy discovered?

A

In Ethiopia and is 3.2 million years old

156
Q

What is Lucy’s feet structure and what does this suggest?

A

arched feet, more adapted to walking than climbing, and no ape-like big toe

157
Q

What is Lucy’s arms and legs height?

A

Between what you would expect to find in an apes and humans

158
Q

How big is Lucy’s brain?

A

Slightly larger than Ardi’s, but still similar to a chimp’s brain

159
Q

Who and when did a scientist organise an expedition to Kenya to look for hominid fossils?

A

1984 Richard Leakey

160
Q

Who did Leakey find in Kenya, and how old was he?

A

Homo erectus - 1.6 million years old

161
Q

What is homo erectus’ brain size, arms and legs?

A
  • short arms and long legs

- Much larger brain than Lucy - similar to human size

162
Q

What is stratigraphy?

A

The study of rock layers - the deeper the layer the older it is

163
Q

What did Homo habilis use tools for?

A

Used to scrape meat from bones or crack bones open

163
Q

How did Homo habilis make tools?

A

Made simple stone tools called pebble tools by hitting rocks together to make sharp flakes

163
Q

How did Homo erectus make tools?

A

Sculpted rocks into shapes to produce more complex tools like simple hand-axes

164
Q

What did Homo erectus use tools for?

A

They could be used to hunt, dig, chop and scrape meat from bones

164
Q

What tools did Homo Neanderthals make?

A

More complex tools - flint tools, pointed tools and wooden spears

165
Q

What tools did Homo sapiens make?

A

Flint tools widely used, including arrowheads, fish hooks and needles

166
Q

What species can the pentadactyl limb be found in?

A

Mammals, reptiles, amphibians

167
Q

What is the structure and function of the pentadactyl limb used in different species?

A

Similar bone structure, different functions

168
Q

Why does the pentadactyl limb provide evidence for evolution?

A

All species have a common ancestor - if they’d enveloped from different ancestors, it’d be highly unlikely that they’d share a similar bone structure

169
Q

Give an example of organisms being selectively bred for useful features

A
  • animals that produce more meat/milk
  • crops with a disease resistance
  • dogs with a good temperament
  • plants that produce bigger fruit
170
Q

What is the process of selective breeding?

A
  • from existing stock, select the ones with desirable characteristics
  • breed them together
  • select the best offspring, breed them
  • continue this process over many generations
171
Q

What is the biggest problem with selective breeding?

A

Reduces the gene pool as all animals are closely related

172
Q

Why can inbreeding cause health problems?

A

There is more chance of an organism inheriting harmful genetic defects when the gene pool is limited

173
Q

Why is selective breeding a concern for if a new disease appears?

A

Not much variation means less chance of resistance alleles - whole population may die

174
Q

Why is selective breeding important in agriculture?

A

Improves yields

175
Q

What does tissue culture involve?

A

Growing cells on an artificial growth medium (agar plates)

176
Q

Why is tissue culture beneficial in growing plants?

A
  • easy
  • plants grow quickly
  • needs very little space
  • grown all year round
  • clones of one another
177
Q

What is the process of tissue culture?

A
  • choose a plant you want to clone based on its characteristics
  • remove several small pieces of tissue from the parent plant
  • to get the best results, take tissue from fast-growing root or shoot tips
  • grow tissue in a growth medium containing nutrients and hormones
  • do this under aseptic conditions
  • move into compost as shoots develop
178
Q

Why is animal tissue culture often used in medical research?

A

It means you can carry out experiments on tissues in isolation

179
Q

How do you use tissue culture in animal cells?

A
  • extract a sample of tissue from animal
  • cells in sample are separated using enzymes
  • placed in a culture vessel and bathed in a growth medium containing nutrients they need
  • this allows them to grow and multiply
  • after several rounds of cell division the cells can be split up again and placed into separate vessels
  • this encourages further growth
180
Q

What do restriction enzymes do?

A

Recognise specific sequences of DNA and cut the DNA at these points

181
Q

What do ligase enzymes do?

A

Used to join two pieces of DNA together at their sticky ends

182
Q

What is recombinant DNA?

A

two different bits of DNA stuck together

183
Q

What is a vector?

A

Used to transfer DNA into a cell

184
Q

Genetic Engineering Vectors

What are plasmids?

A

Small, circular molecules of DNA that can be transferred between bacteria

185
Q

Genetic Engineering Vectors

What do viruses do?

A

Insert DNA into the organisms they infect

186
Q

How does genetic Engineering work?

A
  • DNA you want to insert is cut with a restriction enzyme
  • vector DNA is cut with the same RE
  • vector DNA and insertion DNA are left with sticky ends
  • these a mixed together with ligase enzymes
  • sticky ends join the pieces of DNA to make recombinant DNA
  • recombinant DNA is inserted into other cells
  • cells can now use the gene you inserted to make the protein you want

Biology (12 decks)

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