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Science > biology paper 1 > Flashcards

biology paper 1 Flashcards

1
Q

whats the diffrence between eukaryotes and prokaryotes?

2 marks

A
  • eukaryotes are made from complex eukaryotic cells for things like animals and olants
  • prokaryotes is a single prokaryotic cell made for things like bacteria
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2
Q

what do bacteria cells contain?

5 marks

A
  • chromosomal DNA (in cytoplasm cuz no nucleus)
  • ribosmes
  • cell membrane
  • Plasmid DNA - small loops od extra DNA
  • Flagellum -> hair structure the rotates to move it
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3
Q

what is the diffrence between haploid and diploid?

1 marks

A

haploid have half the number of chromosomes as a diploid cell

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4
Q

explain how the egg and sperm are specialised for there funtion.

6 marks

A

EGG:
- nutrients in cytoplasm
- haploid nucleus
- after fertilisation, the membrane changes structure to block sperm
SPERM:
- long tail to swim
- lots of mitochondria for energy
- acrosome at front stores enzymes to get though eggs membrane
- haploid nucleus

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5
Q

how are ciliated epithelial cells specialised?

3 marks

A
  • line the surface of organ
  • cilla on surface
  • that moves substances in one direction along the surface
  • e.g lining of air ways have them to move mucus away from lungs
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6
Q

What is the difference between a light and an electron microscope?

4 marks

A

light 1590:
- Work by passing light through the specimen
- They let us see cellular structures.

electron 1930:
- They use electrons that can have a very high magnification and resolution
- They let us see internal structures of subcellular structures.

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7
Q

practical

How would you view a specsman using a light microscope?

6 marks

A
  • Take a thin slice of your specimen and put it on a clean slide
  • Use a pipette to put a drop of water in the middle to secure it
  • If specimen is colours or transparent, drop a stain on it (iodine)
  • Gently press down cover slip on so there are no air bubbles trapped under it. Then clip it to the stage.
  • Select the lowest objective lens And used the adjustment knob to move the stage up so The specimen is in close focus.
  • Then adjust the focus with the fine adjustment knob until you get a clear image.
  • If you need greater magnification, switch to a higher objective lens and refocus
  • Position of ruler at the stage and use it to measure the diameter of the area visible To work out the magnification
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8
Q

How would you work out total magnification

1 mark

A

eyepiece lens mag x objective lens mag

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9
Q

practical

How can you investigate the effect of pH on enzyme activity?

6 marks

A
  1. Put a drop of iodine into every hole of a spotting tile
  2. Place a bonson burner on a heap proof mat and tripod and gauze
  3. Put beaker of water on top tripod and heat until thirty five degrees measured using a thermometer
  4. Use syringe to Add 3cm^3 of amylase solution. one centimetres cubed of buffer solution with a pH of 5 using measuring cylinders and put in the beaker and wait 5mins
  5. Use a different syringe to add 3cm^3 of starch solution to a boiling tube
  6. Immediately mix the contents of the boiling tube and start a stopwatch
  7. Use continuous sampling to record how long it takes for the amylase breakdown all of the starch By sampling it in an iodine solution untill it remains browny orange.
  8. Repeat experiment with different ph values and make sure. and make sure to continue any control variables
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10
Q

how do you calculate rate of reaction for the enzyme practicalif you dont know the amount of change?

1 mark

A

1000/time

otherwise change / time

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11
Q

Why do plants and animals have enzymes?

2 marks

A
  • Many molecules in the food we eat are too big So. Digestive enzymes break them down into smaller soluble molecules that can pass through its digestive system
  • Plant store starch, which needs to be broken down into glucose to respire So enzymes need to break them down.
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12
Q

what enzyme breaks down:

  • Carbohydrates (starch)
  • Proteins
  • Lipids

3 marks

and what do they turn to

A
  • amylase turn it it sugar e.g (glucose)
  • protease converts it to amino acids
  • lipase turns it to fatty acids and glycerol
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13
Q

practical:

How can you test for sugar?

3 marks

A
  • Add Benedict’s reagent (blue) to a sample and heat the water to 75 degrees.
  • If it’s positive it will form a Coloured precipitate.
  • The higher the concentration, the further the colour change.e.g the highest is brick red
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14
Q

How can you test for starch?

A
  • Add iodine
  • Is starches present it will go from browny-orange to blue black
  • otherwise it will stay browny-orange
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14
Q

How do you test for lipids?

4 marks

A
  • Shake the substance with ethanol for about a minute until it dissolves.
  • then Pour water
  • If lipids are present a precipitate will form showing up as a Milky colour
  • The more lipids, the more noticeable
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15
Q

How do you test for proteins?

5 marks

A
  • Biruret test
  • Add a few drops of potassium hydroxide to make solution alkaline
  • Add copper sulphate (blue)
  • If proteins solution will go purple
  • else it will stay blue
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16
Q

practical

How can you burn food to see how much energy it contains?

6 marks

calorimetry

A
  • Weigh a small amount of the food then put it onto a mounted needle.
  • Add a set volume of water to a boiling tube Held by a clamp
  • Measure the temperature of the water, then set fire to the food using a bunsen burner flame. Make sure the bunsen burner isn’t near the water or is may mess it up
  • Hold the burning food under the boiling tube until it goes out, then relight the food and hold it under the tube. Keep. doing this until it won’t set fire again.
  • Measure the final temperature of the water
  • mass of water x temp change x 4.2 (SHC of water) = energy in food

food must be flamable

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17
Q

practical

How do you investigate osmosis with diffrent concentrations using pattato?

7 marks

could be with any plant based thing and with pH / temp / conc

A
  • Prepare a bunch of solutions with arranging water concentration
  • Cut a potato into the Same sized pieces (1cm^2)
  • Divide Pieces into groups of 3 and use a electronic balance for the mass of each group.
  • Place one group into each solution
  • Leave cylinders for about 40 minutes.
  • Dry the pieces, to remove any excess water
  • Weigh each group again and record your results
  • Repeat experiment at different water concentrations

You also can say a more concentrated sucrose solution meaning a less concentrated water solution

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18
Q

What do you do with your results after a osmosis practical?

4 marks

A
  • Work out percentage change
  • ((final mass - inital mass)/inital mass) x100
  • Plot a graph.
  • Where percentage change hits the zero on the graph. That is the concentration of water in the plant
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19
Q

what happens in interphase?

3 marks

A
  • DNA is spread out in long strings
  • subcellular structures duplicate
  • DNA is copied and forms X shaped chromosomes that is an exact duplicate of each other
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20
Q

what happens in mitosis?

8 marks

4 stages

A
  • Prophase - chromosomes condense and the membrane around the nucleus breaks down, allowing the chromosomes to lie free in the cytoplasm
  • metaphase - chromosomes lineup in the centre
  • anaphase - spindle fibers pull chromosomes apart, then chromatids are pulled to opposite ends
  • telophase - membranes form around each of the sets of chromosomes becoming nuclei
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21
Q

what is cytokines?

1 marks

A
  • before the end of telophase, the cytoplasm and cell membrane divide to form separate cells.
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22
Q

what is the difference between cell differentiation, cell division and cell elongation?

3 marks

A
  • cell differentiation -> A process where is cell becomes specialised
  • cell division -> mitosis
  • cell elongation -> where a plant cell expands making the cell bigger -> growing the plant
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23
Q

how is cancer caused?

3 marks

A
  • if there is a mutation that causes a change in genes that controls cell division it may start dividing uncontrollably
  • this can result in a mass of abnormal cells (tumour)
  • if the tumour invades and destroys surrounding tissue, it’s called cancer
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24
Q

what is meristem?

3 marks

A
  • cells in plants that divide by mitosis
  • produse unspecilised cells that can divide into any type of cell
  • they can form specilised tissue like xylem and phloem
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25
Q

what is the diffrence between stem cells and adult stem cells?

3 marks

A
  • stem are found in human embryos
  • they can produce any cell
  • adults are in bone marrow and replace damged cells - only producing certain cells
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26
Q

what are the risks of using stem cells in medicine?

3 marks

A
  • Tumour development - stem cells divide and can be unable to be controled
  • disease transmission - viruses live in cells -> if virus is in donor it will be passed on
  • rejection -> cells will see stem as foreign and trigger a immune response -> drugs can be taken to suppress it but there will be a higher risk of getting a disease
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27
Q

what are all the parts of the brain and what do they do?

4 marks

A
  • cerebrum (largest) - right hemisphere controls the left muscles vice versa - it controls movement, intelligents, language and vision
  • cerebellum - coordination and balance
  • medulla oblongata - contols unconscious activities e.g. breathing and heart rate
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28
Q

what are CT scanners?

3 marks

A
  • uses x-rays to produse an image
  • shows main structure
  • can show diseased / damaged structures and is patient has lost function
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29
Q

whta are PET scanners?

4 marks

A
  • use radioactive chemicals to show active parts of the brain
  • they are very detailed can can be used to investigate structure and funtion in real time
  • used for studying disorders that change brains activity
  • compared to normal brain (without e.g. alzheimers)
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30
Q

why is it hard to treat CNS?

3 marks

brain and spinal cord

A
  • hard to repair damage
  • hard to access
  • risk of further damage
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31
Q

how does the CNS coordinate a responce?

6 marks

A
  • receptors detect a stimulus
  • information is coverted into electrical impulses
  • the its sent along sensory neurones to CNS
  • CNS descides what to do
  • impules are sent along relay neurones
  • CNS sends info to effector along a moter neurone and responds (muscle contracts)
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32
Q

what is the difference between the 3 main neurones?

6 marks

A

sensory:
- one long dendron carries impuse from receptor to cell body in the middle
- one short axon carries impuses from cell body to CNS
motor neurone:
- many short dendrites carry nerve impuses from CNS to cell body
- one long axon carries impulses from cell body to effector
relay neurone:
- many short dendrites carry nerve impuses from sensory neurone to cell body
- axon carries impuses from cell body to motor neurones

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33
Q

how do synapses connect neurones?

4 marks

A
  • connection between neurones = synapes
  • signals are transferred by chemicals called neurotransmitters that diffuse across gap
  • neurottransmitters set of new signal on the next neurone
  • transmittion of nervous impuses are very fast but slowed due to synapes rate of diffustion
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34
Q

how do reflexs prevent injury?

7 marks

A
  • reflexs are rapid automatic responces
  • reflex arc
  • no concous thought so its faster
  • stimulus is detected and impuses is sent down a sensory neurone to a relay neurone
  • impuses release neurotransmitters at synapses
  • then its sent along moter neurone
  • then goes to an effector and muscle contacts
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35
Q

how do reflexs protect the eye?

4 marks

A
  • bright light damages eye
  • light receptors can detect bight light and send message along sensory neurone
  • the it travels along relay to a moter neurone which tells the circlar muscles in iris to contract
  • making the pupil smaller
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36
Q

what are all the parts of the eye and what do they do?

7 marks

A
  • cornea - refracts light into eye
  • iris - controls how much light enters pupil (hole)
  • lens - refracts light focusing it on retina
  • retina - light sensitive part covered in receptors cells called rods and cones
  • rods - sensitive to dim light and cant see colour
  • cones - sensitive to clours but not good in dim light
  • optic nerve - caries electrical impuses, coverted from light info, to brain
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37
Q

what is the diffrence between focusing on a near and distant object?

4 marks

A

distant:
- ciliary mustcle relax allowing suspensory ligments to pull tight
- this makes lens less rounded shape so light is refracted less

close:
- ciliary muscles contract which slacks suspensory ligments
- lens becomes more rounded shape so light is refracted more

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38
Q

whats the diffrence between long and short sightedness?

4 marks

A

long:
- when lens doesnt bend light enough or eye is too short (behide the retina)
- you need a convex lens

short:
- lens bends light too much or eye is too long (in front retina)
- you need a concave lens

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39
Q

what causes colourblindness?

2 marks

A
  • cause when cones in retina arent working properly
  • there is no cure
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40
Q

what is catarcts?

3 marks

A
  • cloudy patch on lens stoping light getting in
  • causes burred vision and less vivid colours and hard to see in bright light
  • it can be treated by replacing lens with artificial one
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41
Q

how does sexual reproduction work?

3 marks

A
  • in fertiltsation, a male gamete(23) fuses with female gamete to produse a ferilised egg (zygote(46))
  • zygote goes though cell devision by mitosis to develop an embryo
  • it inherits charicteristics from both
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42
Q

how are gametes produced?

6 marks

meiosis

A
  • DNA duplicates
  • in the first devision chromosomes line up in pairs at the centre (one from male one from female
  • pairs are pulled apart
  • each new cell will have a mix of mother and fathers chromosomes
  • in second division they line up in centre again and get pulled apart
  • you get 4 genetically diffrent haploid daughter cells
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43
Q

what are the advantages and disadvantages of asexual reproduction?

4 marks

A

advantages:
- produces lots very fast
- only one parent needed

disadvantages:
- no genetic variation
- disease can kill whole population

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44
Q

what are the advantages and disadvantages of sexual reproduction?

4 marks

A

advantage:
- gentetic variation
- natuaral selection and evolution
disadvantages:
- takes more time and energy
- 2 parents needed

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45
Q

what is DNA made of?

6 marks

A
  • polymers called nucleotides
  • the consist of a sugar, a phosphate group and one base
  • sugar and phosphate group is the backbone and alternate
  • 2 strands conected in a double helix
  • T-A and C-G
  • base join with weak hydrogen bonds
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46
Q

how do you extract DNA from Fruit cells?

6 marks

A
  • mash you fruit and put it in a beaker containing solution of deterent and salt then mix
  • deternent breaks down the cell membrane to release DNA
  • salt will stick DNA together
  • filter mixture to get froth and big, insoluble bit of cell out
  • gently add ice cold alcohol to filter
  • DNA will start to come out as its not soluble in cold alcohol. it will appear as a stringy white precipitate
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47
Q

what happens in Transcription?

5 marks

A
  • RNA polymerase binds to a region of non-coding DNA
  • the 2 DNA strands unzip and the RNA polymerase moves along one of the strands
  • it uses the coding DNA in the gene as a template to make mRNA
  • Base pairing between the DNA and RNA ensures that the mRNA is complementary
  • after the mRNA moves to ribosomes
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48
Q

what is Translation?

4 marks

A
  • amino acids are bought to ribosomes by tRNA
  • the order of in which the amino acids are bought there match the order of base triplets in mRNA (codons)
  • tRNA’s structure is called an anticodon and is complementary to the codon for the amino acid (makes sure its in correct order)
  • amino acids are joined together by the ribsomes - this makes polypeptide (protein)
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49
Q

what happened during mendels experiments?

2 marks

A
  • he crossed a tall and a short pea plant and all the offspring were tall
  • then he bread 2 of these tall offspring and 1 in 4 of their offspring were short
50
Q

what was mendels conclusions?

3 marks

A
  • characteristics are determined by “hereditary units”
  • units are passed on to offsping unchanged with one unit from each parent
  • units are either domient are recessive
51
Q

how do sex linked disorders work?

3 marks

A
  • Y chromosome is smaller
  • cuz men only have one X if it contains even a recessive disorder it will stay because there is nothing to counter act so men will be more likely to have it
  • 2:1:1 = not:carrier:affected
  • 25% chance of offpring having it means 50% if male and 0% female

page 40

52
Q

what are the blood groups?

3 mark

A

|o|o - recessive
|A|o or |A|A - dominant
|B|o or |B|B - dominant
|A|B - dominant

53
Q

what is genetic variation within a species and hows it caused?

4 marks

A
  • diffrent alleles which lead to diffrences in phenotypes
  • its caused by new alleles though mutations
  • sexual reproduction
  • the enviroment
54
Q

how do alleles arise?

3 marks

is there any affect

A
  • changes to the base sequence
  • most are neutral
  • some have a small effect
55
Q

what happens in cystic fibrosis?

2 marks

A
  • mutation causes a protein that controls movement of water/salt to stop working
  • this leads to production of thick, sticky mucus which makes it difficult to breath and digest food
56
Q

what is the human genome project?

3 marks

A
  • maping over 20,000 human genes
  • collaboraration of lots of scientistis
  • helped identify 1800 genes related disease which has a huge benifit for medicine
57
Q

what are the advantages for the human genome progect?

6 marks

A

prediction and prevention:
- if we knew what genes give what diseases we could find out what lifesyle is best for each person to avoid problems

testing and treatment:
- inherited disorders are caused by faulty alleles so we can identify the suspected gene that could cause it very quickly
- this means they can be tested and be given better treatment therfore a more likelyhood of a cure

new and better medicine:
- some variations affect how we react to certain deseases and posible treatment
- scientists can design new drugs specifically made for each genetic variation
- this will make more effextive treatment with fewer side effects

58
Q

what are the disadvantages of the human genome project?

3 marks

A
  • increase stress - if people think there going to get a disease later on
  • gene-ism - people with genetic problem be be pressured not to have children
  • discrimination - employers / life insurence will be more expencive
59
Q

what is natural selection?

5 marks

survival of the fittest

A
  • Individual in a population shows genetic variation due to a mutation
  • Individuals with characteristics that make them better adapted to surviving are more likely to breed (predation, competition)
  • this means alleles that are better adapted get passed on to offspring
  • those with less better adapted die off and are less likey to pass on alleles
  • overtime beneficial charicterteristics become more common
60
Q

what are the evidences fo evolution?

4 marks

A

Bacteria:
- Bacteria become better adapted to the environment containing antibiotics. due to population becoming resistant to them over time.
- This happens from random mutations being passed on very quickly

fossils:
- By ordering the fossils of age, the newer have changed and developed over many years.
- This can be done due to the deeper the rock the older it is

61
Q

How did Darwin come up with the theory of evolution?

3 marks

A
  • He spent five years on a voyage around the world, studying plants and animals (HSS Beagle)
  • He noticed the Variation in members of the same species. And that those with characteristics most suited to the environment were more likely to survie and pass on characteristics.
  • He wrote the theory of evolution by natural selection
62
Q

What did Wallace do?

2 marks

A
  • Him and Charles Darwin published together
  • He realised warning colours used on species deterred predators from eating them
63
Q

How did ideas about evolution influence modern biology?

3 long marks

A
  • classification - We can now classify organisms based on how closely related they are
  • Antibiotic resistance - understanding the importance of finishing a drug course to prevent the resistance of bacteria spreading and the need of new antibiotics to fight evolving bacteria
  • Conservation - understanding the importance of genetic diversity And how it helps the population adapt to changing environment
64
Q

What were the three fossils And what did they show?

9 marks :)

A

Ardi (4.4mill):
- Feet structure suggest she climbed trees. + ape like toe
- brain the size of a chimpanzees
- Long arms and short legs. and structure suggests she walked upright

Lucy (3.2mill):
- Arched feet adapted for walking
- Brain was slightly larger than Ardi’s
- Arms and legs were between apes and humans

Turkana Boy(1.6mill) discoverd by leakey on expedition:
- Brain size was much larger the lucys
- small, arms and long legs more like humans
- Structure of legs and feet suggests he was better adapted for walking up all right.

65
Q

when was each human species?

4 marks + 4 for the name

A
  • Ardipithecus - 6mill -> 4mill years ago
  • Australopithecus - 4.5mill -> 2mill years ago
  • homo - 2.5mill -> not long ago
  • homo sapiens - 0.2miil -> today
66
Q

What did each species use for tools?

8 marks

how did it provide evidence for evolution?

A

2.5 -> 1.5 million years ago (simple stone tools made by hitting rocks together - used to scrape meat and crack bones)

2 -> 0.3 million years ago (sculpted rock into shape from tools like simple axes for hunting / chopping / scraping / digging)

300k -> 25k years ago ( flint tools / pointed tools / wooden spears)

200k -> present ( flint tools widely used /pointed tools like arrow heads / fidh hooks / needles appeard 50k years ago)

67
Q

How is the Pentadactyl limb evidence for evolution?

4 marks

A
  • Lots of species have similar bone structure
  • Each structure is adapted to different functions
  • And limb with five digits
  • Highly unlikely that they all share A similar bone structure

in a bigger question compare the limps provided

68
Q

In order, what are all the classifications?

7 marks

A
  1. Kingdom
  2. Phylum
  3. Class
  4. Order
  5. Family
  6. Genus
  7. Species

Keep penis clean or face getting STI

69
Q

What are the five groups in Kingdom Classification?

5 marks

A
  • Animals
  • Plant
  • Fungi
  • Prokariotics
  • Protists
70
Q

How is the classification system changed over time?

5 marks

A
  • Five kingdom classification is outdated
  • Over time technology has developed and genetics Have increased
  • It It was said that organisms should first be divided into three large groups
  • We used to classify organisms using observable characteristics.
  • As technology improved this included things you could see with microscopes
71
Q

What are the 3 protential new domains and what do they include?

6 marks

A

Archaea -> Similar to bacteria But with a different DNA and RNA sequence

Bacteria -> true bacteria

Eukarya -> fungi / plants / animals / protists

72
Q

what is selective breading and how is it done?

5 marks

A
  • Artificially selecting organism to breed for a more useful or attractive purposes
  • From existing stock select organisms with characteristics you want
  • breed them together
  • Select the best of the offspring and breed them together.
  • Continue in a many generations until Get a stronger and stronger
73
Q

How is selective breeding useful?

2 marks

A
  • genetic variation Gives better characteristics producing more yeild than others.
  • It can be used in medical research to find the differences between behaviours and the way the brain works.
74
Q

What is the disadvantages of selective breeding?

4 marks

A
  • It reduces gene pool Due to inbreeding.
  • Inbreeding can cause health problems. due to an increase in inheriting harmful genetic defects.
  • This leads to ethical considerations.
  • There can also be a serious problem if a new disease appears, as there’s not much variation, so there’s a less chance a resistance allele.
75
Q

How can plants be grown using tissue culture?

6 marks

A
  • Choose the plant you want to clone based on its characteristic
  • Remove several pieces of the tissue from the parent plant. (Best if you take it from fast growing roots or shoot tip)
  • Grow tissue on a growth medium containing nutrients and growth hormones.
  • This is done under aseptic conditions to prevent microbes harming plants
  • As the tissue produce shoots and roots, they can be moved to potting compost to carry on growing
  • hundreds of cones can be made
76
Q

How can animal tissue culture be carried out?

6 marks

A
  • get Sample the tissue you want to study By extracting it from the animal
  • Separate cells using enzymes
  • It is placed on a culture vessel and bathed in a groove medium containing nutrients, allowing it to grow and multiply.
  • After many cell divisions, the cell can be spill it up again and be. placed on a separate vessel encouraging further growth
  • Then it can be stored for future use
  • This allows you to look at the effect of a particular substance or environment changed on the cells of a single tissue Without needing the whole organism.
77
Q

How come vectors be used to insert DNA into another organism?

6 marks

A
  • DNA you want to insert Is cut out of bacteria using a restriction enzyme
  • The Vector (plasmid / virus) DNA is then cut open using the same enzyme.
  • Both DNA’s are left with sticky ends, then are mixed together with ligase enzymes
  • The ligase joins the piece of DNA together to make recombinant DNA (two bits stuck together)
  • This recombinant DNA is Insert it into the other cells
  • These cells can now use the gene view inserted to make the protein you want.

  • plamids are molecules of DNA that can be transfered between bacteria while viruses insert the DNAinto the organism they infect
78
Q

How is genetic engineering useful?
whta are the concerns?

5 marks

A
  • Crops can be genetically modified to resist chemicals tha kill plants Allowing farmers to Spray the crops to kill the weeds without affecting the crop itself (increasing yield)
  • However, transplanted genes. may get out into the environment. which may also get picked up by weeds creating a new “superweed” variety.
  • Also modified crops could affect food chains or even human health

.
- In medicine, we can use a genetic engineering bacteria to produce human insulin and other useful proteins.
- However, it’s hard to reject what effect. its modifiying will have on the organism As some animals don’t survive or suffer from health problems afterwards

79
Q

How can crops be genetically modified to be resistant to insects?

5 marks

A
  • Bacillus thuringiensis Produces a toxin that kills off many insect larvae that are harmful to crops
  • The gene for the toxin is inserted into the crop, which then produces the toxin in their stem and leaves, making it resistant to the insect pests
  • The toxin is specific to the insect test. It is harmless to humans and plants and other insects. However, the long-term exposure isn’t yet known.
  • Insects that feed on the crops constantly exposed to the toxin. So there is a danger that they will develop resistance.
  • This can be avoided by using other insectatides as well
80
Q

GMO’s be used to provide more food for people.
what are the advantages / disadvantages?

6 marks

Genetically modified organisms

A

good:
- We need food security For the rising population
- Improves crop yield in drought conditions
- Provides the right balance of Nutrition

bad:
- People argue that it’s not because There isn’t enough food, its because they can’t afford it. So we need to tackle poverty first
- Fear that countries may become too dependent on companies who sell genetically modified seeds
- Sometimes poor soil is the main reason crop fails and genetically modified crops would survive anyway

81
Q

what techniques can be used to increase food production?

3 marks

A
  • GMO ‘s is a new way of improving crop yields.
  • if the soil is poor, applying fertilisers is likely to be the best way to increase yield As they contain nutrients. However, it could cause problems in rivers and leaks, causing eutrophication
  • Pests can also be controlled by using other organisms to reduce the number of pests. However, it may lead to more harmful wildlife then I was before
82
Q

how does WHO define health?

1 marks

world health organisation

A

complete physical, mental and social well-being

83
Q

what are is the pathogen / symptoms of cholera and how is it spread and reduced?

4 marks

A
  • It’s a bacterium (Vibrio cholerae)
  • It causes diarrhoea
  • It spreads through contaminated water
  • It’s prevented by having clean water supplies
84
Q

what are is the pathogen / symptoms of Tuberculosis and how is it spread and reduced?

4 marks

A
  • It’s a bacterium (mycobacterium tuberculosis)
  • Coughing and long damage is caused
  • Spreads through the air / coughs
  • Avoided by avoiding crowded spaces and practising good hygiene And having a well ventilated place
85
Q

what are is the pathogen / symptoms of Malaria and how is it spread and reduced?

4 marks

A
  • It’s a protist
  • It causes red blood cell damage and even liver damage sometimes
  • Spreads though mosquitoes acting as a vector. by passing on the protist while not getting the disease themseves
  • Use mosquito nets and insect repellent to provent bits
86
Q

what are is the pathogen / symptoms of stomach ulcers and how is it spread and reduced?

4 marks

A
  • It’s a bacterium (Helicobacter pylori)
  • It causes stomach pain, nausea and vomiting
  • it spreads orally
  • Reduced by having clean water supplies and hygienic living conditions.
87
Q

what are is the pathogen / symptoms of Ebola and how is it spread and reduced?

4 marks

A
  • It is a virus
  • It can cause a fever with bleeding
  • It spread through body fluids
  • It’s prevented by isolating infected individuals and sterilising any areas where the virus may be present.
88
Q

what are is the pathogen / symptoms of chalara ash dieback and how is it spread and reduced?

4 marks

A
  • It’s the fungus that affects ash trees.
  • It causes leaf loss and bark wounds
  • It is carried through the air by the wind and spread when diseased ash trees are moved between areas
  • It can be prevented by removing young, infected ash trees and replanting it with a different species or restricting the import or movement of ash trees
89
Q

What is the lytic pathway?

4 marks

A
  1. A virus attaches itself to a specific host cell and injects its genetic material.
  2. The virus uses proteins and enzymes in the host cell to replicate its genetic material and produce the components of a new virus
  3. The viral components assemble
  4. Host cell splits open releasing the new viruses, which can infect more cells
90
Q

What is the lysogenic pathway?

3 marks

A
  1. A virus can inject genetic material into the genome of the host cell
  2. The viral genetic material gets replicated along with the host’s DNA every time the host cell divides. But the virus is inactive and no new viruses are made.
  3. Eventually, a trigger causes the viral genetic material to leave the genome and enter into the lytic pathway.
91
Q

what is chlamydia?

3 marks

A
  • bacterium that reproduces inside host cell (STI)
  • it dont alway show symptoms but can cause infertility in both sex’s
  • it can be avoided by wearing a condom / avoiding sexual contact or screening them so they can be treated
92
Q

what is HIV?

5 marks

A
  • human immunodeficiency virus (STI) - it kills white blood cells
  • It leads to AIDS when the immune system deteriorates and starts to fails - making them very vulnerable to other pathogens
  • HIV spreads though body fluids so to provent it uses condoms and avoid sharing needles.
  • medication can reduces the risk of an infected person passing it on during sex - or a pregnant person giving it to a baby
  • so screening and proper treatment is very important
93
Q

What are the physical and chemical defences against pathogens in plants?

4 marks

A

physical:
- A waxy cuticle Which provides a barrier to stop pathogens entering them or pests, damaging them
- It also stops a water collecting on the leaf which could reduce the risk of infection transferred in water
- Plants are surrounded by a cell wall made from cellulose Which forms a physical barrier? if they make it past a waxy cuticle

chemical:
- They produce chemicals called antiseptics, which kill bacterial nd fungal pathogens. They also produce chemicals to deter pests.

94
Q

What chemicals and plants treat human disease

2 marks

A
  • quinine Come from the bark of cinchona tree and was used to treat malaria
  • Aspirin is used to relieve pain and fever - it was developed from a chemical found in the bark / leaves of williow trees
95
Q

How can disease be detected in the enviroment?

4 marks

A
  • Through observations And symptoms
  • Sometimes plants may show symptoms which are usually due to environmental causes. such as nutrient deficiency.
  • by changing environment conditions And observing any changes in the plants symtoms It can be determined whether a plant has a disease or not.
  • Different pathogens spread in different ways so. people can analyse the distribution of disease In the plants to identify the kind of pathogen involved.
96
Q

Why might Laboratory based diagnostic testing be done?

1 mark

A
  • To allow for accurate identification of sPacific pathogens
97
Q

How do you detect a disease using antigens?

3 marks

A
  • Pathogens have a unique molecule on their surface called antigens
  • Antigens from a particular pathogen will be present in a plant infected with that Pavagadh, and can be detected in a sample of plant tissue using monoclonal antibodies
  • The detection of an antigen unique to a particular pathogen allows that pathogen to be identified and the disease to be diagnosed.
98
Q

How do you detect a disease using DNA?

2 marks

A
  • If a plant is infected with a pathogen, the pathogen’s D N a will be present in the plant’s tissue
  • Scientists have techniques that allow them to detect even small amounts of pathogen dna in a sample of plant tissue, allowing them to identify the particular pathogen that is present.
99
Q

What are the physical barriers stopping pathogens entering the body?

4 marks

A
  • The skin acts as a barrier to pathogens, and if it gets damaged, blood clots quickly seal the cut and keep organisms out.
  • Here’s a mucus in your nose. Trap particles that could contain pathogens.
  • Cells in your trachea and bronchi also produce mucus which traps pathogens
  • cells that line, the trachea and bronchi have cilia, which. are hair like structures which moves the mucus up to the back of the throat where it can be swallowed
100
Q

What are the chemical barriers of the body?

2 marks

A
  • The stomach produces hydrochloric acid, which kills most pathogens that are swallowed.
  • The eye produces a chemical called lysozyme, which kills bacteria on the surface of the eye.
101
Q

What happens when your B lymphocytes come across an antigen on a pathogen

3 marks

A
  • They start to reduce proteins called antibodies, which bind to the newly invading pathogen so it can be destroy by other white blood cells.
  • Antibodies produced a very Pacific to that pathogen, so they won’t lock them to any of our pathogens.
  • Antibodies are produced rapidly and flow all around the body to find similar pathogens.
102
Q

How do memory lymphocytes give immunity to later infection?

4 marks

A
  • When a pathogen first enters the body, the response will be slow because there aren’t any B lymphocytes that can make the antibody needed to lock onto the antigen.
  • Eventually, the body will produce enough right antibodies to overcome the infection
  • Memory lymphocytes remain the body for a long time.
  • After this happened, the person will become immune as they have the ability to quickly respond to a second infection of that pathogen.
  • The second response will be faster and stronger and normally gets rid of the pathogen before you begin to show symptoms.
103
Q

How can immunisation stop you getting infections?

5 marks

A
  • It involves injecting dead or inactive pathogens into the body
  • They are antigenetic, so even though they are harmless, your body still makes antibodies.
  • Antigens trigger memory lymphocytes to be made.
  • If live pathogens of the same type get into your body, there will already be Memory lymphocytes
  • The second immune response will be fast So you’re less likely to get the disease
104
Q

What other pros and cons of immunisation?

5 marks

A

pros:
- Epidemics can be prevented if a large percentage of the population are immunised.
- Even people who aren’t immunised are unlikely to catch it because there would be few people who can pass it on This is known as herd immunity.
- Some diseases get virtually wiped out by this process

cons:
- Sometimes it doesn’t work
- Some people can get bad reactions to vaccines.

105
Q

How can you create hybridomas to clone lots of identical cells?

5 marks

A
  • Monoclonal antibodies are produced from lots of Clones Meaning the antibodies are identical and will target one specific protein antigen.
  • tumour cells devide lots but B-lymphocytes that produse these antibodys dont
  • However, you can fuse these together using a myeloma tumour cell to make a hybridoma
  • These can clone lots of identical cells very quickly To produce monoclonal antibodies which are collected and purified
  • You can make monoclonal antibodies bind to anything So you can allow them to target a spacific cell or chemical in the body.
106
Q

Have our Monoclonal antibodies used in pregnancy tests?

6 marks

A
  • the stick contains antibodies with blue beads attached.
  • The test strip has some more antibodies that bind to the hormone.
  • If you’re pregnant, the hormone binds to the antibodies on the blue beads.
  • Then the urine moves up the stick and carries the hormone and the beads which bind to the antibodies on the strip
  • leaving the blue beads to get stuck, turning it blue.
  • If you’re not pregnant the urine still moves up carrying the blue beads, but nothing sticks So it doesn’t go blue
107
Q

How can monoclonal antibodies be used to diagnose cancer?

5 marks

A
  • Antibodies are labelled with radioactive elements
  • Then they are given to a patient through a drip and goes into the blood
  • When the antibodies come in contact with a cancer cell, they bind to the tumour markers.
  • A picture of the patient is taken through a special camera that detects radioactivity and will show cancer cells as a bright spot
  • this can be used to show the size and spreading of a tumour
108
Q

how can monoclonal antibodies be used to target drugs to cancer cells?

6 marks

A
  • Anti-cancer drug is attached to monoclonal antibodies
  • Antibodies are given to patients through a drip
  • The antibodies target Pacific cells because they only bind to tumour markers
  • The drug kills the cancer cell, but doesn’t kill any normal body cells
  • Other cancer treatments can affect normal body cells as well as killing the cancers
  • so the side effects of antibody-based drug are lower than other methods
109
Q

How can monoclonal antibodies be used to find blood clots?

5 marks

A
  • When blood clots, protein in the blood joined together to form solid mesh
  • monoclonal antibodies have been developed that bind to these proteins.
  • You can attach a radioactive element to these antibodies.
  • If you inject them into the body and take a picture using a camera that sees radiation, it will have a very bright spot where the blood clot is.
  • This is useful because you can easily find a potential harmful blood clot. (before it becomes harmful)
110
Q

What are the different stages of drug development?

6 marks

A

preclinical testing:
- First tested on human cells and tissue
- After it’s tested on live animals to tested the drug works - Finds how toxic it is and the best dosage.

clinical testing:
- A drug is tested on a healthy volunteer to make sure it has no harmful side effects.
- He is tested on people with illness to find the optimum disc that is most effective and with the fewest side effects.
- Patients are randomly put into two groups and 1 is given the new drug and the other one is given a placebo. - This makes sure it is actually the drug that is helping not just a placebo effect
- Clinical trials are blind, so the patient doesn’t know. whether they are getting the drug or the placebo. - most the time is a double blind, so the patient or doctor doesn’t know So there is no subconscious influence

111
Q

practical

How can you grow bacteria in the lab?

9 marks

how do you make an agar plate

A
  • Bacteria are cultured in a growth medium
  • This contains carbohydrates, minerals, proteins and vitamins needed for it to grow
  • growth mediums can be a solid agar jelly, which form visible colonies on the surface of the jelly or could spread out.
  • To make an agar plate, hot agar jelly is poured into shadow round of plastic called petri dishes.
  • When Jelly is cooled and set - Wire loops can be used to transfer microorganisms to the a agar jelly.
  • Alternatively, a sterile dropping pipette and spreader can be used to get an even covering of bacteria.
  • Then the microorganisms multiply
  • Microorganisms are kept at 25 Degrees Because harmful pathogens are less likely to grow at this temperature.
  • Outside of school, scientists may use higher temperatures to provide optimum temperatures for growth.
112
Q

How can you investigate the effect of substances on bacterial growth?

5 marks

A
  1. Put paper discs soaked in different types of antibiotics on an agar plate that has got an even coating of bacteria.
  2. The antibiotics should diffuse into the agar jelly. Antibiotic resistant bacteria aren’t affected by the antibiotic and will continue to grow on the agar but non resistant ones will die.
  3. Make sure to use a control like a paper disc that has not been soaked in antibiotic. Then you can be sure any difference between the growth of the bacteria and the control disc is due to the effect of the antibiotic alm.
  4. Leave the plate for 48 hours at 25 degrees Celsius.
  5. The more effective that antibiotic is against the bacteria, the larger the inhibition zone
113
Q

To how do you do the aseptic technique?

5 marks

A
  1. The petri dishes and growth medium must be sterilised before use. This can be done by using a scene called an autoclave which uses steam at a high pressure and temperature to kill any microorganisms present.
  2. Put the isoculating loop over a bunsen burner to kill unwanted organisms.
  3. Liquid bacterial cultures should be kept in a cultural vial with a lid To prevent unwanted organisms getting in.
  4. petri dishes should be covered with a lid which should be lightly tapped on to stop Microorganisms from the air getting in.
  5. The dishes should be stored upside down to stop drops of condensation falling on the agar.
114
Q

How do you calculate the size of inhabitation zones to compare results while investigating antibiotics and antiseptics?

3 marks

A
  • You look at the relative size of the inhabitation zone.
  • You can do it by eye or for the most accurate results. Use a ruler to find the diameter.
  • To calculate the area of the inhabitation zone, do Pi R ^2.
115
Q

How does smoking cause cardiovascular disease?

3 marks

A
  • Nicotine increases a heart rate which increases blood pressure.
  • High blood pressure damages artery walls and builds up fatty deposits in the arteries which risks a heart attack or stroke.
  • It increased the risk of blood clots forming in arteries which can restrict or block blood flow, leading to heart attacks or strokes.
116
Q

What are the lifestyle factors associated with different diseases?

4 markd

malnutrition, obesity, liver disease

A
  • A diet with too much or too few nutrients can lead to malnutrition.
  • Not getting enough exercise and having a diet in high fats and sugar risks factors for obesity.
  • Drinking to much alcohol is a major risk factor for the development of liver disease.
  • This is because when alcohol is broken down by enzymes, some of the products are toxic.
117
Q

What are the wide ranging effects of noncommunicable diseases?

4 marks

in terms of a population

A
  • Areas where there is a high level of of obesity, smoking and access to alcohol leads to more likelihood of non-communicable diseases in that area.
  • They are very expensive on a national level because the National Health Service for raised resources for treatments.
  • A reduction in the number of people able to work can affect a country’s economy if They stopped being able to work
  • They are very common and the number and the number one cause of death world wide So these diseases can hold back development of countries.
118
Q

How is BMI not always reliable?

1 mark

A
  • If you have lots of muscle which has a high amount of mass It could say they are overweight, even though they are not.
119
Q

How can cardiovascular disease affect your heart and blood vessels?

4 marks

A
  • Cholesterol is a fatty substance that the body needed to make things like cell membranes, but too much can cause fatty deposits to build up in the arteries restricting blood flow.
  • Deposits appear in areas where the artery wall has been damaged.
  • Fatty deposits also trigger blood clots to form, which can block blood flow completely. If this happens, The heart muscle the artery is supplying will cause a heart attack.
  • A blockage to the brain would deprive the brain of oxygen and cause a stroke.
120
Q

What lifestyle changes can be used to treat cardiovascular disease?

4 marks

A
  • Healthy balanced diet
  • Low saturated fat
  • Regular exercise
  • Stop smoking
121
Q

How can drugs reduce the risk of heart attack or strokes?

3 marks

A
  • Statins reduce the amount of cholesterol in the bloodstream, which slows down the rate which fatty deposits form - could cause liver damage tho
  • Anticoagulant are drugs which make blood clots less likely to form. However, it could cause access bleeding.
  • Antique Hypertensives reduce blood pressure, helping prevent damage to blood vessels, reducing the risk of fatty deposits forming. - but could cause headaches / fainting
122
Q

How are surgical procedures used to repair damage?

3 marks

blood clots, blockages, heart transplants

A
  • Stents are choose inserted inside arteries to keep them open, making sure blood can pass through. Lowering the risk of heart attack. - Over time they can narrow again and irritate the artery and make scar tissue grow. patient also has to take drugs to stop blood clotting
  • If part of a blood vessel is blocked, a piece of healthy vessel is taken from somewhere else and is used to bypass the blocked section.
  • The whole heart can be replaced with a donor heart. However, a new hot does not always start punting properly, and drugs have to be taken to stop the body rejecting it. - Heart surgery has the risk of bleeding blood clots and infection.

Science (7 decks)

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