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Biology Past Paper Q > Paper 1 > Flashcards

Paper 1 Flashcards

1
Q

Describe how energy for photosynthesis is gained by plants

A

Light gets trapped by the chlorophyll within the chloroplasts

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2
Q

How do students deal with anomalous results?

A

They get rid of it when calculating the average

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3
Q

Why does the rate of photosynthesis decrease from 35C to 40C?

A

The enzymes begin to denature at this point

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4
Q

How are human lungs adapted for efficient exchange of gases by diffusion?

A
  • They have many alveoli meaning they have a larger surface area:volume ratio.
  • The capillary walls are thin (one cell thick) which provides a short diffusion path for oxygen or carbon dioxide
  • Breathing moves air in and out. They bring in fresh oxygen for the red blood cells and remove carbon dioxide. This is to maintain a concentration / diffusion gradient.
  • The lungs have a large capillary network around the alveoli. This is to remove oxygenated blood quickly and to bring carbon dioxide to the lungs quickly to maintain a concentration / diffusion gradient
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5
Q

Lung structure:

A

Two Lungs —> Bronchus —> Bronchioles (hundreds of smaller tubes of the Bronchus) —> Alveoli (tiny air sacs, each alveoli is surrounded by at least 1 capillary).

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6
Q

Cell Cycle:

A

Stage 1: DNA and the sub-cellular structures within the cell duplicates.
Stage 2: One set of chromosomes is pulled to one side of the cell and another set of chromosomes is pulled to the opposite.
Stage 3: Cell membrane and cytoplasm divide to form two cells.

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7
Q

The Lock & Key Model:

A
  • The Enzyme binds to the substrate because they are complementary
  • And so the substrate is broken down into it’s products (enzyme-substrate complex)
  • These products get released and the enzyme isn’t changes.
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8
Q

Describe how the students would find out if the liquid from the leaf contained glucose.

A
  • Add Benedict’s solution to the mix
  • Boil it
  • If there’s no glucose present the solution will stay blue. If there’s glucose it changes to brick red
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9
Q

Describe how the students would find out if the leaf contained starch.

A

-Add iodine solution to the leaf liquid
-If starch isn’t present it will stay blue/black. If starch is present it will turn yellow/orange.

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10
Q

Explain why the leaf left in the light for four days contained both glucose and starch.

A

-It obtained glucose from photosynthesis
- Excess glucose converts to starch

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11
Q

Explain why the leaf left in a cupboard with no light for two days contained glucose but didn’t contain starch.

A

-The starch stores get converted into glucose
-Which is used for respiration
-as there’s no light to make glucose by photosynthesis

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12
Q

What type of defence response are thorns?

A

Mechanical

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13
Q

What type of defence response are poisonous berries?

A

Chemical

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14
Q

Explain other possible ways leaves can become discoloured and have stunted growth.

A
  • Magnesium ion deficiency
    —> Magnesium ions are essential for chlorophyll synthesis in plants. If there’s a lack of these ions there won’t be enough chlorophyll for efficient photosynthesis so there won’t be enough glucose to make proteins for growth.
  • Infection by pathogen (e.g. Rose Black Spot)
    —> Leaves become discoloured so less photosynthesis and so there’s not enough glucose to make proteins for growth.
  • Lack of available light
    —> The chlorophyll within the chloroplasts break down and if there’s a lack of sunlight, photosynthesis can’t occur meaning there’s not enough glucose to make proteins for growth.
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15
Q

Describe the effects of liver failure on the human body * write the answer out *

A

-No bile —> lipids can’t be emulsified, pH of small intestine wont be neutralised/alkaline, enzymes in the small intestine will not work effectively so you may lose weight
- Lactic acid can’t be broken down/oxidised —> lactic acid is toxic meaning the body will be poisoned, oxygen debt is higher so you will get muscle pain/fatigue
- Proteins/amino acids will not be broken down in the liver —> amino acids wont deanimate, amino acids not made into urea/or form ammonia however any ammonia formed is toxic so accumulation of amino acids in blood/body
- Liver doesn’t break down toxins (like alcahol) —> toxins accumulate in blood/body making the body poisoned so pain occurs
- Glycogen stores will not be formed —> can’t control blood glucose so diabetes or a coma may occur

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16
Q

Define Deanimation

A

When the liver removes the amino group from the amino acids

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17
Q

Describe how the monoclonal antibodies and a fluorescent dye could be used to see any pathogens on a slide (3 marks)

A
  • Bind fluorescent dye to monoclonal antibodies
  • Put bound fluorescent monoclonal antibodies on the slide (and rinse off)
  • Monoclonal antibodies will bind to the pathogens and show up under the microscope
18
Q

Explain how increased phagocytosis of the pathogen helps the patient

A

More pathogens will be engulfed by phagocytes therefore less damage to cells

19
Q

Describe how clinical trials should be carried out once it’s ready for testing on people (6 marks)

A
  • Given to healthy volunteers first at a very low dose to test if it is safe.
  • Then to some patients with the disease: to test for the optimum dose, to check for any side effects and to test if it works. Do a double blind trial where neither patient nor doctor knows who has the monoclonal antibodies and who has the placebo.
  • Large trial with many the people
20
Q

Suggest why monoclonal antibodies made with human lymphocytes are more successful in treating diseases in humans than in mice

A

The human body wont reject the human lymphocyte monoclonal antibodies

21
Q

Process of phagocytosis

A
  • The phagocyte track the pathogens
  • Binding to them
  • Engulfing them when they get destroyed
22
Q

Define Antigen

A

Substances that our immune system detects as being foreign

23
Q

Define Antibodies and their process

A
  • Small proteins made by our white blood cells
  • Each one is specific to an antigen (the body remembers this so that if the antigen comes back then the body will have loads of these antibodies ready to destroy all pathogens before they have the chance to develop which is what we mean when we say we are immune to a disease)
  • They act as signals for our phagocytes to come and engulf them
24
Q

Explain how blood glucose levels are controlled in the body of someone who doesn’t have diabetes

A

If blood glucose is too high insulin is released from the pancreas into the blood so glucose is moved and stored into cells. If blood glucose is too low, glucagon is released from the pancreas which causes glycogen to be converted to glucose and released into the blood.

25
Q

Suggest how each type of diabetes can be treated.

A

Type 1: minimal insulin produced and is treated with insulin injections
Type 2: type 2 cells don’t respond to insulin and is treated with a carbohydrate-balanced diet and exercise

26
Q

Suggest why a blood test is more reliable than a urine test

A

Blood test gives immediate results

27
Q

Describe how hormones control the menstrual cycle

A
  • FSH from the pituitary gland stimulates maturation of egg
  • Oestrogen from the ovaries inhibits FSH production and stimulates LH production
  • LH from the pituitary stimulates ovulation
  • Progesterone from the ovaries inhibits FSH and LH production
  • Oestrogen and progesterone maintan the uterus lining
28
Q

Function of the mouth in the Digestive system

A
  • Breaks down foods physically by chewing
  • Saliva is produced by the salivary glands —> containing amylase which is an enzyme that breaks down carbohydrates
29
Q

Role of the stomach in the digestive system

A
  • Contracts muscular walls to mix the food around
  • Produces pepsin which is a protease enzyme that breaks down proteins
  • Produces hydrochloric acid and provides the right environment for pepsin to work
30
Q

Role of small intestine in digestive system

A
  • Where the digested food will be absorbed through the lining of the small intestine into the bloodstream
    —> The lining of the small intestine is made up of villi which increase the surface area of it meaning the digested food can be aborbed into the bloodstream a lot quicker
  • Produces digestive enzymes itself to aid digestion
31
Q

Role of the pancreas in the digestive system

A
  • Makes most of the digestive enzymes and pishes them into the small intestine through the form of pancreatic juices (contains amylase, lipase etc.)
32
Q

Role of gall bladder in digestive system

A
  • Stores Bile from the liver (which neutralises the acid from the stomach making the pH more ideal for the digestive enzymes to function also it emulsifies fats (breaking down big globules of fat into smaller droplets so that the fats have bigger surface area for the digestive enzymes to work on))
33
Q

Adaptions of the villi

A
  • Single layer of surface cells meaning the nutrients only have to diffuse a very short distance
  • Very good blood supply which maintains the concentration gradient which increases the effectiveness of exchange
34
Q

Role of the large intestine

A
  • Absorbs all the excess water from the secretions from the pancreas, stomach and gallbladder, leaving behind feaces in the rectum until excreted.
35
Q

What happens after the small intestine in the digestive system

A

All the useful nutrients are absorbed into the bloodstream and what is left is a lot of material in the small intestine, as the majority of food we eat isn’t actually digestable. Also because of all the secretions from the pancreas, stomach and gallbladder the leftover material is very watery.

36
Q

Iris reflex:

A

The Iris reflex controls the size of your pupil
- Bright light can cause damage to your retina so the iris shrinks so less light gets through your pupil and damages your retina. This is when the iris is ‘constricted’. To make the pupil smaller the cillary muscles contract and the suspensory ligaments relax.
- In low light your pupil increases in size to let as much light in as possible which helps us see clearer in the dark. This is when it is ‘dilated’. To make the pupil bigger the cillary muscles relax and the suspensory ligaments tighten.

37
Q

Chemical equation for photosynthesis

A

6CO2 + 6H20 —> C6H12O6 + 602

38
Q

Food sample for presence of lipids:

A
  • Place the food sample in a test tube
  • Add a few drops of ice-cold ethanol down the side of the test tube
  • Shake the test tube gently for a minute
  • A cloudy white layer called precipitate will appear on top if lipids are present
39
Q

Food sample for presence of starch:

A
  • Place a small amount of food on a spotting tile
  • Add 2-3 drops of iodine to the food sample
    -If colour changes from browny-orange to blue/black, starch is present
40
Q

Food test for presence of proteins:

A
  • Place a sample of food in a test tube
  • Add 2-3 drops of biuret solution
  • If the solution changes from pale blue to violet then proteins are present

Biology Past Paper Q (1 decks)

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