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exam questions i got wrong Flashcards

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Biology 101 flashcards
1
Q

explain why bone marrow can be called a tissue

A
  • group/collection of cells
  • working together to produce blood cells
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2
Q

describe the process of active transport in root hair cells

A
  • uptake of (soluble substances) / ions against the concentration gradient
  • energy required FROM RESPIRATION
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3
Q

explain how cell enlargement is part of the growth process of a baby

A
  • cells which are bigger take up more space
    OR
  • cells have to get bigger or mature to divide
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4
Q

why is cell specialisation (differentiation) important for the development and growth of a healthy baby from a fertilised egg?

A
  • babies need or are made of different types of cells or cells that have different functions
  • as fertilised egg starts to divide each cell specialises to form a part of the body
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5
Q

suggest two reasons why viruses are not classed as cells

A

any two from:
- do not have a cell membrane
- do not have cytoplasm
- do not have a nucleus
- do not have mitochondria
- do not have ribosomes

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6
Q

suggest how the honey fungus spores travel from the roots of an infected gorse plant to the roots of a healthy gorse plant

A

in the soil water

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7
Q

describe how the human body prevents pathogens from entering and defends itself against pathogens in the body

A

skin:
- tough/dry/dead outer layer
- acts as a barrier
- sebum/oil on surface of skin repels pathogens
- scabs form over cuts OR scabs form a barrier
- platelets involved in forming clots

stomach:
- contains hydrochloric acid
- which kills bacteria
- in food OR in swallowed mucus

eyes:
- produce tears
- contains enzymes to kill bacteria
- tears are antisteptic

breathing system:
- trachea/bronchi/nose produce mucus
- mucus is sticky
- mucus traps bacteria
- mucus carried away by cilia

defends itself against pathogens inside the body:
- immune system/white blood cells
- WBCs engulf pathogens
- antitoxins are produced
- antitoxins neutralise toxins/poisons
- antibodies are produced
- antibodies help destroy pathogens
- memory cells are formed
- memory cells give a more rapid response if pathogen re-enters

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8
Q

a person with AIDS may take longer than a healthy person to recover from a salmonella infection

A
  • immune system is damaged / weakened OR immune system doesn’t function properly
  • white blood cells cannot kill bacteria as effectively

for second mark, allow:
- no/fewer antibodies so bacteria not killed
OR
- less phagocytosis so bacteria not killed
OR
- no/fewer antitoxins to counter toxins

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9
Q

explain how different types of organism defend themselves against microorganisms

A

animals:
- skin; sebum/oils to kill microbes, dead layer difficult to penetrate
- nose; hair keeps out dust and microbes
- trachea/bronchi; mucus traps microbes, cilia moves mucus
- stomach; hydrochloric acid kills bacteria
- white blood cells; produces antibodies, produces antitoxins, phagocytosis

plants:
- cell wall; tough/difficult to penetrate
- waxy cuticle; tough/difficult to penetrate
- dead cells/bark; fall off, taking pathogens with them
- production of antibacterial chemicals; kills bacteria

fungi:
- antibiotic production; kill bacteria

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10
Q

describe how injecting a monoclonal antibody for RSV helps to treat a patient suffering with the disease

A
  • monoclonal antibody binds to virus OR binds to antigen on surface of virus
  • antibody is specific to antigen
  • white blood cells/phagocytes kill/engulf the virus
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11
Q

explain what testing must be done before this new drug can be tested to treat people with ebola

A
  • pre-clinical trials of new drug on cells/tissues/live animals
  • to test toxicity, dosage and efficacy
  • clinical trials/test on healthy volunteers and ebola patients at very low doses
  • so that you can monitor for safety/side effects
  • and only then do trials to find optimum dosage and test for efficacy
  • double blind trial/use of placebo
  • which does not contain the new drug
  • random allocation of ebola patients to groups
  • so no one knows who has placebo/the new drug
  • peer review of data
  • to help prevent false claims
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12
Q

the use of antibiotics has not reduced the death rate due to all diseases to zero. suggest two reasons why

A
  • antibiotics only kill bacteria
  • some bacteria are resistant to antibiotics
  • (correct) antibiotics not always used
  • inherited/lifestyle diseases cannot be treated by antibiotics as not caused by bacteria
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13
Q

give two ways of reducing the negative effects of human activity on our ecosystems

A
  • protecting rare habitats
  • breeding programmes (for endangered species)
  • regeneration (programmes)
  • reintroduction of field margins / hedgerows
  • awareness raising with politicians / public
  • recycling
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14
Q

the student measured the growth of the duckweed by counting the number of leaves. suggest a better method of measuring the growth of the duckweed and explain why

A
  • mass/weighing the plant
  • length of roots

corresponding explanations:
e.g.
- incudes roots
- includes whole plant OR leaves vary in size OR length / mass / surface area is a continuous variable

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15
Q

explain why the death of the pond snail caused the concentration of carbon dioxide to increase after day 10

A
  • snail is being decayed / decomposed / broken down
  • by decomposers / bacteria (in pond water / snail)
  • therefore respiration (of decomposers / bacteria) releases carbon dioxide
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16
Q

explain the lock and key theory of enzyme action

A
  • active site of enzyme binds to the substrate because they are complementary (shapes)
  • so substrate is broken down (into products)
  • so products are released OR enzyme is not changed
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17
Q

there are many different types of lipase in the human body. why does each different type of lipase act on only one specific type of lipid molecule?

A

each active site has a specific shape (so only fits one type of lipid molecule)

18
Q

explain why single-celled organisms like algae do not need complex structures for gas exchange

A
  • cell has larger SA:volume ratio
  • short diffusion distance
  • diffusion via cell membrane is sufficient
    OR
  • flow of water maintains concentration gradient
19
Q

describe how scientists may use stem cells to create healthy lungs that aren’t rejected by a cf patient

A
  • take stems cells from patient’s bone marrow
  • remove / change / fix the cf gene
  • create an embryo using these stem cells
20
Q

explain how a very low number of blood components in the body can cause these symptoms
- tiredness
- frequent infections
- bleeding that won’t stop after skin is cut

A

tiredness
- fewer red blood cells
- less haemoglobin
- less oxygen transported around body
- less aerobic respiration takes place
- more anaerobic respiration takes place
- less energy released for metabolic processes
- lactic acid produced causes muscle fatigue

frequent infections
- fewer white blood cells / phagocytes / lymphocytes
- fewer antibodies produced
or
- less phagocytosis
- so fewer pathogens / bacteria / viruses killed

bleeding
- fewer platelets
- blood does not clot as easily

21
Q

a person has a tumour blocking the tube leading from the gall bladder to the small intestine. explain why this person would have difficulty digesting fat

A
  • no / less bile reaches small intestine
  • less / no emulsification of fat
  • so smaller surface area for lipase to break down fat
  • pH of small intestine is not neutralised
  • lipase not at optimum pH to break down fat
22
Q

changes during exercise

A

heart rate increased
- to increase blood flowing to muscles
- to provide more oxygen
- to provide more glucose
- to remove carbon dioxide more quickly from muscles
- to remove lactic acid more quickly from muscles

breathing rate increased
- supplies more oxygen to lungs
- so more oxygen to blood
- more carbon dioxide removed

more oxygen to muscles
- needed for increased respiration
- to release energy
- for muscle contraction

anaerobic respiration occurs
- due to lack of oxygen
- causes a build-up of lactic acid
- oxygen debt
- muscle fatigue / pain

23
Q

explain how human lungs are adapted for efficient exchange of gases by diffusion

A

many alveoli
- provide a larger SA:V ratio

capillaries are thin
OR capillary walls are thin OR one cell thick
- which provides short diffusion path (for oxygen / carbon dioxide)

breathing (mechanism) moves air in and out OR lungs are ventilated
- to bring in (fresh) oxygen
- to remove carbon dioxide
- to maintain a concentration / diffusion gradient

large capillary network OR good blood supply
- to remove oxygenated blood quickly
- to bring carbon dioxide to the lungs quickly
- to maintain a concentration / diffusion gradient

24
Q

cirrhosis leads to liver failure. describe effects of liver failure on the human body

A

no bile made
- fats / lipids not emulsified
- SA of fats / lipids not increased
- pH of small intestine won’t be neutralised
- enzymes will not work effectively
- so may lose weight

lactic acid not broken down / oxidised
- accumulation of lactic acid in blood
- lactic acid is toxic
- oxygen debt higher
- so muscle pain / fatigue

protein / amino acids not broken down
- amino acids not deaminated
- not made into urea or will not form ammonia
- any ammonia formed is toxic
- so accumulation of amino acids in blood / body

glycogen stores will not be formed
- cannot control blood glucose
- so diabetes / coma / hyper/hypoglycaemia may occur

liver does not break down / remove other toxins
- toxins accumulate in blood
- body will be poisoned
- so pain or jaundice or swollen liver or portal hypertension occurs

25
Q

explain why a person with a leaking heart valve has difficulty exercising

A
  • backflow can occur OR some blood flows backwards
  • less blood leaves the heart OR less blood is pumped around the body OR some blood stays in the heart OR reduced blood pressure OR reduced flow rate
  • less oxygen supplied to muscles / cells
  • so less aerobic respiration
  • so less energy released
  • so less efficient muscle contraction
  • anaerobic respiration takes place
  • less efficient removal of lactic acid OR lactic acid builds up OR oxygen debt occurs
  • lactic acid building up causes muscle fatigue
  • less efficient removal of carbon dioxide (from blood)
26
Q

evaluate use of mechanical and biological replacement heart valves

A

mechanical valves
- longer lasting OR more durable
- blood clots are more likely
- patient has to take anti-clotting medication for the rest of their lives
- medication can lead to excessive bleeding

biological valves
- no additional medication required
- ethical issues surrounding use of animal tissue
- valve may harden
- more likely to need further operation OR another new valve
- more likely to be rejected
- more likely to need immunosuppressant medication

27
Q

define the term double circulatory system

A
  • blood is pumped to the lungs by one / right side of the heart
    AND
  • blood is pumped to the body by the other / left side of the heart
28
Q

explain why having only one ventricle makes the circulatory system less efficient than having two ventricles

A
  • oxygenated and deoxygenated blood mixes
  • so less oxygen reaches cells
29
Q

explain why an axolotl may die in water with a low conc of oxygen

A
  • conc gradient of oxygen is shallower
  • less oxygen diffuses into blood
  • less aerobic respiration occurs so less energy is released
  • so less metabolism
  • when anaerobic respiration occurs, lactic acid is produced and is toxic
30
Q

monoclonal antibodies have been produced to treat pancreatic cancer. explain how the monoclonal antibody works to treat pancreatic cancer

A
  • monoclonal antibody is attached to radioactive substance / toxin / drug / chemical
  • monoclonal antibody will only attach to antigen on cancer cells
  • so radioactive substance / toxin / drug / chemical will bind to cancer cells and stop them growing / dividing
31
Q

explain how the villi and alveoli are adapted to absorb molecules into the bloodstream

A
  • both have a large surface area
  • villi have many microvilli
  • alveolar walls are folded
  • to maximise diffusion of gases / absorption of food molecules
  • both have many capillaries / good blood supply
  • to maintain concentration gradient / diffusion gradient
  • both have thin walls / one cell thick walls
  • to provide short diffusion distance for molecules to travel
  • villi have many mitochondria
  • to provide energy for active transport
  • cells of the villi have microvilli
  • to further increase the surface area
32
Q

suggest two risk factors for coronary heart disease

A
  • smoking
  • high-fat diet
  • lack of exercise
33
Q

describe how the student could investigate the effect of pH on the breakdown of starch by amylase

A
  • range of at least 3 pH values / use of buffer solutions
  • control variables / keep amount or concentration of starch and amylase the same
  • keep temperature the same using water bath
  • use iodine test to make qualitative observations
  • observe colour changes at different temperatures
  • do repeats at each pH
34
Q

explain how the human circulatory system is adapted to
- supply oxygen to the tissues
- remove waste products from tissues

A
  • double circulatory system meaning higher blood pressure and a greater flow of blood to the tissues
  • heart made of specialised muscle cells which have long protein filaments that can slide past each other to shorten the cell to bring about contraction for pumping blood
  • heart pumps blood to lungs in pulmonary artery so oxygen can diffuse into blood from air in alveoli
  • blood returns to heart via pulmonary vein where muscles pump blood to the body via aorta
  • oxygen carried by RBCs which contain haemoglobin to bind oxygen and have no nucleus so there is more space available to carry oxygen
  • arteries carry oxygenated blood to tissues where capillaries deliver oxygen to cells for respiration and energy release
  • thin walls allow for easy diffusion to cells
  • large surface area of capillaries to maximise exhange
  • waste products removed
  • blood goes back to heart in veins which have valves to prevent blackflow
35
Q

what is an enzyme

A
  • a catalyst / speeds up a reaction
  • it is a protein OR it is specific
36
Q

give two differences in the composition of blood in a vein than in an artery

A
  • artery has more oxygen
  • artery has more glucose
  • artery has less carbon dioxide
  • artery has less lactic acid
37
Q

explain how a pregnancy test strip works to show a positive result

A
  • urine passes through reaction zone
  • HCG hormone binds to mobile HCG antibody in reaction zone
  • passes up the stick and HCG hormone binds to immobilised HCG antibodies in the results window
  • the other antibodies which do not attach to HCG
  • bind to antibodies in control zone
  • blue dye appears in both control and results zones to show positive result
38
Q

give 2 uses of mobile antibodies

A
  • pregnancy testing
  • identify / locate specific molecules / other hormones
  • locate blood clots
  • diagnose / treat some cancers
39
Q

candida albicans lives in the throat of infected patients. a sample is taken from the throat of a patient with a suspected candida albicans infection.
the sample is transferred onto a microscope slide.
describe how the mAbs and a fluorescent dye could be used to see any candida albicans pathogens on the slide.

A
  • bind fluorescent dye to mAbs
  • put bound fluorescent mAbs on the slide (and rinse off)
  • mAbs will bind to Candida albicans / pathogens and show up under the microscope
40
Q

the leaves of some plants release oils onto their surface. suggest how the production of oil on the surface of a leaf may protect the plant from aphids

A
  • prevents aphids from attaching to leaf OR causes aphids to slide off lead
    OR
  • idea that oil may harm / kill the aphid
41
Q

explain how the nettle is adapted for defence and protection

A
  • stinging hairs
  • so this harms herbivores / stops animals eating them
  • so less of the plant is removed / damaged
42
Q

explain why having very few stomata on the upper surface of the leaf is an advantage to the plant

A
  • less water loss
  • so the plant does not wilt

bio spec (9 decks)

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