GCSE Biology: Wrong answered questions

• Explain why NITRATE (mineral), has the greatest effect on crop yield (2 marks)

  1.-Amino Acids

  2.-Protein
• Suggest why an MRSA infection (a superbug resistant to many antibiotic) may have to be treated with many different antibiotics (1 mark)

  Any of these:

  to make sure ALL are killed (or destroyed)

  to find an antibiotic that is kills them all
• Suggest a method that you could use to measure the rate of sweating (3 marks)

  Max 3 of these:

  1.-Measure the : mass or weight or volume or moisture of colour change

  
  

  2.-An apparatus used to measure the clothing/shirt/paper tower -> measuring cylinder (or a moisture sensor!)

  
  

  3.-Reference to time

  
  

  4.-Repeat/average
• In a graph showing the effects of increasing ight intensity, there is a point in which there is NOT exchange of Carbon dioxide. Explain (1 mark)

  Because Respiration = Photosynthesis
• Explain what is meant by the term transgenic organism (1 mark)

  Contains gene (or allele or DNA) from a different SPECIES
• Name 2 large insoluble molecules in food that contain energy (2 marks)

  starch or cellulose or glycogen

  protein

  Note: reject carbohydrates!
• Suggest why cells do not store glucose (instead convert to glycogen). (2 marks)


  1.-It is soluble (dissolves)

  2.-Osmotic effect, etc
• Which blood vessel contains the most glucose after a meal? (1 mark)

  Blood vessel between intestines and liver
• Which blood vessel contain the least oxygen

  Blood vessel between heart and lungs
• SUGGEST how an individual can produce a chromosome such as XYY (1 extra!) (2 marks)

  1.-Failure of chromosomes to separate

  2.-Gamete has an extra chromosome

  3.-Normal egg/gamete fertilised by abnormal sperm/gamete
• Many genetic disorders are caused by recessive allele, rather than a dominant allele.

  Explain how examing a family pedgree would enable you to tell if a condition was caused by a recessive allele.

  (3 marks)

  1.-The condition is present in the offspring but not in parents

  
  

  2.-It skips generations

  
  

  3.- Carriers are present
• Suggest a reason for the difference between the BOD (Biological Oxygen Demand) of raw domestic sewage and the BOD of treated domestic sewage.

  Note: the amount of Oxygen removed from the water is called BOD

  (2 marks)

  1.-Raw domestic sewage has a higher B.O.D.

  2.-There is more bacteria/microorganisms in the raw sewage

  3-and SO there is more RESPIRATION

  4.-Raw seawage has more nutrients
• Suggest two reasons why scientists obtain blood samples from a vein rather than from an artery.

  (2 marks)

  1.-There is a slower blood flow (lower pressure) in a vein (so it will not spurt out :-))

  
  

  2.-A vein has thinner walls (for the syringe to get in....)

  
  

  3.-Easier to see (access) as nearer the surface

  4.-wider lumen
• Suggest 2 reasons why a pregnang woman needs more energy than a non pregnant woman.

  (2 marks)

  1.-A pregnant woman has more mass (is heavier)

  2.-more energy for growth/development or respiration of the fetus
• Suggest how the tissue samples are removed and transferred to the agar medium.

  (Note: this is related to micropropagation of plants)

  (2 marks)

  1.-Cut with scalpel (or razor/scissors/knife)

  2.-Transfer with tweezers

  3.-Sterile the apparatus
• Suggest why blood flow in a leg vein is slow when there is lack of movement (2M)

  .-There is muscles CONTRACTION

  .-Squeeze vein/ push blood
• Suggest how to mantain the water quality in a pond (2M)

  Any 2:

  1-More OXYGEN (prevent stagnation). Could use paddles, pump or water plant to add ore oxygen

  
  

  2.-Remove the waste like faces, dead fish, leaves..

  
  

  3.-Prevent Eutrophication, e.g. don't fertilise nearby fields, so you prevent alga growth etc
• Suggest how to control predation in the pond (2M)

  Any 2

  1.-Separate species/sizes/ages (adults eating babies..)

  
  

  2.-Cover with a net (or fence or cage etc)

  
  

  3.-Shoot birds! or an scarecrow or shoot predators!
• Suggest how to control disease in the pond (2M)


  Any 2

  
  

  1.-antibiotics

  2.-fungicide

  3.-(kill) bacteria/fungi

  4.-remove dead/diseased fish

  5.-Reduce numbers ->do not overcrowd

  6.-Use resistant strains (i.e. fishes that are resistant to illness)

  7.-keep out wild fish (as they maybe sick)
• Suggest feeding methods (for the fish) in the pond (2M)


  any 2 of these

  1.-Small quantities of food (so there is not uneaten food ...)

  
  

  2.-Feed the several times a day

  
  

  3.-High protein food

  
  

  4.-Remove the waste food

  
  

  5.-for less bacterial growth
• Explain the change in water loss of the plant when half the leaves were removed (2M)

  1.-There is less surface area

  2.-There is fewer number of stomata
• Explain what is meant by term hormone (2M)

  .-released from gland/endocrine

  .-travels in blood

  .-to target cells/organs

  .-effect/response/coordination/control/causes change..
• suggest why amino acids are provided in the growth medium

  protein/enzymes/named protein
• what is meant by the term pathogen (1M)

  organism that causes disease
• which of these stop clocks(a digital one and one with min, sec and 1/100 and clock B that has minutes and seconds) give a more precise reading? (1M)

  A because has smaller scale intervals/ more decimals
• Suggest why many plants may find it difficult to grow in sandy soil (2M)

  .-less water/water drains away or eq

  .-less anchorage
• use your knowledge of how plant roots absorb mineral ions to suggest why some plants may find it difficult to grow in clay soil (2M)

  any 2:

  .-less oxygen

  .-active transport/active uptake

  .-respiration/energy/ATP
• Describe what is meant by the term excretion (2M)

  removal

  of waste products of: cells /metabolisim/respiration or chemical reactions
• Explain the rule of insuline in homeostasis (2M)

  lower blood glucose./sugar

  liver/muscle
• Name the part of the gut where faeces are stored (1M)

  recturm
• Selective breeding involves ?????? choosing organisms (1M)


  humans/breeders/scientists/farmers
• Explain what happens in a leaf when it is destarched (2M)

  .-starch is removed

  .-(converted) to glucose

  .-respiration/energy
• Bugs caught in a trap for 10 hours before being counted. How can this affect the results obtained ? (2M)


  results would be inaccurate/different

  bugs can escape

  bugs can be eater

  bugs can reproduce
• Explain how having more red blood cells is an advantage to athletes who take part in long distance races (4M)

  .-more Oxygen

  .-haemoglobin

  .-muscles

  .-respiration

  .-(less) anaerobic respiration

  .-(less) lactic acid/ (less) oxygen debt/ (less) cramps

  .-more energy

  .-run faster/run longer/less tired
• After an infection does the number of red blood cells and white blood cells increase? (2M)

  .-red blood cells numbers : do not increase

  .-white blood celss numbers: increase
• Describe the sequence of events that cause a person to withdraw their hand from a hot object (5M)

  .-receptor/nerve ending

  .-sensory neuron / sensory nerve

  .-impulse / message /signal

  .-CNS/ spinal cord/grey matter

  .-synapse

  .-relay neurone/relay nerve

  .-motor neurone

  .-muscle/effector

  .-contract
• He measured the rate of CO₂ y counting the number of bubbles per minute. How could be improved the accuracy of the measurements of the rate of CO₂ production (1M)


  volume of gas/ measuring cylinder/ syringe
• What is meant by diffusion? (2M)

  .-movement of particles

  .-high concentration to low concentration

  -PASSIVE
• Give 3 advantages of using biological control (in a crop field) instead of chemical pesticide (3M)


  Any 3

  1.-last longer/no need to reapply

  2.-it is specific: no harm to other species

  3.-no bioaccumulation

  4.-no resistance

  5.-no affect to food chain(s)
• Name and describe the process used by root cells to absorb mineral ions (2M)

  .-active transport

  .-low to high conentration (or against concentration gradient)