2018 National 5 Biology MCQS With Answers

In This Article you will get all 2018 National 5 Biology Mcqs with answers. there are national 5 biology mcqs added below with answers.


1. The diagram shows a cell with a section of the cell membrane magnified.


Molecule X is

  • A phospholipid
  • B protein
  • C cellulose
  • D starch.

Ans B

2. The diagram shows an experiment in which a model cell was placed in a sucrose solution.

At the start of the experiment the model cell weighed 25 g and at the end it weighed 30 g.
What was the percentage increase in mass?

  • A 5·0%
  • B 16·7%
  • C 20·0%
  • D 83·3%

Ans C

3. Glucose molecules in low concentration in the kidney have to be moved into the
bloodstream, where there is a higher concentration of glucose.
The process responsible for this action is

  • A osmosis
  • B diffusion
  • C passive transport
  • D active transport.

Ans D


4. Which of the following represents the sequence of events in the production of a protein
from the genetic code?

  • A DNA ______amino _____acids_____ mRNA _____protein
  • B DNA______ mRNA _____amino _____acids ____protein
  • C mRNA_____ DNA____ amino_____ acids_____ protein
  • D amino ______acids______ DNA____ mRNA_____ protein

Ans B

5. Which of the following are all types of proteins?

  • A Hormones, enzymes and nitrates
  • B Antibodies, enzymes and plasmids
  • C Hormones, receptors and antibodies
  • D Receptors, antibodies and nitrates

Ans C

6. The flowchart represents some of the stages of genetic engineering.
stage X

A suitable description of stage X would be

  • A insert bacterial plasmid into required gene
  • B insert bacterial plasmid into source chromosome
  • C insert required gene into host bacterial cell
  • D insert required gene into bacterial plasmid.

Ans D

7. The diagram shows an experiment which can be used to find the energy content of different
foods. Each food was completely burned and the energy content was estimated by the rise
in temperature of the water.

The reliability of this experiment could be improved by

  • A burning each food for the same length of time
  • B repeating the experiment with each food several times
  • C removing the thermometer from the tube to read it accurately
  • D repeating the experiment using a different food each time.

Ans  B


8. The apparatus shown was used to investigate the rate of respiration in yeast at 20 °C.

Which of the following changes would cause a decrease in the rate of respiration of the

  • A Increase the thickness of the layer of oil by 1 mm.
  • B Increase the temperature of the glucose solution by 1 °C.
  • C Decrease the concentration of the glucose solution by 1%.
  • D Decrease the volume of indicator solution by 1 cm3

9. The diagram shows some of the structures found in a reflex arc.

Which row in the table identifies P, Q and R?
                      Motor neuron             Sensory neuron              Inter neuron

  • A                     Q                                                   R                                         P
  • B                      Q                                                  P                                          R
  • C                      R                                                P                                             Q
  • D                       P                                                 R                                          Q

Ans B

10. The diagram represents a section through the brain.

Which of the following links a letter to its correct structure and function?

  • A G is the cerebrum and is the site of reasoning and memory.
  • B G is the cerebellum and is the site of reasoning and memory.
  • C H is the medulla and controls muscle coordination.
  • D H is the cerebellum and controls breathing and heart rate.

Ans A

Questions 11 and 12 refer to the following flow diagram related to blood glucose

11. Which row in the table identifies organ X and hormone Y?
Organ X Hormone Y

  • A Liver Insulin
  • B Liver Glucagon
  • C Pancreas Insulin
  • D Pancreas Glucagon

Ans D

12. Specialised cells allow organ Z to respond to hormone Y.
This is because the surface of the cells in organ Z have complementary

  • A synapses
  • B neurons
  • C effectors
  • D receptors.

Ans D

13. An increase in which of the following factors would decrease the rate of transpiration in

  • A Wind speed
  • B Humidity
  • C Surface area
  • D Temperature

Ans B

14. Which of the following statements about blood cells is false?

  • A White blood cells are part of the immune system.
  • B Phagocytes are a type of white blood cell.
  • C Red blood cells contain haemoglobin.
  • D Phagocytes transport nutrients around the body.

Ans D

15. Which row in the table identifies how lymphocytes destroy pathogens?
                       Antibody production                  Phagocytosis

  • A               Yes                                                      No
  • B                  No                                                           No
  • C                  No                                                            Yes
  • D                  Yes                                                           Yes

Ans A

16. The following key can be used to identify the different components of blood.
1. Nucleus absent                           go to 2
Nucleus present                            go to 3  

2. Diameter greater than 0·005 mm              red blood cell
Diameter less than 0·005 mm                        platelet

3. Nucleus is circular                              lymphocyte
Nucleus is not circular                           macrophage

Use the key above to identify which of the diagrams represents a platelet.

Ans D

17. Which of the following statements is true of villi?

  • A Blood capillaries absorb glycerol and amino acids.
  • B Blood capillaries absorb glucose and fatty acids.
  • C Lacteals absorb glycerol and fatty acids.
  • D Lacteals absorb glucose and amino acids.

Ans C

18. An ecosystem consists of abiotic factors plus a

  • A community and its biodiversity
  • B population and its biodiversity
  • C population and its habitat
  • D community and its habitat.

Ans D

19. The diagram shows part of a food web.

A chemical was used to control the number of slugs.
Which of the following could be a result of a large decrease in slug numbers?

  • A An increase in snails.
  • B An increase in hawks.
  • C A decrease in caterpillars.
  • D A decrease in oak trees.

20. The diagrams show an investigation into seed germination.

For a valid conclusion to be drawn, which two tubes should be compared to show the effect
of temperature on germination?

  • A 1 and 3
  • B 3 and 6
  • C 2 and 5
  • D 4 and 6

Ans C

21. The diagram represents a pyramid of energy.

There is less energy at level X in the pyramid because

  • A there are fewer organisms at each level in the food chain
  • B the organisms at level X are very small
  • C energy is lost at each level in the food chain
  • D energy is stored in each level and not passed on.

Ans C

22. Mutations result in changes to genetic material.
Which of the following is not true of mutations?

  • A Radiation can increase their rate.
  • B They always have a harmful effect.
  • C Genetic material is affected at random.
  • D New alleles may be produced.

Ans B

23. Natural selection occurs when there are selection pressures.
Which of the following could be a result of selection pressures?

  • A Organisms with favourable alleles survive and reproduce.
  • B Organisms with new alleles always have an advantage.
  • C All alleles in a population increase in frequency.
  • D All alleles in a population decrease in frequency.

Ans A

24. Pesticides sprayed onto crops can get into food chains. The following statements refer to
stages in this process.
J Pesticides are absorbed by plants.
K Pesticides build up in animals.
L Plants are eaten by animals.
Identify the order of steps by which pesticides could reach lethal levels in the bodies of

  •                Step 1            Step 2               Step 3
  • A               J                      K                        L
  • B               L                      J                          K
  • C               L                      K                         J
  • D              J                      L                         K

Ans D

25. Which row in the table identifies biotic and abiotic factors which can affect a population?
                         Biotic factors                                   Abiotic factors

  • A                   grazing and predation                       pH and temperature
  • B                  predation and temperature                 pH and grazing
  • C                  pH and temperature                            grazing and predation
  • D                 pH and grazing                                      predation and temperature

Ans A

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