Introduction to Biology
20 Grade 10 Biology questions on Introduction to Biology, with worked marking schemes. 20 questions are available on this topic in full.
Question 1
4 marksA learner viewing onion epidermal cells under a light microscope complains that the image is too dark and blurred. Suggest two adjustments the learner should make and state the effect of each.
(4 marks)
Marking scheme
1 mark for each adjustment and 1 mark for its matching effect, maximum 4 marks. - Adjust the mirror/condenser or open the diaphragm wider (1) so that more light passes through the specimen and the field of view becomes brighter. (1) - Turn the fine adjustment knob (1) to bring the specimen into sharp focus / obtain a clear image. (1) Other acceptable pairs: - Cut a thinner section of the onion epidermis (1) so that enough light passes through the specimen. (1) - Clean the eyepiece and objective lens (1) to remove dirt that blurs the image. (1) An adjustment given without its effect scores 1 mark only.
Question 2
1 markWhich of the following is the strongest evidence that a tilapia taken from Lake Victoria is a living organism and not a model?
A. It is made of matter that occupies space
B. It increases in mass and responds to changes in its surroundings
C. It can be moved from one place to another
D. It has a definite shape and colour
(1 mark)
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3 marksExplain why biologists use scientific (binomial) names rather than local names when referring to organisms.
(3 marks)
Marking scheme
Any three of the following, 1 mark each: - One organism may have many different local names in different languages/communities, which causes confusion. - The same local name may be used for two different organisms in different places. - The scientific name is universal / the same to all biologists worldwide, so it allows accurate communication. - The scientific name shows relationship, since organisms sharing a generic name are closely related. - It allows records, research findings and trade in specimens to be exchanged internationally without ambiguity. Maximum 3 marks.
Question 4
1 markA learner views a small insect using a hand lens marked X10 and then views the same insect using a microscope with a X10 eyepiece and a X40 objective lens. How many times larger than the actual insect does it appear under the microscope?
A. 60 times
B. 4000 times
C. 50 times
D. 400 times
(1 mark)
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1 markA learner is about to heat a liquid in a test tube during a Biology practical. Which practice is correct?
A. Fill the test tube to the brim so heating is even
B. Point the mouth of the test tube towards a neighbour so the learner is not splashed
C. Hold the test tube with a holder and point its mouth away from all people
D. Seal the mouth of the test tube with a stopper so nothing escapes
(1 mark)
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2 marksSuggest two ways in which the study of Biology contributes to food security in Kenya.
(2 marks)
Marking scheme
Any two of the following, 1 mark each: - It enables breeding/selection of high-yielding and drought-resistant crop varieties. - It enables identification and control of crop pests and diseases, reducing losses. - It informs proper animal husbandry, improving milk, meat and egg production. - It guides soil conservation and use of appropriate fertilisers to maintain soil fertility. - It informs better storage methods that reduce post-harvest spoilage by moulds and weevils. - It supports fish farming and management of fish stocks in lakes. Maximum 2 marks.
Question 7
1 markWhich statement best explains why Biology is described as a science?
A. It cannot be wrong once a fact has been published in a textbook
B. It uses Latin names for organisms, which makes it more accurate than other subjects
C. It relies on observation, experimentation and evidence to explain natural phenomena
D. It is concerned only with living things and therefore needs no evidence
(1 mark)
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1 markA learner wishes to collect small insects from the bark of a tree and take them to the laboratory without touching or injuring them. Which apparatus is most suitable?
A. A sweep net
B. A pair of forceps
C. A pitfall trap
D. A pooter
(1 mark)
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2 marksDistinguish between a hypothesis and a theory as used in the scientific method.
(2 marks)
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1 markA scientist in Homa Bay studies the structure and the life cycle of Plasmodium, the organism that lives inside human beings and causes malaria. In which branch of Biology is the scientist working?
A. Mycology
B. Palaeontology
C. Parasitology
D. Entomology
(1 mark)
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1 markA Grade 10 learner in Kisii observes that tea bushes on the shaded side of the farm have larger leaves than those in full sun. Which of the following is a hypothesis about this observation?
A. Tea is an important cash crop in the highlands of Kenya
B. Leaf size in tea increases when the bushes receive less direct sunlight
C. The tea bushes on the shaded side have larger leaves
D. Measure the length and width of 20 leaves from each side of the farm
(1 mark)
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1 markIn an experiment to find out whether the amount of fertiliser affects the height of maize seedlings, which of the following is the dependent variable?
A. The volume of water given to each pot
B. The mass of fertiliser added to each pot
C. The type of soil used in all the pots
D. The height of the maize seedlings
(1 mark)
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3 marksExplain why a control set-up is necessary in a biological experiment.
(3 marks)
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1 markA student writes the name of the domestic cattle kept in Nyandarua as 'bos Taurus' in a report. What is wrong with the way the name is written?
A. Both parts of the name should begin with capital letters
B. The generic name should begin with a capital letter and the specific name with a small letter
C. Nothing is wrong; that is the correct binomial form
D. The name should be written in the learner's own language, not Latin
(1 mark)
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3 marksState three characteristics that distinguish a living maize plant from a plastic maize plant used for decoration.
(3 marks)
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1 markWhich career below applies Biology mainly to the improvement of crop yields and soil productivity?
A. Physiotherapy
B. Radiography
C. Pharmacy
D. Agronomy
(1 mark)
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6 marksA farmer in Kirinyaga claims that soaking bean seeds in water overnight before planting makes them germinate faster. Describe how you would carry out an experiment to test this claim.
(6 marks)
Marking scheme
Any six of the following, 1 mark each: - Take two equal groups of bean seeds of the same variety, size and age (e.g. 50 seeds per group). - Soak group A in water overnight (about 12 hours); leave group B dry / unsoaked as the control. - Plant both groups in the same type of soil, at the same depth, in separate labelled trays/plots. - Keep all other conditions the same: same amount of water, same temperature, same light, same position. - Count the number of seeds that have germinated in each group each day, at the same time of day. - Record the results in a table / calculate the percentage germination and the mean number of days to germination for each group. - Repeat the experiment or use large numbers of seeds to improve reliability. - Conclude that the claim is supported if group A germinates in a significantly shorter time than group B. Maximum 6 marks.
Question 18
3 marksIdentify the taxonomic unit that is immediately above the species and explain why members of a species are grouped separately from other closely related organisms.
(3 marks)
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3 marksDuring a Biology practical lesson a learner spills a small amount of dilute acid on the hand. Describe the immediate action that should be taken and explain why it is necessary.
(3 marks)
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4 marksState two branches of Biology and, for each, give one activity a specialist in that branch would carry out.
(4 marks)
Marking scheme
1 mark for each correctly named branch (max 2) and 1 mark for each matching activity (max 2). The activity must match the branch named. Acceptable pairs include: - Entomology - studying the life cycle of the desert locust to plan its control. - Microbiology - culturing and identifying bacteria that spoil milk at a dairy. - Botany - studying the growth requirements of indigenous tree species. - Zoology - studying the feeding behaviour of elephants in a national park. - Genetics - studying how disease resistance is inherited in dairy cattle. - Ecology - studying the relationship between organisms and a wetland habitat. Reject a branch given without a matching activity.
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