Question 1
- Name the laboratory apparatus used for the following.
- Catching small flying insects
- Sucking small animals from rock surfaces or barks of trees
- State the functions of the following cell organelles in a cell
- Nucleouls
- Lysosomes
- Ribosomes
- State three differences between a plant cell and an animal cell
Answer
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- Sweep net
- Pouter
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- Synthesis of ribosomes
- Destroy worn out cell organelles/cells
- Synthesis of protein
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Question 2
The diagram below represents the nitrogen cycle.
- Letters A and D represent biological processes in plants
- Name the structures in which the processes A and D take place
A
B - Name the compound represented by B
- What is nitrogen fixation?
- Name the structures in which the processes A and D take place
- The food chain below represents a feeding relationship observed in an ecosystem
Planktonic → tilapia → Nile perch
Algae(1000) (300) (100)- What is a food chain?
- Name the trophic level occupied by Tilapia in this habitat.
- Draw a pyramid of numbers for the above food chain.
- Explain the trend in numbers represented by the pyramid of numbers in b(iii) above.
Answer
-
- A- Root nodules
D – Root hairs; - – Nitrates
- – It’s the conversion of free nitrogen in air into nitrates
- A- Root nodules
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- – It’s the linear flow of energy through different trophic levels in an ecosystem
- – Primary consumers
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- -There is gradual decrease in numbers due to energy loss through respiration, defecation, urination
Question 3
- Distinguish between homodont and heterodont dentition
- Below is a dental formula of an animal
i0/3 C0/1 Pm3/2 m3/3- Calculate the total number of teeth
- Identify the likely mode of feeding for the above animal
- Give a reason for your answer in b(ii) above
- State one function and one adaptation for each of the teeth below
Answer
- – Homodont – dentition with one type and shape of teeth
- Heterodont - dentition with different types and shape of teeth -
- 30 teeth
- - Herbivorous/herbirory
- - Lack upper incisors and canines
- 1. Mortar tooth – has broad surface with cusps
Function: Increases surface area for grinding
2. Carnassial tooth – sharp edge for shearing
Function: - Slicing flesh/for crushing bones
Question 4
In an experiment to investigate a physiological process in onion cells a thin epithelium of onion bulb leaf was placed on a glass slide and drops of concentrated salt solution added. After 3 minutes the cells were observed under medium power objective lens of a light microscope.
-
- Draw a labeled diagram showing how one of the cells will appear
- Account for the observation made in a(i) above.
- Name the process that occurred in the cell in a (i) above.
Answer
-
-
- – The salt solution was hypertonic to the cell sap; the vacuole lost water to the solution by osmosis; hence reducing in size
- - Plasmolysis
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Question 5
- What is meant by the term binomial nomenclature?
- Give three reasons why classification is important
- State three differences between class insect and Arachnida.
Answer
- - Scientific system of giving organisms two names; Generic and specific names
- - Identification/placing them in their correct groups;
- To understand the evolutionary relationship between organisms;
- To arrange information about living organisms in an orderly manner for easy study/avoid confusion - State three differences between class insect and Arachnida.
