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SULIMO BIOLOGY PAPER 1 MARKING SCHEME

Name the taxonomic unit grouping that contains individuals with most similarities. (1mark)

Species;

Give two rules of binomial nomenclature (2 marks)

The name of the genus must start with a capital letter while that of the species is written in small letter;

The two names should be italicized when printed or underlined separately when handwritten;

A marine amoeba does not burst when transferred into fresh water. Explain. (2 marks)

Amoeba has contractile vacuole which excretes excess water that gets into the body/cell by osmosis;

Explain what would happen to red blood cells if they are placed in a concentrated salt solution (2 marks)

They lose water by osmosis; shrinks and becomes crenated;

Briefly describe the events of the dark stage of photosynthesis (2 marks)

Carbon (IV)oxide is taken in through the stomata;

The carbon (IV)oxide combines with the hydrogen atom from light stage to form glucose;

a) What characteristic of living organism is shown when;

i. A cat produce kittens Reproduction(1 mark)

ii. A girl drops a hot plate Irritability (1 mark)

b) State the functions of the following cell organelles:(2 marks)

Ribosomes; Sites of protein synthesis

Nucleus; Controls all the activities of the cell;

(a) State two ways in which the stomach is prevented from digestion by protein digesting enzymes (2 marks)

They are secreted in inactive forms;

Goblet cells in the stomach secrete mucus that lines the stomach lining preventing contact with digestive enzymes

Name two enzymes secreted in inactive form (2 marks)

Pepsin; Rennin; Trypsin

(a) Define the term ‘‘field of view’ ’as used in microscopy. (1 mark)

The circular lit area that is visible when you look through the microscope;

(b) State two functions of the body tube of a light microscope. (2 marks)

It supports the eyepiece and objective lenses;

It blocks stray light;