Question

1. the diagram below represents a microscope.

a. name the structures labelled e and f
e. (2mks)
f. (1mk)
b. state the function of the part labelled e (1mk)

1. name the organelle that performs the functions listed below.

(i). breaks down old cell organelles (1mk)
(ii). synthesis of atp (1mk)

1. peter was using a light microscope to view onion cells with lens combination of eye piece x10 and objective lens x20.

a. calculate the total magnification (1mk)
b. if he changed the objective lens magnification to x40, would the cells appear bigger or smaller? (1mk)

Explanation:

1. a. Based on the general structure of a microscope, E is the coarse adjustment knob and F is the stage.

b. The coarse adjustment knob (E) is used to bring the specimen into general focus.

1. (i) Lysosomes break down old cell organelles.

(ii) Mitochondria are the site of ATP synthesis.

1. a. The total magnification of a microscope is calculated by multiplying the magnification of the eyepiece by the magnification of the objective lens. So, \(10\times20 = 200\) times.

b. When the objective lens magnification is increased (from \(×20\) to \(×40\)), while the eyepiece magnification remains the same (\(×10\)), the total magnification increases (\(10\times40=400\) times compared to \(10\times20 = 200\) times). A higher magnification makes the cells appear bigger.

Answer:

1. a. E: Coarse adjustment knob; F: Stage

b. To bring the specimen into general focus

1. (i) Lysosome

(ii) Mitochondrion

1. a. \(200\) times

b. Bigger