Question 1
State the functions of each of the following organelles
(i) Ribosomes
(ii) Golgi apparatus
Answer
(a) (Provide) site for protein synthesis;
(b) Site for packaging and transport of glycoproteins;
(b) Site for packaging and transport of glycoproteins;
Question 2.
The diagram below represents the pathway of water from soil into the plant
(a) Name the structures labeled T and S.
(b) State two ways in which the structure labeled R is adapted to its functions.
Answer
(a) T – Xylem vessel;
S – Endodermis;
(ii) - Root hair cell;
- Narrow and elongated to increase surface area for absorption of water and mineral salts.
- Thin to reduce diffusion distance.
S – Endodermis;
(ii) - Root hair cell;
- Narrow and elongated to increase surface area for absorption of water and mineral salts.
- Thin to reduce diffusion distance.
Question 3
A student added equal amounts of blood to equal volumes of salt of different concentrations. She observed and counted the red blood cells at the beginning of the experiment and at end of the experiment. The results were as shown:-
Account for the results in:
(a) Set up A
(b) Set up B
Answer
(a) A – Concentration of salt was isotonic; to that of the cytoplasm of the Red blood
cells hence no change;
(b) B – most cells haemolysed; due to hypotonic salt solution;
(b) B – most cells haemolysed; due to hypotonic salt solution;
Question 4
Below is a dental formula of certain organisms. Use it to answer the questions that follow
I 0 ⁄ 3, C 0 ⁄ 1, PM 3 ⁄ 2, M 3 ⁄ 3
(i) Calculate the total number of teeth in the mouth of the organisms
(ii) Name the organisms.
(iii) Identify the mode of nutrition of the organisms
Answer
(i) (3 + 3 + 3 + 1 + 2 + 3) x 2
= 15 x 2 = 30; teeth
(ii) Herbivore
(iii) Heterotrophic;
= 15 x 2 = 30; teeth
(ii) Herbivore
(iii) Heterotrophic;
Question 5
(a) Give a reason why glucose does not normally appear in urine even though it is filtered in mammalian Bowman’s capsule
(b) Which hormones are involved in the salt-water balance in human body
Answer
(a) Its actively reabsorbed back to blood system within the proximal convoluted tubule;
(b) - Anti-diuretic hormone (ADH)
- Aldosterone
(b) - Anti-diuretic hormone (ADH)
- Aldosterone