Answers to Pg 13

Section A

1. a) X : Animal cell

Y : Plant cell

b) i) A plant cell has cell wall

ii) A plant cell has large vacuole

iii) A plant cell has chloroplasts.

c) i) P : mitochondrion

ii) R : Golgi apparatus

iii) S : Chloroplast

d) -Completes the synthesis of carbohydrates and hormones

- Processes, modifies and packs protein

e) Organelle P is a mitochondrion, which is the site for generating energy. Energy is requiredfor cell division, excretion and respiration. If there is no organelle P, all cell activities will stop.

2. a) Stomach. Digestion of food

b) Epithelial and smooth muscle

c) The tissue which are found in the skin are epithelial tissues, connective tissues and nerve tissues. Epithelial tissues function as a protective layer. Connective tissues such as blood, supplies oxygen and nutrients to the skin. Muscle tissues are used for the movement of hair in the hair follicles of the skin. Nerve tissues receive stimulus and send impulses from the skin to the central nervous system.

d) Cells --> Tissues --> Organs --> Systems --> Organism

Section B

3a) Refer to notes.

b)

Organelle	Function
Nucleus	Controls cell activities and contains genetic material
Mitochondria	Site for generating energy through cellular respiration
Chloroplast	Site for photosynthesis
Golgi apparatus	Complete the synthesis of proteins, glycoproteins and hormones.

c)

Animal cell	Plant cell
Similarity
Both cells have nucleus, cytoplasm, plasma membrane, mitochondrion, ER, Golgi body, ribosomes
Differences
Has irregular shape	Has regular shape
No cell wall	Has cell wall
No chloroplast	Has chloroplast
Has glycogen granules	Has starch granules
Has none or small vacuoles	Has big vacuoles

4. (a) Adaptations in the structure and physiology of to carry out certain function

(b) Cell

- Both its structure and shape differ from one type to another.

- Each cell carries out specific function.

- A group of cells that have similar structures and perform similar functions form tissue.

Tissue

-Epithelial tissue functions as a protective layer.

- Muscular tissues are able to contract and produce motion for movement purposes.

- Nervous tissues consist of neurons and are specialised in transmitting nerve impulses.

- A group of different types of tissues together to form an organ.

Organ

- Stomach is made up of epithelial and muscular tissues .

- Kidneys are made up of muscular tissues, connective tissues and epithelial tissues.

- A few organs interrelate to form an organ system.

System

- Digestive system consists of mouth cavity, oesophagus, stomach, intestines and pancreas.

- Respiratory system consists of lungs, trachea, bronchus and the nose.

- Nervous system consists of the brain and spinal cord.

- All the organ systems work together to form a multicelullar organism.