CE

Question 1

What is division of labour in a unicellular organism

Answer 1

It is where different parts of a single cell perform different functions in a coordinated way to ensure that the cell functions effectively

Question 2

What is division of labour at a multicellular level

Answer 2

It is the sharing of different functions among an organism’s cells, tissues, organs, and organ systems to ensure the smooth running and effective working of the different parts in an organism as a whole

Question 3

What is a cell, tissue, organ, organ system and organism

Answer 3

A cell is the basic structural and functional unit of life
A tissue consists of a grp of similar cells working together to carry out a specific function
An organ is a structure made of different tissues working together to carry out a particular function
An organ system consists of several organs working together to perform a particular function
An organism has several organ systems working together to support the life of an organism

Question 4

Arrange organisms in increasing levels of organisation

Answer 4

Simple molecule -> complex molecule -> organelle -> cell -> tissue -> organ -> organ system -> organism

Question 5

State the properties and function of a cellulose cell wall

Answer 5

Made up of cellulose fibres, fully permeable

Provides mechanical support for the cell

Question 6

State the properties and function of a cell membrane

Answer 6

Partially permeable

Separates and protects a cell from its surrounding environment, controls movement of substances in and out of the cell

Question 7

State the properties and function of a cytoplasm

Answer 7

Jelly-like medium, contains aqueous solutions of essential ions, soluble proteins, sugars, and amino acids and organelles

Site of cellular activities and chemical reactions

Question 8

State the properties and function of a ribosome

Answer 8

Either found as a free ribosome or attached to structures in the cytoplasm

Involved in the synthesis of proteins

Question 9

State the properties and function of a nucleus

Answer 9

Largest organelle in animal cell, contains genetic material, found in all plant and animal cells except mature xylem and red blood cells

Controls the activities of the cell

Question 10

State the properties and function of mitochondria

Answer 10

Found in all animal and plant cells, occurs in very large numbers. Especially abundant in more metabolically active cells

Carries out cellular respiration to release energy

Question 11

State the properties and function of chloroplast

Answer 11

Contains chlorophyll, present in leaf cells and other green organs of plants and algae

Site of photosynthesis

Question 12

State the properties and function of a large central vacuole

Answer 12

Fluid filled sac surrounded by partially permeable membrane, largest organelle in plant cells

Contains cell sap which is a solution of sugars and dissolved minerals

Question 13

State the properties and function of vacuoles

Answer 13

Fluid-filled sac surrounded by a single membrane, small and numerous

Stores water and food substances

Question 14

Where does bacteria keep its DNA

Answer 14

nucleoid region

Question 15

how does bacteria reproduce

Answer 15

binary fission

Question 16

why is a virus not considered a living thing

Answer 16

It has no cytoplasm, nucleus, organelles or its own membrane

Question 17

where does a virus keep its genetic material

Answer 17

capsid

Question 18

what is the structure of a root hair cell and how is it useful

Answer 18

Presence of long narrow extension (surface area to volume ratio increase -> rate of absorption of water and mineral salts)
Large central vacuole (storage of water in the cell)
Thin cell wall (reduce distance water and mineral salts need to diffuse

Question 19

what is the structure of a red blood cell and how is it useful

Answer 19

Presence of haemoglobin (combines with oxygen)
Biconcave shape (increases surface area to volume ratio -> increase rate of diffusion of oxygen)
Absence of nucleus (allow more haemoglobin to be packed in the cell -> more oxygen)

Question 20

what is the structure of a sperm cell and how is it useful

Answer 20

Streamlined shape (allow it to move towards egg at faster pace)
Presence of flagellum (propel the cell towards the egg at a faster pace)
Mid-piece packed with mitochondria (Provie energy for the movement of the flagellum