Topic 1 - Specialised Cells And Their Functions

Question 1

What is the process by which cells specialise?

Answer 1

Differentiation

Differentiation involves cells gaining new sub-cellular structures to suit their specific roles.

Question 2

What type of cells have the ability to differentiate throughout their whole life?

Answer 2

Stem cells

Stem cells can differentiate at any point in their life cycle.

Question 3

In which organisms do most cells only differentiate once?

Answer 3

Animals

Most animal cells undergo differentiation only a single time.

Question 4

Do many plant cells retain the ability to differentiate?

Answer 4

Yes

Unlike most animal cells, many plant cells can continue to differentiate throughout their life.

Question 5

Fill in the blank: Cells can either differentiate once early on or have the ability to differentiate their whole life (these are called _______).

Answer 5

stem cells

Question 6

What are the new structures that cells gain during differentiation called?

Answer 6

Sub-cellular structures

These structures enable the cell to perform its specific functions.

Question 7

What is the function of sperm cells?

Answer 7

Specialised to carry the male’s DNA to the egg cell (ovum) for successful reproduction

Sperm cells have a streamlined head and long tail to aid swimming.

Question 8

What adaptations do sperm cells have to aid in movement?

Answer 8

Streamlined head and long tail, many mitochondria

Mitochondria supply the energy for movement.

Question 9

What is the role of the acrosome in sperm cells?

Answer 9

Contains digestive enzymes that break down the egg cell’s membrane

This allows the sperm to penetrate the egg during fertilization.

Question 10

What does haploid mean in relation to sperm cells?

Answer 10

Contains 23 chromosomes

Most other body cells have 46 chromosomes.

Question 11

What is the primary function of egg cells?

Answer 11

Specialised to accept a single sperm cell and develop into an embryo

Egg cells are crucial for reproduction.

Question 12

How do egg cells prevent multiple sperm from fertilising them?

Answer 12

Surrounded by a special membrane that becomes impermeable after one sperm enters

This ensures only one sperm fertilises the egg.

Question 13

What is the significance of mitochondria in egg cells?

Answer 13

Provide an energy source for the developing embryo

Energy is essential for early cell division.

Question 14

What adaptations do ciliated epithelial cells have?

Answer 14

Long, hair-like processes called cilia

Cilia waft bacteria trapped by mucus to the stomach.

Question 15

What is the function of root hair cells?

Answer 15

Specialised to take up water by osmosis and mineral ions by active transport

Found in the tips of roots.

Question 16

How do root hair cells maximize water uptake?

Answer 16

Have a large surface area due to root hairs

This allows more water to move in.

Question 17

What role does the large permanent vacuole play in root hair cells?

Answer 17

Affects the speed of movement of water from the soil to the cell

It helps maintain turgor pressure.

Question 18

What is the function of xylem cells?

Answer 18

Specialised to transport water and mineral ions up the plant

They move nutrients from roots to shoots.

Question 19

What happens to xylem cells upon formation?

Answer 19

Lignin is deposited causing the cells to die and become hollow

This creates a continuous tube for transport.

Question 20

Why is lignin important for xylem cells?

Answer 20

Helps cells withstand the pressure from water movement

Lignin is deposited in spirals.

Question 21

What are phloem cells specialised for?

Answer 21

To carry the products of photosynthesis (food) to all parts of the plants

Question 22

What structures do the cell walls of phloem cells form when they break down?

Answer 22

Sieve plates

Question 23

How do sieve plates function in phloem cells?

Answer 23

Allow the movement of substances from cell to cell

Question 24

What do phloem cells lose during their development?

Answer 24

Many sub-cellular structures

Question 25

How do phloem cells obtain the energy they need to be alive?

Answer 25

From the mitochondria of the companion cells