Specialised cells

Question 1

What is Differentiation?

Answer 1

is the process of specialisation occurring HOW A CELL BECOMES DIFFERENT

Question 2

What are the features of the upper epidermis?(1)

What are the functions of the upper epidermis?(1)

Answer 2

Features:
Transparent

Functions:
To let light through to the Palisade Layer beneath

Question 3

What are the features of the palisade layer? (3)

What are the functions of the palisade layer?(1)

Answer 3

Features:
consists oflong, thin Palisade Mesophyll Cells.
large amounts of Chlorophyll,
long shapemaximizes light absorption

Functions:
They are specialized for carrying outPhotosynthesis

Question 4

What are the features of the Spongy Mesophyll? (1)

What do Spongy Mesophyll contain? (2)

Answer 4

has many air spaces to maximize gas circulation

has veins that contain the xylem and phloem
they transport water and products of photosynthesis to other parts

Question 5

What are the features of the Lower Epidermis? (1)

What are the functions of the Lower Epidermis?

Answer 5

contains Stomata, which allow themovement of gases in and out of the leaf.

A Stoma is made from twoGuard Cells. These have spiral thickenings of Cellulose which means that when the Cells are Turgid, theStoma opens, and when they are Flaccid, the Stoma closes.

Question 6

What is the function of sperm cell Undulipodium(tail)

What does it contain

Answer 6

propels
the cell

which moves by energy generated bymany mitochondria

Question 7

What is the function of sperm cell Acrosome(head)

Answer 7

specialized Lysosome that releases enzymes so that the Sperm Cell can penetrate the membrane of the Egg

Question 8

how does the shape of the sperm cell help it?

Answer 8

verysmall and thin/streamlined, which aids their movement.

Question 9

What is the function of Zona (egg cell)

Answer 9

is the outer protective membrane of the egg

Question 10

What is the function of corona radiate? (egg cell)

Answer 10

consists of two or three layers whose function is to supply proteins needed to the fertilized egg cell.

Question 11

What are Neutrophils ?

Answer 11

type of White Blood Cell that ingests and destroys invading microorganisms

Question 12

what are the features of neutrophils?(3)

Answer 12

They have large amounts of Lysosomes, which contain enzymes that kil l ingested cells

a Lobed Nucleus , which allows for greater flexibility so they can squeeze through small gaps when travelling to the site of infection.

They have cell surface receptors to detect antigens from foreign pathogens

Question 13

What happens when antigens are detected?

Answer 13

white blood cell produce antibodies to counter the antigens and stop the bacteria from causing infection in the body.

Question 14

What are the features and functions of the Red Blood Cell?

Answer 14

1. carry oxygen from the lungs to respiring tissues
2. They contain large amounts of Haemoglobin , that holds oxygen
3. many of the organelles (including the nucleus) present in normal cells are not present to make space for more Haemoglobin
4. Their shape is biconcave , which maximises surface area , and so the speed of movement of Oxygen into and out of the cell.

Question 15

MAHRAN LOOK AT POWERPOINT FOR DIAGRAMS

Answer 15

MAHRAN LOOK AT POWERPOINT FOR DIAGRAMS

Question 16

What is a zygote?

Answer 16

sperm cell and egg cell

Question 17

Explain how the structure of the sperm cell is adapted to its function. (8 marks)

Answer 17

The sperm has enzymes in its acrosome [1], which allows it to digest the egg cell membrane [1] and fertilise the egg

It has many mitochondria [1] which provide the energy [1] needed for the sperm to move.

It has a tail [1] allowing it to swim [1]
It has a streamlined body [1] allowing it to swim quickly

Question 18

Explain how the structure of the root hair cell is adapted to its function. (8 marks)

Answer 18

Root hair cells have a large surface area to volume ratio due to their hair-like projections [1] which increases uptake of water and minerals [1].

They have a large amount of mitochondria [1] which provide more energy [1] for active transport.

The cells have thin cellulose walls [1] which allow easy transfer of fluids[1]

They also have a vacuole [1] that has a low water potential to encourage water to entre [1].

They have carrier proteins in the plasma membrane [1]which allow active transport to occur [1].