B2

Question 1

what are palisade cells?

Answer 1

they are plant cells located in leaves

Question 2

describe features of palisade cells

Answer 2

1. they are cylindrical shapes, so they pack tightly in the upper part of the leaf, which increases the surface area for absorption of sun light energy
2. they contain many chloroplasts to capture/ trap as much energy from light as possible for photosynthesis
3. they have large vacuoles which store water and other substances and which helps to keep the cell and leaf structure rigid.
4. they have mitochondria that create ATP to support photosynthesis

Question 3

examples of organs in a plant and what do they contain?

Answer 3

leaves and roots contain some cells that are specially adapted for their function

Question 4

where are root hair cells found?

Answer 4

in the epithelium near the root tip

Question 5

explain how root hair cells are adapted for their function

Answer 5

they have a long cell extension into the soil which increases their surface area for absorption
thin cell wall makes it easier for substances to cross into the cell
many mitochondria supply energy for active transport of minerals from the soil into the cell

Question 6

what is the function of the root hair cells?

Answer 6

to absorb water and dissolved minerals

Question 7

what is the main function of the palisade mesophll cells?

Answer 7

to capture energy transferred by light

Question 8

what does the undulipodium do?

Answer 8

helps with movement to swim to the egg

a long tail

Question 9

what does the nucleus do?

Answer 9

the haploid nucleus contains one set of chromosomes

Question 10

what is the acrosome?

Answer 10

it contains enzymes to digest the outer layers of the egg

Question 11

what does the mid region contain

Answer 11

it contains mitochondria to provide the energy for movement

Question 12

what is the function of the sperm cell

Answer 12

to get the male DNA to the female DNA

it has a stream lined head to help it swim to the egg

Question 13

what are sperm cells specialised for

Answer 13

reproduction

Question 14

what are root hair cells specialised for

Answer 14

absorbing water and minerals

Question 15

egg cells: cytoplasm

Answer 15

it is full of energy-rich material

Question 16

in egg cells, what is the haploid nucleus

Answer 16

it contains half the chromosomes of a body cell, so that when the nucleus from the sperm fuses with the egg cell nucleus the full number of chromosomes is restored at fertilisation

Question 17

in egg cells, what are the special vesicles

Answer 17

they contain a substance that helps stop more than one sperm fertilising the egg

Question 18

in egg cells, what is the zona pellucida?

Answer 18

it is a jelly layer which stops more than one egg fertilising the egg

Question 19

in egg cells, what are follicle cells

Answer 19

they supply vital proteins

Question 20

identify two organelles in a palisade mesophyll cell that help it maintain its rigid structure

Answer 20

cell wall

vacuole

Question 21

explain what white blood cells are

• types
• state their function
• where they are found

Answer 21

1. white blood cells have a large nucleus
2. there are different type of white blood cells such as phagocytes and lymphocytes
3. their function is to fight pathogens and protect the body
4. they can squeeze through capillary walls and are found in tissues and blood
5. they have a nucleus so can divide
6. are made in the bone marrow and lymph nodes.

Question 22

explain what red blood cells are

• structure
• where they are made
• function

Answer 22

1. red blood cells have NO nucleus or organelles, this gives them a bigger surface area and more room for haemoglobin, which is a protein that carries oxygen
2. they are small, round and biconcave discs, which allows more o2 and co2 to diffuse into the haemoglobin.
3. their size and shape allows them to squeeze through narrow blood vessels
4. as they have NO NUCLEUS, they CANNOT divide
5. they are made in the bone marrow
6. is to carry oxygen from the lungs to the body tissues and carbon dioxide as a waste product, away from the tissues and back to the lungs.

Question 23

difference between red and white blood cells

Answer 23

1. white blood cells have a nucleus so can divide whereas red cells dont
2. red blood cells are red due to the presence of haemoglobin, whereas white blood cells are colourless

Question 24

describe structural differences between a human sperm cell and a human egg cell

Answer 24

sperm cell has a flagellum
overall sperm cell shape is streamlined
sperm cell has less mitochondria and other organelles
sperm cell has an acrosome
egg cell has a jelly layer
egg cell has cortical granules
sperm cell has less cytoplasm

Question 25

function of white blood cells

Answer 25

cells of the immune system

protect the body against both infectious disease and foreign invaders, pathogens

Question 26

function of red blood cells

Answer 26

to transport oxygen and carry carbon dioxide to the lungs for you to exhale

Question 27

How are red blood cells specialised

Answer 27

• No nucleaus / other organelles = room for more haemoglobin (protein that carries O2)
• small, round bicóncave = optimises surface area to volume ratio, which allows more O2 and CO2 to diffuse into the haemoglobin
• size and shape = allows them to squeeze through narrow blood vessels

Question 28

How are white blood vessels specialised?

Answer 28

• large nucleus

* can squeeze through capillary walls = can move to sites of infection quickly

Question 29

Where are white blood cells made and where are they found?

Answer 29

Made in the bone marrow

Found in tissues and the blood