1. producing new cells

Question 1

describe stage 1 of mitosis

Answer 1

At the start of cell division the DNA becomes shorter and thicker and is more easily seen as chromosomes inside the nucleus of the cell.

Question 2

describe stage 2 of mitosis

Answer 2

Each DNA strand (chromosomes) copies (duplicates) itself. The original DNA and the copy join together temporarily.

Question 3

describe stage 3 of mitosis

Answer 3

The chromosomes line up along the equator of the cell along string-like structures known as spindle fibres.

Question 4

describe stage 4 of mitosis

Answer 4

The duplicated chromosomes are pulled apart to opposite ends of the cell by spindle fibres

Question 5

describe stage 5 of mitosis

Answer 5

A nuclear membrane forms around each group of chromosomes. There are now 2 nuclei in this dividing cell.

Question 6

describe stage 6 of mitosis

Answer 6

Two daughter cells have been formed. They have the same number of chromosomes (DNA strands) as the parent cell.

Question 7

what is a chromosome compliment

Answer 7

number of chromosomes in an organisms cell

Question 8

describe a haploid cell

Answer 8

it has one set of chromosomes (e.g. sex cells)

Question 9

describe a diploid cell

Answer 9

it has two sets of chromosomes (e.g. zygote)

Question 10

order of organisation in a multicellular organism

Answer 10

cells, tissues, organs, systems, organisms

Question 11

specialised feature and function of red blood cell

Answer 11

small size and biconcave shape presents a large surface area and is able to absorb more oxygen; rich supply of haemoglobin

uptake and transport of oxygen to living cells

Question 12

specialised feature and function of white blood cell

Answer 12

able to change shape; sacs of microbe-digesting enzymes present in some types

destruction of invading microbes

Question 13

specialised feature and function of sperm cell

Answer 13

has a tail

to help to swim through the female reproductive system to the egg

Question 14

specialised feature and function of palisade mesophyll

Answer 14

chloroplasts present; columnar shape (allows densely packed green layer to be presented to light)

primary region of light absorption and photosynthesis

Question 15

specialised feature and function of spongy mesophyll

Answer 15

‘round’ shape allows loose arrangement in contact with moist air spaces for absorption of of carbon dioxide

secondary region of photosynthesis

Question 16

specialised feature and function of the sieve tube (in phloem)

Answer 16

sieve plates and continuous stream of cytoplasmic strands

transport of soluble carbohydrates up and down the plant

Question 17

specialised feature and function of companion cell (in phloem)

Answer 17

large nucleus in relation to cell size

control of sieve tube functions

Question 18

specialised feature and function of vessel (in xylem)

Answer 18

hollow tube; wall strengthened by ligin; ligin deposited as rings or spirals allowing expansion or contraction

support and water transport up the plant

Question 19

specialised feature and function of the root hair cell

Answer 19

long extension of an epidermal cell presenting a large surface area in contact with soil solution

absorption of water and mineral salts

Question 20

describe STEM cells

Answer 20

unspecialised animal cells involved in tissue growth and repair (embryo or tissue)

• can divide (by mitosis) in order to self-renew
• have the potential to become different types of cells

Question 21

describe an embryonic stem cell

Answer 21

can be obtained from the embryo at very early stage, have the potential to become any cell type found in the body

(e.g. nerve cell, skin cell, bone cell, blood cell)

Question 22

describe a tissue stem cell

Answer 22

can be found in the body throughout life

can only become a few types of cells (e.g. types of white blood cells and red blood cells - no other cell)