What is

phototropism?

You are provided with several plant shoots and a sample of auxin.

Describe an experiment that you could carry out to show that auxin causes a

shoot to bend.

What are

auxins and

what do they

do?

Why might a plant breeder

may take many cuttings from a

particular plant?

Describe how

to take a

cutting.

5 a day revisionB5 – Plant development

@aegilopoides

A plants response to the

direction of light.

Paint auxin onto one side of shoot.Place in a dark for a period of time.

Until shoot grows/changes direction.Refer to repeats/ control without auxin.

Auxins are plant hormones that control growth near the tips of shoots and roots. They cause cells to elongate and grow.

The plant has desirable

characteristics.

Remove part of plant (must contain

meristem cells).Dip in rooting powder.

Place in water/soil.

5 a day revisionB5 – Plant development

@aegilopoides

Which DNA

bases always

pair together?

DNA is made up of four different bases, A T, C and G. In a DNA sample, 23% of the bases are T. Calculate the percentage of

bases that are G.Show your working!!

How does the

order of bases in

a gene determine

which protein is

made?

Why is a RNA copy of the DNA made

before proteins are produced?

Where in the cell

are proteins

made?

5 a day revisionB5 – DNA to protein

@aegilopoides

A and TG and C

If 23% are T then 23% = AA + T = 46%G + C = 54%

G = C G = 542G = 27%

Each triplet of DNA bases codes for an amino acid. The order of amino acids

is different for each protein.

DNA is too large to leave the nucleus. A

copy of the information is

made.

In the cytoplasm – by ribosomes.

5 a day revisionB5 – DNA to protein

@aegilopoides

In a human

embryo, all the

cells are

unspecialised

until what stage?

Explain how animals and plants different in terms of their capacity to grow.

How are

embryonic stem

cells different to

adult cells?

What name is

given to the parts

of plants where

mitotically active

cells are found?

5 a day revisionB5 - Development

What is a zygote?

@aegilopoides

8 cell stage

At a certain point animals stop growing and only certain cells are capable of

dividing to produce new cells.Plants are able to keep growing

throughout their entire life.

They have the potential to

become any type of cell.

Meristems

5 a day revisionB5 - Development

The cell produced when an egg and sperm fuse together.

@aegilopoides

What name is

given to the

process of stem

cells becoming

specialised?

Describe how cloning can be used to produce embryonic stem cells.

Why can

embryonic stem

cells produce any

type of cell?

Give an example of an application for embryonic stem cells.

Myosin is a protein

found in muscle

cells. Why is it not

found in other cell

types?

5 a day revisionB5 – gene switching and stem cells

@aegilopoides

Differentiation

• Nucleus removed from a human egg cell• Nucleus from a patient's cell put into the egg

cell• Egg cell stimulated to develop into an embryo• Stem cells taken from the embryo

All of the genes are switched on.

• Making new brain cells to treat people with Parkinson's disease

• Rebuilding bones and cartilage

• Repairing damaged immune systems

• Making replacement heart valves

In other cells the gene for making

myosin is switched off.

5 a day revisionB5 – gene switching and stem cells

@aegilopoides

What are the

main processes

in the cell

cycle?

The nucleus of a cell

contains 2 pairs of

chromosomes. Draw a

diagram to show the

daughter cells

produced after

mitosis.

Give two differences between mitosis and meiosis.

Why are gametes

produced by

meiosis and not

by mitosis?

5 a day revisionB5 – cell division

Every nucleus in the body cell of an elephant contains 56 chromosomes. Read the statements about cell division and put a tick in the correct box for each statement.

@aegilopoides

• Number of organelles increases.

• Chromosomes are copied.

• Chromosomes separate.

• Cell divides• Mitosis produces 2

daughter cells, meiosis produces 4.

• Daughter cells in mitosis are identical, in meiosis they are not.

• Meiosis has 2 divisions, mitosis only 1.

Gametes need to have half the number of chromosomes so that

when they combine during fertilisation they have the correct

number of chromosomes.

5 a day revisionB5 – cell division

Every nucleus in the body cell of an elephant contains 56 chromosomes. Read the statements about cell division and put a tick in the correct box for each statement.

@aegilopoides