B5 - Growth and Development

Question 1

Explain Mitosis with diagrams.

Answer 1

Question 2

Explain Meiosis with diagrams.

Answer 2

Question 3

Explain Fertilisation with diagrams.

Answer 3

Question 4

Draw a diagram of a nucleotide.

(DNA is this x2, flipped).

Answer 4

Question 5

Draw a diagram of RNA.

Answer 5

Question 6

Draw a diagram of tRNA and mRNA in action.

Answer 6

Question 7

What are meristems?

Answer 7

Where plant growth occurs. They are sites where unspecialised cells are dividing by mitosis.

There are two types:

Lateral - Long - increased girth.

Aprical - Increased height/roots.

Question 8

What are Xylem tubes?

Answer 8

Tubes used to transport water and soluble mineral salts from the roots up to the stem and leaves.

They also replace water lost through transpiration and photosynthesis.

Question 9

What are Phloem tubes?

Answer 9

Tubes used to transport dissolved food to the whole plant for respiration (Up) or storage (Down).

Question 10

What is phototrophism?

Answer 10

Plants growing in the direction of light.

Question 11

Complete the sentence:

All cells contain the _______ _______ however many are __________ so that the cell only produces the proteins it needs to carry out its role.

Answer 11

All cells contain the same genes however many are not active (Switched off) so that the cell only produces the proteins it needs to carry out its role.

Question 12

What are the two types of meristem?

Answer 12

Question 13

Why do cuttings work?

Answer 13

In plants, some cells remain unspecialised and can develop into any plant cell.

These cells allow clones of plants with desirable features to be produced from cuttings.

Question 14

What causes unspecialised cells to specialise?

Answer 14

Hormonal conditions.

Question 15

Name examples of 2 plant tissues.

Answer 15

• Xylem.
• Phloem.

(The transport tubes)

Question 16

What are the two types of transport tubes?

Answer 16

Question 17

Explain the 3 stages of theraputic cloning for humans.

Answer 17

1. Nucleus is removed from an egg cell and replaced with one from the patient’s cells.
2. The egg is stimulated so that it starts to divide as if it were a zygote.
3. At the 8 cell stage, cells can be removed as they’re still unspecialised.

Question 18

Explain in 3 stages how you can clone plants.

Answer 18

1. Take a plant cutting.
2. Put cutting in a rooting hormone.
3. Roots start to form and the new plant develops.

Question 20

What is the name of the hormone responsible for causing cells to expand in size.

Answer 20

Auxin.

Question 21

Where is Auxin produced?

Answer 21

At the shoot tip.

Question 22

Explain why plants bend towards light.

Answer 22

Because Auxin near light is destroyed, and therefore moves to the side of the tip furthest away from the light source, causing this side to grow/lengthen faster and consequently, due to weight, the shoot bends towards the light.

Covering the tip in an opaque cap causes upward growth, irrelevant of the light.

Covering the tip in a transparent cap or with an opaque cap on the stem will cause the shoot to grow towards the light.