Explain Mitosis with diagrams.
Explain Meiosis with diagrams.
Explain Fertilisation with diagrams.
Draw a diagram of a nucleotide.
(DNA is this x2, flipped).
Draw a diagram of RNA.
Draw a diagram of tRNA and mRNA in action.
What are meristems?
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.
What are Xylem tubes?
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.
What are Phloem tubes?
Tubes used to transport dissolved food to the whole plant for respiration (Up) or storage (Down).
What is phototrophism?
Plants growing in the direction of light.
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.
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.
What are the two types of meristem?
Why do cuttings work?
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.
What causes unspecialised cells to specialise?
Name examples of 2 plant tissues.
(The transport tubes)
What are the two types of transport tubes?
Explain the 3 stages of theraputic cloning for humans.
Nucleus is removed from an egg cell and replaced with one from the patient's cells.
- The egg is stimulated so that it starts to divide as if it were a zygote.
- At the 8 cell stage, cells can be removed as they're still unspecialised.
Explain in 3 stages how you can clone plants.
- Take a plant cutting.
- Put cutting in a rooting hormone.
Roots start to form and the new plant develops.
What is the name of the hormone responsible for causing cells to expand in size.
Where is Auxin produced?
At the shoot tip.
Explain why plants bend towards light.
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.