1. B3 Revision Posters

3. B3a – Molecules of Life DNA Fingerprinting
Controls movement in & out of cell
Chemical reactions take place here – e.g. enzymes
Site of respiration (provides energy)
Site of Protein Synthesis
DNA Fingerprinting
Comparing samples of DNA to help identify samples

4. B3b - Diffusion Lungs: Leaves: Placenta: Intestines: FOR EXAMPLE:
The movement of a substance from a region of high concentration to a region of low concentration
FOR EXAMPLE:
Lungs:
Leaves:
Placenta:
Intestines:
To INCREASE the rate of diffusion – have a LARGE surface area and GOOD blood supply

5. B3c - Keep it Moving The Heart 4 chambers – ventricles - atrium
Plasma – yellow-ish fluid, carries glucose and CO2
Red Blood Cells – carry the oxygen
Platelets – clot the blood
White Blood Cells – fight off infection
The Heart
4 chambers – ventricles - atrium
Too much saturated fat and cholesterol – fatty deposits in blood vessels – coronary heart disease

6. B3d – Divide & Rule MITOSIS MEIOSIS To make gametes (egg and sperm)
A diploid cell produces two diploid cells
For growth, repair and replacement
MEIOSIS
A diploid cell produces four haploid cells
To make gametes (egg and sperm)
FERTILISATION
When sperm joins with egg

7. B3e – Growing up
A gestation period is the time spend developing in the womb in most animals.
Growth involves (a) Cell Division – by MITOSIS (producing identical cells) and (b) Cell Differentiation.
Cell differentiation involves producing different types of cells from undifferentiated cells called STEM CELLS

8. B3f – Controlling plant growth
Plant hormones (also known as PLANT GROWTH REGULATORS or AUXINS) are chemicals that control
growth of ROOTS and SHOOTS
Leaves are positively phototropic, towards light
Leaves are negatively geotrophic, away from gravity
AUXINS are hormones which collect on the dark side of a shoot causing the cells to lengthen
Roots are negatively phototropic, away from light
Roots are positively geototropic, towards gravity

9. B3g – New genes for old
1 – select the characteristic you want to improve – larger eggs
2 – cross breed the best hen with the best cockerel
3 –select the offspring which produce the largest eggs and mate that with your best cockerel
4. and repeat this over several generations
GENETIC ENGINEERING
Is when scientists transfer one gene from one living organism to another.
The order of triplets in a gene determines the sequence
of amino acids.
The amino acids join together to form a protein molecule.
If genes produce incorrect proteins, cells may not function properly. This is the cause of many inherited diseases.

10. B3h – More of the same ADVANTAGES OF CLONING DISADVANTAGES OF CLONING
Why clone animals? Animals or plants with special qualities could be mass produced to help in the manufacture of important drugs.
DISADVANTAGES OF CLONING
About 98% of cloning efforts fail.
Usually a cloned embryo dies before birth but sometimes afterwards too.
Stem cells have the ability to differentiate into different sorts of cells – muscle, liver, bone, etc
Cells lose this ability as the human gets older