B3, C3 AND P3

1.How many sets of chromosomes are in

a.Diploid cells?

b.Haploid cells

2.Why is an ovum (egg cell) a large cell?

3.What is the acrosome in a sperm cell?

4. Mitosis produces two genetically identical diploid cells. What are the steps?

5.Meiosis produces 4 cells with different sets of chromosomes. What are the steps?

1a.2

1b.1

2.Needs to contain food reserves for developing embryo.

3.Acrosome bursts when in contact with ovum. This releases enzymes that digest egg cell's membrane allowing sperm nucleus to enter.

4.-Chromosome copies itself. Replicas separate from originals and move to opposite poles of cell. Celldivides. Daughter call has same number of chromosomes and genes as parent.

5.-Chromosome replicate itself. Move to opposite sides with copies.Cell divides for 1st time. Copies separate. 2nd division occurs. Four haploid cells are produced(not genetically identical).

1.Fill in the gaps: The ________ contains the genetic information. Respiration takes place inside _______________. This supplys _________________ for the cell. Most chemical reaction take place in the ________________.

2.What happens to enzyme molecules when temperature becomes too high?

3.Other than temperature what factor affects enzyme activity?

4.What are the 4 letters that code for the bases

1. nucleus, mitochondria, energy, cytoplasm

2. Molecules become denatured i.e irrevesible change shape so they can't fit inside active site.

3.pH

4.A, C ,G T

1.Define diffusion

2. Give two ways diffusion can be increased.

3.Fill in the gaps:

a.In animals, ___________enters the blood in the _________.It leaves the blood in the _____ tissues.

b. In the lungs, ____________ diffuses from the blood into the alveoli. ______________ diffuses from the alveoli into the blood.

4. How are alveoli well adapted for efficient gas exchange?

1.Diffusion is the movement of particles from a high concentration to a low concentration.

2.Greater surface area, greater difference between concentrations, shorter distance for particles to travel

3a.oygen, lungs, body

b.carbon dioxide, oxygen,blood

4.large surface area, thin cell walls, good supply of blood, they are moist

1What are the functions of the following components of blood?

a. Platelets b. Plasma c. White blood cells d.Red blood cells

2.Finish this word equation: oxygen + haemoglobin=

3.Write the function of the following and its adaptation:

a.Artery

b,Capillary

c.Vein

4.Write two important factors that must be considered before a patient is offered a heart transplant

1a.Produce blood clots b. Liquid that transports many substances. c. Protect against disease. d. Transport oxygen

2.Oxyhaemoglobin

3a.takes blood away from the heart at high pressure. Thick, elastic, muscular walls to withstand pressure.

b.Allow exchange of materials. Thin, permeable walls

c.Return blood to heart at low pressure. Valves to prevent backflow.

4.Major, expensive operation; long time waiting; patient must take immunosuppressants for the rest of their life