Definition of Meiosis
Meiosis is the process by which sex cells are formed from a body cell by reducing the number of chromosomes by half.
Two reasons for doing meiosis
Genetic diversity-think crossing over -To make sex cells that have a different combination of chromosomes than the body cells from which they were made.
7 Parts of the Flower
1. petal 2. pollen 3. filament 4. sepal 5. anther 6. stigma 7. Style
Difference between pollination and fertilization
in pollination the pollen meets with the stigma, and in fertilization the sperm cells meet with the egg cells.
Types of Pollination
1. Self Pollination and 2. Cross Pollination
Description of Self Pollination
In self pollination the pollen and the egg used are from the same flower/ plant
Description of Cross Pollination
In cross pollination the pollen and egg used are from different flowers/plants.
Explain which type of pollination is better
Cross pollination is better because 1. More genetic variation 2. Results in offspring that are more adapted to the environment.
Four methods of seed transfer
1.Carried by wind 2.Carried on the body of animals 3. Carried by water 4. animal waste
Description of Wind as seed transfer
Wind is used to spread the seeds by blowing them in multiple places.
the reproductive organs (glands) that produce sexual reproductive cells (gametes). Male gonad is the testis. The female gonad is the ovaries.
sexual reproductive cells having the haploid number of chromosomes that unites with a gamete of the opposite sex to produce a fertilized egg. Male gamete is sperm. Female gamete is eggs.
gamete cells that have a half set of chromosomes
body cells that have a full set of chromosomes
the set of information that controls a trait; a segment of DNA on a chromosome that codes for a specific trait.
the different forms of a gene
An allele whose trait always shows up in the organism when the allele is present.
An allele that is masked when a dominant allele is present.
Having two identical alleles for a trait
Having two different alleles for a trait
An organisms physical appearance, or visible trait
An organisms genetic makeup' or allele combination
A characteristic that an organism can pass on to its offspring through its genes.
a chart that shows all the possible combinations of alleles that can result from a genetic cross.
Four blood types
A, B, AB, O
Three alleles for blood type
IA, IB, i
Which alleles for blood type are dominant
IA and IB are co-dominant
Which alleles for blood type are recessive
Identify the six blood genotypes
IAIA, IBIB, IAIB, ii, IAi, IBi
What blood genotypes are A
What blood genotypes are B
What blood genotypes are AB
What blood genotypes are O
What is a "universal recipient"
Antigens (foreign invaders) are found in red blood cells. Antigens cause an organism to make antibodies. Antibodies are found in the blood plasma. Antibodies are molecules that attack foreign molecule (antigen). A person who has group AB blood and is therefore able to receive blood from any other group on the ABO system.
What is a "universal donor"
A person who has group O blood and is therefore able to serve as a donor to a person with any other blood type. Group O blood contains red blood cells that do not have any antigens (a molecule that causes an organism to make antibodies) so no immune response
Why is RH factor an important consideration in pregnancy
If the blood of anyone who is Rh - comes into contact with Rh+ blood, it will react to it as "foreign" and develop antibodies to the Rh+ cells that will kill them off. Once the antibodies to Rh+ cells have developed in the blood of someone who is Rh- they stay there. If a woman who is pregnant is Rh- and her baby's blood is Rh+ then if her blood comes onto contact with that of her baby's , she will develop antibodies to t the Rh+ blood. They won't affect her first pregnancy , but they will stay in her blood and if she becomes pregnant again, problems can arise. If a Rh- woman who has antibodies in her blood is pregnant with a Rh+ baby, it's possible for her antibodies to pass through to the baby and damage or even destroy the baby's red blood cells. This problem can be prevented by giving the woman a substance called Anti-D which destroys any Rh+ cells that may have got into her bloodstream so her blood won't produce anymore antibodies.
How dolly the sheep was cloned
1. Scientists removed the cell nucleus of an egg from a female sheep. The egg cell nucleus is haploid. 2. A mammary gland cell is removed from an adult female sheep. This cell and the egg cell are placed next to each other in a bath of chemicals. 3. A jolt of electricity causes the two cells to fuse. 4. The fused cell, complete with a diploid nucleus, begins dividing to form an embryo 5. The embryo is then inserted into into the uterus of a surrogate mother to complete its development. The resulting lamb is a clone of the sheep that donated the mammary gland cell.
State two methods for making a desired offspring
1. Cloning 2. Genetic Engineering