Grant Sanders

We are starting our next unit called "Master and Commander" about DNA. This is a wiki assignment based on questions from the book. It is due on Monday.

Chapter 18 Patterns of Chromosome Inheritance. (20 Questions total)

pp.378-379 Chromosomes and the Cell Cycle
1. What is interphase and what are the three stages of interphase. Describe them in detail.
Interphase makes up most of the cell cycle, and it is when the organelles carry on their usual functions. The three stages of interphase are G1 phase which is growth, S phase which is growth and DNA replication, and last is G2 phase which is growth and final preperation for division.
2. Define Mitosis and Cytokinesis and Apoptosis.
Mitosis is duplication division which began when fertilized egg started dividing, ensuring that every cell has 46 chromosomes. Cytokinesis is the division of the cytoplasm. Apoptosis is programmed cell death that does away with any cell that are dividing when they shouldn’t be.
3. Insert a picture of the "cell cycle". Label it as :The cell cycle.
4. Insert a picture of a human chromosome "karyotype". Label it as karyotype and define karyotype.

pp. 380 Obtaining Fetal Chromosomes
1. Why would it be important to obtain fetal chromosomes?
If fetal chromosomes are obtained the child can be born with a short amount and be a down syndrome baby.
2. Describe the two ways to obtain fetal chromosomes. Chorionic Villi Sampling is when the doctor insert a long thin white tube into the vagina so that the ultra sound can be heard, and Amniocentesis is when a long needle is passed into the abdominal wall to withdraw a small amount of amniotic fluid, along with a few fetal cells.
3. Insert a picture of a drawing of aminiocentesis. Label it as amniocentesis.

pp.381-384 Mitosis
1. Describe the structure of a chromosome before duplication and after duplication.
Before duplication the chromosome is just single, but when the duplication is complete there are two chromosomes formed with the genes from the sister chromatids.
2. What does the cell use to pull the duplicated chromosomes apart?
The cell uses the centrioles to pull the chromosomes apart in Mitosis.
3. Describe the important parts of each phase of mitosis: Prophase, Metaphase, Anaphase, and Telophase.
Prophase- Cell prepares for division and the Nucleolus disappears, and chromosomes form.
Metaphase- Chromosomes are at the equator of the cell, and the spindle forms fully.
Anaphase- The centromeres divide, the sister chromatids separate causing the chromosomes to move to opposite sides of the cell.
Telophase- Daughter cells are forming, and chromosomes become indistinct chromatin again.
4. How is the cytoplasm divided between the daughter cells following mitosis?
The cytoplasm is divided through a process called Cytogenesis following mitosis.
5. When do human body cells go through mitosis normally?
The human body goes through mitosis when humans begin to grow.

6. What is a result of mitosis that is not in control? Give an example of what can occur. When mitosis is not in control, cancer can form in the cell.
7. Insert a picture that includes each of the phases of mitosis in real cell photographs. Make sure the phases are labeled.

Meiosis see p. 389
1. Define gamete, haploid chromosome number, diploid chromosome number. You may need to look these up. Gamete is the haploid sex cell for the egg or sperm, which join in fertilization to form a zygote, and haploid is half the set of diploid which contains 46 chromosomes, which leaves the haploid cells with 23 chromosomes.
2. Which cells of your body have a diploid number of chromosomes?
3. Which process makes cells with a diploid number of chromosomes?
Mitosis makes cells with a diploid number of chromosomes.
4. What is the purpose of meiosis? (see page 389)
Meiosis forms two haploid daughter cells.
5. Which cells of your body have a haploid number of chromosomes?
Sperm and the egg
6. Which process uses meiosis: sexual or asexual reproduction? Why?
Sexual reproduction, because it occurs when the reproductive organs produce the gametes.
7. Which takes less time: sexual or asexual reproduction? Why? Asexual reproduction takes less time because only one person is needed to complete the process.
8. Why is sexual reproduction more complicated then asexual reproduction? Sexual reproduction is more complicated because the chromosomes are duplicated and the process lasts much longer, and doctors do asexual reproduction very quickly.
9. How do the benefits of sexual reproduction outweigh the costs?
Sexual reproduction is much safer, and the offspring receive the parents chromosomes.