mitosislongho

Chromosomes SCI Human Biology - 1 Assigned: 11/6 Due: 11/10 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 is the time in the cell cycle that the organelles carry on their usual functions. Also the cell gets ready do divide: it grows larger, the number of organelles doubles, and the amount of chromatin doubles as DNA synthesis occurs. The three stages are, the G1 stage is before the DNA synthesis, the S stage is includes DNA synthesis and the G2 stage occurs after DNA synthesis.

2. Define Mitosis and Cytokinesis and Apoptosis. Mitosis is a type of nuclear diviion Cytokinesis is devision of the cytoplasm Apoptosis is the process of programmed cell death to do away with cels that are dividing when they shouldn’t.

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. A karyotype is a picture of all the chromosomes in pairs pp. 380 Obtaining Fetal Chromosomes 1. Why would it be important to obtain fetal chromosomes? To see if the baby will have anything wrong with it 2. Describe the two ways to obtain fetal chromosomes. You can stick a long needle through the belly and suck up sone amniotic fluids. Or you can stick a suction thing up her vagina and suck out some cells from the chorion where the placenta will develop 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. The chromosomes become visible. After it divides, it has an identical twin 2. What does the cell use to pull the duplicated chromosomes apart? The centromeres 3. Describe the important parts of each phase of mitosis: Prophase, Metaphase, Anaphase, and Telophase. Prophase is when the cell begins to indicate it will divide. The centrosomes outside the nucleus have duplicated, and they begin moving away from one another towards opposite ends of the nucleus spindle fibers appear between the separating centrosomes. The nuclear envelops begin to fragment and the nucleolus a special region of the dna disappears as the chromosomes coil and become condensed. During the metaphase, the nuclear envelope is fragmented and the spindle occupies the region formly occupied by the nucleus. The chromosomes are now at the equator of the spindle. Anaphase is when the centomeres uniting the sister chromatids divide. Then the sister chromatids separate, becoming chromosomes that move toward opposite poles of the spidle. Seperation fo the sister chromatids ensures that each cell receives a copy of each type of chromosome. And thereby has a full complement of genes. 4. How is the cytoplasm divided between the daughter cells following mitosis? A slight indentation called a cleavage furrow passes around the circumference of the cell actin filaments form a contractile ring, and as the ring gets smaller and smaller the cleavage furrow pinches the cell in half. 5. When do human body cells go through mitosis normally? It happens when we grow or we need repairs done. 6. What is a result of mitosis that is not in control? Give an example of what can occur. A benign tumor or a cancerous tumor develops when the cell cycle control system is not functioning properly. A benign tumor is confined to a particular location such as nicks keliod. 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 sex cell like sperm or egg. haploid chromosome number is the number of chromosomes in an individual gamete. diploid chromosome number is that diploid ones have two sets of chromosomes, one from mom one from dad 2. Which cells of your body have a diploid number of chromosomes? Retroviruses that contain two copies of their RNA genome in each viral particle are also said to be diploid. Examples include human foamy virus, human T-lymphotropic virus, and HIV. also sperm and eggs 3. Which process makes cells with a diploid number of chromosomes? mitosis 4. What is the purpose of meiosis? (see page 389) it occurs only in the reproductive organs and in the gametes 5. Which cells of your body have a haploid number of chromosomes? all your other cells 6. Which process uses meiosis: sexual or asexual reproduction? Why?

7. Which takes less time: sexual or asexual reproduction? Why? 8. Why is sexual reproduction more complicated then asexual reproduction? 9. How do the benefits of sexual reproduction outweigh the costs?