Chromosomes and Cell Division Essay Assignments

Chromosomes and Cell Division Essay Assignments

Chapter 6

Chromosomes and Cell Division

Learning Objectives

• Identify different types of cell division and their purpose(s)

-Mitosis-replaces worn-out old cells with fresh new duplicates.

-Meiosis- generates sperm and eggs and a great deal of variation.

• Explain the process by which prokaryotic cells divide

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-Binary Fission

• Describe the major phases of the cell cycle

– Interphase: In Preparation for Mitosis, the Chromosomes Replicate

-Prophase- following replication, the sister chromatids condense. The spindle forms and the nuclear envelope breaks down. Chromosomes and Cell Division Essay Assignments.

-Metaphase- Metaphase: the chromatids congregate at the cell center. After condensing, the     pairs of sister chromatids seem to move aimlessly around the cell, but eventually they line up at                 the cell’s center.

– Anaphase: the chromatids separate and move in opposite directions

-Telophase: new nuclear membranes form around the two complete chromosome sets.

(Followed by cytokinesis).

• Describe the process of DNA replication

, and enzymes link the nucleotides of the new strand together. Unwinding and separation. Replication begins at a specific site, called the origin of replication, where the coiled,  Chromosomes and Cell Division Essay Assignments                                                                                                                                                                                                                                                                                   double-stranded DNA molecule unwinds and separates into two strands, like a zipper unzipping. In prokaryotes, there is a single origin of replication, while eukaryotes have multiple origin sites on each chromosome. At the origin of replication, a complex of proteins binds to the DNA. One of the proteins, an enzyme called DNA helicase, unwinds the coiled DNA and separates the two complementary strands. The unwinding and separating of the two DNA strands creates what is called a replication fork.

Reconstruction and elongation. In the reconstruction and elongation process, each of the single strands becomes a double strand as the appropriate complementary base of a nucleotide pairs with the exposed base

• Explain how the cell cycle and cancer are related

Cancer is an example of cell division out of control. Chromosomes and Cell Division Essay Assignments.

• Define cancer -an unrestrained cell growth and division.
• Can damage adjacent tissues.

Some can metastasize.

Can cause serious health problems and is the second leading cause of death in the United States!

• Explain how cancer can be treated

-To treat cancer, the rapidly dividing cells must be removed surgically or killed, or their division at least slowed down. Currently, the killing and slowing down are done in two ways: by chemotherapy and by radiation.

• Explain the steps of meiosis

– Unlike mitosis, which has only one cell division, cells undergoing meiosis divide twice. In the first division, the homologues separate. In other words, for each of the 23 chromosome pairs, the maternal sister chromatid pairs and the paternal sister chromatid pairs separate into two new cells. In the second division, each of the two new cells divides again, so that each of the four daughter cells contains a single chromosome from the homologous pair. At the end of meiosis, there are four new cells, each of which has 23 strands of DNA—that is, 23 chromosomes Chromosomes and Cell Division Essay Assignments

• Compare and contrast meiosis in males versus females

-The female gamete is larger than the male gamete because it has more cytoplasm.

• Understand the differences in asexual and sexual reproduction

-Asexual reproduction involves only one individual.

• Explain the impact of having an abnormal number of chromosomes

-They can lead to chromosomal disorders such as Down syndrome. Chromosomes and Cell Division Essay Assignments.