Question

Question 1: Please consider gametes in animals.

Part a. Are gametes diploid or haploid, and what process (mitosis or meiosis) forms them? Sketch this process and include this labeled drawing in your submission. Remember that your drawing must not be an exact copy of a published figure, although you may use a published figure as a guide if you reference it.

Part b. What occurs when two gametes unite, and what is the ploidy of the resulting zygote? Through which process, mitosis or meiosis, does that cell develop into an adult? (2 pts.)

Question 2: Cancers generally involve mutations in the DNA that lead to improper control of cell cycle checkpoints. Draw and label the cell cycle and identify the checkpoints in the cell cycle. Remember that your drawing must not be an exact copy of a published figure, although you may use a published figure as a guide if you reference it. What are the two general types of loss of control (positive and negative) that can occur? Please explain, and provide a couple of examples of mutations in genes that can lead to the development of cancers.

please reference where you get your sources or information from

Answer 1

1.- a) Gametes are haploid and get formed by meiosis. Here is the sketch:

Telophase 2 v — X Duplicated chromosomes Aligned homologous chromosomes Aligned sister chromatides Single X * X X chromosomes - Centrosomes Prophase 1 Metaphase 1 Anaphase 1 Telophase 1 Prophase 2 Metaphase 2 Anaphase 2

b) The result of such gametes uniting is a zygote, a new organism that is starting to form. The ploidy is 2n. Mitosis is the process undergone by the zygote to develop into an adult

2.- There are three cell cycle checkpoints:

1.- In G1 stage, before entering S stage DNA is checked for damage so S stage can safely replicate healthy chromosomes

2.- In G2 stage, before entering M stage a chromosome check ensures that every chromosome was correctly replicated

3.- In M stage, during mitosis the cell check if every sister chromatide is attached correctly to the spindles

Here are located such checkpoint in the diagram.