Connecting concepts #5 PDF

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Summary

Mandatory assignment ...

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For each type of cell division… Is the parent cell a diploid or a haploid cell? How many daughter cells are produced from the division of one parent cell? Are the daughter cells diploid or haploid? Does the parent cell divide once or twice? Where in the human body is this type of cell division taking place? What is the physical arrangement of the chromosomes before the 1st (or only) cell division? (Single line? Homologous pairs?) Does crossing over (or recombination) happen before the 1st (or only) division? Does independent assortment happen before the 1st (or only) division? Did you observe this type of cell division during Lab #4 (sea urchins)? When?

How will you remember which term (mitosis or meiosis) corresponds to which cell division process? Come up with an effective way and describe it here.

Mitosis

Meiosis

Haploid

diploid

2

4

haploid

haploid

once

twice

In the cells of the human body Single pairs Yes crossing over happens

Ovaries and testis

Doesn’t happen I observed mitosis in the sea urchins during fertilization of the eggs and sperm Only separates once, the end result is 2 cells

Homologous pairs Yes recombinatio n happens Yes in the 1st division I observed meiosis when we added the sperms and eggs together.

Separates 2 different times, the end result is 4 cells

2a. When testosterone is produced in the testes the hormone LH is stimulated. After LH is stimulated, FSH and testosterone both stimulate the production of sperm. b. When testosterone travels through the body’s circulatory system to the brain, the hypothalamus is inhibited. The hypothalamus releases GnRH hormones which then trigger the release of FSH and LH hormones. c. I think that the male reproductive hormone cycle is an example of a positive feedback cycle because the brain sends signals to release different hormones throughout the body to the testes with the goal of releasing sperm. In the male reproductive system, the ultimate goal is to release sperm for fertilization and the body’s way of doing that is to continue the cycle and to intensify it until the goal is reached. d. The two major roles that both estrogen and progesterone play in a female reproductive hormone cycle are to inhibit further secretion of FSH and LH and to promote the thickening of endometrium. e. I think that the female reproductive system is an example of negative feedback because the body releases hormones that trigger levels of ovulation and a change in hormone levels. Due to the surges of hormone levels during ovulation, the body’s way of dealing with all these changes in the female system is by mensuration....