Week 1 - Fertilization

Front 1

Gamete

Back 1

a cell with a haploid number of chromosomes involved in reproduction (ovum or sperm)

Front 2

Fertilization

Back 2

the penetration of the ovum by the sperm results in the conception of the zygote

Front 3

Meiosis

Back 3

cell division in germ cells of the type that forms haploid gametes from diploid cells; there are two meiotic divisions, I and II, and the reduction to haploidy occurs in meiosis I

Front 4

What cells do gonads / gametes develop from? What determines the differentiation of gonads to ovaries or testes?

Back 4

Primordial germ cells. The SRY gene on the Y chromosome determines what type of gonads will be formed

Front 5

When does female meiosis begin?

Back 5

It begins when the mother herself was a fetus. The primary oocytes are all in prophase I by birth, and are arrested in this stage until puberty

Front 6

When does male meiosis begin?

Back 6

It begins at puberty and continues daily.

Front 7

What happens after female puberty? What happens during fertilization?

Back 7

The follicles mature one by one. As the follicle matures, meiosis I is completed, which results in the creation of the first polar body. During ovulation, the oocyte proceeds to metaphase II and is arrested there. If the ovum is fertilized, meiosis II goes to completion, creating the second polar body.

Front 8

How are sperm formed?

Back 8

Spermatagonia, which line the seminiferous tubules. These develop into primary spermatocytes. Primary spermatocytes undergo meiosis I to become secondary spermatocytes. Secondary spermatocytes undergo meiosis II to become spermatids. Spermatids eventually become sperm, with no additional division required

Front 9

Is cytokinesis even in female gamete development?

Back 9

No, most of the cytoplasm is used by one cell, while the other becomes a polar body.

Front 10

In what stage does crossing over occur in prophase I?

Back 10

The pachytene stage.

Front 11

Why are the four haploid cells produced from meiosis not identical? What is this called?

Back 11

Because of crossing over! "Patchwork inheritance"

Front 12

Which is worse - nondisjunction in Meiosis I or II? Why?

Back 12

Nondisjunction in meiosis I is worse, because all four gametes will have an abnormal number of chromosomes. In meiosis II only half of them will.

Front 13

What happens after the sperm fertilizes the egg?

Back 13

A chemical cascade occurs, preventing more sperm from fertilizing the egg. The membranes of the gametes stay intact, while the egg completes meiosis II. Mitosis begins and embryonic development starts

Front 14

What structures does the egg contribute to the new embryo?

Back 14

The cytoplasm, including organelles, nutrients, proteins, mRNAs.

Front 15

From which parent are mitochondria inherited? What are the consequences for mitochondrial disease inheritance?

Back 15

Mitochondria are inherited from the mother, meaning mitochondrial diseases are inherited from the mother