(5) Ch. 22 Overview
Terms
undefined, object
copy deck
- gametes
- In sexual reproduction, each parent produces cells, each of which contain a copy of 1/2 of his or her genetic material.
- spermatozoa (sperm)
- What is the name for male gametes?
- ova (ovum)(egg)
- What is the name for female gametes?
- 1/2
- Gametes have ____ the number of chromosomes that most cells have.
- Diploid
-
they contain 2 sets of 23 chromosomes (2n)
most of the cells are described as this - Haploid
-
this is what gametes are
contains a single set of 23 chromosomes (n). - fertilization
- As a result of mating, gametes from each parent may fuse together to produce a new cell, a phenomenon known as ____________.
- zygote
- This new cell, known as a _______, has the potential to develop into a completely new individual and is DIPLOID, having received half of it chromosomes from one parent and the other half from the other parent.
- gametogenesis
- A process in which the diploid germ cell undergo a series of cell divisions that ultimately reduces the number of chromosomes in each cell by half (2n -n).
-
23
22
1 - A single sperm or ovum contains __ chromosomes, __ autosomes, and ___ sex chromosome.
-
Sex chromosomes
Y
X - ___ _________ are the chromosomes that determine an individual's sex and are of two types - the _ or male chromosome and the _ or female chromosome.
- Autosomes
- ________ are the chromosomes other than the sex chromosomes.
- homologous
- As a reflection of this, the members of each pair of autosomes are said to be _________.
-
genes
alleles - The ______ in each pair, though similar in many important respects, are not necessarily identical because genes generally come in a variety of differ versions or _______.
- mitosis
- A process in which a set of diploid cells produce a colony or clone of daughter cells, each possessing an exact copy of all 46 of the individual chromosomes.
- meiosis
- a series of 2 cell divisions following only a single replication of DNA, thereby generating daughter cells with half the normal chromosome number. These will eventually become mature sperm or ova.
-
1
1
22 - In meiosis, an individual's chromosomes are soted and packaged in such a way that each of the final daughter cells receives ___ sex chromosome plus ___ chromosome from each of the ___ pairs of autosomes.
- gonads
- The ______ are considered the primary reproductive organs because they perform 2 functions that ultimately govern all reproductive activity: They produce ________, and they secrete sex hormones, a variety of steroids that promote gametogenesis, growth and maintanence of reproductive organs, development of secondary sex characteristics, and etc.
- androgens
- The testes secrete a class of sex hormones called _________.
-
estrogens
progesterone - The ovaries secrete __________ and ____________.
- adrenal cortex
- Sex hormones are not only secreted by the gonads, but also by the _______ _______.
- women
- In _______ the adrenal cortex is the primary source of androgens, which are responsible for promoting the sex drive in either sex.
- sperm
- The sex of the offspring is determined entirely by the genetic makeup of the ______, not the egg.
- genes
- Although a person's sex is normally determined by the _____ he or she inherits, the _____ themselves do NOT confer the full complement of male or female traits; they determine whether a fetus will develop ovaries or testis.
- sex determination
- The role of genes in deciding a person's sex is referred to as ___ __________.
- srY gene
- If there is a Y chromosome present, the ____ gene instructs the primative gonads to become testis; when the embryo inherits 2 X chromosomes the ____ gene is absent, so the primative gonads develop into ovaries.
-
Wolffian ducts (mesonephric ducts)
Mullerian ducts (paramesonophric ducts) - In the first few weeks of development, the embryo is said to be sexually indifferent and possesses rudimentary female and male reproductive systems, called __________ _____ and __________ _____.
-
testosterone
mullerian inhibiting substance (MIS) - Whether these characteristics are male or female depends on the presence or absence of 2 hormones normally secreted by the testes - ___________ and _________ _________ ________.
-
testosterone
MIS - _________ acts on the Wolffian ducts to promote the development of male reproductive organs, whereas ___ promotes the regression and eventual disappearance of the Mulleriam ducts, thereby preventing the development of female organs.