Meiosis (Chromosome Reduction)
How many homologues does one receive from their mother and father? Total?
23, 23, 46
Humans have how many chromosomes? How many pairs?
46 chromosomes 23 pairs
What are ONE of the 23 pairs of chromosomes in humans that contain genes that will determine the sex of the child.?
The sex chromosomes
In each cell, females have what?
two X chromosomes
In each cell, males have what?
males have one X and one Y chromosome
N
n is the number of different chromosomes or number of homologue sets
Autosomes are chromosomes that are what?
not directly involved determining the sex (gender) of the child.
Each of the chromosomes contain what?
Different sets of genetic information
Haploid Cellls
cells with a ½ the number of chromosomes as the parent cells
In humans and many other organisms, the two sex chromosomes are referred to as what?
the X and Y chromosomes.
What does O indicate?
Absence of of a chromosome
Why do chromosomes come in pairs
Chromosomes come in pairs because the organism received one set will come from the MOTHER and the other set will come from the FATHER.
When a cell contains 2 homologues of each chromosome it is said to be what?
Diploid or 2n
Each chromosome pairs have similar what? And located where?
Each chromosome pairs have SIMILAR size and shape and SIMILAR genetic information with the genes are located in the same place on the chromosome
Homologue
Each individual chromosome of the set
Each chromosome contains different what?
Each of these chromosomes contains different set of genetic information (traits e.g. eye color, foot size etc.)
Each type of organism has a specific number of what?
Each type of organism has a specific number of chromosomes in their body cells or somatic cells.
N and 2n for humans
For humans the n number is 23 and the 2n number is 46
Sex cells are produced from what type of cells? And are reduced by what amount by what process to produce what?
Sex cells are produced from cells that are diploid (humans 46 chromosomes) and are reduced by ½ to using the process of MEIOSIS to produce Gametes (sex cells)
If a gamete that fertilizes the egg contains an Y chromosome, that egg will produce a what?
Male child
Diploid organisms use what to reduce their chromosome number to produce Haploid Gametes?
Meiosis
Is the structure and number of sex chromosomes the same in every organism?
No
Are all cells an organism produce diploid? Which are not?
No Gametes (egg and sperm cells)
Female eggs only contain what?
One X chromosome
Gametes (sex cells) have only what?
Only ½ The Chromosome Number As The Body (Somatic) Cells.
Organisms receive homologues from where?
Organisms received ONE HOMOLOGUE from the MOTHER and ONE HOMOLOGUE FROM the FATHER
Our somatic body cells each contain what?
Our somatic (body) cells each contain 2 COPIES of these 23 chromosomes for a total of 46 chromosomes (23 pairs)
Homologous chromosomes?
Similar size, shape, and location Pairs of similar Mother-Father chromosomes
Is the X chromosome larger or smaller than a Y chromosome? And it contains many more what?
The X chromosome is a much larger chromosome and contains many more genes than that the Y chromosome.
Fertilization restores what?
The diploid number
Zygote
When two Haploid gametes (egg + sperm) come together to form a fertile egg
When Haploid gametes fuse in fertilization, the Zygote will have a what?
a 2N chromosomes number like the parent
Haploid (N)
a cell with one set of chromosome
Diploid (2N)
a cell with two sets of chromosomes
Of the 23 pairs of chromosomes in human somatic cells, 22 are called what?
autosome
Because a male contains both X and Y chromosomes, it is there what that does what?
gametes (sperm) that determines the sex of the child.
Human gametes contain how many chromosomes?
contain 23 chromosomes -or -- one chromosome from each homologue pair.
If a gamete that fertilizes the egg contains an X chromosome, that egg will produce a what?
female child
