Topic 4: 2 Cell Types Based on Chromosome Content Flashcards
What are the two cell types based on chromosome content?
Gametes and somatic cells
What type of cells do gametes include?
ova (eggs) and sperm
How many different chromosomes do gametes have? (2)
- 23 different xmes
- haploid (n)
What type of cells do somatic cells include?
- includes all cells of body except cells undergoing/resulting from meiosis
- muscle cell, nerve cell, etc.
How many chromosomes do somatic cells have? Thus, how many pairs? (3)
- 46 xmes
- dipoid (2n)
- 23 homologous pairs
Since somatic cells contain 23 homologous pairs, how do they get these chromosomes?
- 23 xmes from mom (ovum) PAIRED with 23 xmes (sperm) from dad
- thus diploid or 2n
What are homologous chromosomes?
- a chromosome pair (1 from each parent) that are identical in length, centromere (center) position, and have genes for the same trait (eg. eye colour) in the same location (locus)
What is a gene? (2)
- unit of heredity
- a region of DNA which contains information for synthesis of proteins
Even though somatic cells have 23 homologous pairs, what is different about them?
- They may have different versions (alleles) of that gene that codes for different versions of that trait
- ex. blue eyes xm from dad and brown eyes xm from mom
Chromosomes and chromosome pairs are ordered 1-23. What are those called that are numbered 1-22?
- autosomal chromosomes
- autosomes
What are autosomes?
- contain genes for somatic characteristics
- ex. hair and eye colour, height
What is the 23rd chromosome or pair called?
sex chromosome
What are sex chromosomes?
- contain genes that determine sex
Give the chromosomal pair for the following:
- female
-male
XX is female
XY is male
Which type of sex chromosome do males and females give to their offspring?
- males give X or Y
- females give X
