150 likes | 455 Vues
Karyotype Lab. The Role of DNA and Chromosomes. 1 . During cell division, DNA condenses and coils to form chromosomes . Each chromosome contains millions of nitrogen base pairs which serve as genes .
E N D
The Role of DNA and Chromosomes 1. During cell division, DNA condenses and coils to form chromosomes. • Each chromosome contains millions of nitrogen base pairs which serve as genes. • Each gene controls the production of a proteinin the organism which creates a trait(characteristic).
Chromosomes 4.The chromosomes in a diploid cell can be organized into Homologous pair = matched sets of chromosomes. Pairs are matched on the basis of: *Overall length of the chromosomes *Bandingpattern on the chromosomes *Location of the centromere
Human Chromosomes 5.The 46 chromosomes in a diploid human cell create 23 homologous pairs of chromosomes. *Pairs 1-22 are referred to asAUTOSOMES
6. Pair #23 = the Gender Determining Chromosomes (Sex Chromosomes) *may or may not match exactly. *referred to as the X sex chromosome and theY sex chromosome. *The Y sex chromosome carries the Sex Determining Gene (SRY gene) which is the master switch to the male gender.
7. If the 23rd pair of chromosomes matches exactly, then the combination is referred to as XX = Female 23rd pair of chromosomes match = female
8.If the 23rd pair of chromosomes does not match, then the combination is referred to as XY = Male . 23rd pair of chromosomes do not match = male
Karyotype 9. A Karyotype is a technique used to identify and evaluate the size, shape, and number of chromosomes in a sample of body cells. *Extra, missing, or abnormal positions of chromosome pieces can be determined. *The gender of the organism can also be determined.