1 / 6

Chromosomes

Chromosomes. During cell division, DNA must be neatly packed into structures called chromosomes Chromosomes- rod shaped structures made of DNA and proteins Contain our genes. Chromosome structure Consists of 2 identical halves Each half- chromatid Each chromatid represents one DNA molecule

kasen
Télécharger la présentation

Chromosomes

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chromosomes • During cell division, DNA must be neatly packed into structures called chromosomes • Chromosomes-rod shaped structures made of DNA and proteins • Contain our genes

  2. Chromosome structure • Consists of 2 identical halves • Each half- chromatid • Each chromatid represents one DNA molecule • Two chromatids of chromosome are attached at a point called a centromere • Chromatin- uncoiled DNA; present in between cell divisions

  3. Chromosome Numbers • Each species has a characteristic number of chromosomes in each cell ( ex: humans = 46; dogs = 78) • Sex Chromosomes- chromosomes that determine sex of organism • Human females have two X chromosomes • Males have one X and one Y chromosome

  4. Autosomes- all other chromosomes in an organism • Every cell has two copies of each autosome, one from each parent • The 2 copies of each autosome called homologous chromosomes • Homologous chromosomes are same size, shape and carry genes for same traits

  5. Chromosome numbers • Karyotype- photomicrograph of chromosomes in a normal dividing human cell

  6. Chromosome numbers • Diploid- cells having 2 sets of chromosomes • 2 autosomes for each homologous pair • 2 sex chromosomes • Abbreviated 2n • In humans, diploid or 2n number is 46- 22 pairs of homologous autosomes and 2 sex chromosomes • Haploid- cells containing only one set of chromosomes (ex. Sperm and egg) • Only one autosome of each homologous pair and only one sex chromosome • Abbreviated - n • n number = 23 in humans

More Related