Chromosomes PowerPoint 2009-2010
Chromosomes PowerPoint 2009-2010
Chromosomes PowerPoint 2009-2010
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• Defined: Tightly coiled<br />
DNA<br />
• Forms during cell<br />
division<br />
– New chromosomes<br />
created for new cells<br />
• 2 Parts:<br />
– 1) Ch Chromatids: tid ttwo<br />
identical parts of a<br />
chromosome h<br />
–2) Centromere:<br />
Joins i chromatids h id<br />
together
• Defined: Picture of an<br />
individuals chromosomes<br />
– Identify sex & chromosome<br />
defects<br />
• Size of final pair identifies<br />
sex<br />
– Same size: XX = female<br />
– Different size: XY = male<br />
• Normal human will have<br />
Normal human will have<br />
46 chromosomes
Down Syndrome: What’s Wrong?<br />
• Writing notation:<br />
1 t – 1 l st : total<br />
chromosome #<br />
2nd – 2 S nd : Sex<br />
chromosomes<br />
3rd – 3 : extra or<br />
rd : extra or<br />
missing<br />
• Down Syndrome:<br />
• Down Syndrome:<br />
47, XY, +21
Turner’s Syndrome: What’s Wrong?<br />
• Write the notation<br />
for Turner’s T rner’s<br />
Syndrome.<br />
45, X, -23<br />
or<br />
445, XO, O -23<br />
23
Patau’s Syndrome: What’s Wrong?<br />
• Write the notation<br />
for Patau’s Pata ’s<br />
Syndrome.<br />
47, XY, +13
Klinefelter’s Syndrome: What’s Wrong?<br />
• Write the notation<br />
for Klinefelter’s<br />
Syndrome.<br />
47, XXY, +23
• Diploid Cells = Cells<br />
with the full set of<br />
chromosomes<br />
– Paired chromosomes<br />
• Half of our chromosomes<br />
come from each parent<br />
(23 from each parent)<br />
• Somatic (non-sex) cells<br />
are diploid<br />
• Created by mitosis<br />
• Ex: Skin, Muscle, Nerve,<br />
Blood Cells
What is the human diploid chromosome<br />
number?<br />
Remember Remember…Diploid Diploid = total number of chromosomes<br />
Answer = 46
What is the human somatic chromosome<br />
number?<br />
Remember…Somatic cells are non-sex cells…<br />
…Somatic cells are diploid…<br />
…Diploid cells have the full set of chromosomes<br />
Answer = 46
How many chromosomes are in brain cells?<br />
Remember…Brain cells are non-sex cells…<br />
Answer = 46<br />
…Somatic cells are non-sex cells…<br />
…Somatic cells are diploid…<br />
…Diploid cells have the full set of chromosomes
• Haploid Cells = Cells with ½ the<br />
total number of chromosomes<br />
• Gametes (sex cells) are the only<br />
haploid cells<br />
– Ex: Sperm, Egg, Pollen<br />
• Chromosome number is reduced<br />
by meiosis<br />
• How do humans get g 46<br />
chromosomes?<br />
Haploid sperm cell (23) + Haploid egg cell (23) = Diploid zygote (46)
What is the human haploid chromosome<br />
number?<br />
Remember Remember…Haploid Haploid = half number of chromosomes<br />
Answer = 23 chromosomes
What is the human gamete chromosome<br />
number?<br />
Remember…Gamete cells are sex cells…<br />
…Sex cells are haploid…<br />
…Haploid cells have ½ the set of chromosomes<br />
Answer = 23
How many chromosomes are in female egg<br />
cells?<br />
Remember…Egg cells are sex cells…<br />
Answer = 23<br />
…Sex cells are gametes…<br />
…Gamete cells are haploid…<br />
…Haploid cells have ½ the set of chromosomes
• What is the diploid chromosome number?<br />
42
• What is the haploid chromosome number?<br />
21
• How many chromosomes would be in somatic cells?<br />
42
• How many chromosomes would be in brain cells?<br />
42
• How many chromosomes would be in gamete cells?<br />
21
• How many chromosomes would be in egg cells?<br />
21
• How many chromosomes would be in muscle cells?<br />
42
• How many chromosomes would be in sperm cells?<br />
21
• Is this a male or female rat?<br />
male
Quick Review<br />
• Chromsomes are tightly coiled<br />
strands t d of f DNA<br />
• Diploid (somatic) cells contain the<br />
entire set of chromosomes<br />
• Haploid (gametes) cells contain only<br />
½ the total number of chromosomes
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