Chromosomes carry genetic information Chromosomes are wound up DNA Diploid Every body cell has 2 sets of chromosomes n number of chromosomes Normal body cells have 2n 2 x n chromosomes ID: 774793
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Slide1
Chromosomes
“Colored Bodies”
Slide2Chromosomes carry genetic information
Chromosomes are wound up DNA
Slide3Diploid – Every body cell has 2 sets of chromosomes
n = number of chromosomes
Normal body cells have 2n (2 x n) chromosomes
Humans have 23 pairs = 46 chromosomes
2n =
Diploid
(double)
Slide4Cell cycle chromosome numbers
G1 – normal growing cell =S – DNA duplicates = G2 – cell grows =M – Mitosis, cell divides
2n
2n
4n
4n
4n
2n
Slide5Haploid - Sex Cells
Sexual reproduction Produces sperm and egg with only one set of chromosomes (1n)
1n =
haploid
(half)
Sperm = 1n Egg = 1n
Fertilized zygote = 2n
Slide6Sex determination
What causes Male and female?Female= XXMale= XYAutosome vs sex chromosomes
Slide7Karyotype
Sorting chromosomes photo to check for chromosome abnormalitiesWhat is the sex of this patient?Male = XY
Slide8Chromosomes are only visible during mitosis
Chromosomes must be photographed and sorted
Slide9Non – Disjunction
When chromosomes do not separate during meiosisThis forms an abnormal number of chromosomes in sex cellsTrisomy – 3Monosomy – 1
Slide10Down’s syndrome - Trisomy 21
extra 21st chromosomeCharacteristic facial flatteningDecreased mental ability
Slide11Edward’s Syndrome - Trisomy 18
Extra 18th chromosomeOrgan and body deformationEarly death.
Slide12Patua Syndrome or Trisomy 13
Extra chromosome 13Early Death. External symptoms are similar to Edward's. Cleft palate
Slide13Turner syndrome = XO female
Only one X chromosomeshort statureBroad / thicklack of secondary sex characteristics
Slide14Klinefelter Syndrome - XXY male
Male with Slight female characteristicslower IQ and mild mental handicap
Slide15Trisomy X - XXX female
lowered intelligence. lack of secondary sex characteristics.SterileCan be “normal”
Slide16Cri du Chat (cat cry) Syndrome
Deletion of a small arm of chromosome 5cat-like cry round face, heart disease mental handicap.
Slide17Wolf-Hirschhorn Syndrome
Deletion of a segment of chromosome 4's short arm. Affects scalp, nose, lips, palate
Slide1813 q -Syndrome
Deletion of the long arm of chromosome 13. Severe malformations of face