Genetics & heredity



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tarix01.05.2023
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Genetics Heredity

GENETICS & HEREDITY

  • GENETICS - The study of the way animals & plants pass on to their offspring such as:
  • eye color, hair color, height, body build, blood types, intelligence, gender, etc.
  • HEREDITY - Characteristics that a child receives from both parents
  • CELL: Basic unit of all living matter (Adult = over 10 trillion cells)
  • NUCLEUS: Central point of cell / contains genetic coding for maintaining life systems and issuing commands for growth & reproduction
  • CYTOPLASM: Substance of a cell outside of the nucleus
  • CHROMOSOMES:
  • 46 in each Nucleus (23 pairs)
  • GENES: bands on chromosomes (thousands of genes)
  • DNA on genes (billions of DNA)

? ? ? ? ? ? ? ?

  • How many chromosomes are there in each cell?
  • 46 CHROMOSOMES or 23 PAIRS
  • How many chromosomes are in Reproductive (egg & sperm) or Germ cells?
  • 23 CHROMOSOMES
    • (combined = the 46 chromosomes)

CELL DIVISION

  • MITOSIS: Cell divides by copying the DNA - cell splits - new cell with normal number of chromosomes (Cell growth & repair)
  • MEIOSIS: Creates 1/2 sets of chromosomes
    • Women = 23 Men = 23 Combined = 46
  • Female Sex Cells XX (Ovum or Egg)
  • Male Sex Cells XY (Sperm)
  • Baby Girl = XX Baby Boy = XY
    • Conception is the union of an OVUM and the SPERM
  • Gender is determined by the father!
    • Someone should have told King Henry VIII!
  • DOMINATE Gene: More powerful - trait seen in person
  • RECESSIVE Gene: Weaker and hides in the background. Trait can only determine when two of them are present - may show up in future generations.
  • CARRIER: Has a recessive gene that is not visible
  • SEX-LINKED: Mother passes the recessive X to son
    • Color-blind male receives the trait from his mother.
    • The mother is usually not color-blind herself.
  • B = BROWN eyes (dominate) b = BLUE eyes (recessive)
  • BB = BROWN eyes
  • bb = BLUE eyes
  • Bb = BROWN eyes but carry the recessive BLUE eye gene

MULTIPLE BIRTHS

  • ZYGOT: the cell that is formed when a sperm fertilized an egg (ovum)
  • MONOZYGOT: Identical Twins 1 Egg + 1 Sperm
    • Fertilized ovum splits into 2 identical cells - Always the same gender
  • DIZYGOT: Fraternal Twins 2 Eggs + different Sperm
  • MULTIPLE BIRTHS: More than 2
    • May be identical, fraternal or both - May be different or the same gender
  • CONJOINED (Siamese) TWINS: Ovum splits apart, but the separation is not completed. Babies are joined at some part of their bodies.

What 4 FACTORS may contribute to Multiple Births?

  • 1) History in the family
  • 2) Increased hormones naturally
  • 3) Fertility Drugs
        • More than 1 egg released
  • 4) Age 32-36
  • Likelihood of multiple pregnancies in the United States
    • Twins: Blacks- 1 in 73 Whites 1 in 93
    • Triplets: 1 in 10,000
    • Quadruples: 1 in 620,000
  • Sex - Linked or X - Linked Defect: When an X-gene from the mother is faulty. There is a 50/50 chance of the child inheriting the disorder.
  • Syndrome: When a group of signs and symptoms occur together and characterize a particular problem.
  • Congenital Malformation: A condition that is present at birth.
  • Multi-factorial Defects: Interaction of genes with other genes OR with environmental factors.
  • Chromosomal Error: The fertilized egg cell that contains chromosomes in an abnormal number, structure or arrangement.

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