KEY CONCEPT Gametes have half the number of chromosomes that body cells have. - PowerPoint PPT Presentation

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KEY CONCEPT Gametes have half the number of chromosomes that body cells have.

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KEY CONCEPT Gametes have half the number of chromosomes that body cells have. Human body cells have 23 pairs of chromosomes and 46 total Each pair of chromosomes is ... – PowerPoint PPT presentation

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Title: KEY CONCEPT Gametes have half the number of chromosomes that body cells have.


1
KEY CONCEPT Gametes have half the number of
chromosomes that body cells have.
2
Mom
Dad
  • Human body cells have 23 pairs of chromosomes and
    46 total
  • Each pair of chromosomes is called Homologous
    pairs and have copies of the same genes
  • In each pair, one chromosome comes from each
    parent.

Homo same
3
  • You have two types of specialized cells
  • Somatic cells and
    Germ cells

Will become
4
  • Somatic cells- are body cells and make up most of
    your body tissues and organs.
  • Liver cells
  • Lung cells
  • Heart cells etc

Red blood cells
skin cells
bone cells intestinal cells
5
  • Somatic (body) cells are Diploid (2n) cells have
    two copies of every chromosome (23 from mom, 23
    from dad) for a total of 46 chromosomes

di 2
n
n
2n
6
  • Germ cells- are the cells in your reproductive
    organs
  • located in the ovaries and testes
  • Develop into gametes

7
  • Gametes are sex cells egg and sperm
  • Both have DNA that can be passed to offspring.

Egg
Sperm
8
  • Gametes are Haploid (n) cells have one copy of
    every chromosome.
  • Have 22 autosomes 1 sex chromosome 23
    chromosomes each

23
23
9
  • You have two types of specialized cells
  • Somatic cells Germ
    cells
  • Undergo meiosis
  • Cells in reproductive organs (ovaries/testies)
  • Become gametes (sperm/eggs)
  • Haploid
  • 23 chromosomes
  • Each are Unique
  • Undergo mitosis
  • body cells
  • Diploid
  • 46 chromosomes
  • Identical to parent cell

10
  • You have two types of chromosomes
  • Autosomes and Sex Chromosomes

11
  • Chromosome pairs 1-22 are called autosomes
  • Contain genes not directly related to your gender

12
  • Pair 23Sex chromosomes X and Y
  • determine gender
  • Control the development of sexual characteristics

XX female
XY male
XX
XY
13
Points to Ponder
  1. Where are germ cells located in the human body (2
    places)
  2. Do you think that Y chromosomes contain genes
    that are critical for an organisms survival?
    Explain.

14
Points to Ponder
  • Where are germ cells located in the human body (2
    places)
  • In the reproductive organs The ovaries in women
    and the testes in men.
  • 2. Do you think that Y chromosomes contain genes
    that are critical for an organisms survival?
    Explain.
  • No, a Y chromosome is not necessary for survival.
    Females do not have a Y chromosome, and they are
    able to survive.

15
  • Mitosis makes more diploid cells.
  • Produces genetically identical cells
  • Results in diploid cells (46 chromosomes each)
  • Takes place throughout an organisms lifetime
  • Involved in asexual reproduction
  • Somatic (body) Cells

16
DNA replicates
2 identical daughter cells
17
  • Meiosis makes haploid cells (23) from diploid
    germ cells (46).
  • produces gametes (sperm/eggs)
  • Produces genetically unique cells
  • Takes place only at certain times in an
    organisms life cycle
  • Involved in sexual reproduction
  • Germ cells

18
(diploid- 46)
Germ cell
4 haploid (23) unique daughter cells
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