1. Functions and Pictures…
Meiosis Vocabulary
Functions and Pictures…

2. What is DNA?
DeoxyriboNucleic Acid
the genetic material that carries information about an organism and is passed from parent to offspring

3. What are Chromosomes?
Rod-shaped cellular structures made of condensed chromatin; contain DNA that carries the genetic information which controls inherited characteristics such as eye color and blood type
A chromosome pair looks like an X
You have 23 PAIRS(2n-diploid) in every cell
(one from dad / one from mom)
Except for sperm or egg cells which have only 23 (no pairs)

4. What is Asexual Reproduction?
The reproductive process that involves only one parent and produces offspring that are identical to the parent

5. What is Sexual Reproduction?
The reproductive process that involves two parents who combine their genetic material to produce a new organism, which differs from both parent

6. What is Meiosis?
Produces gametes- sex cells (sperm and egg) by which the number of chromosomes is reduced by half

7. What are Homologous chromosomes?
Chromosomes from the female and male that contain the same genes (ex. #1 from male and #1 from female)

8. Random Chromosome Segregation
Are all the four haploid cells that result from meiosis the exact same? Why or why not?
What causes this randomness?
Random segregation of homologous chromosomes and sister chromatid
Crossing over

9. Independent Assortment

10. A sperm cell or an egg cell, haploid = n
What are Gametes?
A sperm cell or an egg cell, haploid = n

11. The joining of a sperm cell and an egg cell
What is Fertilization?
The joining of a sperm cell and an egg cell

12. First…the sperm has to get there!

13. What is a Zygote?
A fertilized egg, produced by the joining of a sperm and an egg
This is right after fertilization happening

14. Mitosis vs. Meiosis

15. What happens in Reproduction
What happens in Reproduction? DNA is passed from parent to offspring in two possible ways…
Sexual Reproduction
2 parents
Produces a combination of chromosomes that is different from the parent
Creates genetic diversity
Asexual Reproduction
1 parent
Offspring have same chromosomes and is identical to the parent

16. What are the benefits? Sexual Reproduction Creates Genetic Diversity
Children are different from the parents
If one dies from a disease, others MAY be able to survive it
Asexual Reproduction
It is Fast…
Can produce lots of offspring (kids) really fast! (20 minutes)
Only need one “parent”

17. What are the drawbacks? Sexual Reproduction You need two “parents”
Can be slow
Elephants are pregnant for 2 years!
Asexual Reproduction
The offspring (kids) are the same as the “parents”
If one can die from a disease, then all can die from the same disease…
All may have illness

18. What happens in Sexual Reproduction?
Produces gametes (sex cells)
Female (eggs)
Large cells
Don’t move
Male (sperm)
Smaller cells
Flagella: used to move
cell toward egg cell
Fertilization (joining of egg & sperm)
Zygote (fertilized egg)
New living organism with genetic variation
Advantage: creates offspring with genetic diversity

19. How many chromosomes does a human cell have?
46 or 23 pairs

20. What happens in meiosis?46
Meiosis is the process when chromosome pairs separate to form four new sex cells with half the number of chromosomes
Parent cell
(copies DNA)
Mitosis
(cell divides)
Meiosis:
cells divide
again
(sperm or egg cells) 92 46 46 23 23 23 23

21. What happens when sex cells combine?
When sex cells (gametes) combine to produce offspring, each sex cell will contribute to the offspring half (23) the normal number of chromosomes (46)
sperm egg 23 23 46

22. Closure Questions
Explain the difference between asexual and sexual reproduction.
What is the advantage of sexual reproduction?
What are the two types of gametes made in sexual reproduction?
4. How many chromosomes do human cells have?
5. At the end of meiosis how many cells are made?
6. At the end of meiosis, the new cells have how many chromosomes compared to the original parent cell?
7. When sex cells combine to produce offspring, each sex cell will contribute how many number of chromosomes?