1. Meiosis

2. Haploid, diploid Monoploid, biploid Monosomic, disomic Asexual, sexual
Gametes are ____, meaning that they carry one of each type of chromosome, while zygotes formed by fertilization are ______ containing two of each type of chromosome.
Haploid, diploid
Monoploid, biploid
Monosomic, disomic
Asexual, sexual 8

3. If an organism contains 20 chromosomes in each body (somatic) cell, then its gametes each contain __ chromosomes. 10 20 5 15 1

4. Which figure shows mitosis?
The figure on the left
The figure on the right
Neither
both 9

5. Meiosis, mitosis Mitosis, meiosis 9
_________ is used to produce new cells for growth and repair or for generation of clones of an organism during asexual reproduction. _______ is used to generate gametes for use in sexual reproduction.
Meiosis, mitosis
Mitosis, meiosis 9

6. II. What is meiosis?
Meiosis is a process in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid (2n) cell.
This will form 4 genetically different sex cells (gametes) that are haploid (n).
This means that it increases the differences between people’s DNA so that every person is genetically different.

7. II. What is meiosis? 23 23 23

8. III. Why does meiosis happen?
Meiosis happens so that sperm and egg cells can be produced so that sexual reproduction can occur.
Sexual reproduction is when two organisms combine their genetic information to produce genetically different offspring (babies).

10. Karyotype
Picture that shows all the chromosomes in a body cell= of an organism = 23 pairs of homologous chromosomes
used to diagnose
chromosomal disorders
(ex: Trisomy 21-Down Syndrome)

11. VI. What Happens During Meiosis?
Before meiosis, our sex cells go through interphase, where the DNA replicates and the cell grows.
DNA replication only occurs once in meiosis, but there are two divisions!!! (Meiosis I and Meiosis II)

12. VI. What happens during meiosis?
Meiosis I:
There are four parts of Meiosis I;
Prophase I, Metaphase I, Anaphase I and Telophase I.

13. VI. What happens during meiosis?

14. VI. What happens during meiosis?
The most important part of Meiosis I is Prophase I. During Prophase crossing over occurs.
Crossing over is when parts of a chromosome exchange with another chromosome. This occurs within each homologous pair of chromosomes. This is important because it increases genetic variation.

16. Independent Assortment
Independent Assortment occurs during metaphase I.
Creates genetic variation between gametes
Homologous pairs of chromosomes line up in the middle of the cell in a random order each time.

17. VI. What happens during meiosis?
Meiosis II:
There are four parts of Meiosis II;
Prophase II, Metaphase II, Anaphase II and Telophase II.

18. VI. What happens during meiosis?
At the end of Meiosis II, cytokinesis occurs.
Meiosis II resembles Mitosis.
The end result of the entire process of Meiosis (all 8 steps) is four haploid cells that are genetically different. .

19. Mitosis vs. Meiosis Mitosis Meiosis 1 division
daughter cells genetically identical to parent cell
produces 2 cells
2n  2n
produces cells for growth & repair
Meiosis
2 divisions
daughter cells genetically different from parent
produces 4 cells
2n  1n
produces gametes

20. Non-disjunction- chromosomes do not separate properly during meiosis

21. Trisomy 21 : Down Syndrome
Delayed mental and social skills
Decreased muscle tone at birth
Asymmetrical or odd-shaped skull
Small skull
Small mouth with protruding tongue
Broad short hands
Increased risk of developing
Leukemia and Alzheimer’s later in life

23. Trisomy 18 : Edward’s Syndrome
Most children die in the first year of life, some have lived 10 years
Growth deficiency
Feeding difficulties
Breathing difficulties
Developmental delays
Mental Retardation
Overlapped, flexed fingers
Webbing of the second and third toes
Clubfeet
Structural heart defects at birth

24. Mitosis vs. Meiosis

25. Mitosis vs. Meiosis Mitosis Meiosis 1 division
daughter cells genetically identical to parent cell
produces 2 cells
2n  2n
produces cells for growth & repair
Meiosis
2 divisions
daughter cells genetically different from parent
produces 4 cells
2n  1n
produces gametes

27. Mitosis Asexual Reproduction Fusion Meiosis
Cell A has 4 chromosomes and Cell D has 2 chromosomes. What process created Cell D?
Mitosis
Asexual Reproduction
Fusion
Meiosis
Cell A
Cell B
Cell C
Cell D 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 10

28. Cell A is considered _______ while Cell D is considered ________.
Haploid; Diploid
Tetrad; Diploid
Diploid; Haploid
Homologous; Haploid
Cell A
Cell B
Cell C
Cell D 10 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

29. Which of the numbers below best represents a chromatid?1 2 3 4
Cell A
Cell B 1 2 3 4 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 10

30. Which of the numbers below best represents homologous chromosomes?1 2 3 4
Cell A
Cell B 1 2 3 4 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 10

31. How can we best describe the diagram below?
Two sister chromatids
Homologous chromosomes
One replicated chromosome
Haploid chromsomes 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 10

32. What process is best demonstrated by the diagram below?
Anaphase I
Segregation of alleles
Crossing over
Independent assortment 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 10

33. Which of the following leads to genetic variation during meiosis?
Crossing Over
DNA replication
Independent assortment
Mitotic spindle formation
All of the above (A, B, C, D)
A & B
A & D
A, B, & D
A & C 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 10

34. Which of the chromosomes below are homologous to chromosome number one?
A and B
B and C B C
B and D
Blonde hair
Brown hair
Blue Eyes A C D B
ONE 10

35. Model Meiosis with Pop Beads!!
Diploid =
4 chromosomes
(2 homolgous pairs)
Haploid =
2 chromosomes
Gametes should be genetically different due to crossing over and independent assortment.