1. MEIOSIS 11-4 Making gametes…
Making gametes…

2. Remember from Chapter 1: CHARACTERISTICS OF LIVING THINGS ALL LIVING THINGS __________
Planaria animation: Family

3. ASEXUAL REPRODUCTION Bacteria reproduce using
Bacteria reproduce using
__________________________________
Budding & regeneration are used by plants and animals to reproduce asexually (mitosis)
Planaria animation:

4. MITOSIS
Produces cells that are __________ copies of parent cell

5. ADVANTAGES OF ASEXUAL REPRODUCTION
Can make offspring faster
Don’t need a partner

6. DISVANTAGES OF ASEXUAL REPRODUCTION
ALL ALIKE
Species CAN’T change and adapt
One disease can wipe out whole population

7. SEXUAL REPRODUCTION Combines genetic material
Family image from:
Combines genetic material
from 2 parents (sperm & egg)
so offspring are
genetically __________
from parents

8. ADVANTAGES OF SEXUAL REPRODUCTION
Allows for variation in population
Individuals can be different
Provides foundation for EVOLUTION
Allow species adapt to
changes in
their environment

9. + EGG SPERM  If egg and sperm had same number of
Image by Riedell
Image by Riedell
EGG +
SPERM 
If egg and sperm had same number of
chromosomes as other body cells . . .
baby would have too many chromosomes!

10. MEIOSIS is the way… to make cells with ½ the number of chromosomes
for sexual
reproduction

11. Click the image to play the video segment 11A.
Meiosis Overview
Click the image to play the video segment 11A.
Video 1

12. DIPLOID & HAPLOID HOMOLOGOUS CHROMOSOMES
Most cells have 2 copies of each chromosome = ______________
(one from mom; one from dad)
All BODY (___________) cells are diploid
HOMOLOGOUS CHROMOSOMES

13. DIPLOID & HAPLOID
Some cells have only one copy of each chromosome = _____________
All sperm and egg cells
are haploid

14. MITOSIS
Makes ___ cells genetically _________ to parent cell & to each other
Makes ___ cells
Makes __________
Used by organisms to: increase size of organism, repair injuries, replace worn out cells

15. MEIOSIS
Makes ____ cells genetically different from parent cell & from each other
Makes _____ cells
Makes ______________
Used for ____________

16. WHAT MAKES MEIOSIS DIFFERENT ?
SYNAPSIS & CROSSING OVER (PROPHASE I)
SEGREGATION &
INDEPENDENT ASSORTMENT (ANAPHASE I)
3. Skip INTERPHASE II (NO S)
CELL DIVIDES TWICE, BUT…
ONLY COPIES DNA ONCE

17. WHAT MAKES MEIOSIS DIFFERENT ?
Homologous chromosomes pair up during ____________= ______________
This group of FOUR (4)
chromatids is called a
_________________
Images modified from:

18. WHAT MAKES MEIOSIS DIFFERENT?
1. Exchange of DNA between homologous pairs = _____________ during PROPHASE I
Allows shuffling of genetic material

19. Click the image to play the video segment. 11E
Crossing Over
SEE CROSSING OVER ANIMATION
Click the image to play the video segment. 11E
Video 5

20. HOMOLOGOUS CHROMOSOMES
SAME SIZE
SAME SHAPE
CARRY GENES for the SAME TRAITS
BUT ______________!
(Don’t have to have the SAME CHOICES)
Image modified by Riedell

21. Allows for_________________ in different combinations
Image modified by Riedell
CROSSING OVER
Allows for_________________
in different combinations
After crossing over, chromatid arms are________________ anymore

22. WHAT MAKES MEIOSIS DIFFERENT ?
2.Separation during ANAPHASE I
__________________ &
_______________________
Separates gene choices and allows shuffling of genetic material

23. Click the image to play the video segment 11D.
Segregation of Chromosomes
Click the image to play the video segment 11D.
Video 4

24. SEGREGATION (Anaphase I)

25. SEGREGATION & CROSSING OVER together make even more combinations
See an animation

26. INDEPENDENT ASSORTMENT

27. INDEPENDENT ASSORTMENT at ANAPHASE I
Lots of different combinations are possible!
This is why you don’t look exactly like your brothers and sisters even
though you share the same parents!

29. WHAT MAKES MEIOSIS DIFFERENT ?
Crossing over Segregation Independent assortment
are ALL ways MEIOSIS results in =______________________________
So daughter cells are ______________
from parents and from each other

30. WHAT MAKES MEIOSIS DIFFERENT ?
3. Skip INTERPHASE II (No S)
CELL DIVIDES TWICE, BUT …
ONLY COPIES ITS DNA ONCE
MITOSIS: G1 S G2 P M A T C       
MEIOSIS:
( I ) G1 A T C S G2 P M        P M A T C
( II )    

31. Click the image to play the video segment 11B. & C
Animal Cell Meiosis, Part 1 & Part 2
Click the image to play the video segment 11B. & C

32. Figure Meiosis
Section 11-4
Meiosis I

33. Figure 11-17 Meiosis II Meiosis II Section 11-4 Prophase II
Metaphase II
Anaphase II
Telophase II
Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original.
The chromosomes line up in a similar way to the metaphase stage of mitosis.
The sister chromatids separate and move toward opposite ends of the cell.
Meiosis II results in four haploid (N) daughter cells.

34. MITOSIS vs MEIOSIS INTERPHASE INTERPHASE I
DNA is spread out as chromatin
Nuclear membrane/ nucleolus visible
DNA is copied during S phase
Makes stuff new cell needs in G2
_______________

35. MITOSIS vs MEIOSIS PROPHASE PROPHASE I
DNA scrunches into chromosomes Nuclear membrane/ nucleolus disappear Centrioles/spindle fibers appear
DNA scrunches into chromosomes
Nuclear membrane/
nucleolus disappear
Centrioles/ spindle fibers appear
_________________________

36. MITOSIS vs MEIOSIS METAPHASE METAPHASE I
Chromosomes line up in middle
Chromosomes line up in middle
______________________________

37. MITOSIS vs MEIOSIS ANAPHASE ANAPHASE I
APART:
APART:
Chromatids split
Chromatids stay together ________________________

38. MITOSIS vs MEIOSIS TELOPHASE TELOPHASE I
See TWO nuclei
Nuclear membrane/
nucleolus return
DNA spreads out as chromatin
Spindle/centrioles disappear
____________________

39. MITOSIS vs MEIOSIS CYTOKINESIS CYTOKINESIS I
Cytoplasm splits
into 2 cells
______________________

40. MITOSIS vs MEIOSIS INTERPHASE II
DNA is spread out as chromatin
Nuclear membrane/ nucleolus visible
DNA is copied during S phase
__________________ __________________ __________________

41. MITOSIS vs MEIOSIS PROPHASE PROPHASE II
DNA scrunches into chromosomes
Nuclear membrane/ nucleolus disappear
Centrioles/ spindle fibers appear
____________________

42. MITOSIS vs MEIOSIS METAPHASE METAPHASE II
Chromosomes line up in middle
______________________

43. MITOSIS vs MEIOSIS ANAPHASE ANAPHASE II
Chromatids split and move apart
__________________________

44. MITOSIS vs MEIOSIS TELOPHASE TELOPHASE II
Two nuclei
Nuclear membrane/ nucleolus returns
Centrioles/spindle fibers disappear
DNA spreads out as
chromatin
_______________________

45. MITOSIS vs MEIOSIS CYTOKINESIS CYTOKINESIS II
_____________________
Cytoplasm splits

46. Ways Meiosis is different?
Homologous pairs match up & trade DNA (SYNAPSIS & CROSSING OVER) in PROPHASE I
SEGREGATION
& INDEPENDENT ASSORTMENT in Anaphase I
create genetic recombination
Skipping INTERPHASE II-
(Dividing TWICE but copying DNA once)
produces 1n cells

47. MAKING SPERM & EGGS

48. ___________________= MAKING MATURE SPERM
Mature & grow flagella

49. Sperm provides DNA
All the starting nutrients,
organelles, molecule building blocks,
etc. have to come from the egg.

50. __________________ =
MAKING a MATURE EGG
Produces:
1 “good” egg
3 __________
CYTOPLASM DIVIDES UNEVENLY

51. Sperm donates mostly DNA
WHY MAKE ONLY ONE “GOOD” EGG?
Sperm donates mostly DNA
Most of the cell parts and nutrients needed for baby come from EGG!

52. POLAR BODIES DEGENERATE (DIE)
“Self digest”
Using
________________
= __________________
“cell suicide” for good of organism