1. MEIOSIS 8-3
Making gametes…

2. ALL LIVING THINGS Reproduce
_______________
REPRODUCTION
No recombination of genetic material; ONLY ONE parent
Seen in bacteria and some animals
Planaria animation:

3. CELL DIVISION in PROKARYOTES
Bacteria
reproduce
using
__________________
DNA is copied
Cell splits into two
new cells

4. BINARY FISSION Makes ____ cells genetically identical Used to for
___________
reproduction
in bacteria

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. ALL LIVING THINGS Reproduce
____________
REPRODUCTION
Combines the
genetic material from
2 parents (sperm & egg)
Family image from:

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

9. + EGG SPERM  If egg and sperm had same number of
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 HAPLOID (1n) cells for sexual reproduction

11. DIPLOID & HAPLOID (one from mom; one from dad)
Some cells have 2 copies of each chromosome = _______________
(one from mom; one from dad)
All BODY cells are diploid
Image from:

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

13. MITOSIS
Makes 2 cells genetically identical to parent cell & to each other
Makes 2n cells
Makes body cells
Used to grow organisms, repair injuries, replace worn out cells

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

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

16. WHAT MAKES MEIOSIS DIFFERENT ?
Homologous chromosomes pair up during PROPHASE I = ______________________
Images modified from:

17. WHAT MAKES MEIOSIS DIFFERENT?
Exchange of DNA between homologous pairs = ________________________
during PROPHASE I
Produces daughter cells with different gene combinations

18. HOMOLOGOUS PAIR Same size Same shape
Carry genes for the same traits, but ….
THEY ARE NOT IDENTICAL
Can carry different gene choices
Image modified from:

20. WHAT MAKES MEIOSIS DIFFERENT ?
2. Mixing up of maternal and paternal chromosomes during ANAPHASE I = ________________________________

21. INDEPENDENT ASSORTMENT

22. INDEPENDENT ASSORTMENT at ANAPHASE I
Lots of different combinations are possible!
This is why you don’t look exactly like your brothers and sisters.

24. WHAT MAKES MEIOSIS DIFFERENT ?
____________________________
and
__________________________________
Produce daughter cells that are
___________ from the parent cells
= ________________________________

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

26. MITOSIS vs MEIOSIS INTERPHASE INTERPHASE I
DNA spread out as chromatin
Nuclear membrane/ nucleolus visible
DNA copied during S phase
Make stuff new cell needs G2
Same as MITOSIS

27. 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

28. MITOSIS vs MEIOSIS METAPHASE METAPHASE I
Chromosomes line up in middle
Chromosomes line up in middle

29. MITOSIS vs MEIOSIS ANAPHASE ANAPHASE I
APART:
APART:
Chromatids split
Chromatids stay together Homologous pairs split

30. MITOSIS vs MEIOSIS TELOPHASE TELOPHASE I
See TWO nuclei
Nuclear membrane/
nucleolus return
DNA spreads out as
chromatin
SAME AS MITOSIS

31. MITOSIS vs MEIOSIS CYTOKINESIS CYTOKINESIS I
Cytoplasm splits
into 2 cells
SAME AS
MITOSIS

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

33. MITOSIS vs MEIOSIS PROPHASE PROPHASE II
DNA scrunches into chromosomes
Nuclear membrane/ nucleolus disappear
Centrioles/ spindle fibers appear
SAME AS MITOSIS

34. MITOSIS vs MEIOSIS METAPHASE METAPHASE II
Chromosomes line up in middle
SAME AS MITOSIS

35. MITOSIS vs MEIOSIS ANAPHASE ANAPHASE II
Chromatids split and move apart
SAME AS MITOSIS

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

37. MITOSIS vs MEIOSIS CYTOKINESIS CYTOKINESIS II
SAME AS MITOSIS
Cytoplasm splits

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

39. WHAT CAN GO WRONG? One pair of chromosomes fails to separate
One daughter cell
gets one extra chromosome
is missing one chromosome

40. WHAT CAN GO WRONG?

41. MAKING SPERM & EGGS

42. PRODUCTION OF MATURE SPERM = __________________________
Mature & grow flagella

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

44. PRODUCTION OF A MATURE EGG= __________________________
Produces:
1 “good” egg
3 POLAR
BODIES
CYTOPLASM DIVIDES UNEVENLY

45. POLAR BODIES DEGENERATE (DIE)
“Self digest”
Using
________________
= __________________
“cell suicide”