1. Meiosis Say what?!? Only 5 Mondays until finals?!
Work with ALL of your teachers to get late work in!

2. Holding Hands When a man and a woman love each other very much…
And they are financially stable…
And they are in a committed relationship…
Only then will they get together and hold hands.
After holding hands for a long time…
The two people decide to combine chromosomes…
Combining their chromosomes will allow them to produce a new organism
Let’s call this organism a “baby”
But first, they run into two problems…

3. Healthy Baby = 46 chromosomes
Problem #1…
The man inherited 23 chromosomes from his mom and 23 chromosomes from his dad.
This woman inherited 23 chromosomes from her mom and 23 chromosomes from her dad .
Each of them have 46 individual chromosomes in their somatic cells.
If they combine their somatic cells, how many chromosomes would that give the baby?
Healthy Baby = 46 chromosomes
NOT 92 chromosomes
23 pairs of chromosomes

4. Problem #2…
Not Clones
Genetic diversity and variation is critical to the ongoing survival of our species.
Somatic cells make EXACT copies of their DNA during mitosis.
Babies are NOT clones of their parents
How do we ensure that our babies are unique from ourselves?
Also not clones
Unsure…

5. MEIOSIS! Somatic cells use MITOSIS to reproduce
GAMETES (sperm, eggs) use MEIOSIS to reproduce
Meiosis will…
#1: Divide the chromosomal count in half
#2: Recombine and independently assort chromosomes

6. Somatic Cells Reproduce using MITOSIS Somatic cells are BODY CELLS
Somatic cells are diploid.
“Di” is a root word that means “two”
Diploid = two copies of each chromosome.
Diploid = 2n
Total chroms. = 46 (2*23)
Reproduce using MITOSIS

7. Gamete Cells Gametes are sex cells, aka germ cells Gametes are haploid
Haploid cells have one copy of each chromosome
Haploid = n
“Hap” sounds a bit like “Half”…Haploid cells have half as many chromosomes as diploid cells
Total chroms. = 23
Reproduce using MEIOSIS

8. Two halves make a whole Gametes are haploid Two halves make a whole
Two haploid cells fuse to make one diploid cell
23 chromosomes from mom and 23 chromosomes from dad gives you 46 total chromosomes
TADA! Happy diploid cells!

9. How do gametes form? There are TWO nuclear divisions

10. Making Gametes Spermatogenesis Oogenesis Results in four sperm
Produces one egg
Produces 3 “polar bodies”
Cytoplasm divides unevenly
Egg provides cellular machinery
Ribosomes
Mitochondria

11. Asexual vs. Sexual Reproduction
Can reproduce faster
Don’t need to find a partner
All are identical
Disease can easily wipe out population
Sexual
Allows for variation
Allows for quicker adaptation to the environment
Population is more resilient

12. Source of Genetic Variation
Crossing over
Independent Assortment
Shuffles genetic material

13. Independent Work Genetic Vocabulary Worksheet
Study for a vocabulary quiz next class
Collect missing assignments
Work on missing assignments