1. SU: Vocabulary for cell division (Mitosis)
Define each word and then use the word in a complete sentence. Use pp
Mitosis
Cytokinesis
Interphase
Prophase
Metaphase
Anaphase
Telophase

2. Chapter 10 Section 2 Chapter 11 Section 4
Cell Division
Chapter 10 Section 2
Chapter 11 Section 4

3. What’s a gene?

4. Process of Making a Chromosome
Nucleosome
DNA
double
helix
Coils
Supercoils
Histones
Chromatin – DNA tightly coiled around proteins called Histones
Nucleosome – beadlike structure made of chromatin
Supercoils – nucleosomes packed together
Chromosome – tightly packed supercoils
Go to Section:

5. Chromosomes Function :
Made of DNA and Histones (protein)
Function :
- passes genetic info. from 1 generation to the next
Genes- located on chromosomes
- information about traits are located here
Traits – characteristics passed on by your parents

6. Chromosomes Numbers Humans = 46 chromosomes
Every organism has a specific # of chromosomes
Humans = 46 chromosomes
The # of chromosomes DOES NOT indicate the COMPLEXITY of an organism
Example – a goldfish has 124 chromosomes

7. Structure of Chromosomes
Each chromosome consists of:
* CHROMATIDS – identical parts
- called “sister chromatids”
* CENTROMERE – point at which each chromatid are attached to each other
chromatid
centromere

8. Structure of Chromosomes (cont.)
When the cell divides into 2 new cells – the “sister chromatids” separate and each one goes into a new cell
Each chromosome consists a pair of chromatids (2)
Humans = 46 chromosomes
= 92 chromatids

9. Chromosome Quiz
Name the 2 substances that make up chromosomes. (2 points)
How many chromosomes do humans have? (1 point)
What is the function of chromosomes? (1 point)
At what point are chromosomes visible in the nucleus? Why? (2 points)
Draw and label a chromosome. (4 points)

10. SU: Meiosis
Copy and Answer both questions. You may use your textbook, Section 11-4
What process produces gametes?
Mitosis
Meiosis
Fertilization
Chromosome replication
Haploid cells are cells that have
One chromosome of each type
Two chromosomes of each type
Pairs of homologous chromosomes
Two sets of chromosomes

11. Classroom Business Meiosis Quiz on Thursday Closed Book
Top scorer in each class gets +5
Have your completed Genetics Packet on Thursday! This is worth 50 points. If you do not have one, you will have to spend a lot of time copying the information.

12. Then each daughter cell prepares to
Cell Cycle
The series of events that cells go through as they grow and divide.
During this cycle the cell:
1. grows
2. prepares for division
3. divides to form 2 “daughter” (identical) cells
Then each daughter cell prepares to
begin the cycle again

13. Events of the Cell Cycle
includes
M phase
(Mitosis)
Interphase
is divided into
is divided into
G1 phase
S phase
Prophase
G2 phase
Metaphase
Telophase
Anaphase
Go to Section:

14. Interphase Longest phase of the cell cycle
Known as the “in-between” period of growth
Divided into 3 Phases: G1, S, and G2

15. G1 (Gap 1) Phase Cells do most of their growing during this phase
Cells increase in size
Manufacturing of new proteins & organelles

16. S (Synthesis) Phase DNA is replicated
Synthesis of DNA molecules & Histones occur

17. G2 (Gap 2) Phase Shortest of the phases
Organelles & molecules needed for cell division are produced
When this phase is complete, cells are ready for the M Phase (mitosis) and begin the process of cell division

18. Mitosis The 1st stage of cell division in eukaryotic cells
Depending on type of cell, this phase can last from a few minutes to several days.
Divided into 4 phases

19. Prophase The 1st & longest phase of Mitosis (50 – 60%of whole process)
A. Chromatin condense to form chromosomes
B. Centrioles separate and move to opposite sides of the nucleus
C. structures called SPINDLES begin to form – they help to separate chromosomes
D. Nucleolus disappears & nuclear envelope breaks down

20. Metaphase Often last only a few minutes
Chromosomes line up across the center of the cell
Each chromosome is connected to a spindle fiber at its centromere

21. Anaphase The spindle fibers pull apart the sister chromatids
Each chromatid becomes its own chromosome
and move towards the centrioles at opposite ends of the cell
The phase ends when the chromosomes reach the centrioles & stop moving

22. Telophase Chromosomes lose their distinct shapes
Nuclear envelope re-forms around each group of chromosomes
Spindle fibers disappear & a nucleolus becomes visible in each new nucleus
Mitosis is complete, but cell division is not

23. Cytokinesis Cytoplasm pinches in half
Each daughter cell has an identical set of chromosomes from the parent cell
Usually occurs at the same time as telophase
Cell division is not complete until cytokinesis is complete

24. Overview of Mitosis

25. SU: Identification of P.M.A.T.
Pick up the handout in the front of the room and match the picture to the step in mitosis.
These pictures are of cells in the root of an onion plant and the show one of the major phases in cell division. (Interphase, Prophase, Metaphase, Anaphase, or Telophase)

26. Today’s Assignment Objective: Create a study guide for meiosis.
Step 1: Take a clean piece of paper and fold it in half three times so that you have 8 squares.
Step 2: Turn to page
Step 3: Turn the paper horizontal and label each box left to right, top to bottom.
Prophase I
Metaphase I
Anaphase I
Telophase I Cytokinesis
Prophase II
Metaphase II
Anaphase II
Telophase II
Cytokinesis

29. SU: Meiosis (copy and answer)
What is the outcome of meiosis II
Four diploid cells
Two diploid cells
Two haploid cells
Four haploid cells
All cells that divide by meiosis are
Haploid cells
Called oogonia
Called Spermatogonia
Found in reproductive organs

30. Asexual Reproduction
This bud’s for you!
Hydra

33. Human Life Cycle

34. Homologous chromosomes
Karyotype

35. Cell Cycle Quiz

36. Label each picture with the correct phase of mitosisD C

37. Label each picture with the correct phase of mitosis or meiosis.D C

38. Homologous Chromosomes
Chromosomes that are in all sexually reproducing organisms
Occur in pairs
2 identical chromosomes = homologous chromosomes
same size and shape.
are different than all other chromosomes

39. Diploid Cells
Diploid Cells – contain both chromosomes of a homologous pair
Human cell = 23 pairs of homologous chromosomes
2 x 23 = 46
Human Chromosome # = 46

40. Haploid Cells Haploid Cells – contain only 1 chromosome
of a homologous pair
23 pairs of homologous chromosomes
1 x 23 = 23
**all egg & sperm cells = 23 chromosomes
ALSO KNOWN AS GAMETES
(egg)23 + (sperm) 23 = 46 chromosomes – human baby
Zygote – a new cell formed by a sperm & egg cell - has the normal number of chromosomes

41. MEIOSIS
The process of reducing the number of chromosomes per cell in half
Separating homologous chromosomes in a diploid cell
Making a diploid (46) into a haploid (23)

42. Process of Meiosis Involves 2 distinct divisions: Meiosis I Meiosis II
Begin with 1 diploid cell (46)
End with 4 haploid cells (23)

43. Meiosis I Looks like MITOSIS
But in Meiosis I, each chromosome is paired with it corresponding HOMOLOGOUS CHROMOSOME
This forms a TETRAD – 4 chromatids
( 2 from each chromosome)

44. Crossing Over
TETRAD
When homologous chromosomes pair up to make tetrads – they exchange portions of their chromatids
This is called CROSSING OVER
This results in the exchange of genes between the homologous chromosomes
This produces new combinations of genes

45. RESULTS OF MEIOSIS I
The chromosomes go through the same phases as Mitosis
Produces 2 new cells with 46 chromosomes each
BUT ………………..
1. the new “daughter” cells DO NOT have identical sets of chromosomes like the parent
2. are different from each
- because of crossing over & the separation of the homologous chromosomes

46. Meiosis II The 2 cells from Meiosis I enter this 2nd division
Unlike Meiosis I – the 2 cells …..
do not replicate the chromosomes
The cells go through each phase just like in Meiosis I

47. Results of Meiosis II 4 daughter cells that are haploid cells
Have only half of the # of chromosomes
All are different from each other
All are different from its parent cell

48. Gamete Formation The making of reproductive cells
MALE GAMETE = SPERM CELLS
Through meiosis – males produce 4 new sperm cells
FEMALE GAMETE = EGG CELLS (OVUM)
Through meiosis – females produce only 1 egg cell and 3 polar bodies (incomplete)