1. Cell Growth and Division

2. Purpose of the cell cycle which includes the mitosis:
-To produce new and identical body cells with identical copies of DNA.
-Example: 1 skin cell will divide into 2 new and
identical skin cells
-All human body cells contain :
46 chromosomes or pieces of DNA
-23 from your mom
-23 from your dad

3. Mitosis produces body cells known as 2N or diploid cells.
Known as 2N or diploid because they contain 2 of every chromosome in each cell.
-one of each from your mother
-one of each from your dad

4. When a sperm with 23 chromosomes (1N)
fertilizes an
egg with 23 chromosomes (1N) it produces the first body cell, called the 2N
zygote
which has a total of 46 chromosomes.

5. 11 N egg is fertilized by a 1N sperm creating a 2N zygote or body cell.
Fertilization: 1N sperm unites with 1N egg creating a 2N zygote.

6. Twin Formation Identical twins:
-1 sperm and 1 egg unit forming one zygote.
-Zygote goes through mitosis creating two identical cells.
-The two identical cells split apart and both form into a fetus/baby.
-Babies must be of the same sex.

7. Fraternal twins:
-2 separate sperm fertilize 2 separate eggs forming two separate zygotes.
-Each zygote goes through mitosis creating 2 separate babies.
-The two babies may be the same sex or of opposite sex.

8. DNA -DNA is our genetic code -we inherit our DNA from our parents
-DNA has the code for making
all of our proteins which determine our traits.

9. Examples of human traits

10. DNA is located in the
nucleus
of every cell in a relaxed,
uncondensed form known
as chromatin.
2. DNA supercoils into chromatids the loops of tightly coiled DNA of a chromosome.

11. Chromosome:
-1 piece of DNA
Gene:
-1 segment of DNA on a chromosome that codes for a protein.
Allele:
-a specific form
of a gene

12. Allele: A specific form of a gene Each trait has 2 possible forms
Dominant form or allele:
The overpowering form of a gene
Represented by a capital letter
Recessive form or allele:
The weaker form of a gene
Represented by a lower case letter

13. 2 alleles combine to determine a trait.
1 allele/gene from the sperm

14. A physical trait that you can see Examples: Red hair, blue eyes, etc…
Phenotype:
A physical trait that you can see
Examples:
Red hair, blue eyes, etc…
Genotype:
The genetic make up /gene or allele combination
Three types of genotypes:
BB…..
Homozygous dominant
Bb……
Heterozygous
bb…….
Homozygous recessive

15. Law of Dominance
Anytime a dominant allele is present the dominant trait will be seen, it overpowers the recessive allele.

16. Black fur is dominant ………… B White fur is recessive………… b
Example:
Black fur is dominant ………… B
White fur is recessive………… b B b B B b b Bb BB b B bb

18. Let us review: Purpose of the cell cycle which includes the mitosis:
To produce new and identical body cells with identical copies of DNA.
-Example: 1 skin cell will divide into 2 new and
identical skin cells

19. One cell cycle is made up of:
Interphase
Gap 1
Synthesis phase
Gap 2
2. Mitosis
Prophase
Metaphase
Anaphase
Telophase
3. Cytokinesis

20. DNA Replicates
Cell divides in half

21. Interphase A. Occurs in three sub phases:
Gap 1: Cell grows and matures from a daughter cell into a parent cell.
S phase: DNA is replicates
Gap 2: New and needed organelles are formed

22. B. DNA is in a loosely coiled, uncondensed from of chromatin.
C. Two pairs of centrioles are present outside the nucleus.

23. Gap 0
Non dividing cells like nerve, brain and heart cells do not go through cell division. Therefore, they remain in Interphase for their entire existence. This is referred to as Gap 0.

24. Interphase

25. Prophase A. First phase of mitosis. B. Longest phase of mitosis.
C. Sets the stage for the rest of cell division.

26. Early prophase

27. 1. Nucleus and nucleolus breakdown into their components of proteins, lipids and carbs.
2. Chromatin supercoils into chromatids.
3. Centrioles pairs split apart and move to opposite sides of the cell/the poles.
4. Centrioles stretch spindle fibers/microtubules across the cell.

29. Late prophase

30. Metaphase A. Second phase of mitosis B. Shortest phase of mitosis.
1. Replicated chromosomes move to the
middle/equator of the cell.
- 2. Each chromosome attaches to its own
spindle fiber using the centromere.

32. Metaphase

33. Anaphase A. Third phase of mitosis
B. Replicated chromosomes split apart and move away to opposite poles.
ASTERS
Sister chromatids split apart from each other.
One single, unreplicated copy of the chromosome is at each pole.
Spindle fibers break down.

34. Asters End of spindle fibers at the pole
Push against cell membrane causing the cell to elongate or get wider.

35. Anaphase

36. Telophase A. Final phase of mitosis B. Exact opposite of prophase.
1. A nucleus reappears around each set of chromosomes at the poles
2. A nucleolus reappears in each nucleus.
- 3. Chromatid uncoils into
chromatin.

37. Telophase

38. Cytokinesis A. One cell divides into two new identical daughter cells.
Animal cells:
Cell membrane pinches together forming a cleavage furrow.
Two ends eventually join separating the one cell into two cells.

39. Plant cells: - The formation of a cell plate occurs
Plant cells: - The formation of a cell plate occurs. - The cell plate is a collection of sacks of cellulose that collect in the center of the cell. -The cell plate eventually matures into a cell wall.

40. Cytokinesis

41. End Result:
One mature parent cell divides into two new and genetically identical daughter cells.
Cell starts over…………………………hence the cell cycle.

43. MITOSIS

44. Cell division video