1. CELL GROWTH & REPRODUCTION

2. Cells cannot grow indefinitely ... they can mature then divide OR die
If the cell is going to divide, new cells need both
*cytoplasm (cytokinesis =division of cytoplasm)
*copies of nuclear material
In unicellular organism, reproduction=cell division
In multicellular organism, cell reproduction allows growth, replacement of cells that wear out (skin, blood, etc), NOT reproduction of whole organism

3. Mitosis
Mitosis- the process by which the nucleus of a cell divides, while maintaining the chromosome number.
Cytokinesis- the division of the cytoplasm of the cell after mitosis or meiosis.

5. Mitosis Mitosis is essential for growth & repair of an organism
It is the process that distributes the genetic material evenly between two daughter cells, so that each daughter cell is genetically identical to the parent cell.
It’s simply a way to make more of the same cell

6. In animals…
Somatic cells (cells of the body) are diploid. This means that each cell has two chromosomes of each type. They are in PAIRS.
Biologists use “2N” to symbolize diploid.
Gamete cells (egg, sperm) are haploid. This means that each cell has only one of each type of chromosome.
Biologists use “1N” to symbolize haploid.

7. MITOSIS
When somatic cells reproduce themselves the process is called MITOSIS.
Mitosis leads to the production of two “daughter cells”.
Each daughter cell has the same number of chromosomes as the parent cell. 2N
Parent Cell
Daughter Cells

8. Terminology: DNA= hereditary information, found in nucleus
Chromosomes= DNA wrapped around proteins, thick rod-like structures – (cells undergoing division)
Chromatin= DNA in form of long, thin, twisted threads “ball of yarn” – (non-dividing cells)

9. Replicated Chromosomes
Sister chromatids
Bound at center by centromere
Product of DNA replication
Chromatids are identical
How many chromatids are in a human cell that is going through Prophase & Metaphase???
centromere
chromatid

10. Homologues versus chromatids
Homologous chromosomes
One from Mom and One from Dad
Have different versions of the same genes
Sister chromatids
Bound at center by centromere
Product of DNA replication
Chromatids are identical

12. Chromosomes What’s a homologous pair?
Chromosomes that code for the same traits
They code for the same traits but each member of the pair has different information (different versions of the same genes)

14. Chromosomes (n)
n refers to the number of pairs (or the number of different types of chromosomes)
2n refers to the total number of chromosomes
In humans n = 23
In chimpanzees n = 24
In the king crab n = 104

16. Phases of Mitosis

17. Mitosis Interphase Prophase Metaphase Anaphase Telophase REPEAT
(This process produces two identical cells. The process then repeats for each of the new cells.)

18. Mitosis

19. The Cell Cycle
The repeating set of events that make up the life of a cell is known as the Cell cycle
The life cycle of a cell consists of interphase and cell division
Interphase occurs between cell divisions and includes
G1phase- cell grows to mature size
S phase- DNA is copied
G2 phase- cell prepares for cell division
Cell division consists of the M phase and Cytokinesis
M phase- (Mitosis) where nucleus divides
Cytokinesis- cytoplasm divides
Some cells exit the cell cycle after interphase and enter the G0 phase, these cells are fully developed and never divide again

21. Mitosis Interphase Prophase DNA replication
Centrioles replicate & become visible
Cell spends most of life carrying on 8 life processes (all but reproduction)
Prophase
Chromatin condenses become visible as sister chromatids (chromosomes)
Centrioles move toward the poles
Asters & Spindle form
Nuclear membrane disappears

22. Metaphase Anaphase Centrioles at opposite poles
Chromosomes line up at metaphase plate/equator
Spindles attach to each replicated chromosome at the centromere
Anaphase
Each of the sister chromatids separate at the centromere and move toward the opposite poles of the cell

23. Mitosis Telophase Cell divides  2 identical copies
New Interphase begins
And the process starts
all over in each
daughter cell
Telophase
Chromosomes decondense to chromatin
Formation of cleavage furrow (animal cell), or cell plate (plant cell)
spindle disappears
New nuclear membranes form
the cytoplasm divides in two, this is called cytokinesis

24. INTERPHASE - DNA replicates centrioles
The steps of Mitosis:
INTERPHASE - DNA replicates centrioles
replicate; cell spends most of life (carries on all life processes except reproduction)
PROPHASE - chromatin condenses into discrete chromosomes, centrioles move to poles, spindle forms; nuclear membrane disappears
METAPHASE – chromosomes (attached to centromere) are lined up at the equatorial plane (in the middle)
ANAPHASE - Sister chromatids separate at the centromere and migrate to opposite poles.
TELOPHASE - chromosomes decondense to chromatin, a cleavage furrow deepens in the middle of the cell, nuclear membranes form, spindle disappears. Finally, the cytoplasm divides in two, this is called cytokinesis. 2 form identical cells, Interphase begins.

25. Plant Mitosis vs. Animal Mitosis
CELL PLATE
NO CENTRIOLES
NO ASTERS
ANIMAL:
CLEAVAGE FURROW
CENTRIOLES
ASTERS
Animal & plant cell mitosis QT video clips

26. Reproduction
Asexual reproduction (1 parent gives rise to 1 or more clones)
Offspring are identical to the parents (Identical hereditary information)
Accomplished by mitosis and cytokinesis
Types of Asexual Reproduction
Binary fission, budding, spore formation, regeneration, vegetative reproduction/propagation
What are some examples of organisms that reproduce asexually?
Amoeba, bacteria, sponge

27. BACTERIA
Binary fission

28. PORIFERA (SPONGE)
Budding
(additional example= worms, yeast)

29. PLANARIA (FLATWORMS) Regeneration
(additional example= starfish, earthworm)

30. HYDRA
budding

31. AMOEBA
Binary fission

32. https://youtu.be/4JIytOL-Q18

33. TULIP vegetative propagation/reproduction
Small new buds sprout from old ones
(additional example= onion, lily)

34. STRAWBERRY vegetative propagation/reproduction
Uses “runners” (stem that grows sideways along ground and has buds)  new plant develops

35. POTATOES Vegetative propagation/reproduction
Tuber: enlarged underground stem with stored food
Eyes: tiny buds – send shoots upward – new plant

36. Geraniums / Poinsettias
“cuttings”  vegetative part of plant (stem, leaf, root) placed in moist sand/water to develop roots
Independent plant

37. Asexual reproduction advantages
Genetically identical
Cheaper
Quicker