Mrs. Stewart
Honors Biology: Cell Growth and Division
1
1

11/01/11

BELL WORK
How do little elephants grow up to be BIG elephants?

BELL WORK
Are the cells of the adult elephant larger than those of the baby?


CLE 3210.4.2
Describe the relationships among genes, chromosomes, proteins, and hereditary traits.
11/01/11


Evaluate the reasons for asexual reproduction in organisms

Differentiate between the different stages of the cell cycle in terms of order of occurrence, and chromosome location
11/01/11


What do they look like?
They look like an “X” just before the cell divides and an
“I” after they divide.

How many do humans have?
• 46 (23 pairs)
•(23 from mom, 23 from dad)

There are two different types of cell division
Which type is performed depends on the kind of “daughter cells” that are desired

Mitosis = identical daughter cells with same amount of DNA

Meiosis = genetically different daughter cells with half the amount of DNA
11/01/11

 Every cell in the body EXCEPT reproductive cells
 Have all 46 chromosomes
 Sexual reproduction cells
(Example: sperm for males,
Ova/eggs for females)
 have half the amount DNA (23 chromosomes)
11/01/11


Somatic
OR

Gametes
11/01/11

Why do animals shed their skin?
11/01/11

11/01/11


Three reasons why cells reproduce by asexual reproduction:
1. Growth
2. Repair
3. Replacement
11/01/11

When the cells resources are under too great a strain from it’s size
• Cell Membrane not large enough to maintain needs coming in/going out
• DNA, used for protein synthesis, cant keep up with demands
• Organelles unable to keep up with demands (ie: waste removal)
11/01/11

11/01/11

Which phase does the cell spend the most time in?
Interphase
11/01/11

11/01/11

INTERPHASE ANAPHASE
PROPHASE TELOPHASE
METAPHASE CYTOKINESIS
11/01/11


Create a mnemonic device to help you remember –

We will vote on the best one tomorrow in class. Winner gets a two day “slack” pass.
11/01/11


Mitosis animation – mcgraw-hill

Cell cycle animation – cells alive website

Mitosis – sumanas (step by step w/ tutorial and quiz)
11/01/11

• Time between cell divisions
• 90% of a cell’s life
3 phases:
1.
G1: Growth and everyday activities
2.
S: DNA replication
3.
G2: preparation for Mitosis
(production of necessary proteins/organelles)
11/01/11

The process of dividing the nucleus to create two daughter cells, identical to the mother cell

• Creates two daughter cells that are identical to each other AND identical to the parent cell
• Creates diploid cells (two sets of chromosomes in each daughter cell)
• Allows organisms to grow
• Allows organisms to replace damaged/worn out cells
• P-M-A-T-C
11/01/11

• The DNA (chromatin) organizes into chromosomes
• The nuclear membrane disappears
• Centrosomes (centrioles) move to opposite ends of cell
11/01/11

Chromosomes attach to spindle fibers (by their centromeres), and line up at the center of the cell
Spindle Fibers – microtubules that help separate chromosomes during division
11/01/11

Chromosomes separate at the centromere, and the sister chromatids are pulled toward opposite ends of the cell.
11/01/11

Chromosomes disorganize and the nuclear membrane begins to reform.
11/01/11

The division of the cell cytoplasm, usually beginning during Telophase and finalizing the production of two new daughter cells.
Each new cell will have about ½ of the cytoplasm and organelles of the parent cell
.
11/01/11

ANIMAL
Plants
Cleavage furrow indentation of the cell membrane to form two separate cells
Cell plate
A cell wall is rigid and cannot flexibly move and pinch together to separate the newly formed cells. So, a cell plate forms between the two new cells. This cell plate will harden and become a cell wall for each.
11/01/11

11/01/11


I nterphase

P rophase

M etaphase

A naphase

T elophase

C ytokinesis
I P M A T C

I P LAY M USIC A T T HE C LUB
11/01/11

11/01/11

Interphase
Metaphase
Telophase
Prophase
Anaphase
Cytokinesis

Interphase
Metaphase
Telophase
Prophase
Anaphase
Cytokinesis

Reflection:
Y
Identify the following:
• Structure X
• Structure Y
Which stage of the cell cycle is shown?
11/01/11