Download 11-7-12 Cellular Reproduction PPT FILL IN THE BLANK NOTES

Chromosomes & Cell Division Notes
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DNA (__________________): Stores info and tells the cells when to make ___________, and
what _____________________________.
_____________: unit of heredity, enough DNA to instruct for the construction of one protein.
Each DNA molecule is made up of thousands of genes.
Forms of DNA
1. _______________________genetic material in __________________ cell’s nucleus;
DNA in thin, non-coiled strands.
 DNA is in this form 99% of the time because cells are generally not dividing.
 DNA must be in this form in order to be copied (replicated).
2. ________________ - genetic material in _________________ cell’s nucleus; DNA in
coiled, rod-shaped form.
1. DNA must be in chromosome form in order for the cell to divide or reproduce.
Steps in Chromosome Formation
1.
2.
3.
4.
Chromatin  DNA in _____________________________________.
DNA __________________________.
DNA _____________________________.
______________________________  DNA in 2 joined identical ________________________.
Chromosomes
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_________________________- one of two duplicated, joined, ____________________parts of a
chromosome; found after DNA replication but before cell division.
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_______________________ – Point at which sister chromatids are attached
Draw picture of chromosome here
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Chromosome Number
Every species has a characteristic number of chromosomes which is different from other
species.
Example:
nematode worm
2 pairs
protozoan
300 pairs
human
23 pairs
Chromosomes __________________ in sexually reproducing organisms. One of the pair comes
from the ________________, the other comes from the ______________.
________________________________________: two members of a pair of chromosomes that
carry genes for the same traits, have the same size and shape. (ONE FROM MOM AND ONE
FROM DAD)
Human Chromosomes - Karyotype
Diploid vs. Haploid
 ______________________ total chromosome number in a ____________________, having
both chromosomes of a __________________________________________.
Diploid or 2N number in humans is 46 chromosomes or 23 homologous pairs.
 _________________________ chromosomes number in ________________________ only one
chromosome from each homologous pair.
Haploid or 1N number in human egg or sperm is 23, there are no homologous chromosomes.
Mitosis
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Mitosis - the division of the nucleus into two equal halves or sets of genetic information
Basically, _____________________________________
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Purpose: Each cell must _________________________________________________________
Every time the cell divides, it must pass on a copy of each chromosome.
Every cell in the body (except 1 kind that we will talk about later) _________________________.
Each cell will just ____________________________. (Ex. Heart cells will use heart DNA).
Therefore; all cells divide using _______________.
 Cells divide as part of growth or reproduction
“Growth” includes:
*__________________________________________________
*__________________________________________________
*__________________________________________________
Mitosis is part of the cell cycle
 The cell cycle is divided into 5 phases
1. ________________________
2. ________________________
3. ________________________
4. ________________________
5. ________________________
Interphase – period of normal cell activity and growth
Events of Interphase:
• The cell spends _________________________________in interphase.
• DNA is in _______________________________ form, spread throughout the nucleus.
• DNA __________________________, cell then contains two exact copies of each chromosome.
• Centrioles found just outside the nuclear membrane of the cell.
Stages:
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G1 (Gap 1) – __________________________________ ____________
• S (Synthesis) – ____________________________________________ _
• G2 (Gap 2) – _______________________________________________
Mitosis
Stage 1: Prophase
 3 major things happen
1. ________________________________ coil and become visible
2. The ____________________________________ breaks down and disappears
3. The _________________________ forms
*Animal cells have centrioles
Stage 2: Metaphase
 Chromosomes line up on the __________________ (__________________________________)
 __________________________attach to the ______________________ at the
_____________________________.
3rd stage: Anaphase
• _____________________________split _______________________
• __________________________ move ______________ from each other toward opposite poles
4th stage: Telophase
The opposite of __________________________ (the cell is ending its division and going back to normal).
 Chromosomes __________________________ to form chromatin
 Two new ____________________ form with new membranes
 The spindle _________________________
Stages of Mitosis
1.
2.
3.
4.
___ ___ ___ ___
Cytokinesis
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Division of the ______________
_______________________________ pinch inward forming a __________________________.
______________________________ divide from the inside towards the outside by forming a
____________________________ which becomes the ________________________.
Animal
Centrioles
______________________
Differences between Animal and Plant Cells
Plant
No centrioles
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