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23 terms

7th grade science - Mitosis

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Interphase
1st stage
Chromosomes are copies (# doubles)
Chromosomes appear as threadlike coils (chromatin) at the start, but each chromosome and its copy (sister chromosome) change to sister chromatids at end of this phase.
This is where DNA is replicated and its centrioles divide and new organelles are made.
Chromosomes are not visible during interphase!
Prophase
2nd stage
Mitosis begins (cell begins to divide)
Centrioles (or poles) appear and begin to move to opposite ends of cell
Spindle fibers form between the centrioles and attach to the centromeres. The nuclear membrane breaks apart. Chromosomes condense into rodlike structures.
Metaphase
3rd stage
Chromatids (or pairs of chromosomes) attach to the spindle fibers
The chromatids are lined up at the equator
Anaphase
4th stage
Chromatids (or pairs of chromosomes) separate and begin to move to opposite ends of the cell by the spindle fibers.
Telophase
5th state
Two new nuclei form
Chromosomes appear as chromatin (threads rather than rods)
The spindle disappears
Mitosis ends
Cytokinesis
6th stage
Cell membrane moves inward to create two daughter cells - each with its own nucleus with identical chromosomes
The cell cycle is complete
Which nitrogen base pairs up with Thymine to make up the rung of the DNA ladder
Adenine
Which nitrogen base pairs up with Cytosine to make up the rung of the DNA ladder
Guanine
How does your body grow as you get older?
Your cells divide, producing new cells
Mitosis begins in which cell organelle?
The nucleus
How does the number of chromosomes in a daughter cell compare to the number of chromosomes in a parent cell?
The daughter cell has the exact same number of chromosomes.
What is a chromosome?
A pair of DNA molecules
How is mitosis in plant cells different from mitosis in animal cells?
Plant cells have rigid cell walls and no centrioles
What are the four stages of mitosis?
Prophase, metaphase, anaphase, telophase
When do spindle fibers first become visible?
Prophase
What happens at the very end of mitosis?
The cell membrance splits
Where do duplicated chromosomes line up during metaphase?
In the center of the cell
During cytokinesis the _________ divides, distributing the organelles into each of the two new cells.
cytoplasm
What are the two molecule that make up the sides of the DNA ladder?
deoxyribose and phosphate
Why does a cell make a copy of its DNA before mitosis occurs?
DNA replication ensures that each daughter cell will have the genetic information it needs to carry out its activities
The regular sequence of growth and division that cells undergo is called the _______ __________
cell cycle
List three things that the cell is doing during interphase
cell grows
copy of its DNA
prepares to divide into two cells
What is the name of the process during which the cell copies its DNA
replication