Download DNA Replication and Cell Division Notes

DNA Replication and Cell Division Notes
__________ ___________- series of events during which the cell grows, replicates its DNA
and divides to form two daughter cells, each of which begin the cycle again.
Chromosome Structure
chromatids- each contains the
DNA double helix inside
centromere
Terms to Know:
____________________: structures containing the DNA and they help pass this genetic info
from one generation to the next; they’re usually visible as an ___ _______________ during
_____ _______________
____________________: identical “sister” structures of the replicated chromosomes; each
chromatid contains a double helix _____ and chromatids _______________ from each other
during cell division
____________________: area that attaches each pair of chromatids _______________;
usually located near the _______________ of the chromatids
____________________: structure of DNA tightly coiled around histones proteins and appear
as a mass of threadlike material when cell is not dividing
____________________paired structures found in _____________ cells which help __________
chromosomes during __________
Different levels of DNA
condensation during Cell Cycle 2
1. DNA double helix
2. Chromatin (DNA around histones)
3. Condensed chromatin with
centromere visible
4. Chromatin with replicated DNA &
centromere
5. Chromosome “X” structure
Terms Continued…
_______________: (n) having a single set of chromosomes in the cell. ex. __________; humans
have 23 chromosomes in sex cells (egg and sperm cells)
_______________: (2n) having two sets of homologous chromosome in the cell. ex. Somatic
(__________) cells; humans have 23 pairs or 46 chromosomes in body cells
It’s all about the chromosomes!
– There are _____ chromosomes in the human body cells
– The __________of chromosomes remain constant during __________-division of the ______
Why Do Cells Divide?
Maintain workable _______________ __________ to ______________ - too big-can’t work!!
Replace damaged cells; _______________
Produce __________ __________
Increase in __________ and for __________
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Cell ____________________, making of more cells or making offspring, can be ____________
(offspring produced from _____ parent) or sexual (union of _____ parental cells)
Forms of Asexual Reproduction (one parent)
• __________ __________-cell division in bacteria whereby one parent splits into two cells
• __________-cell division in yeast (fungi) whereby daughter cell protrudes (buds) from parent
• _______________ Propagation- production of new plant structures without seed or spore
formation
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_______________ ability to recreate lost or damaged body parts, tissue or cells
Advantages of Asexual Reproduction
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__________production of offspring (bacteria)
___________________ of body parts
_______________ ____________________ are continually passed on
DNA Replication
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Before a cell can divide the DNA must _______________ (make a copy of itself)
Replication Steps…
1. DNA __________
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An _______________unzips the molecule
The enzymes break the hydrogen bonds that hold the nitrogen bases together.
2. Base Pairing
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_____________________ bases match with each DNA strand on the open helix
3. DNA Zips Up
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An enzyme zips the new molecules back up.
• _____ _______________ strands of DNA!
• Now that DNA has replicated, we are ready to begin __________
(__________ of the cell divides)
Phases of Mitosis- Name each phase shown in the diagrams below:
1.
3.
5.
2.
4.
Cytokinesis- division of the _______________
________ Cells: In plant cells, cytokinesis occurs by the formation of a ________ __________.
The cell plate is a new cell ________ assembled from the inside of the dividing cell outward.
___________ Cells:In animals, cytokinesis occurs by the formation of a ____________ furrow.
The cleavage furrow forms from the outside inward. Microfilaments (part of the cytoskeleton)
pull the cell _____________ from each end inward. When the cell membranes meet, the
cell splits in half.
Mitosis Review
1. Is the beginning parent cell diploid or haploid (2n or n)?
2. Are the daughter cells diploid or haploid (2n or n)?
3. How many daughter cells are produced?
4. Are the resulting daughter cells different from the parent cell?
5. Are the resulting daughter cells different from each other?
6. How many chromosomes are in a human body cell?
7. Are the chromosomes in human body cells identical?
8. What types of cells are produced by mitosis?
9. Why (when) does a cell go through mitosis?
10. How is cytokinesis different in plant and animal cells?