Chapter 12 Flashcards
The life of a cell from the time it is first formed from a dividing parent cell until its own division into two cells is called the
Cell Cycle
All of a cells genetic information in DNA is called
Genome
DNA molecules are packaged into
Chromosomes
Eurkaryotic chromosomes that are a complex of DNA and the associated protien molecules are called
Chromatid
Are units that specify an organism’s inherited traits. Each single chromosome contains one very long, linear DNA molecule that carries several hundred to a few thousand
Genes
Each duplicated chromosome has two
Sister Chromatids
Sister Chromatids are initially attached all along their lenghts by adhesive protein complexes known as
Cohesions
Specialized region where the two sister chromatids are most closely attached “waist”
Centromere
Division of the nucleus
Mitosis
Division of the cytoplasm
Cytokinesis
What are the 2 phases of the cell cycle
Mitotioc and interphase
Mitotic phase includes what
Mitosis and cytokinesis-shortest part of the cell cycle
What is interphase
when cell growth occcurs and chromosomes are copied-90% of cell cycle is in this phase
Stages of interphase
G1-First gap
S-DNA synthesis
G2-Second gap
Subcellular region containing materials that function throughout the cell cycle to organize the cell’s microtubules
Centrosome
A radial array of short microtubules that extends from each centromere
Aster
Structure of proteins associated with specific sections of chromosomal DNA at the centromere where the spindle microtubules attach are called
Kinetochores
The imaginary plane midway between the spindles of the 2 poles where the centromeres of all duplicate chromosomes line up is called
Metaphase plate
What is cytokinesis in an animcal cell
Cleavage furrow-a shallow groove in the cell surface neat the metaphase plate
What is cytokinesis in a plant cell
No cleavage furrow-a cell plate forms which enlarges to form a cell wall between 2 daughter cells
How do prokaryotes reproduce?
Binary Fission “Origin of replication”
Binary Fission consists of
Single Bacterial chromosome consists of a circular DNA molecule and associated protein
Frequency of cell division varies with
Type of cell
What is G0 phase?
Non dividing state–i.e. nerve cells
What controls the cell cycle?
Driven by specific signaling molecules present in the cytoplasm
Cyclic operating set of molecules in the cell that both triggers and coordinates key events in the cell cycle is called
Cell cylce control system
There is a lot of cell cycle controls in cancer cells
- Cancer cells do not heed to normal signals that regulate the cell cycle
- Divide excessively and invade other tissues
- Do not stop dividing when growth factors are depleated
- Transformation converts a normal cell into a cancer cell
- May proliferate and form a tumor, a mass of abnormal cells
Benign tumor
If abnormal cells in lump remain at original site
What is a malignant tumor
abnormal cells becomes invasive enough to impair the functions of one or more organs
Details of maligant tumor
- Excessive proliferation
- May have unusual number of chromosomes
- Metabolism may be disabled
- May cease to function in any constructive pathway
- Changes on cell surface can cause cancer cells to lose attachements to neighboring cells and this all them to spead into nearby tissues-Metastasis
- May secrete signal molecules that cause blood vessels to grow toward tumor
Most cells are in nondividing phase G0 except cancer cells because
Cancer cells are actively dividing and often skip G0
Drugs that are toxic to actively dividing cells are admistered through circulatory system. These drugs interfere with specific steps in the cell cycle
Chemotherapudic
Drug taxol
freezes mitotoc spendle-stops actively dividing cells from proceeding past metaphase
Side effects to chemotherapy
Often due to drug’s effects on normal cells that divide often
- Nausea-effects on intestinal cells
- Loosing hair-effects on hait follicle cells
- Susceptible to infecction-effects on immune system cells
Cellular transformation always involves…
The alteration of genes that somehow influence the cell cycle control system
Most of the cell cycle is spent in?
Interphase
When a cell is not dividing, it is in what phase?
G0
When DNA replication occurs what stage of cell cycle is that?
S
A chromosome that has not replicated has how many chromatids?
Zero
A replicated chromosome has how many chromatids?
2
Division of the nucleus, producing 2 identical daughter cells is called?
Mitosis
How does reproduction of prokaryotes occur?
Binary Fission
Most body cells are in what phase?
G0
Correct order of mitosis
Prophase
Metaphase
Anaphase
Telophase
Which phase do the chromosomes meet at the middle of the nucleus?
Metaphase
Which phase do the chromatids seperate and become chromosomes?
Anaphase
During G1 how many chromatids per chromosome
Zero
During G2 how many chromatids per chromosome
2
How many chromatids per chromosome in the beginning of mitosis
2
Chromosomes condense and becomes visible in this phase
Prophase
Chromosomes line up in the middle of cell in this phase
Metaphase
Includes genes that determine an indiviuals sex
X and Y chromosomes
Gamtes have how many chromosomes in karotype
23
Ordering of human chromosomes images displaying each chromosomes of a single cell
Karotype
In a cell that has completed meiosis one has
half the amount of DNA of the cell that began
Common characteristics of a karotype
Lenght, Chromsomes position, staining pattern, amd traits coded for
Conclusion of Meiosis 1
Homologous pair seperate
Product is 2 genetically different daughter cells
Meiosis 1
Independent assortment of chromosomes occur
Meiosis 1
Occurs in meiosis but not in mitosis
Synapsis of chrosomsomes
What is a tetrad
2 sets of sister chromosomes that have synpased
What phase is when tetrads allign at equator
Metaphase 1
Sister chromatids disjoin and seperate
Anaphase 2
23 chromosomes in gamets can produce how many possibilites
8 million
How often does crossing over occur
1-2 per chromosome
When homologous pairs cross over
Specific protein break and re-join
Replicated chromosome
Chromatid
Crossing over occurs in
Prophase
