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47 Cards in this Set
- Front
- Back
Cell division in unicellular organisms |
Used to reproduce the entire organism |
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Three uses of cell division in multicellular organisms |
Development from a fertilized cell, growth, repair |
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Cell cycle |
Life of a cell from formation to its own division |
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Most cell division is ______ and results in _________ |
Mitotic, and results in daughter cells with identical genetic information, DNA |
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Genome |
All the DNA in a cell |
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DNA molecules in a cell are packaged into |
Chromosomes |
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Somatic cells (2n) |
Most body cells, they have two sets (pairs) of chromosomes |
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Gametes (n) |
Reproductive cells, sperm and eggs, have half as many chromosomes as somatic cells |
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Eukaryotic chromosomes consist of |
Chromatin, a complex of DNA and protein that condenses during cell division |
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What happens to DNA in preparation for cell division |
DNA is replicated |
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Describe duplicated chromosomes |
They have two sister chromatids, which separate during cell division |
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Centromere |
The waist of the duplicated chromosome, where the two chromatids are most closely attached |
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Eukaryotic cell division consists of |
Mitosis and cytokinesis |
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Mitosis |
The division of the nucleus |
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Cytokinesis |
The division of the cytoplasm |
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The cell cycle consists of |
Mitotic (M) phase (mitosis and cytokinesis) Interphase: G1, normal cell growth S, copying of chromosomes G2, growth in preparation for cell division |
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Which phase of the cell cycle is a cell in for the majority of its lifespan |
A cell will spend most of its life time in interphase |
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List the five phases of mitosis |
Prophase, prometaphase, metaphase, anaphase, telophase |
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When is cytokinesis taking place |
It is well underway by late telophase |
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Mitotic spindle |
Apparatus of microtubules that controls chromosome movement during mitosis |
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Where does microtubule assembly begin during prophase |
Microtubule assembly begins in the centrosome |
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What happens to the centrosome |
The centrosome replicates, forming two centrosomes that migrate to opposite ends of the cell |
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What is an aster |
Radio array of short microtubules that extends from each centrosome |
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Prophase |
Centrosomes appear, nuclear membrane disappears |
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Prometaphase |
Spindle microtubules attached to the kinetochores of chromosomes begin to move the chromosomes |
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Metaphase |
The chromosomes are all lined up at the metaphase plate, the midway point between the spindles two poles |
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Anaphase |
Sister chromatids separate and move along with the kinetochore microtubules toward opposite ends of the cell |
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Telophase |
Genetically identical daughter nuclei form at opposite ends of the cell, nuclear membranes reappear |
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How do microtubules shortem |
By depolymerizing at their kinetochore ends |
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How does a cell elongate |
Nonkinetochore microtubules from opposite poles overlap and push against each other |
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Cytokinesis in animal cells |
Cytokinesis occurs by a process known as cleavage, forming a cleavage furrow in the plasma membrane |
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Cytokinesis in plant cells |
A cell plate forms from Golgi vesicles (membrane) |
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How do you prokaryotes reproduce |
Prokaryotes reproduce by type of cell division called binary fission, |
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Binary fission |
Chromosome replicates and the two daughter chromosomes move apart as the cell elongates |
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What drives the cell cycle |
Specific chemical signals present in the cytoplasm |
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Cell cycle control system |
System that directs cell cycle events, it is similar to a Clock |
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Describe the cell cycle control system analogy to a clock |
The clock has specific check points where the cell cycle stops until I go ahead signal is received |
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What is the most important checkpoint and why |
G1 checkpoint is the most important, if it receives the go ahead signal at the G1 checkpoint a cell will usually complete the S, G2, and M phases and divide |
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If the cell does not receive the go ahead signal |
It will exit the cycle, switching into a nondividing state called the G0 phase |
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Two types of regulatory proteins that are involved in cell cycle control |
Cyclins and cyclin dependent kinases |
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MPF |
Maturation promoting factor, a cyclin dependent kinase that triggers a cells passage past the G2 checkpoint into the M phase |
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Density dependent inhibition |
Crowded cells stop dividing |
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Anchorage dependence |
Cells must be attached to a substratum in order to divide |
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Cancer cells |
Do not respond normally to the bodies control mechanisms, they divide add an accelerated rate, causing a lump or tumor |
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What is the process by which a normal cells convert it to a cancerous cell |
Transformation |
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Benign tumor |
Abnormal cells remain at the original site, can be removed easily |
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Malignant tumor |
Cancer cells invade surrounding tissues and can metastasize, exporting cancer cells to other parts of the body, where they may form secondary tumors |