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Questions and Answers
What occurs before DNA replication in the cell cycle?
What occurs before DNA replication in the cell cycle?
What structure holds the identical DNA molecules together after replication?
What structure holds the identical DNA molecules together after replication?
During which phase are the cohesin loops cut?
During which phase are the cohesin loops cut?
What is the condition of DNA before it is replicated?
What is the condition of DNA before it is replicated?
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What is a false hypothesis regarding the behavior of chromatids during division?
What is a false hypothesis regarding the behavior of chromatids during division?
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What is the process called by which a mother cell produces new cells?
What is the process called by which a mother cell produces new cells?
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Which statement accurately reflects the theory of cell generation?
Which statement accurately reflects the theory of cell generation?
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What happens to the mother cell during cell division?
What happens to the mother cell during cell division?
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From what did all cells in a person's body originate?
From what did all cells in a person's body originate?
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Which component is NOT a direct ancestor of the cells in our bodies today?
Which component is NOT a direct ancestor of the cells in our bodies today?
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What does the continuity of life imply about human cells?
What does the continuity of life imply about human cells?
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Which statement best describes the significance of cell division in living organisms?
Which statement best describes the significance of cell division in living organisms?
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Which organization is attempting to create new living cells from lifeless components?
Which organization is attempting to create new living cells from lifeless components?
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What occurs at the end of prophase regarding the nuclear membrane?
What occurs at the end of prophase regarding the nuclear membrane?
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Which structure grows microtubules towards the end of prophase?
Which structure grows microtubules towards the end of prophase?
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During metaphase, what is the role of spindle microtubules?
During metaphase, what is the role of spindle microtubules?
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What is tested during metaphase to ensure proper attachment?
What is tested during metaphase to ensure proper attachment?
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What type of structure do the microtubules form during prophase?
What type of structure do the microtubules form during prophase?
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What happens to sister chromatids during metaphase?
What happens to sister chromatids during metaphase?
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Which of the following structures directly interact with the chromosomes during metaphase?
Which of the following structures directly interact with the chromosomes during metaphase?
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What is the primary function of microtubules during the metaphase stage of mitosis?
What is the primary function of microtubules during the metaphase stage of mitosis?
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What prevents chromosomes from being pulled to either pole during the late stages of metaphase?
What prevents chromosomes from being pulled to either pole during the late stages of metaphase?
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At what stage are chromosomes aligned at the equator of the cell?
At what stage are chromosomes aligned at the equator of the cell?
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Which structure is responsible for pulling chromosomes to the poles during anaphase?
Which structure is responsible for pulling chromosomes to the poles during anaphase?
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What happens to the cohesin loops during anaphase?
What happens to the cohesin loops during anaphase?
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What initiates the movement of chromosomes towards the poles in anaphase?
What initiates the movement of chromosomes towards the poles in anaphase?
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By the end of which phase are chromosomes no longer held together by cohesin?
By the end of which phase are chromosomes no longer held together by cohesin?
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What stabilizes the chromosomes at the equator during metaphase?
What stabilizes the chromosomes at the equator during metaphase?
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What defines the formation of genetically identical chromosomes in anaphase?
What defines the formation of genetically identical chromosomes in anaphase?
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What happens to chromosomes during interphase?
What happens to chromosomes during interphase?
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What is a key event that occurs during telophase?
What is a key event that occurs during telophase?
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What primarily occurs in the cytoplasm during interphase?
What primarily occurs in the cytoplasm during interphase?
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What occurs immediately after cytokinesis?
What occurs immediately after cytokinesis?
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What is the state of genes in decondensed chromosomes?
What is the state of genes in decondensed chromosomes?
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What occurs at the end of anaphase?
What occurs at the end of anaphase?
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What happens to the chromosomes during telophase?
What happens to the chromosomes during telophase?
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What initiates cytokinesis during the mitotic process?
What initiates cytokinesis during the mitotic process?
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What typically happens to daughter cells after completing mitosis?
What typically happens to daughter cells after completing mitosis?
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Where does the nuclear membrane reform during telophase?
Where does the nuclear membrane reform during telophase?
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During which phase are chromosomes tightly grouped near the MTOC?
During which phase are chromosomes tightly grouped near the MTOC?
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What is the primary characteristic of chromosomes at the conclusion of anaphase?
What is the primary characteristic of chromosomes at the conclusion of anaphase?
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Which of the following statements is true concerning the events of cytogenesis?
Which of the following statements is true concerning the events of cytogenesis?
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Study Notes
Cell Division in Living Organisms
- All organisms need new cells for growth, maintenance, and reproduction.
- This is achieved through cell division.
- A mother cell divides into two daughter cells.
- The mother cell is no longer a separate entity.
- New cells are always created from pre-existing cells (strong evidence for this theory).
- Our bodies are made of trillions of cells, each originating from the initial zygote.
- The zygote is formed from the fusion of sperm and egg.
- The origins of our cells can be traced back to earlier generations.
- This demonstrates continuity of life from the earliest cells to the cells in our bodies today.
Cytokinesis in Animal Cells
- Cytokinesis divides the cytoplasm during cell division.
- It happens after nuclear division (mitosis in mother cells).
- Cytoplasm and contents are divided between two daughter cells.
- Animal cells form a cleavage furrow around the center.
- Contractile proteins (actin and myosin) pull the plasma membrane inwards, pinching it apart.
Cytokinesis in Plant Cells
- Plant cells use a different approach.
- Microtubules form a scaffold at the equator.
- Vesicles fuse to create a cell plate.
- This develops into a new cell wall, separating the two cells.
- The cell plate connects to existing plasma membranes to complete cell division.
Equal and Unequal Cytokinesis
- Equal cytokinesis divides cytoplasm evenly. Happens in growing root tips.
- Unequal cytokinesis divides cytoplasm unequally.
- Resulting smaller cells can still function if they receive enough organelles.
- Mitochondria, for instance, require pre-existing ones to be viable.
Budding in Yeast
- Yeast reproduces asexually.
- A small outgrowth (bud) forms on the mother cell.
- Nuclei divide.
- Bud receives a portion of cytoplasm.
- Bud eventually separates from the mother cell, leaving a scar.
Oogenesis in Humans
- One large oocyte and small polar bodies are produced in each meiotic cycle.
- The large oocyte receives most of the cytoplasm, providing resources for the developing embryo.
- The polar bodies eventually degenerate and are not involved in fertilization.
Mitosis and Meiosis in Eukaryotes
- Mitosis creates genetically identical cells.
- The diploid chromosome number is maintained.
- Meiosis halves the chromosome number (from diploid to haploid).
- Meiosis generates genetic variation for sexual reproduction.
DNA Replication for Mitosis and Meiosis
- DNA replication is necessary before mitosis/meiosis.
- It ensures that each daughter cell receives a complete set of genetic information.
- Chromosomes, initially long strands of DNA, condense into visible structures during cell division.
- Each chromosome duplicates (during interphase) and becomes two sister chromatids.
- Cohesin loops hold chromatids together until anaphase.
Chromosome Condensation and Movement
- Chromosomes condense to become easier to move during cell division (mitosis/meiosis).
- Microtubules are used in the structure of the spindle which separates the chromosomes in mitosis/meiosis.
- Kinetochores, protein structures on chromosomes, link chromosomes to microtubules.
Mitosis Phases
- Mitosis is divided into interphase (preceding mitosis), prophase, metaphase, anaphase, and telophase.
- Key events like chromosome condensation, alignment at the cell equator, separation of chromatids, and nuclear membrane reformation occur in each.
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Description
This quiz covers key concepts related to the cell cycle and cell division, including DNA replication, the role of cohesin, and the processes involved in cell generation. Test your knowledge on crucial phases of cell division and the origins of cells within the human body.