Podcast
Questions and Answers
What is the primary function of the nucleus in a cell?
What is the primary function of the nucleus in a cell?
Which statement accurately describes a key feature of asexual reproduction?
Which statement accurately describes a key feature of asexual reproduction?
What problem does cell division primarily address related to cell size?
What problem does cell division primarily address related to cell size?
What is the role of centromeres in chromosome structure?
What is the role of centromeres in chromosome structure?
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Which of the following is not a phase of the cell cycle?
Which of the following is not a phase of the cell cycle?
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During which stage of mitosis do chromosomes become visible?
During which stage of mitosis do chromosomes become visible?
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What happens to the nuclear envelope during prophase?
What happens to the nuclear envelope during prophase?
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What is the main activity occurring during anaphase?
What is the main activity occurring during anaphase?
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What is the primary event that occurs during cytokinesis?
What is the primary event that occurs during cytokinesis?
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Which phase of the cell cycle does the cell's DNA double?
Which phase of the cell cycle does the cell's DNA double?
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What occurs at the end of telophase?
What occurs at the end of telophase?
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During which phase of mitosis do the chromosomes line up at the center of the cell?
During which phase of mitosis do the chromosomes line up at the center of the cell?
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What is the role of spindle fibers during mitosis?
What is the role of spindle fibers during mitosis?
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Study Notes
The Nucleus
- Houses DNA
- Cells begin as a single cell; as an adult that cell has grown and divided multiple times.
Size Limits
- When cells become too large, they become less efficient at moving material in and out of the cell
- Too large of a cell causes an increased demand on the cell's DNA.
Cell Division
- The process by which a single cell divides into two daughter cells
- DNA must be copied (replicated)
- Solves the problems of:
- Cell size becoming too large
- Information overload (demand on DNA)
Reproduction
- Asexual Reproduction: production of genetically identical offspring - occurs in bacteria and some plants.
- Sexual Reproduction: offspring inherit some genetic information from each parent - occurs in animals and most plants.
Chromosome Structure
- Chromosomes are found in the nucleus
- Made of identical sister chromatids
- Held together by a centromere
The Cell Cycle
- Includes:
- Interphase
- Mitosis
- Cytokinesis
Interphase
-
G1: Cell Growth
- The cell increases in size and makes new proteins and organelles
-
S: DNA Replication
- New DNA is synthesized; chromosomes are replicated
- By the end of this phase, the cell has twice the amount of DNA
-
G2: Preparing for cell division
- Organelles and molecules needed for cell division are produced
Mitosis
-
Prophase
- First phase of mitosis
- Genetic material inside the nucleus condenses, and duplicated chromosomes become visible
- The spindle starts to form outside of the nucleus
- Spindle fibers extend from centrioles
- Duplicated chromosomes condense to appear as two thick strands, called chromatids
- Chromatids attach to the centromere
- The nuclear envelope begins to break down
-
Metaphase
- Second phase of mitosis
- Centromeres of duplicated chromosomes line up across the center of the cell
- Spindle fibers connect to the centromere of each chromosome
-
Anaphase
- Third phase of mitosis
- Chromosomes separate and move along the spindle fibers to opposite ends of the cell
- Rapid breakdown of microtubules as chromosomes move toward the poles
-
Telophase
- Final phase of mitosis
- Chromosomes begin to spread out into a tangle of chromatin (which were distinct and condensed during earlier phases)
- The nuclear envelope re-forms
- The nucleolus becomes visible in each daughter cell
End of Mitosis
- Each daughter cell will have two nuclei, each with a duplicated set of chromosomes.
Cytokinesis
- Usually occurs at the same time as telophase
- Cell division is completed by separating one cell into two new cells
- The cell membrane is drawn inward until the cytoplasm is pinched into two equal parts.
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Description
Explore the fascinating world of cell biology in this quiz focused on the structure and division of cells. Learn about the role of the nucleus, chromosome composition, and the processes of asexual and sexual reproduction. Test your knowledge on the cell cycle and the limitations of cell size.
