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Questions and Answers
What happens to the nuclear envelope during early prophase?
What happens to the nuclear envelope during early prophase?
What defines the metaphase plate in the context of mitosis?
What defines the metaphase plate in the context of mitosis?
Which structure develops on sister chromatids during mitosis?
Which structure develops on sister chromatids during mitosis?
What occurs during anaphase in mitosis?
What occurs during anaphase in mitosis?
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Which phase follows metaphase in the mitotic process?
Which phase follows metaphase in the mitotic process?
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What completes the process of cell division in mitosis?
What completes the process of cell division in mitosis?
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What is the primary role of cohesion proteins during mitosis?
What is the primary role of cohesion proteins during mitosis?
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During which phase do chromosomes become maximally condensed?
During which phase do chromosomes become maximally condensed?
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What is the primary function of microvilli?
What is the primary function of microvilli?
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What role do tight junctions play in epithelial layers?
What role do tight junctions play in epithelial layers?
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Which statement is true about desmosomes?
Which statement is true about desmosomes?
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Which of the following best describes the extracellular matrix (ECM) in animal cells?
Which of the following best describes the extracellular matrix (ECM) in animal cells?
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What distinguishes hemidesmosomes from desmosomes?
What distinguishes hemidesmosomes from desmosomes?
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What characterizes interkinesis during meiosis?
What characterizes interkinesis during meiosis?
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Gap junctions in animal cells are primarily responsible for:
Gap junctions in animal cells are primarily responsible for:
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What is a common feature of adhering junctions?
What is a common feature of adhering junctions?
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What happens during Anaphase I of meiosis?
What happens during Anaphase I of meiosis?
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During which phase do the tetrads line up at the center of the cell?
During which phase do the tetrads line up at the center of the cell?
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Which of the following statements about villi is correct?
Which of the following statements about villi is correct?
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Which type of junction is characterized by its role in preventing leakage of extracellular fluid?
Which type of junction is characterized by its role in preventing leakage of extracellular fluid?
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What is a significant outcome of the first meiotic division?
What is a significant outcome of the first meiotic division?
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In plant cells, what structure serves as the extracellular matrix?
In plant cells, what structure serves as the extracellular matrix?
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Which process occurs during Telophase II?
Which process occurs during Telophase II?
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What is true about Prophase II?
What is true about Prophase II?
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What pulls sister chromatids apart during Anaphase II?
What pulls sister chromatids apart during Anaphase II?
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What is a key difference between Meiosis I and Meiosis II?
What is a key difference between Meiosis I and Meiosis II?
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What is an isochromosome?
What is an isochromosome?
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What type of damage do X-rays and gamma rays primarily cause?
What type of damage do X-rays and gamma rays primarily cause?
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Which chemical mutagen directly deaminates cytosine to produce uracil?
Which chemical mutagen directly deaminates cytosine to produce uracil?
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What results from the pathway of mutagens leading to mutations?
What results from the pathway of mutagens leading to mutations?
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What role do oncogenes play in cancer development?
What role do oncogenes play in cancer development?
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What is the term for an individual missing a chromosome from a pair?
What is the term for an individual missing a chromosome from a pair?
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Which of the following is a form of aneuploidy involving four copies of a particular chromosome?
Which of the following is a form of aneuploidy involving four copies of a particular chromosome?
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What is the genetic abnormality where there are three copies of a chromosome instead of two?
What is the genetic abnormality where there are three copies of a chromosome instead of two?
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Which process can lead to the occurrence of aneuploidy due to improper separation of chromosomes?
Which process can lead to the occurrence of aneuploidy due to improper separation of chromosomes?
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Which of the following factors can contribute to the development of aneuploidy?
Which of the following factors can contribute to the development of aneuploidy?
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What is a common syndrome associated with trisomy?
What is a common syndrome associated with trisomy?
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What karyotype characteristic is used to compare an individual's chromosomes?
What karyotype characteristic is used to compare an individual's chromosomes?
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What could increase the likelihood of delayed fertilization after ovulation?
What could increase the likelihood of delayed fertilization after ovulation?
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Study Notes
Cell Modifications
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Villi and Microvilli - Bulge outward to increase surface area for easier absorption and adsorption of nutrients.
- Villi - Small fingerlike projections
- Microvilli - Even smaller projections that arise from villi
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Extracellular Matrix (ECM) - Secreted by the cell on its apical surface
- Main component of ECM in animal cells is Glycoprotein
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Lateral Modifications - Modifications found on the lateral surface of the cell
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Tight Junctions - Act as barriers that regulate the movement of water and solutes between layers
- Prevents leakage of extracellular fluid
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Gap Junctions - Allow direct exchange of chemicals between the cytoplasm of two cells
- Connexon facilitates the direct exchange of chemicals
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Tight Junctions - Act as barriers that regulate the movement of water and solutes between layers
- Adhering Junctions - Anchoring junctions on the lateral surface of the cell, fasten cells to one another
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Desmosomes/Hemidesmosomes - Anchoring junctions on the basal surface of the cell, rivet-like links between the cytoskeleton and ECM
- Hemidesmosomes - Found on the lateral surface of the cell
- Composed of keratin, integrins, and cadherins.
Mitosis
- Karyokinesis (division of the nucleus) is also known as mitosis.
- The phases of mitosis are: Prophase, Metaphase, Anaphase and Telophase.
- Early Prophase: The nuclear envelope disassociates, organelles fragment and disperse.
- Metaphase: Chromosomes align at the metaphase plate.
- Anaphase: Sister chromatids are pulled apart.
- Telophase: Nuclear envelopes reform around the chromosomes.
- Cytokinesis: Cell division is completed by physically separating the cytoplasm into two daughter cells.
Meiosis
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Meiosis I - The first meiotic division results in two haploid cells, homologous chromosomes are pulled apart
- Prophase I: The nuclear envelope breaks down, homologous chromosomes pair and exchange genetic material (crossing over).
- Metaphase I: Tetrads line up at the metaphase plate.
- Anaphase I: Homologous chromosomes are pulled apart.
- Telophase I: Two haploid cells are formed.
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Meiosis II - The second meiotic division results in four haploid gametes, sister chromatids are pulled apart.
- Prophase II: Spindles form and attach to chromosomes.
- Metaphase II: Chromosomes line up at the metaphase plate.
- Anaphase II: Sister chromatids are pulled apart.
- Telophase II: Four haploid cells are formed.
- Karyotype: A full set of chromosomes from an individual.
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Aneuploidy: Abnormal number of chromosomes, occurs when an individual is missing or has extra chromosomes.
- Monosomy: Missing a chromosome from a pair
- Trisomy: 3 copies of a chromosome instead of the normal 2
- Tetrasomy: 4 copies of a chromosome instead of the normal 2
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Causes of Aneuploidy: Aging effect on the primary oocyte, Radiation, Delayed fertilization.
- Syndromes involving Aneuploidy: Down syndrome (Trisomy 21), Turner syndrome.
- Isochromosome: Mirror image copy of a chromosome segment including the centromere.
Mutations and Mutagens
- Mutations: Changes in a DNA sequence
-
Mutagens: Agents that cause mutations
- Ionizing radiation: X-rays and gamma rays can damage DNA.
- Non-ionizing radiation: UV rays cause pyrimidine dimers.
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Chemical mutagens:
- Base analogs: Direct mutagenesis
- Nitrous acid: Deaminates cytosine to produce uracil
- Alkylating agents and intercalating agents: Lesions (indirect mutagenesis)
- Pathway to Mutation: Mutagens to Mutagenesis to Mutation
- Oncogenes: Mutated genes that can cause cancer.
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Description
Explore the various cell modifications such as villi, microvilli, and the extracellular matrix. Understand the significance of lateral modifications like tight junctions and gap junctions in cellular functions. This quiz covers essential topics in cellular biology.
