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Questions and Answers
What is the primary purpose of mitosis in eukaryotic cells?
Which phase of the cell cycle is primarily responsible for DNA replication?
During which phase of mitosis do the chromosomes align at the cell's equator?
What is cytokinesis?
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In which type of cells does mitosis primarily occur?
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What is the primary function of chromosomes?
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Which of the following best describes the structure of DNA?
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What is the name of the protein-DNA complex that makes up chromosomes?
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How many chromosomes are typically found in a human somatic cell?
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Which of the following is NOT a component of a nucleotide in DNA?
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What role do histones play in the structure of chromosomes?
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What are chromatids?
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What is the primary characteristic of the centromere in a chromosome?
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What is the primary function of non-histone proteins?
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How many chromosomes do normal human females have?
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Which of the following statements regarding haploid and diploid cells is true?
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During which process do chromosomes number become halved?
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If a diploid cell has 24 chromosomes, how many chromosomes will be found in its haploid cells?
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What defines the sex chromosomes in humans?
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What is the total number of chromosomes found in a cat?
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Which statement about the number of chromosomes across different organisms is accurate?
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Study Notes
Chromosomes
- Thread-like structures found in the nucleus of cells.
- Composed of DNA and proteins.
- Carry genetic information that determines traits and functions.
- Humans have 23 pairs of chromosomes (46 total).
- Compact packages of genes and other DNA in cells.
DNA
- Long thin molecule that stores genetic information.
- DNA in a human cell is estimated to consist of six billion pairs of nucleotides.
Structure of Chromosomes
- Two main parts:
- Chromatids: identical copies of genetic material
- Centromere: where chromatids join
Importance of Chromosomes
- Store and protect genetic material.
- Ensure accurate distribution of DNA during cell division.
- Determine inheritance of traits.
- Essential for proper growth, development, and function of organisms.
Histones & Non-Histones
- DNA in eukaryotic cells wraps tightly around proteins called histones.
- Histones help maintain the shape of chromosomes and aid in the tight packing of DNA.
- Non-histone proteins are generally involved in controlling the activity of specific regions of the DNA.
- Chromatids form as the DNA makes a copy of itself before cell division.
- When cells divide, each new cell receives one chromatid from each chromosome.
Centromeres
- Especially important for the movement of chromosomes during cell division.
Chromosome Numbers
- Human and animal chromosomes are categorized as either sex chromosomes or autosomes.
- Sex chromosomes determine the sex of an organism and may carry genes for other characteristics in humans.
- Sex chromosomes are X or Y.
- Normal females have two X chromosomes.
- Normal males have an X and a Y chromosome.
- Humans have 46 chromosomes = 23 pairs.
Number of Chromosomes in Other Organisms
- Cat = 32
- Dog = 78
- Horse = 64
- Fruit fly = 8
Cell Division
- Process by which cells produce offspring.
- In prokaryotes:
- Binary fission: division of a prokaryotic cell into two offspring cells.
- Binary fission consists of three general stages.
The Cell Cycle
- Repeating set of events that make up the life of a cell.
- Cell division is one phase of the cell cycle.
- The time between cell division is called interphase.
- During cell division, the chromosomes and cytoplasm are equally divided between two offspring cells.
- Cell division consists of mitosis and cytokinesis.
- Mitosis, or M phase, is the division of the nucleus of a cell.
- Cytokinesis is the division of the cytoplasm of the cell.
Mitosis
- Division of the nucleus, occurring during cell division.
- A continuous process divided into four phases:
- Prophase
- Metaphase
- Anaphase
- Telophase
Meiosis
- Process of cell division in eukaryotic cells, resulting in the production of four daughter cells, each with half the number of chromosomes as the parent cell.
- Crucial for sexual reproduction.
- Occurs in germ cells (reproductive cells).
- Produces gametes (sperm and egg cells).
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Description
Explore the fundamental concepts of chromosomes and DNA in this quiz. Learn about the structure, function, and importance of these genetic materials in living organisms. Test your knowledge on genetic inheritance, the role of histones, and the mechanics of cell division.
