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Questions and Answers
What is one of the fundamental principles of modern biology?
What is one of the fundamental principles of modern biology?
Cell theory
Which of the following is NOT a major point of cell theory?
Which of the following is NOT a major point of cell theory?
- All organisms are composed of cells or cell products.
- All cells arise from pre-existing cells.
- All cells have the same number of chromosomes. (correct)
- All cells have the same DNA and number of chromosomes.
- The chemical reactions characteristic of living systems occur within cells.
Which of the following is NOT a key role of cell division?
Which of the following is NOT a key role of cell division?
- Growth and Development
- Photosynthesis (correct)
- Reproduction
- Cell repair and regeneration
What is the process by which a single cell becomes two daughter cells called?
What is the process by which a single cell becomes two daughter cells called?
During cell division, what two processes are essential for the creation of two new cells?
During cell division, what two processes are essential for the creation of two new cells?
For successful cell division, the parent cell must be large enough to divide in two while still contributing enough cytoplasmic components to each daughter cell.
For successful cell division, the parent cell must be large enough to divide in two while still contributing enough cytoplasmic components to each daughter cell.
Which of the following processes is used by prokaryotes to reproduce?
Which of the following processes is used by prokaryotes to reproduce?
Which of the following is NOT a characteristic of binary fission?
Which of the following is NOT a characteristic of binary fission?
Mitosis occurs in somatic cells and produces exact copies of parental chromosomes.
Mitosis occurs in somatic cells and produces exact copies of parental chromosomes.
Meiosis is responsible for making sexual reproduction possible.
Meiosis is responsible for making sexual reproduction possible.
During binary fission, two important regions on DNA are involved. What are they?
During binary fission, two important regions on DNA are involved. What are they?
What happens to two origins of replication attached to the plasma membrane during binary fission?
What happens to two origins of replication attached to the plasma membrane during binary fission?
What is the process called when the cytoplasm divides during binary fission?
What is the process called when the cytoplasm divides during binary fission?
What is the purpose of mitosis in eukaryotic cells?
What is the purpose of mitosis in eukaryotic cells?
The steps involved in mitosis are more complex than binary fission.
The steps involved in mitosis are more complex than binary fission.
What is the term for the time between two successive M phases in the eukaryotic cell cycle?
What is the term for the time between two successive M phases in the eukaryotic cell cycle?
Which of the following phases is NOT part of Interphase?
Which of the following phases is NOT part of Interphase?
The Go phase is a resting phase where cells are not actively dividing.
The Go phase is a resting phase where cells are not actively dividing.
All body cells actively participate in the cell cycle.
All body cells actively participate in the cell cycle.
Liver cells can metabolize and detoxify, even when they are in the Go phase.
Liver cells can metabolize and detoxify, even when they are in the Go phase.
Nerve cells enter the Go phase permanently after differentiation.
Nerve cells enter the Go phase permanently after differentiation.
In eukaryotic cells, DNA is organized with histones and other proteins into what structure?
In eukaryotic cells, DNA is organized with histones and other proteins into what structure?
Chromatin can be looped and packaged to form chromosomes.
Chromatin can be looped and packaged to form chromosomes.
What is the term used to describe the portrait formed by the number and shapes of chromosomes representative of a species?
What is the term used to describe the portrait formed by the number and shapes of chromosomes representative of a species?
What is the typical number of chromosomes in human somatic cells?
What is the typical number of chromosomes in human somatic cells?
How many chromosomes are there in human gametes?
How many chromosomes are there in human gametes?
What is the term used to describe two chromosomes of the same type?
What is the term used to describe two chromosomes of the same type?
Homologous chromosomes carry the same set of genes.
Homologous chromosomes carry the same set of genes.
One homologous chromosome is referred to as the paternal chromosome, while the other is the maternal chromosome.
One homologous chromosome is referred to as the paternal chromosome, while the other is the maternal chromosome.
What is the term used to describe the duplicated copies of a single chromosome held together after DNA replication?
What is the term used to describe the duplicated copies of a single chromosome held together after DNA replication?
During which phase of the cell cycle does DNA duplication occur?
During which phase of the cell cycle does DNA duplication occur?
What is the structure called where sister chromatids are held together?
What is the structure called where sister chromatids are held together?
To count the number of chromosomes, count the centromeres.
To count the number of chromosomes, count the centromeres.
Which of the following is NOT a stage of mitosis?
Which of the following is NOT a stage of mitosis?
What are mitotic spindles made of?
What are mitotic spindles made of?
What is the significance of the centrosome during prophase?
What is the significance of the centrosome during prophase?
Sister chromatids are joined together by cohesins.
Sister chromatids are joined together by cohesins.
During prometaphase, the nuclear membrane breaks down.
During prometaphase, the nuclear membrane breaks down.
What specialized structures on chromosomes do spindle fibers attach to?
What specialized structures on chromosomes do spindle fibers attach to?
Microtubules polymerize and depolymerize during mitosis.
Microtubules polymerize and depolymerize during mitosis.
What are kinetochores composed of?
What are kinetochores composed of?
Each kinetochore is associated with one of the sister chromatids.
Each kinetochore is associated with one of the sister chromatids.
Kinetochores act as the attachment site for a single spindle microtubule.
Kinetochores act as the attachment site for a single spindle microtubule.
What happens to chromosomes during metaphase?
What happens to chromosomes during metaphase?
During anaphase, sister chromatids separate.
During anaphase, sister chromatids separate.
Anaphase is characterized by cleavage of cohesin proteins.
Anaphase is characterized by cleavage of cohesin proteins.
Equal segregation of chromosomes is achieved during anaphase.
Equal segregation of chromosomes is achieved during anaphase.
During telophase, the nuclear envelope re-forms, and chromosomes decondense.
During telophase, the nuclear envelope re-forms, and chromosomes decondense.
What is the process called that divides the cytoplasm during cell division in animals?
What is the process called that divides the cytoplasm during cell division in animals?
Cytokinesis is characterized by the formation of a cleavage furrow in animal cells.
Cytokinesis is characterized by the formation of a cleavage furrow in animal cells.
What is the cell plate, and what role does it play during cytokinesis in plant cells?
What is the cell plate, and what role does it play during cytokinesis in plant cells?
The result of mitosis and cytokinesis is two diploid cells, genetically identical to the parent cell.
The result of mitosis and cytokinesis is two diploid cells, genetically identical to the parent cell.
Flashcards
Cell Theory
Cell Theory
One of the fundamental principles of biology stating that all living organisms are composed of cells, cells are the basic unit of life, and new cells arise from pre-existing cells.
Cell division
Cell division
The process by which a single cell divides into two daughter cells.
Karyokinesis
Karyokinesis
The division of the nucleus during cell division.
Cytokinesis
Cytokinesis
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Binary fission
Binary fission
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Mitosis
Mitosis
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Meiosis
Meiosis
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M phase
M phase
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Interphase
Interphase
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G1 phase
G1 phase
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S phase
S phase
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G2 phase
G2 phase
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G0 phase
G0 phase
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Chromatin
Chromatin
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Chromosome
Chromosome
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Karyotype
Karyotype
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Homologous chromosomes
Homologous chromosomes
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Sister chromatids
Sister chromatids
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Centromere
Centromere
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Kinetochores
Kinetochores
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Mitotic spindle
Mitotic spindle
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Prophase
Prophase
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Prometaphase
Prometaphase
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Metaphase
Metaphase
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Anaphase
Anaphase
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Telophase
Telophase
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Phragmoplast
Phragmoplast
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Cleavage furrow
Cleavage furrow
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Cytokinesis (Animal)
Cytokinesis (Animal)
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Cytokinesis (Plant)
Cytokinesis (Plant)
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Study Notes
Cell Division and Cell Cycle (Part 1)
- Cell theory is a fundamental principle of modern biology
- Four main points in cell theory:
- All organisms are made of cells or cell products.
- All cells in an organism have the same DNA and chromosome number, unless they are sex cells.
- Chemical reactions of living systems happen inside cells.
- All cells come from pre-existing cells.
Overview of Cell Division
- Cells reproduce through cell division
- Key roles of cell division:
- Reproduction (unicellular organisms)
- Growth/development (multicellular organisms)
- Cell repair/regeneration (multicellular organisms)
Overview of Cell Division - Processes
- Cell division is the process where one cell becomes two daughter cells.
- Cell division includes the division of the nucleus and cytoplasm
- Karyokinesis: nucleus division
- Cytokinesis: cytoplasm division, via cleavage furrow
- Requirements for successful cell division:
- Full DNA complement distributed to daughter cells from the parent cell.
- Parent cell must be large enough to divide and still contribute cytoplasmic components to each daughter cell.
Methods of Cell Division
- Prokaryotes (example: bacteria and single-celled organisms):
- Binary fission: asexual reproduction
- New copy may be identical or have mutations
- Eukaryotes (example: somatic cells):
- Mitosis (exact copies of parental chromosomes)
- Meiosis (makes sexual reproduction possible. Daughter cells have half the number of chromosomes compared to parent cell; Not exact copies)
Prokaryotic Cell Division (Binary Fission)
- Most bacteria have one circular chromosome.
- DNA Replication:
- Cell increases in size
- Two important regions on DNA: origin of replication and terminus of replication
- DNA Segregation:
- Two origins attached to plasma membrane move apart
- Cytokinesis: pinching of the plasma membrane; new cell wall material synthesis
Eukaryotic Cell Division (Mitosis)
- Result: two identical daughter cells with the same number of chromosomes as the parent cell.
- Still involves general steps as seen in binary fission, but more complex than in prokaryotes.
- Reason for complexity: Eukaryotes have a nucleus and more complex DNA.
Eukaryotic Cell Cycle
- Cell division proceeds through a number of steps that make up the cell cycle.
- Two distinct stages:
- M phase: period of cell division. Parent cell divides into two daughter cells
- Interphase: time between two successive M phases
- Stages of interphase: G₁, S, and G₂ (G₁ – cell growth, S – DNA synthesis, G₂ – preparation for mitosis)
- Go phase: cells not actively dividing
Eukaryotic Cell Division (Mitosis)- Chromosome Structure
- In eukaryotes, DNA is organized with histones and other proteins into chromatin
- Chromatin can be looped and packaged to form chromosomes
Mitotic Cell Division (Eukaryotes) - Karyotype
- Karyotype: A visual representation of the chromosome complement of a cell, showing the number, size, and shape of chromosomes
- Humans:
- Somatic cells: 46 chromosomes (22 pairs of homologous chromosomes and 2 sex chromosomes)
- Gametes (sperm or egg): 23 chromosomes
Mitotic Cell Division (Eukaryotes) - Homologous Chromosomes
- Two chromosomes of the same type
- Have genes for same traits
- One homologue is paternal and other maternal.
Mitotic Cell Division (Eukaryotes) - Homologous Chromosomes and Sister Chromatids
- For cell division to occur, each chromosome must be duplicated for each daughter cell to receive full chromosomes.
- Duplication occurs during the S phase of the cell cycle (synthesis).
- After DNA duplication, each chromosome consists of two sister chromatids, held together by cohesins at the centromere.
Exploring Mitosis (Stages)
- Prophase: Condensation of chromosomes; centrosomes migrate to opposite poles; mitotic spindle formation; nuclear envelope begins to disappear
- Prometaphase: Nuclear envelope breaks down completely; spindle fibers attach to kinetochores of chromosomes
- Metaphase: Chromosomes align at the metaphase plate (center of the cell); Spindle fibers fully attached to kinetochores
- Anaphase: Sister chromatids separate (at the centromere), each becoming a chromosome and move to opposite poles
- Telophase: Chromosomes reach opposite poles; nuclear envelopes reform; chromosomes decondense; two separate nuclei form
- Cytokinesis: Cytoplasm divides; two separate diploid daughter cells result.
- Animal cells: contractile ring
- Plant cells: cell plate formation
Test Your Understanding
- Questions about chromosome replication, cell cycle stage, and cell type
Next Time:
- Topics for future lectures: Control of the cell cycle, Meiosis
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Description
Explore the fundamental principles of cell division and the cell cycle in this quiz. Understand key processes such as karyokinesis and cytokinesis, along with the significance of cell theory. Ideal for students studying biology, this quiz delves into how cells reproduce, grow, and repair themselves.
