Cell Cycle Overview Quiz

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Questions and Answers

What triggers the movement from one phase of the cell cycle to another?

Centrosomes

Cyclins (correct)

Cyclosomes

Cytokines

Which phase of interphase is primarily focused on DNA replication?

M phase

G2 phase

G1 phase

S phase (correct)

What occurs during the G1 phase of interphase?

Cell growth and synthesis of proteins (correct)

DNA synthesis

Chromosome separation

Cell division

What is the main role of the G2 phase in the cell cycle?

Repairing errors in newly synthesized DNA (C) Signup and view all the answers

What happens to the cell during the M phase?

Cell division occurs (C) Signup and view all the answers

What is the primary function of cytokinesis?

Dividing the entire cell into two daughter cells (B) Signup and view all the answers

Which type of cell division results in genetically identical daughter cells?

Mitosis (C) Signup and view all the answers

How often do onion root tip cells typically divide during the cell cycle?

Every 20 hours (D) Signup and view all the answers

What is the primary function of xylem vessels?

Transport of water and dissolved ions (D) Signup and view all the answers

Which of the following statements accurately describes phloem vessel cells?

They retain some organelles and are composed of living cells (A) Signup and view all the answers

What is the significance of the thickening of outer walls in xylem cells?

Strengthens the tubes for structural support (B) Signup and view all the answers

What is a key adaptation of skeletal muscle cells?

Fusing to form multinucleated cells (C) Signup and view all the answers

How does ciliated epithelium aid in protecting the body from infections?

By trapping dust and microorganisms in mucus (C) Signup and view all the answers

What is the primary function of squamous epithelium?

Surface covering or outer layer (A) Signup and view all the answers

Which characteristic of cartilage contributes to its flexibility?

It is a strong and flexible tissue (C) Signup and view all the answers

What is meant by potency in the context of stem cells?

The potential to remain a stem cell or differentiate into specialized cells (A) Signup and view all the answers

What distinguishes totipotent stem cells from other types of stem cells?

They can differentiate into any cell type and extra-embryonic cells (A) Signup and view all the answers

Which of the following is NOT a function of muscle cells?

Transporting oxygen (D) Signup and view all the answers

What is the end result of cytokinesis in meiosis I?

Two haploid cells (B) Signup and view all the answers

Which process results in genetic variation due to the exchange of alleles?

Crossing over (A) Signup and view all the answers

In meiosis II, what happens during Anaphase II?

Sister chromatids are pulled to opposite poles (D) Signup and view all the answers

What occurs during Metaphase I of meiosis?

Homologous pairs align at the equator (D) Signup and view all the answers

How does independent assortment increase genetic diversity?

By allowing random orientation of homologous pairs (A) Signup and view all the answers

How many combinations of chromosomes can be produced in humans due to independent assortment alone?

8,324,608 (C) Signup and view all the answers

What is the primary structural feature that allows erythrocytes to function effectively?

Biconcave shape (B) Signup and view all the answers

What phase precedes Prophase II in meiosis?

Telophase I (C) Signup and view all the answers

What phase of meiosis does crossing over occur during?

Prophase I (B) Signup and view all the answers

What is true about the DNA content during meiosis II?

DNA content does not change from meiosis I (D) Signup and view all the answers

What are chiasmata?

Crossing points of non-sister chromatids (B) Signup and view all the answers

Which stage in meiosis I leads to two haploid daughter cells?

Telophase I (D) Signup and view all the answers

How does meiosis contribute to natural selection?

By increasing genetic diversity (D) Signup and view all the answers

Which option describes the result of gamete fusion during fertilization?

Unique combinations of alleles in the zygote (B) Signup and view all the answers

What type of stem cells can differentiate into any cell type found in an embryo?

Pluripotent stem cells (B) Signup and view all the answers

Which of the following best describes multipotent stem cells?

Can differentiate into a limited range of cell types. (C) Signup and view all the answers

Which cell type is specifically produced from multipotent stem cells in the bone marrow?

Erythrocytes (B) Signup and view all the answers

During erythropoiesis, the ejection of the nucleus from the precursor cell allows for what adaptation?

More space for haemoglobin (D) Signup and view all the answers

Which statement accurately describes how neutrophils are structurally modified during differentiation?

They accumulate lysosomes containing enzymes. (A) Signup and view all the answers

What is the main function of erythrocytes in the body?

Transporting oxygen and carbon dioxide (D) Signup and view all the answers

Where in the body can multipotent adult stem cells be found?

In various tissues including bone marrow and skin (A) Signup and view all the answers

Which of the following is NOT a characteristic of totipotent stem cells?

Are found only after the 16-cell stage (B) Signup and view all the answers

What clinical application is being researched with adult stem cells?

To treat diseases and injuries (B) Signup and view all the answers

The biconcave shape of erythrocytes enhances their ability to function by providing what advantage?

Greater surface area for gas absorption (B) Signup and view all the answers

During which phase of the cell cycle does the most mRNA production occur?

G1 phase (A) Signup and view all the answers

What is the primary purpose of checkpoints in the cell cycle?

To ensure genetic information is accurate (A) Signup and view all the answers

What occurs during prophase of mitosis?

Chromosomes condense and the nuclear envelope breaks down (C) Signup and view all the answers

Which phase is characterized by sister chromatids being pulled to opposite poles?

Anaphase (B) Signup and view all the answers

How many checkpoints are present in the cell cycle?

Four (C) Signup and view all the answers

What specific event happens during the S phase of the cell cycle?

DNA is replicated (A) Signup and view all the answers

Which structure is essential for the attachment of spindle fibres to chromosomes during metaphase?

Centromeres (C) Signup and view all the answers

What happens to the sister chromatids during metaphase?

They align at the metaphase plate (A) Signup and view all the answers

What is a key characteristic of telophase in mitosis?

Nuclear envelopes begin to reform (C) Signup and view all the answers

What does the diploid number represent in human cells?

Total number of chromosomes in the cell nucleus (C) Signup and view all the answers

What type of regions in plants are primarily responsible for growth?

Meristems (B) Signup and view all the answers

Why might a cell undergo self-destruction during the cell cycle?

To prevent harmful mutations (D) Signup and view all the answers

How is mitosis in animal cells simplified in educational diagrams?

By using cells with two chromosomes (A) Signup and view all the answers

What is the immediate outcome of mitosis?

Two genetically identical daughter cells (B) Signup and view all the answers

What is the primary function of red blood cells?

Transport oxygen and carbon dioxide (D) Signup and view all the answers

What adaptation do sperm cells have that aids their motility?

A tail for propulsion (D) Signup and view all the answers

What is a primary function of mitosis in multicellular organisms?

Repair and replacement of damaged tissues (C) Signup and view all the answers

How do root hair cells maximize their ability to absorb water?

Through an extension of cytoplasm increasing surface area (C) Signup and view all the answers

What unique structure do neutrophils utilize to engulf microorganisms?

Pseudopodia (D) Signup and view all the answers

Which stage of mitosis is characterized by chromosomes aligning at the center of the cell?

Metaphase (C) Signup and view all the answers

Which cell type has adaptations to easily diffuse gases?

Squamous epithelium (A) Signup and view all the answers

What occurs during Prophase I of meiosis that is not seen in mitosis?

Homologous chromosomes pair up (D) Signup and view all the answers

How do optical microscopes compare to other types of microscopes?

They often cannot resolve smaller structures at high magnifications (C) Signup and view all the answers

Why do palisade cells have a large number of chloroplasts?

To maximize light absorption for photosynthesis (C) Signup and view all the answers

What is the function of goblet cells in ciliated epithelium?

To secrete mucus (A) Signup and view all the answers

In which phase of meiosis do homologous chromosomes separate?

Anaphase I (C) Signup and view all the answers

How do guard cells regulate the opening of stomata?

By changing their shape due to turgor pressure (C) Signup and view all the answers

What is significant about the daughter cells produced at the end of mitosis?

They are genetically identical to the parent cell. (D) Signup and view all the answers

What type of tissue is formed when similar specialized cells group together?

Tissue (D) Signup and view all the answers

What process follows telophase in both mitosis and meiosis?

Cytokinesis (B) Signup and view all the answers

What is the major function of ciliated epithelium in the respiratory system?

To push dirt and microbes away from the lungs (B) Signup and view all the answers

Which of the following best describes asexual reproduction?

Produces offspring that are genetically identical to each other (B) Signup and view all the answers

What is a common limitation when identifying the stage of mitosis in cells?

Prophase and telophase may appear very similar (B) Signup and view all the answers

What characteristic of red blood cells allows for maximum oxygen-carrying capacity?

Biconcave shape and lack of nucleus (D) Signup and view all the answers

What is the role of mitochondria in root hair cells?

To provide energy for active transport of minerals (A) Signup and view all the answers

What occurs during Cytokinesis in plant cells?

Vesicles form a cell plate at the equator (C) Signup and view all the answers

What adaptation allows squamous epithelial cells to effectively cover and protect organs?

They consist of a single layer of flattened cells. (B) Signup and view all the answers

What does the term 'bivalent' refer to during Prophase I of meiosis?

A pair of homologous chromosomes (A) Signup and view all the answers

Which statement regarding the replacement of cells in humans is true?

Mitosis occurs rapidly to replace dying cells (A) Signup and view all the answers

What function does the acrosome in sperm cells serve?

Break down the egg's outer layer (D) Signup and view all the answers

What role does crossing over play in meiosis?

It increases genetic diversity between gametes (C) Signup and view all the answers

What might cause inconsistency in cell size or structure observed in specimen slides?

Inconsistent staining protocols (D) Signup and view all the answers

What process do neutrophils use to destroy pathogens?

Phagocytosis (B) Signup and view all the answers

What is the role of the cambium in plants?

Generating new cells for xylem and phloem (B) Signup and view all the answers

Which type of stem cells can develop into a limited range of cell types and are found in adult tissues?

Multipotent stem cells (B) Signup and view all the answers

How do cambium cells differentiate to form xylem?

By depositing lignin and losing their end cell walls (B) Signup and view all the answers

What is the primary function of lysosomes in neutrophils?

Digesting foreign cells (B) Signup and view all the answers

What type of stem cells are used in research and can differentiate into any cell type?

Totipotent stem cells (D) Signup and view all the answers

What causes the differentiation of cambium cells into xylem or phloem?

Hormonal balance (D) Signup and view all the answers

What characterizes adult stem cells compared to embryonic stem cells?

Limited range of cell types produced (D) Signup and view all the answers

Which organelle is primarily involved in modifying proteins and lipids?

Golgi apparatus (C) Signup and view all the answers

What happens to embryonic stem cells on day 5 after fertilization?

They become pluripotent. (B) Signup and view all the answers

Why is the use of adult stem cells considered less controversial than embryonic stem cells?

Donors can give permission. (D) Signup and view all the answers

What is a key role of the nucleus in eukaryotic cells?

Controlling cellular activities through DNA (D) Signup and view all the answers

Which component of the Golgi apparatus is responsible for packaging proteins?

Vesicles (C) Signup and view all the answers

What is the primary function of mitochondria in cells?

Producing ATP during aerobic respiration (D) Signup and view all the answers

Which structure is responsible for the engulfing and destruction of old organelles?

Lysosomes (C) Signup and view all the answers

What unique feature do chloroplasts possess that is crucial for photosynthesis?

Thylakoid membranes arranged in stacks (D) Signup and view all the answers

Which statement best describes the function of the plasma membrane?

Regulating membrane fluidity with cholesterol (B) Signup and view all the answers

What role do centrioles play during cell division?

Form spindle fibers to separate chromatids (C) Signup and view all the answers

What are pili used for in prokaryotic cells?

Communication and plasmid transfer (C) Signup and view all the answers

Which of the following organelles is involved in protein modification and processing?

Golgi apparatus (B) Signup and view all the answers

What is the main component of a plant cell wall?

Cellulose (B) Signup and view all the answers

Which characteristic is true for both prokaryotic and eukaryotic cells?

Both contain ribosomes (C) Signup and view all the answers

What is a common function of vacuoles in plant cells?

Holding cell sap to maintain turgidity (C) Signup and view all the answers

What is the main structural difference between eukaryotic and prokaryotic flagella?

Eukaryotic flagella contain microtubules (B) Signup and view all the answers

Which type of microscope allows you to visualize living cells in real time?

Light microscope (A) Signup and view all the answers

What are mesosomes theorized to be involved in?

Chemical reactions such as respiration (D) Signup and view all the answers

What is the main disadvantage of using a transmission electron microscope (TEM)?

The sample must be fixed and placed in a vacuum. (D) Signup and view all the answers

Which type of microscope uses a laser beam to produce clear, 3D images?

Confocal microscope (B) Signup and view all the answers

What is the maximum magnification achieved by a scanning electron microscope (SEM)?

500,000 x (A) Signup and view all the answers

What does resolution in microscopy refer to?

The level of detail and distinction between two close points. (C) Signup and view all the answers

Which of the following methods is used to create contrast in a specimen before viewing it under a light microscope?

Applying a stain (C) Signup and view all the answers

What type of images can a scanning electron microscope (SEM) produce that a transmission electron microscope (TEM) cannot?

3D images of cells and organelles (C) Signup and view all the answers

How is the magnification of a specimen calculated?

Total image size divided by the size of the real object. (C) Signup and view all the answers

Which of the following is NOT a feature of electron microscopes?

Ability to view live samples (A) Signup and view all the answers

What is the maximum resolution achieved by a light microscope?

0.2 μm (B) Signup and view all the answers

Which step is first when calibrating the eyepiece graticule?

Focus the lens with the stage micrometer. (D) Signup and view all the answers

Study Notes

Cell Cycle

The cell cycle is a precisely controlled process with three phases: interphase, nuclear division (mitosis), and cell division (cytokinesis).
Interphase: Cell growth, normal function, and DNA replication for mitosis.
- Consists of three phases: G1 (growth), S (DNA synthesis), and G2 (growth and error checking).
- G1 is when cells produce RNA, enzymes, and other proteins.
- S phase replicates DNA, creating sister chromatids.
- G2 checks newly synthesised DNA for errors and makes necessary repairs.
Mitosis: Nuclear division creating identical daughter nuclei.
- Divided into four stages: prophase, metaphase, anaphase, and telophase.
- Prophase: Chromosome condensation, centrosome movement, spindle fibre emergence, nuclear envelope breakdown, and nucleolus disappearance.
- Metaphase: Centrosomes at poles, spindle fibres extend and attach to chromosomes at kinetochores, chromosomes line up at metaphase plate.
- Anaphase: Sister chromatids separate, spindle fibers shorten and pull separated chromatids (now chromosomes) to opposite poles.
- Telophase: Chromosomes decondense, nuclear envelopes reform, spindle fibers break down, and nucleoli reform.
Cytokinesis: Full cell division creating two identical daughter cells.
- Animal cells: Cytoplasm constriction.
- Plant cells: New cell wall formation.
Cell Cycle Length: Varies based on environmental conditions, cell type, and organism.
- Onion root tip cells divide roughly every 20 hours.
- Human intestine epithelial cells divide roughly every 10 hours.
Cell Cycle Regulation: Chemical signals called cyclins trigger transitions between phases. Checkpoints ensure accurate DNA replication and prevent errors.
- Four checkpoints: G1 (DNA damage), S (replication completeness), G2 (DNA damage), Metaphase (chromosome attachment).
Flow Cytometry: Measures DNA mass in cells during the cell cycle.

Mitosis in Plant Cells

Mitosis in plants is studied in actively dividing meristem regions (e.g., root tips).
Techniques: Pre-prepared or temporary slides (squash technique) using stains (e.g., acetic orcein).
Limitations: Difficulty in distinguishing prophase and telophase; inconsistent cell and tissue sizes; low magnification of simple microscopes.

Significance of Mitosis

Growth of multicellular organisms: Creates genetically identical cells for growth.
Cell replacement & tissue repair: Replaces damaged or dying cells with identical ones.
Asexual reproduction: Creates genetically identical offspring in unicellular and multicellular organisms.

Meiosis

Meiosis: Nuclear division producing haploid cells from diploid cells; used in sexual reproduction.
Two divisions: Meiosis I and Meiosis II.
Meiosis I: Homologous chromosomes pair, crossover, separate.
- Prophase I: Homologous chromosome pairing, crossover, centriole migration, spindle formation, nuclear envelope breakdown, and nucleolus disintegration.
- Metaphase I: Homologous pairs align at the metaphase plate, independent assortment.
- Anaphase I: Homologous pairs separate.
- Telophase I: Chromosomes at poles, spindle fibers break, nuclear envelopes reform, and nucleoli reform.
Meiosis II: Similar to mitosis; sister chromatids separate, resulting in four haploid cells.
Crossing Over: Exchange of alleles between non-sister chromatids during Prophase I. Creates genetic variation.
Independent Assortment: Random alignment of homologous chromosomes during Metaphase I, adding to variation.
Random Fusion of Gametes: Fusion of any gamete increases genetic variation between zygotes.

Specialised Cells

Eukaryotic cells specialize for specific functions in complex organisms.
Adaptations: Shape, organelles, and absence of certain organelles.
- Examples: Erythrocytes (oxygen transport), Neutrophils (phagocytosis), Sperm cells (reproduction), Root hair cells (water absorption), Ciliated epithelium (substance movement), Squamous epithelium (diffusion), Palisade cells (photosynthesis), Guard cells (stomata regulation), Xylem vessels (water transport), Phloem cells (sugar transport), Muscle cells (movement), Cartilage (support).

Stem Cells

Stem cells: Divide indefinitely and differentiate into specialized cells.
Potency:
- Totipotent: Differentiate into any cell type.
- Pluripotent: Differentiate into any cell type in an embryo.
- Multipotent: Differentiate into a limited range of specialized cells.
Uses in research and medicine: Stem cells offer potential for disease treatment and injury repair.
Multipotent stem cells: Found in bone marrow and used for blood cell production.

Eukaryotic Cell Ultrastructure

Organelles: Nucleus, nucleolus, nuclear envelope, rough ER, smooth ER, Golgi apparatus, ribosomes, mitochondria, lysosomes, chloroplasts, plasma membrane, centrioles (animal cells only), cell wall, flagella, cilia, vacuole, cytoskeleton.
- Functions: Protein synthesis, energy production, waste disposal, photosynthesis, etc.
Prokaryotic vs. Eukaryotic Cells: Key differences include absence of membrane-bound organelles & nuclear envelope in Prokaryotes, distinct DNA structure, size, and cell wall composition

Microscopy

Techniques: Light microscopy, Transmission electron microscopy (TEM), Scanning electron microscopy (SEM).
- Applications: Visualizing cells, organelles, and tissues. High-resolution, color & 3-D image capture & analysis are possible.
Magnification and Resolution: Key concepts for evaluating images.

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Description

Test your knowledge of the cell cycle with this quiz that covers key phases like interphase, G1, G2, M phase, and cytokinesis. Understand the roles and functions of each phase and how cell division leads to genetically identical daughter cells. Perfect for biology students studying cell biology or genetics.