Cell Division: Mitosis and Meiosis

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Questions and Answers

What occurs during anaphase in relation to sister chromatids?

Sister chromatids separate and move towards opposite poles. (correct)

Sister chromatids undergo mutation during separation.

Sister chromatids align at the equatorial plate.

Sister chromatids replicate to form double the amount.

Which process describes the arrangement and separation of homologous pairs prior to receiving maternal or paternal DNA?

Anaphase I (correct)

Telophase II

Metaphase II

Cytokinesis

What is the role of mitotic spindle fibers during telophase II?

They facilitate the disintegration of sister chromatids.

They disintegrate before cytokinesis is completed. (correct)

They help in the replication of DNA.

They align the chromosomes at the spindle equator.

What defines a chromosome in genetic terms?

A DNA molecule consisting of two sister chromatids. Signup and view all the answers

Which of the following statements about sister chromatids is incorrect?

Sister chromatids undergo replication during cytokinesis. Signup and view all the answers

What is the purpose of genetic engineering in organisms?

To add, remove, or change specific genes for new traits Signup and view all the answers

How does meiosis contribute to genetic diversity?

By reducing the genetic material and enabling sexual reproduction Signup and view all the answers

What is indicated by the term adaptation in biology?

An organism's ability to thrive in altered environments Signup and view all the answers

Which statement accurately portrays GMOs?

Genetically engineered organisms are a subset of GMOs Signup and view all the answers

What happens when a cell error occurs in the body?

The body compensates by attempting to repair the error Signup and view all the answers

What occurs when an animal cell is placed in a hypotonic solution?

The cell will swell and may burst. Signup and view all the answers

What is the role of the large central vacuole in plant cells?

It stores nutrients and water, creating turgor pressure. Signup and view all the answers

What happens during plasmolysis in plant cells?

The cytoplasm shrinks due to loss of water. Signup and view all the answers

What defines an isotonic solution?

The solute concentration is equal inside and outside the cell. Signup and view all the answers

What is the primary cause of turgor pressure in plant cells?

Movement of water into the central vacuole. Signup and view all the answers

What happens to a cell if it is not repairable?

It will undergo programmed cell death. Signup and view all the answers

What is a common consequence of mitotic errors?

Passing DNA modifications to daughter cells. Signup and view all the answers

What type of chromosomal abnormality occurs during nondisjunction?

Abnormal separation of sister chromatids. Signup and view all the answers

Which of the following is associated with an increased risk of cancer?

Exposure to radiation. Signup and view all the answers

What is the result of aneuploidy?

Abnormal number of chromosomes. Signup and view all the answers

Which of the following cancers is commonly recognized by WHO?

Lung cancer. Signup and view all the answers

Which factor is NOT associated with increased cellular mutations?

Adequate nutrition. Signup and view all the answers

What is polyploidy characterized by?

An increased number of sets of chromosomes. Signup and view all the answers

What happens to the lipid tails in the plasma membrane when they become straight?

The membrane becomes rigid and viscous. Signup and view all the answers

How does the fluid mosaic model describe the nature of the plasma membrane?

It has a balance of fluidity and rigidity. Signup and view all the answers

Which type of diabetes results from the body not producing insulin?

Type I Diabetes Mellitus. Signup and view all the answers

Which statement accurately describes Type II Diabetes Insipidus?

The body produces insulin but does not recognize it. Signup and view all the answers

What is one symptom common in both Type I and Type II Diabetes?

Polydipsia. Signup and view all the answers

What role does flexibility in the plasma membrane play for cells?

It facilitates locomotion and growth. Signup and view all the answers

How does the presence of unsaturated fats affect the fluidity of the plasma membrane?

They introduce kinks that promote fluidity. Signup and view all the answers

What is a consequence of a rigid plasma membrane in a cell?

Decreased cell flexibility. Signup and view all the answers

What is the primary function of mitosis?

To create genetically identical somatic cells Signup and view all the answers

During which phase of mitosis do microtubules attach to the chromosomes?

Metaphase Signup and view all the answers

Which phase of the cell cycle includes checkpoints to monitor cell health before mitosis?

Gap 1 Signup and view all the answers

What happens to the chromatin during prophase?

It condenses into visible chromosomes Signup and view all the answers

Which statement regarding cytokinesis is true?

It divides the cell into two daughter cells. Signup and view all the answers

In which phase do the centrosomes migrate to opposite poles?

Prometaphase Signup and view all the answers

How does the chromosome number change during meiosis compared to mitosis?

It decreases by half. Signup and view all the answers

What is one of the key differences between mitosis and meiosis?

Meiosis goes through PMAT twice. Signup and view all the answers

Study Notes

Mitosis

Mitosis is a process where a cell divides to produce two identical daughter cells.
It only occurs in somatic (body) cells, and takes up about 10% of the cell cycle.
The other 90% is interphase, which is the preparation phase for mitosis, where the chromosome is in the form of chromatin.
Interphase consists of Gap 0, Gap 1, S phase, and Gap 2.

Mitosis Phases

Prophase: Chromatin condenses, nucleus disintegrates and spindle fibers form.
Prometaphase: Nuclear envelope dissolves, centrosomes move to opposite poles, and spindle fibers finish forming.
Metaphase: Microtubules attach to chromosomes in the middle of the cell.
Anaphase: Mitotic spindle fibers separate sister chromatids and move them to opposite poles.
Telophase: The now daughter chromosomes decondense.
Cytokinesis: The cell divides into two daughter cells.

Meiosis

Meiosis is a process that undergoes PMAT and cytokinesis twice to produce sex cells (gametes).
The number of chromosomes decreases to half during meiosis.
Meiosis 1 is a reduction division, reducing the number of chromosomes.
Meiosis 2 is an equational division, restorering the chromosome number during fertilization.

Significance of Mitosis and Meiosis

Mitosis maintains genetic material (genome).
Mitosis ensures proper cell function and maintains the same number of chromosomes by duplicating and dividing chromosomes.
Meiosis reduces chromosome number by half producing gametes for sexual reproduction.
Meiosis also introduces genetic variation through crossing over.

Significance of Meiosis

Reduction of genetic material and sexual reproduction.
Genetic diversity.
Survival.

Biological Significance of Crossing Over

Crossing over is an exchange of genetic material/segments which helps to increase genetic diversity and enhances genetic variation.

Cancer

Cancer is an error in cell checkpoints that stops apoptosis which causes abnormal growth.
Neoplasm forms when defective cells grow into tumors.
Early detection is the most effective way to treat cancer.

Nondisjunction Disorders

Polyploidy: Abnormal number of sets of chromosomes.
Aneuploidy: Abnormal number of chromosomes.
- Down syndrome: An example of an aneuploidy disorder where there is an extra chromosome 21 (Trisomy 21).

Other Genetic Disorders

Patau Syndrome (Trisomy 13): Characterized by cleft lip, cleft palate, cerebral defects, and holoprosencephaly.
Edward Syndrome (Trisomy 18): Characterized by heart complications.
Turner Syndrome (Monosomy X): A chromosomal disorder affecting females, causing characteristic features, short stature, broad shoulders, and developmental delays.
Warkany Syndrome (Chromosome 8): Characterized by stiff joints, congenital abnormalities, and delayed development.

Stem Cells

Undifferentiated cells that can become specialized cells.
Stem cell technology is used in replacing old and damaged cells.
Stem cells derive from embryonic stem cells or adult stem cells.

Genetic Engineering

Genetic engineering is a process to directly modify the DNA of an organism to produce new traits.
All genetically engineered organisms are GMOs, but not all GMOs are genetically engineered.

Cellular Transport

Diffusion: Movement of molecules from a higher concentration to a lower concentration until equilibrium is reached.
Osmosis: Movement of water across a semi-permeable membrane from a lower solute concentration to a higher solute concentration.

Passive Transport

Simple Diffusion: Movement of small, nonpolar molecules across a membrane without the aid of transport proteins.
Facilitated Diffusion: Movement of molecules across a membrane with the help of transport proteins.

Active Transport

Active Transport: Movement of molecules against their concentration gradient, requiring energy.
Sodium-Potassium Pump: An example of an active transport mechanism that moves sodium ions out of a cell and potassium ions into a cell.

Bulk Transport

Vesicles: Small sacs that transport materials within and between cells.
Exocytosis: Vesicles fusing with the plasma membrane to release their contents outside the cell.
Endocytosis: The process of taking substances into the cells by enveloping them in a vesicle.
- Phagocytosis: Cell eating, engulfing particles (bacteria).
- Pinocytosis: Cell drinking, engulfing fluids.
- Receptor-mediated Endocytosis: Specialized endocytosis usingreceptor proteins to capture specific molecules.

Factors Affecting Cell Transport

Concentration Gradient: Difference in concentration between two areas.
Size of molecules: Smaller molecules diffuse faster than larger ones.
Membrane permeability: How easily substances can pass through a membrane.

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Description

Explore the processes of cell division through this quiz on mitosis and meiosis. Understand the stages of mitosis including prophase, metaphase, anaphase, and more. Additionally, learn how meiosis ensures genetic diversity in gametes.