Cell Biology: Cell Death and Reproduction

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Questions and Answers

What significant event occurs during Metaphase?

The nuclear envelope begins to reform.

DNA replication takes place.

Chromosomes align along the cell's equator. (correct)

Centrioles migrate to the center of the cell.

Which of the following describes the role of spindle fibers in cell division?

Spindle fibers attach to centromeres of sister chromatids. (correct)

Spindle fibers prevent chromosome condensation.

Spindle fibers dissolve the nuclear envelope.

Spindle fibers synthesize DNA during Prophase.

What is indicated by errors in chromosome alignment during Metaphase?

Enhanced cell division efficiency.

Successful completion of Anaphase.

Improved chromosome condensation.

Potential genetic abnormalities. (correct)

What marks the beginning of Prophase in cell division?

Disappearance of nucleoli. Signup and view all the answers

Which type of radiation includes sources such as X-rays and gamma rays?

Ionizing radiation. Signup and view all the answers

Why is sexual reproduction important for a species?

It promotes genetic diversity. Signup and view all the answers

What is the role of meiosis in sexual reproduction?

It generates haploid gametes. Signup and view all the answers

What happens to neurons in terms of the cell cycle?

They can exit the cell cycle and remain in G0 phase. Signup and view all the answers

What is the primary role of spindle fibers during cell division?

They segregate chromosomes. Signup and view all the answers

During which phase do sister chromatids separate?

Anaphase Signup and view all the answers

What characterizes malignant tumors compared to benign tumors?

Malignant tumors spread to other parts of the body. Signup and view all the answers

What occurs concurrently with telophase?

Cytokinesis Signup and view all the answers

What do sister chromatids carry?

Identical genetic information Signup and view all the answers

What is the function of the centromere in relation to sister chromatids?

It connects identical copies of a chromosome. Signup and view all the answers

What can disrupt proper chromosome separation during cell division?

Spindle fiber malfunction Signup and view all the answers

How is cytokinesis achieved in plant cells?

Development of a cell plate Signup and view all the answers

What is apoptosis primarily associated with?

Programmed cell death Signup and view all the answers

Which phase of mitosis is characterized by the separation of chromatids?

Anaphase Signup and view all the answers

How does asexual reproduction differ from sexual reproduction?

Asexual reproduction involves only one parent. Signup and view all the answers

What is the primary consequence of cell injury?

Necrosis Signup and view all the answers

What is one of the primary functions of mitosis in organisms?

Repair and growth of tissues Signup and view all the answers

In which organisms is asexual reproduction most commonly observed?

Bacteria and fungi Signup and view all the answers

What role do cohesins play during mitosis?

They bind sister chromatids together. Signup and view all the answers

Which of the following types of reproduction increases genetic diversity?

Sexual reproduction Signup and view all the answers

What is the primary purpose of chemotherapy?

To destroy cancer cells Signup and view all the answers

What is the key characteristic of chromatin?

It packages and condenses DNA. Signup and view all the answers

What signifies the end of cytokinesis?

Division of the cytoplasm into two daughter cells Signup and view all the answers

During which phase of the cell cycle does DNA replication occur?

S phase Signup and view all the answers

How many chromosomes are typically found in a human cell?

46 Signup and view all the answers

What is a major side effect of chemotherapy?

Fatigue Signup and view all the answers

What distinguishes euchromatin from heterochromatin?

Euchromatin is loosely packed and more transcriptionally active. Signup and view all the answers

In plant cells, what structure separates the daughter cells during cytokinesis?

Cell plate Signup and view all the answers

Study Notes

Cell Death

Cell death is a natural physiological process, either through programmed cell death (apoptosis) or cell injury (necrosis).
Apoptosis is essential for tissue homeostasis and crucial in development and immune regulation.
Cell injury from toxins/trauma results in necrosis, an uncontrolled form of cell death.
Removal of dead cells prevents inflammation and tissue damage.

Mitosis

Mitosis is cell division creating two genetically identical daughter cells.
It occurs in somatic (body) cells.
The phases are prophase, metaphase, anaphase, and telophase.
Mitosis enables growth, repair, and asexual reproduction.
Abnormalities can lead to cancer.

Types of Reproduction

Reproduction is either sexual (genetic variation, two parents) or asexual (identical offspring, one parent).
Sexual reproduction involves meiosis and gamete fusion.
Asexual reproduction includes methods like binary fission, budding, and fragmentation.
Asexual reproduction is more efficient energetically.

Key Terms - Anaphase

Anaphase is a stage of cell division where chromatids separate and move to opposite poles.
Facilitated by microtubule shortening.
Proteins called cohesins hold chromatids together until anaphase.

Asexual Reproduction

An organism can reproduce without another organism.
Creates genetically identical offspring.
Common in bacteria, fungi, and plants.
Enables rapid population growth.

Chemotherapy

A treatment method using drugs to destroy cancer cells.
Can be used alone or with other treatments like surgery or radiation.
Administered orally, by injection, or IV infusion.
Targets rapidly dividing cells, including cancerous cells.
Possible side effects include nausea, hair loss, fatigue, and weakened immune system.

Chromatin

Complex of DNA and proteins within the nucleus.
Packages and condenses DNA.
Crucial for gene expression and regulation.
Condenses further into chromosomes during cell division.

Chromosome

Thread-like DNA and protein structures in the nucleus.
Carry genes, the units of heredity.
Humans have 46 chromosomes (23 pairs).
Prokaryotes have a circular chromosome.
Visible during cell division when condensed.
Abnormalities can lead to genetic disorders.

Cytokinesis

Final stage of cell division where cytoplasm divides.
Occurs after mitosis/meiosis.
Ensures equal distribution of organelles/cytoplasm in daughter cells.
Different mechanisms in animal vs. plant cells. (animal cell contractile ring, plant cell cell plate).

Interphase

Phase of cell cycle where a cell prepares for division by duplicating DNA and growing in size.
Consists of G1, S, and G2 phases.
Cell growth happens in G1 and G2.
DNA replication takes place in the S phase.
Most of the cell cycle is spent in interphase.
Some cells exit the cycle and enter G0.

Metaphase

Chromosomes align along the cell's center (equator).
Spindle fibers attach to chromosome centromeres.
Ensures proper chromosome division

Prophase

The initial phase of mitosis.
Chromosomes condense.
Spindle fibers form and start to attach to chromosomes.
Nucleolus disappears (breakdown of the nucleus).

Radiation

Emission of energy in the form of particles or electromagnetic waves.
Ionizing radiation has enough energy to remove electrons from atoms.
Common sources: X-rays, gamma rays, radioactive materials.
Exposure can damage cells/DNA.
Non-ionizing radiation is generally considered safe.

Sexual Reproduction

Genetic material from two parents combines to create offspring with varied genetic composition.
Promotes genetic diversity.
Involves meiosis.
Sperm and egg unite during fertilization to form a zygote.

Sister Chromatids

Identical copies of a single chromosome.
Connected at the centromere.
Produced during the S phase of the cell cycle.

Spindle Fibers

Microscopic structures involved in cell division (mitosis/meiosis).
Composed of microtubules.
Attach to chromosomes.
Help segregate chromosomes to daughter cells.

Telophase

Final stage of mitosis
Chromosomes decondense
Nuclear envelopes re-form.
Cytokinesis usually happens at the same time to divide the cytoplasm.

Tumour

Abnormal mass of tissue formed by uncontrolled cell growth and division.
Can be benign (non-cancerous) or malignant (cancerous).
Malignant tumors invade nearby tissues and can metastasize.
Metastasis is the spread of cancer cells in the body.

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Description

This quiz covers essential concepts in cell biology, focusing on cell death (apoptosis and necrosis), the process of mitosis, and the types of reproduction (sexual and asexual). It highlights how these processes are fundamental for growth, development, and homeostasis in living organisms.