Cell Biology Quiz

Questions and Answers

What is the primary difference between apoptosis and necrosis?

Apoptosis is accidental cell death, while necrosis is programmed cell death.

Apoptosis leads to tissue regeneration, while necrosis leads to cell replacement.

Apoptosis involves rapid cell swelling and lysis, necrosis is controlled autodigestion.

Apoptosis is a controlled process, while necrosis results from unfavorable conditions. (correct)

Which of the following cell types typically undergo apoptosis during development?

All types of cells in the body

Ovarian follicles

Immature T lymphocytes (correct)

Epithelial cells of the skin

What triggers the apoptosis of developing T lymphocytes?

Natural cell programming (correct)

Infection by pathogens

External injury or trauma

Overproduction of hormones

Which phenomenon is NOT an example of apoptosis?

Spontaneous cell lysis due to environmental factors Signup and view all the answers

Which cells are primarily responsible for forming the framework of tissues and organs?

Stroma cells Signup and view all the answers

Which morphological characteristic is used to classify parenchyma cells?

The shape of the cell Signup and view all the answers

What distinguishes parenchyma cells from stroma cells?

Stroma cells are less specialized than parenchyma cells. Signup and view all the answers

What is the role of apoptosis in relation to abnormal cells?

To eliminate cells infected by viruses Signup and view all the answers

What is the primary function of the plasma membrane?

Physical barrier and selective permeability Signup and view all the answers

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

S phase Signup and view all the answers

What is a key difference between mitosis and meiosis?

Mitosis produces diploid cells, while meiosis produces haploid cells. Signup and view all the answers

Which cytoskeletal component is primarily responsible for maintaining cell shape and rigidity?

Microtubules Signup and view all the answers

What occurs during the anaphase of mitosis?

Chromosomes are pulled apart toward opposite poles. Signup and view all the answers

Which of the following cells are defined as 'rapidly renewing'?

Blood cells Signup and view all the answers

What describes the structural organization of microfilaments?

Thin, twisted strands made of actin protein monomers Signup and view all the answers

What characterizes the process of apoptosis?

Regulated cell death without releasing contents Signup and view all the answers

Which cell division process involves the separation of germ cells?

Meiosis Signup and view all the answers

What is the function of ribosomes during cellular activities?

Synthesis of proteins Signup and view all the answers

Study Notes

Cell Overview

Basic structural and functional unit of living organisms.
Smallest living parts of the body, comprising plasma membrane, nucleus, and cytoplasm.

Cell Differentiation

Specialization process allowing cells to develop distinct functions.
Involves gene expression related to cytoplasmic activities.
Organized into tissues with specific functions and shapes.

Plasma Membrane

Composed of a phospholipid bilayer with cholesterol, proteins, and carbohydrates.
Functions include serving as a physical barrier, selective permeability, maintaining electrochemical gradients, and facilitating communication.

Cytoplasm

Contains cytosol, a viscous fluid for organelle support and diffusion of solutes.
Organelles perform specific metabolic activities essential for cellular function.

Cytoplasmic Organelles

Rough Endoplasmic Reticulum (Rough ER): Modifies, transports, and stores proteins synthesized by ribosomes.
Smooth Endoplasmic Reticulum (Smooth ER): Synthesizes lipids, metabolizes carbohydrates, and detoxifies drugs and poisons.
Golgi Apparatus: Modifies, packages, and sorts materials from the ER; creates secretory vesicles and lysosomes.
Lysosomes: Digest microbes or damaged cellular components through enzymatic action.
Peroxisomes: Detoxify harmful substances, engaging in fatty acid metabolism.
Mitochondria: Synthesize ATP via aerobic cellular respiration by converting glucose and oxygen.
Ribosomes: Sites of protein synthesis, with bound ribosomes producing proteins for export and free ribosomes synthesizing proteins for internal use.
Cytoskeleton: Provides structural support, aids organelle movement, and facilitates cell division and shape changes.

Cytoskeleton Components

Microfilaments: Composed of actin, maintaining cell shape and supporting muscle contraction.
Intermediate Filaments: Provide structural stability and support cell junctions.
Microtubules: Organize cellular structure, transport organelles, and assist in cell division.

Nucleus

Largest cell structure, containing the nuclear envelope, chromatin, and nucleolus.
Houses genetic material, directing cellular activities and producing ribosomal units.

The Cell Cycle

Series of events for cell proliferation, consisting of four phases:
Mitosis: Cell division producing two identical diploid cells.
G1 Phase: Gap between cell division and DNA synthesis.
S Phase: DNA synthesis and replication occurs.
G2 Phase: Gap before the next mitosis.

Mitosis Phases

Prophase: Chromosomes condense; nuclear structures begin to dissolve.
Metaphase: Chromosomes align at the equatorial plate.
Anaphase: Centromeres split, ensuring equal genetic material distribution.
Telophase: Chromosomes uncoil and the nuclear envelope reassembles.

Mitosis vs. Meiosis

Mitosis results in 2 diploid cells; Meiosis results in 4 haploid gametes (eggs and sperm).
Mitosis maintains chromosome number; Meiosis halves the chromosome number (23 pairs to 23).

Stem Cells

Undifferentiated cells renewing differentiated tissues as needed.
Characterized by asymmetric division; one daughter cell remains a stem cell.
Progenitor cells are committed to differentiation.

Cell Population Types

Rapidly Renewing: Cells dividing rapidly, e.g., blood cells.
Stable: Cells dividing slowly and episodically, stimulated by injury, e.g., periosteal cells.
Static: Non-dividing cells, e.g., CNS cells.

Apoptosis

Highly regulated process of programmed cell death, eliminating defective cells without rupture.
Examples include epithelial cells, T lymphocytes, and embryonic cells.

Apoptosis Examples

Cells with preset lifetimes or those that need to be eliminated during development, e.g., webbed digits in embryos.

Cell Death Types

Apoptosis: Physiological, controlled process; involved in development and tissue homeostasis.
Necrosis: Accidental, pathological cell death due to unfavorable conditions.

Classification of Cells

Parenchyma: Functionally specialized cells, main characteristic cells in an organ, e.g., hepatocytes in the liver.
Stroma: Supporting, less specialized tissue; includes other cells and structural fibers.

Morphological Characteristics

Parenchyma classification based on cell shape, arrangement, number, and location of nuclei.

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Description

Test your knowledge on cell structure, cellular differentiation, and the functions of various organelles. This quiz includes concepts such as the plasma membrane, cytoskeleton, and the nucleus. Perfect for students in human biology.