Cell Theory and Structure

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Questions and Answers

What is the primary function of centrosomes in muscle tissues?

Involvement in peristalsis

Connection of cells and tissues

Production of microtubules (correct)

Production of glycoproteins

Which type of muscle tissue is associated with voluntary movement?

Cartilage cells

Skeletal muscle (correct)

Smooth muscle

Cardiac muscle

What role do plasmodesmata play in plant cells?

Transport food within the plant

Link one plant cell to another (correct)

Control the movement of water

Provide structural strength

What process is primarily associated with smooth muscle in the intestine?

Peristalsis Signup and view all the answers

What is the main function of blood cells?

Transport nutrients and have limited lifespan Signup and view all the answers

Which type of connective tissue cell is an adipocyte?

Flat cell Signup and view all the answers

What characterizes cartilage cells compared to bone cells?

They are surrounded by loose and flexible material Signup and view all the answers

What is the role of tight junctions in cellular structure?

Regulate water movement between cells Signup and view all the answers

Which of the following correctly describes a ribosome?

Tiny spherical organelle that makes protein Signup and view all the answers

What is the function of plasmids in prokaryotic cells?

They carry non-essential genes for genetic engineering. Signup and view all the answers

Which statement is true regarding the similarities between prokaryotic and eukaryotic cells?

Both have plasma membranes and cytoplasm. Signup and view all the answers

Which of the following statements is NOT one of the postulates of Cell Theory?

Cells arise spontaneously from non-living matter. Signup and view all the answers

What role do pili play in prokaryotic cells?

They assist in adherence to surfaces. Signup and view all the answers

What is primarily found in the nucleoid of a prokaryotic cell?

DNA Signup and view all the answers

Which of the following organelles controls the passage of molecules in a cell?

Plasma membrane Signup and view all the answers

What is the primary function of flagella in prokaryotic cells?

For cell motility and movement. Signup and view all the answers

What are adherens junctions primarily characterized by?

Calcium and phosphate binding with adjacent cells Signup and view all the answers

What is the main function of microvilli?

Increase surface area for absorption Signup and view all the answers

What characterizes the structure of a red blood cell?

A biconcave-disc shape providing high deformability Signup and view all the answers

What occurs during the G1 phase of interphase?

The cell undergoes its longest growth phase Signup and view all the answers

Desmosomes primarily link which of the following?

Cytoskeleton to extracellular matrix components Signup and view all the answers

What is primarily composed of keratin, integrins, and cadherins?

Desmosomes/Hemidesmosomes Signup and view all the answers

Which of the following statements best describes gap junctions?

They are channels that allow communication between cell cytoplasms Signup and view all the answers

What is the key role of cell modifications after cell division?

They help cells acquire beneficial characteristics for their functions Signup and view all the answers

What is the primary function of nematocytes?

To inject toxic substances Signup and view all the answers

During which phase of the cell cycle is DNA replicated?

S Phase Signup and view all the answers

What occurs during karyokinesis?

The nucleus divides Signup and view all the answers

What is the primary outcome of cytokinesis?

Separation of the cytoplasm Signup and view all the answers

Which of the following describes a characteristic of root hairs?

Elongated structure for absorption Signup and view all the answers

In which phase does the cell prepare for mitosis by growing and duplicating its organelles?

G1 Phase Signup and view all the answers

What happens during the G2 Phase of the cell cycle?

Centrosomes are duplicated Signup and view all the answers

Which structure disappears or breaks down during telophase?

Spindle fibers Signup and view all the answers

What is the primary outcome of meiosis?

Production of four haploid daughter cells Signup and view all the answers

During which phase of meiosis does crossing over occur?

Prophase I Signup and view all the answers

What is the purpose of apoptosis in the body?

To remove damaged or non-functioning cells Signup and view all the answers

Which of the following statements about spermatogonia and oogonia is correct?

Oogonia are produced at a rate of one per month Signup and view all the answers

What happens during Telophase I of meiosis?

Nuclear envelope reforms and chromosomes decondense Signup and view all the answers

Which type of tumor is characterized by being more difficult to treat due to its ability to spread?

Malignant tumor Signup and view all the answers

What phenomenon describes the exchange of genetic material between non-sister chromatids?

Crossing over Signup and view all the answers

What is a characteristic of cancer cells?

They compete for nutrients and blood supply Signup and view all the answers

What is the consequence of non-disjunction during meiosis?

Production of gametes with abnormal chromosome numbers Signup and view all the answers

Which of the following features characterizes oocytes compared to spermatogonia?

Are non-motile cellular structures Signup and view all the answers

Study Notes

Cell Theory and Cell Structure

Robert Hooke discovered the cell, providing foundational insight into cellular biology.
Cell Theory states:
- All living organisms are composed of one or more cells.
- The cell is the fundamental unit of life.
- New cells arise from pre-existing cells.
Ribosomes are tiny organelles responsible for protein synthesis.
Plasmids carry non-essential genes, important for genetic engineering.
Pili serve motility functions and assist in adhering to surfaces.
Flagellum enables movement in cells.
The nucleoid contains DNA, regulating growth, reproduction, and functions in prokaryotic cells.

Similarities and Differences in Cell Types

Both prokaryotic and eukaryotic cells share organelles, including:
- Cell wall, plasma membrane, cytoplasm, and ribosomes.
- Presence of DNA, with some having flagella for motility.

Eukaryotic Cell Components

Centrosome produces microtubules, critical for cell structure.
Plasmodesmata are small pits connecting plant cells, facilitating intercellular communication.
Pseudopods allow for movement and engulfing prey in certain cells.
Extracellular matrix, a secreted compound, provides structural support and communication between cells.

Cell Junctions

Long-term cell associations are formed through various junctions:
- Tight Junctions regulate water movement.
- Adhering Junctions anchor cells together.
- Gap Junctions are closable channels connecting cytoplasm.
- Desmosomes link cytoskeletons to the extracellular matrix (ECM).

Cell Modifications

Microvilli increase cell surface area for absorption and facilitate impulse transmission.
Red blood cells are biconcave and deformable, aiding in their function.
Nematocytes are stinging cells that inject toxins.

The Cell Cycle

Comprised of Interphase (growth and DNA replication), Mitotic Phase (cell division), and Cytokinesis (cytoplasmic separation).
Interphase includes:
- G1 phase (growth and organelle increase).
- S phase (DNA replication).
- G2 phase (final preparations for mitosis).

Meiosis

Meiosis produces sex cells (spermatogonia and oogonia) with distinct characteristics:
- Spermatogonia: millions produced per day, located in testes, motile.
- Oogonia: one produced per month, located in ovaries, non-motile.
Examines genetic variations via crossing over and recombination during meiosis.

Cancer Biology

Apoptosis is programmed cell death, contrasting with uncontrolled cell death from injury.
Cancer characterized by uncontrolled cell division, with tumor types categorized as:
- Benign tumors (non-threatening, manageable).
- Malignant tumors (potentially harmful, capable of metastasis).
Cancer cells disrupt normal functions and compete for nutrients.

Membrane Transport

Essential for controlling molecular passage into and out of the cell, maintaining homeostasis.

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Description

Explore the fundamentals of cell theory and the differences between prokaryotic and eukaryotic cells. This quiz covers essential cell components and their functions, including organelles like ribosomes and flagella. Understand the significance of plasmids and the nucleoid in cellular biology.