Biology Cell Structure and Function Quiz

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is a key difference between eukaryotic and prokaryotic cells?

Eukaryotic cells contain a nucleus and membrane-bound organelles. (correct)

Prokaryotic cells contain membrane-bound organelles.

Eukaryotic cells lack a nucleus.

Prokaryotic cells carry genetic information in RNA.

Which type of cell would most likely be specialized for hormone production?

Fibroblast cells

Secretory cells (correct)

Epithelial cells

Muscle cells

What characterizes the internal organization of both eukaryotic and prokaryotic cells?

Both have a nucleus.

Both contain DNA. (correct)

Both lack membrane-bound organelles.

Both can perform photosynthesis.

What do certain cells require that makes them unsuitable for oxygen-rich environments?

Anaerobic conditions Signup and view all the answers

Which of the following statements about cell function is true?

Cell shape is correlated with its function. Signup and view all the answers

What common factor do all living cells share chemically?

Similar basic chemistry Signup and view all the answers

Why can some cells utilize carbon dioxide, sunlight, and water while others cannot?

Cell structure influences chemical capabilities. Signup and view all the answers

Which of the following cell components performs specific functions within the cell?

Organelle Signup and view all the answers

What is the primary function of the Golgi apparatus?

Modification, sorting, and packing of synthesized materials Signup and view all the answers

Which structure within the mitochondria is involved in energy production?

Cristae Signup and view all the answers

How is mitochondrial DNA inherited?

Only from the mother Signup and view all the answers

What type of enzymes do lysosomes contain?

Hydrolytic enzymes Signup and view all the answers

Which cellular organelle is primarily associated with waste disposal?

Lysosomes Signup and view all the answers

What happens to the number of mitochondria in highly active cells?

They increase in number Signup and view all the answers

What is the matrix in a mitochondrion?

The space containing enzymes inside the inner membrane Signup and view all the answers

What is one of the main functions of the Golgi apparatus in terms of vesicle production?

Formation of lysosomes Signup and view all the answers

What is the primary function of the cytoskeleton?

Mechanical resistance and shape maintenance Signup and view all the answers

Which of the following describes microfilaments?

Composed of polymers of actin Signup and view all the answers

What type of electron microscope is primarily used to study the internal structure of cells?

Transmission electron microscope (TEM) Signup and view all the answers

How do microfilaments exhibit polarity?

They have distinct positive and negative ends. Signup and view all the answers

Which electron microscope provides images that appear three-dimensional?

Scanning electron microscope (SEM) Signup and view all the answers

What role do intermediate filaments serve within the cell?

Provide structural support Signup and view all the answers

What is the diameter of intermediate filaments?

10 nm Signup and view all the answers

What is the primary purpose of cell fractionation?

To separate cellular components while preserving their functions Signup and view all the answers

Which technique is primarily employed to fractionate cells into their components?

Ultracentrifugation Signup and view all the answers

Which statement about the composition of intermediate filaments is true?

They consist of fibrous proteins in strands. Signup and view all the answers

Which type of protein is primarily involved in the composition of microfilaments?

Actin Signup and view all the answers

In the context of cell biology, what does biochemistry and cytology help to correlate?

Cell function with structure Signup and view all the answers

What distinguishes the types of intermediate filaments in animal cells?

Their amino acid sequence and protein structure Signup and view all the answers

Which of the following components is not considered a basic structure of the cell?

Endoplasmic reticulum Signup and view all the answers

What feature distinguishes scanning electron microscopes from transmission electron microscopes?

Type of images produced (surface vs internal) Signup and view all the answers

What is a primary use of transmission electron microscopes?

Examining the internal structure of cells Signup and view all the answers

What describes the process of simple diffusion?

The passive movement of a solute from an area of high concentration to low concentration. Signup and view all the answers

Which factor does NOT affect the rate of diffusion?

Color of the solute. Signup and view all the answers

What is a key characteristic of facilitated diffusion?

It involves the use of transmembrane protein molecules. Signup and view all the answers

How does temperature influence the rate of diffusion?

Higher temperatures increase molecular movement, thus increasing diffusion rate. Signup and view all the answers

What happens to the rate of diffusion as two concentrations become more similar?

It begins to slow down. Signup and view all the answers

What effect does solvent density have on the diffusion process?

Increased solvent density decreases the rate of diffusion. Signup and view all the answers

Which statement accurately represents the concept of equilibrium in diffusion?

Equilibrium occurs when concentrations are equal on both sides of the membrane. Signup and view all the answers

What is the first step in the process of exocytosis?

Vesicle trafficking Signup and view all the answers

Which of the following substances typically moves through the plasma membrane by simple diffusion?

Ethanol Signup and view all the answers

Which process requires specific modifications of molecules in the cell membrane to trigger exocytosis?

Priming in regulated exocytosis Signup and view all the answers

What characterizes the 'kiss-and-run fusion' method of exocytosis?

It allows a temporary fusion and release of contents. Signup and view all the answers

Which motor proteins assist in the movement of vesicles during vesicle trafficking?

Kinesins, dyneins, and myosins Signup and view all the answers

What happens during the 'docking' step of exocytosis?

The vesicle membrane merges with the cell membrane. Signup and view all the answers

Complete fusion during exocytosis is characterized by what?

Formation of a fusion pore allowing contents to be expelled. Signup and view all the answers

Which step occurs only in regulated exocytosis and not in constitutive exocytosis?

Priming Signup and view all the answers

What is the purpose of the fusion pore created during complete fusion?

To expel vesicle contents into the extracellular space. Signup and view all the answers

Study Notes

Cell Biology Course Outline

This course covers cell biology (cytology)
Topics include: Cell Structure, Cell Signaling, Cell Cycle, Cellular Communication/Tissue Organization & Advanced Topics in Cell Biology
The academic year is 2024-2025 and the course is for 2nd year medicine students.
The course is illustrated by Dr. Ghenwa NASR.

1. The Cell

The cell is the basic structural and functional unit of living organisms.
Cells are the 'building blocks' of all living organisms.
The term 'cell' comes from the Latin word 'cellula', meaning 'small room'.
Cells are small membrane-enclosed units filled with a concentrated aqueous solution of chemicals, the cytoplasm.
Many cells contain organelles with specific functions.
Cells are complex and their individual components have various functions in an organism.
Cells are responsible for the continuity of life through their growth and division.

1.2. The Cell: A Historical Overview

Pre-17th Century: The concept of the cell wasn't understood.
1590s: Hans and Zacharias Janssen created the first compound microscope, enabling observation of small structures.
1665: Robert Hooke used a microscope to examine cork, coining the term 'cell' to describe the box-like structures observed.
1830: The development of the cell theory.

1.3. The Cell Theory

Until microscopes became powerful enough to view individual cells, the composition of living organisms was unknown.
Robert Hooke is considered the first person to view cells, and coined the term.
Matthias Schleiden and Theodor Schwann proposed the cell theory in 1837.
The cell theory states that:
- All living organisms are composed of one or more cells.
- Cells are the basic functional units in living organisms.
- New cells are produced from pre-existing cells.
The modern cell theory elaborates on the original theory by adding:
- Cells contain hereditary information (DNA).
- Cells share a fundamental chemical composition.
- Energy flow occurs within cells.
- Cell activity depends on the activities of sub-cellular structures (organelles).

2. The Diversity of Cells

Cells vary greatly in shape and function.
Unicellular organisms differ from multicellular organisms.
Even cells within the same multicellular organism can vary widely in appearance and activity.
- Despite these differences, all cells share a fundamental chemistry and other common features.
Cells vary enormously in appearance and function due to: size, shape, chemical requirements, function, and internal organization.
Size: Cells vary in size, most being microscopic but some macroscopic, such as ostrich eggs.
Shape: Shapes vary depending on the cell type and function. Example: human RBCs are biconcave to fit through capillaries while nerve cells have branching shapes to transmit impulses across the body.
Chemical Requirements: Some cells require oxygen while others may find it deadly. Some require CO2, sunlight or water for basic function, others require complex mixtures of molecules produced by other cells.
Function: Cells function varies depending on the type or organism
Internal Organization: The internal organization of cells determines whether they are prokaryotic or eukaryotic cells.

3. Prokaryotic and Eukaryotic Cells

Based on complexity, cells are categorized into prokaryotic and eukaryotic.

3.1. Prokaryotic Cells

Prokaryotes are single-celled organisms without a nucleus or other membrane-bound organelles.
They are derived from the Greek words "pro" (before) and "karyon" (kernel).
Prokaryotes include two domains: Bacteria and Archaea
Prokaryotes are typically spherical, rod-shaped, or spiral-shaped.
Prokaryotic cells range in size from 0.1 to 5.0 µm in diameter.
The cell's hereditary material (DNA) is often found in a region called the nucleoid.

3.2. Eukaryotic Cells

Eukaryotes are advanced organisms with a well-defined nucleus and membrane-bound organelles.
They are thought to have originated from the prokaryotes about 2.7 billion years ago.
Eukaryotes can be unicellular or multicellular.
Eukaryotes reproduce both asexually (mitosis) and sexually (meiosis and gamete fusion)
Eukaryotic cells are categorized into four groups or domains: protozoa (or protists), fungi, plants, and animals.

4. Techniques in Cell Biology

Microscopy: Light and electron microscopy are used to visualize and study cells.
Cell Fractionation and Imaging: separating cell components to determine functions of organelles.

5. Cellular Organelles and Their Function

Cells are composed of various organelles
Nucleus: The largest organelle, containing genetic material (DNA) and controlling cell activities.
Endoplasmic Reticulum (ER): A network of interconnected tubules and vesicles involved in protein and lipid synthesis, folding, and transport.
- Rough ER (RER): has ribosomes and synthesizes proteins.
- Smooth ER (SER): lacks ribosomes and synthesizes lipids.
Golgi Apparatus: Modifies, sorts, and packages materials for transport within or outside the cell.
Mitochondria: The powerhouse of the cell; responsible for cellular respiration.
Lysosomes: Degradative organelles containing enzymes to digest organic materials.
Peroxisomes: Oxidative organelles involved in breaking down fatty acids and other substances.
Cytoskeleton: A network of protein filaments providing structural support, facilitating movement and cell shape.
- Microtubules: tube-like structures, aiding in transportation and cell division.
Ribosomes: Involved in protein synthesis.

6. The Plasma Membrane

Structure and Composition: The plasma membrane is a phospholipid bilayer with proteins and carbohydrates embedded in it, acting as a selective barrier to regulate what enters and leaves the cell.
Membrane Lipids:
- Phospholipids: form the basic structure of the membrane (bilayer), with hydrophobic tails facing inwards and hydrophilic heads toward the exterior/interior.
- Cholesterol: maintains membrane fluidity (rigidity) in animals.
- Glycolipids: carbohydrate chains attached to lipids, important in cell communication.
Membrane Proteins:
- Integral Proteins: permanently embedded within the membrane (transmembrane).
- Peripheral Proteins: temporarily associated with the membrane.
Membrane Carbohydrates:
- Glycoproteins: linked to proteins, crucial in cell signaling and communication.
- Glycolipids: linked to lipids, maintain membrane stability and facilitate communication.
Properties: the membrane has asymmetry; the lipid bilayer has fluidity, influenced by temperature; and it's selectively permeable, allowing certain substances to pass.
Functions:
- Maintaining cell shape; protecting and defending the cell (barrier); and maintaining homeostasis and concentration gradient.
- Signal transduction: Receiving and processing extracellular signals.
- Catalysis of chemical reactions: Using enzymes.
- Cell communication: Allows exchange (receiving and sending) of messages between adjacent cells.
Transport Mechanisms:
Passive Transport: (no energy required)
- Simple Diffusion: movement of substances from high to low concentration (across the membrane).
Facilitated Diffusion: Diffusion with the help of transport proteins (channel or carrier proteins specific to certain molecules).
Active Transport: (requires energy - ATP)
- Primary Active Transport: directly uses ATP to move substances against their concentration gradients (such as sodium-potassium pump).
- Secondary Active Transport: couples the movement of one substance down its gradient to the movement of another against its gradient (against the electrochemical gradient).
Vesicular Transport: (Large materials - requires energy)
- Exocytosis: Moves materials from inside the cell to outside; fuses with cell membrane to release contents.
- Endocytosis: Brings materials from outside the cell into a vesicle by engulfing it..
  - phagocytosis (large particles in vesicles),
  - pinocytosis (fluid in vesicles)
  - receptor-mediated endocytosis (specific molecules and their receptors).

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on the fundamental differences between eukaryotic and prokaryotic cells. This quiz covers key cell functions, organelles, and the unique characteristics that define each cell type. Delve into topics such as mitochondrial function, lysosomes, and the role of the Golgi apparatus.