Biology Module 1: Cells as the Basis of Life

Questions and Answers

Which statement correctly describes prokaryotic cells?

Prokaryotic cells have membrane-bound organelles.

Prokaryotic cells contain a true nucleus.

Prokaryotic cells are generally larger than eukaryotic cells.

Prokaryotic cells can only exist as unicellular organisms. (correct)

What is the primary chemical composition of bacterial cell walls?

Peptidoglycan (correct)

Cellulose

Pseudomurein

Chitin

What is a characteristic of eukaryotic cells?

They have no membrane-bound organelles.

They are always smaller than prokaryotic cells.

Their DNA is found within the cytoplasm.

They generally evolved from prokaryotic cells. (correct)

Which of the following is NOT a shape associated with bacterial cells?

Hexagon Signup and view all the answers

Which term correctly describes the process by which cells arise from pre-existing cells?

Cell division Signup and view all the answers

What is the size range of eukaryotic cells compared to prokaryotic cells?

Eukaryotic cells are generally larger than prokaryotic cells. Signup and view all the answers

Which statement about the antibiotic action on bacteria is accurate?

Antibiotics target the cell wall and hinder its formation. Signup and view all the answers

Which characteristic is shared by both prokaryotic and eukaryotic cells?

Existence of ribosomes for protein synthesis. Signup and view all the answers

What is the primary function of the electron gun in an electron microscope?

To shoot a beam of electrons towards the specimen Signup and view all the answers

What is the main difference in the final images produced by TEM and SEM?

TEM uses a broad beam while SEM uses a super fine beam. Signup and view all the answers

What treatment is performed on a specimen before using a transmission electron microscope?

Embedding in resin and cutting into thin slices Signup and view all the answers

Which statement accurately describes the use of a confocal microscope?

It employs a highly focused laser for generating 3D images of a specimen. Signup and view all the answers

What is required for the direct beam of electrons in an electron microscope to function properly?

Vacuum conditions to prevent interference Signup and view all the answers

During the preparation of a specimen for both TEM and SEM, what step is common?

Removing all water using alcohol Signup and view all the answers

Which device is used in a light microscope to control the brightness of the specimen's illumination?

The diaphragm Signup and view all the answers

What feature distinguishes an electron microscope from a light microscope in terms of radiation type?

Light microscopes use light while electron microscopes use electrons. Signup and view all the answers

What is the primary function of chloroplasts in plant cells?

Convert light energy to chemical energy Signup and view all the answers

Which organelle is known for producing and assembling ribosomes?

Nucleolus Signup and view all the answers

What is a significant characteristic of mitochondria?

They perform chemical respiration to create ATP Signup and view all the answers

Which structure is responsible for providing structural support in plant cells?

Cell wall Signup and view all the answers

What role does the Golgi apparatus play in the cell?

Processes and packages substances made by the cell Signup and view all the answers

In which type of cells would you find lysosomes, and what is their primary function?

Animal cells; digest cellular waste Signup and view all the answers

What is the main distinction between rough and smooth endoplasmic reticulum (ER)?

Rough ER has ribosomes; smooth ER does not Signup and view all the answers

Which cell organelle is most important for energy transformation?

Mitochondria Signup and view all the answers

What distinguishes the cell membrane from the cell wall?

The cell membrane controls substance movement, while the cell wall provides structure Signup and view all the answers

What is the primary role of the cytoskeleton in a cell?

Maintain cell shape and support organelles Signup and view all the answers

Which of the following statements about vacuoles is true?

Plant cells have large vacuoles for storage and maintaining turgor pressure Signup and view all the answers

Which feature is indicative of the endosymbiotic theory?

Presence of double membranes in mitochondria and chloroplasts Signup and view all the answers

What is the function of pilli and flagella?

Assist in cell movement Signup and view all the answers

What is the role of the light microscope in cell biology?

To magnify specimens using visible light Signup and view all the answers

Study Notes

What are Cells?

Cells serve as the fundamental unit of life and reproduction.

Cell Theory

Composed entirely of cells or derived from them, including viruses.
All cells arise from pre-existing cells.
Cell discoveries are attributed to advanced microscopy technology.

Size of Cells

Plant cells range between 20-100 micrometers (μm).
Animal cells measure 5-20 μm.
Bacteria cells are the smallest, measuring 0.1-5.0 μm.

Prokaryotic Cells

Lack a nucleus and membrane-bound organelles; DNA resides in the cytoplasm.
Generally smaller and more ancient than eukaryotic cells.
Exist predominantly as unicellular organisms.
Major groups include bacteria and archaea.

Cell Shapes

Bacillus: Rod-shaped (example: Lactobacillus).
Coccus: Spherical or round (example: Streptococcus).
Spirillum: Curved or corkscrew shaped.
Vibrio: Straight rods with a single rigid curve.

Cell Wall Composition and Antibiotics

Stiff cell walls stem from proteins and acids.
Bacterial cell walls typically contain peptidoglycan, while archaea use pseudomurein.
Antibiotics can disrupt cell wall formation, leading to cell destruction.

Eukaryotic Cells

Distinguished by a true nucleus containing genetic material (DNA/chromosomes).
Encompass organelles, which are membrane-bound structures.
Evolved from prokaryotic cells supporting the endosymbiotic theory, evidenced by mitochondria and chloroplasts having their own DNA.

Cell Organelles and Their Functions

Chloroplasts: Convert light energy into chemical energy via photosynthesis (found in plants).
Mitochondria: Conduct cellular respiration to produce ATP energy (found in both plant and animal cells).
Cell Wall: Provides structural support, made from cellulose (found in plants and fungi).
Cell Membrane: Regulates substance movement and acts as a barrier to the external environment (found in both).
Cytoplasm: Jelly-like substance that suspends organelles (found in both).
Cytoskeleton: Maintains organelle positions and cell shape (found in both).
Centrioles: Assist in cell division by organizing chromosomes (found in both).
Vacuole: Storage structures; larger and permanent in plant cells, small and temporary in animal cells.
Nucleus: Stores genetic information necessary for cell function (found in both).
Nucleolus: Produces and assembles ribosomes (found in both).
Ribosomes: Synthesize proteins based on genetic information (found in both).
Endoplasmic Reticulum (ER): Transports substances; has smooth (lipid production) and rough (protein processing) types (found in both).
Golgi Body: Modifies, processes, and packages cellular products (found in both).
Lysosomes: Digest waste and foreign materials using enzymes (found in animals).
Pili and Flagella: Appendages aiding movement in prokaryotic cells and some fungi.

Microscopy Technologies

Light Microscope: Utilizes visible light and lenses for magnification, crucial for developing cell understanding.
Electron Microscope: Uses electron beams for high-resolution imaging; operates under vacuum conditions.
- Transmission Electron Microscope (TEM): Provides internal images by slicing specimens thinly.
- Scanning Electron Microscope (SEM): Scans surfaces to produce external images.

Advanced Microscopy

Confocal Microscope: Employs focused lasers for high-quality imaging and creates 3D images through computer enhancement.

Comparing Microscopes

Light microscopes use light for magnification, while electron microscopes use electrons for higher resolution imagery.

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Description

Explore the fundamental concepts of cells, their differentiation, and the cell theory in this quiz based on Biology Module 1. Understand the sizes of various cell types and the technological advances that allow us to study them effectively. Test your knowledge of what distinguishes different cells and their role as the building blocks of life.