Cell Basics and Structures

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Questions and Answers

What is a key characteristic of prokaryotic cells?

They lack ribosomes.

They contain membrane-bound organelles.

They have a true nucleus.

They are unicellular organisms (correct)

Which of the following correctly describes the role of the Golgi apparatus?

It acts as the digestion machine in the cell.

It produces proteins by assembling amino acids.

It packages and transports lipids and proteins. (correct)

It is the main control center of the cell.

Which statement accurately contrasts plant cells with animal cells?

Animal cells can photosynthesize.

Plant cells possess a cell wall and chloroplasts. (correct)

Only animal cells contain centrioles.

Only plant cells have ribosomes.

What function does the plasma membrane serve?

It surrounds and protects the cell. Signup and view all the answers

Which organelle is responsible for the breakdown of waste materials in the cell?

Lysosomes Signup and view all the answers

What is not a part of the cell theory?

All cells are made of proteins. Signup and view all the answers

What distinguishes eukaryotic cells from prokaryotic cells?

Eukaryotic cells have a true nucleus. Signup and view all the answers

What is the primary function of ribosomes in the cell?

Protein synthesis Signup and view all the answers

What role does the diaphragm play in a compound microscope?

It controls the amount of light reaching the specimen. Signup and view all the answers

Which statement accurately reflects the contributions of Theodor Schwann to cell theory?

He concluded that all animals are composed of cells. Signup and view all the answers

Which part of a compound microscope provides support and houses the light source?

Base Signup and view all the answers

What does the second part of cell theory, stated by Rudolf Virchow, emphasize?

Cells arise from preexisting cells. Signup and view all the answers

Who was the first to declare that all living things are made of cells?

Theodor Schwann Signup and view all the answers

What feature distinguishes prokaryotic cells from eukaryotic cells?

Prokaryotic cells lack a nucleus, while eukaryotic cells have one. Signup and view all the answers

What component of a compound microscope is responsible for capturing light from an external source?

Illuminator Signup and view all the answers

What was William Henry Perkin's contribution to the study of cells?

He developed a dye used for staining slides. Signup and view all the answers

What is the primary function of the fine focus in a compound microscope?

To bring the specimen into sharp focus under all magnifications. Signup and view all the answers

Which component of the microscope holds the objective lenses and permits rotation to change magnification?

Revolving nosepiece Signup and view all the answers

Which of the following correctly describes the function of the coarse focus?

To move the stage up and down for initial focusing. Signup and view all the answers

What role does the specimen stage play in the use of a microscope?

It holds the specimen in place for viewing. Signup and view all the answers

How does the body tube contribute to the function of a microscope?

It connects the eyepiece and objective lenses at the correct distance. Signup and view all the answers

What is the typical magnifying power range of the objective lenses in a compound microscope?

4x to 100x Signup and view all the answers

Which part of the microscope stabilizes the head and allows for adjustments during viewing?

Arm Signup and view all the answers

Which component of a microscope is primarily responsible for focusing at high power?

Fine focus Signup and view all the answers

Study Notes

Cell Basics

All living organisms are composed of cells
Cells originate from pre-existing cells.
The cell is the fundamental unit of life.
Cells are classified into two main categories: prokaryotic and eukaryotic.

Prokaryotic Cells

Lack a true nucleus and membrane-bound organelles.
Examples include bacteria.
They are unicellular, comprised of a single cell.

Eukaryotic Cells

Have a true nucleus and membrane-bound organelles.
Include both multicellular organisms (animals and plants) and some single-celled organisms.

Cell Structures:

Plasma membrane: A thin membrane surrounding cells and organelles, playing a vital role in regulating what enters and exits.
Cytoplasm: Gel-like substance containing chemicals and organelles, supporting metabolic reactions, organelle movement, and structural support.
Nucleus: The control center enclosed by a membrane, containing DNA, providing instructions for protein production and cell functions. It's crucial for cell division.
Ribosomes: These are like construction workers, building proteins.
Endoplasmic reticulum (ER): Functions as a manufacturing and packaging system, working with the Golgi apparatus and ribosomes. It produces and transports lipids, and packages proteins.
Golgi apparatus: Also known as the Golgi complex, Golgi body, or simply the Golgi. It's the packaging organelle and packages vesicles.
Lysosomes: Also known as "little digestion machines," they break down food particles, waste, and foreign substances within the cell.
Centrioles: Found in animal cells, they help in cell division.

Plant Cell Specific Structures

Cell wall: Made of cellulose, it provides structural support for plant cells.
Chloroplasts: These are the food producers, carrying out photosynthesis.

Compound Microscope Components

Stage clips: Hold slides in place during viewing.
Illuminator: Provides light for viewing, replacing the traditional mirror.
Diaphragm (also known as the iris): Controls the amount of light that reaches the specimen.
Base: Offers stability, houses the light source, and provides a platform for microscope placement.
Eyepiece: Contains the lens used for viewing, allowing comfortable observation.
Body Tube: Holds the objective lenses and eyepiece at a fixed distance for proper viewing.
Coarse Focus Knob: Moves the stage to bring the specimen into initial focus.
Fine Focus knob: Refines the focus, often located within the coarse focus knob, for sharp viewing under different power levels.
Objective Lenses: Magnify the specimen for detailed observation, ranging from 4x to 100x magnification.
Body Tube: Holds the objective lenses and eyepiece in proper alignment.
Revolving Nosepiece: Holds the objective lenses and allows rotation to select different magnifications.
Arm: Connects the microscope head to the base, providing stability.
Specimen Stage: Platform where the slide is placed for viewing.

Cell Theory

Matthias Schleiden (1838): discovered that plants were made of cells through extensive microscopic observation.
Theodor Schwann (1839): expanded Schleiden’s findings to animals, concluding that all living things are made of cells through his own microscopic studies.
Rudolf Virchow (1858): proposed the principle that new cells arise from pre-existing cells, forming the second part of the cell theory.

Summary of Cell Theory

All living organisms are composed of cells.
All cells come from pre-existing cells.
The cell is the fundamental unit of life.

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Description

Explore the fundamental concepts of cell biology, including the differences between prokaryotic and eukaryotic cells. Learn about essential cell structures such as the plasma membrane, cytoplasm, and nucleus that are vital for cellular functions and organism life. Test your understanding of these foundational topics.