Cell Biology Basics Quiz

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Questions and Answers

Which statement accurately describes the cell theory?

Single-celled organisms do not perform all life processes.

Cells are the largest units of life.

Cells can arise spontaneously from non-living materials.

All organisms are made of one or more cells. (correct)

What is a key characteristic of cells as described in the overview?

Cells can survive without genetic information.

All cells have similar structures regardless of their type.

Cells are always visible to the naked eye.

Cells contain DNA surrounded by cytoplasm. (correct)

Which of the following is true about light microscopy?

It can only be used for very small organisms.

It is the only method to view dead specimens.

It uses electrons to illuminate the specimen.

It allows for the observation of living cells. (correct)

Which of the following processes do cells NOT typically carry out?

Growing indefinitely without division. Signup and view all the answers

Which cellular structure is absent in prokaryotic cells?

Nucleus Signup and view all the answers

What distinguishes prokaryotic cells from eukaryotic cells?

Eukaryotic cells possess membrane-bound organelles. Signup and view all the answers

What is the best definition of magnification in microscopy?

The ratio of the object as seen under the microscope to its actual size Signup and view all the answers

What role do specialized cells in multicellular organisms serve?

Carry out unique tasks tailored to the survival of the organism Signup and view all the answers

Which of the following structures is found in both prokaryotic and eukaryotic cells?

Ribosomes Signup and view all the answers

Which of the following is a characteristic feature of prokaryotic cells?

Lack of a defined nucleus Signup and view all the answers

What is the correct sequence according to the central dogma of molecular biology?

DNA – RNA – Protein Signup and view all the answers

Where is the DNA located in prokaryotic cells?

In the nucleoid region as a single circular chromosome Signup and view all the answers

Which structure is found in both prokaryotic and eukaryotic cells?

Cytoplasm Signup and view all the answers

In eukaryotic cells, where does transcription occur?

In the nucleus Signup and view all the answers

What role does the plasma membrane play in a cell?

It serves as a protective barrier and regulates the movement of substances. Signup and view all the answers

What is the main structural difference between prokaryotic and eukaryotic cells?

Prokaryotic cells have a nucleoid region instead of a nucleus. Signup and view all the answers

Which of the following is NOT a feature of prokaryotic cells?

Nucleus Signup and view all the answers

Which statement accurately describes eukaryotic cells?

They can have specialized cells in multicellular organisms. Signup and view all the answers

What is the function of pili in some bacteria?

To adhere to surfaces and exchange genetic information. Signup and view all the answers

What is the main role of the nucleus in eukaryotic cells?

To serve as a storage for linear chromosomes. Signup and view all the answers

Which of the following types of cells typically have a cell wall?

Prokaryotic cells Signup and view all the answers

What distinguishes the DNA structure in prokaryotic cells from that in eukaryotic cells?

Prokaryotic cells have a single circular chromosome, while eukaryotic cells have multiple linear chromosomes. Signup and view all the answers

What are glycocalyx layers in prokaryotic cells?

Carbohydrates coating the cell wall. Signup and view all the answers

What are the main components of the cytoplasm in eukaryotic cells?

Cytosol, organelles, and cytoskeleton Signup and view all the answers

Which of the following is NOT a function of the cytoskeleton in eukaryotic cells?

Facilitating cellular respiration Signup and view all the answers

What distinguishes the cytoplasm of prokaryotic cells from that of eukaryotic cells?

Eukaryotic cells contain compartments formed by membranes Signup and view all the answers

Why was it initially thought that prokaryotes did not have a cytoskeleton?

Prokaryotes were considered too simple to possess such structures Signup and view all the answers

What major feature is shared by all prokaryotic organisms?

They are unicellular organisms Signup and view all the answers

What is the primary role of the cytosol within the cytoplasm?

Containing various molecules for cellular functions Signup and view all the answers

Which feature about archaea is true in comparison to bacteria?

Archaea are more closely related to humans than bacteria Signup and view all the answers

What is a correct statement about the cytoskeleton in prokaryotic versus eukaryotic cells?

Eukaryotic cytoskeleton is more complex and serves additional purposes Signup and view all the answers

What is a characteristic of the phospholipid bilayer in the plasma membrane?

It consists of amphipathic molecules. Signup and view all the answers

Which statement about ribosomes in prokaryotes and eukaryotes is correct?

Eukaryotic ribosomes can be anchored to the endoplasmic reticulum. Signup and view all the answers

What defines the process of translation?

It refers to the assembly of amino acids into proteins. Signup and view all the answers

Which of the following adequately describes the fluid mosaic model?

It illustrates a dynamic and flexible arrangement of lipids and proteins. Signup and view all the answers

What differentiates the cytoplasm from the cytosol?

Cytoplasm includes all components within the plasma membrane. Signup and view all the answers

Which of the following statements is true regarding membrane fluidity in prokaryotes and eukaryotes?

Both groups have similar mechanisms to regulate membrane fluidity. Signup and view all the answers

What is the primary role of ribosomes in a cell?

To read mRNA and build proteins. Signup and view all the answers

Which of the following is the main distinguishing feature of prokaryotic ribosomes?

They are smaller and freely suspended in the cytoplasm. Signup and view all the answers

Study Notes

Structured Study Sessions (SSS)

Bio 120 SSS sessions led by Janelle and Steve
Offered September 17, 2024
Materials developed by peer mentors, not course professors
Session content selected based on peer mentor knowledge, experiences, and input from the SSS Peer Mentor Team

What is SSS?

Structured study sessions (SSS)
Weekly sessions reviewing course material
Opportunities to ask questions and better understand topics
Four 80-minute sessions per week, students can attend any or all
Focuses on deepening lecture material understanding
Sessions facilitated by peer mentors who have previously taken and excelled in Bio 120

Icebreaker Activity

Students introduce themselves, their program, and a favorite aspect of university

In This Session

Topics covered in session include:
- Macromolecules
- Early Microscopy
- Cell Theory
- Microscopy types and their uses
- Features common to all cells
- Prokaryotic vs. eukaryotic cells

Let's See What You Already Know!

Introduction to a knowledge check activity

Question 1 - Cell Theory

Option B is part of the cell theory: Cells arise when pre-existing cells divide

Question 2 - Magnification

Option A describes magnification: The ratio of the object as you see it under the microscope to its real size.

Question 3 - Prokaryotic Cells

Option A (Nucleus) is not found in prokaryotic cells

Macromolecules

Life is composed of four macromolecules:
- Proteins (monomer: amino acids)
- Nucleic acid (DNA/RNA, monomer: nucleotides)
- Carbohydrates (monomer: monosaccharides)
- Lipids (not made of monomers)

Hooke and van Leeuwenhoek

Hooke: First to use a microscope to observe cells
van Leeuwenhoek: First to use a microscope to observe living organisms (pond water, bacteria)

Cell Theory

Proposed in the mid-19th century
Three key tenets:
- All organisms are made of one or more cells
- The cell is the basic structural and functional unit of all living organisms
- Cells only arise when pre-existing cells divide

Overview of Cells

Cells carry out essential life processes
Cells are too small to be seen without a microscope
All cells contain a central region with DNA surrounded by cytoplasm
Cells utilize DNA and RNA for genetic information and protein synthesis
Cells utilize energy, respond to environmental changes, reproduce, and transmit genetic information
Two main types of cells: prokaryotic and eukaryotic

Light Microscopy

Uses light to illuminate the specimen
Advantages: living specimens, inexpensive
Ideal for: bacteria, protists, larger cells, plasma membrane, nucleus and organelles
Types include bright field, phase contrast, dark field, and confocal laser scanning microscopy (with different advantages in usage)

Electron Microscopy

Uses a beam of electrons to illuminate the specimen
Specimens must be fixed (dead) and usually stained/coated with a metal
Higher resolution than light microscopy
Types include SEM (scanning electron) and TEM (transmission electron)

SEM (Scanning Electron Microscopy)

Allows 3D visualization of specimen surfaces, like insects or viruses

TEM (Transmission Electron Microscopy)

Viewing very tiny structures, like organelles, requires thin sectioning and staining

Magnification

Ratio of the image as seen under the microscope to its real-life size
Microscope lenses responsible for magnification

Resolution

Ability to distinguish two points in a specimen as separate
Higher resolution with shorter wavelengths of light or electrons

Contrast

How sharp the borders of the specimen appear
Increasing contrast does not improve resolution.

Question 4 - Resolution

Option C (Cut the specimen into smaller pieces) will enhance resolution. This improves clarity and visibility.

Question 5 - Microscopy

Bright field microscopy best for observing a paramecium in pond water--because it can look at living specimens

Why are Cells So Small? Considerations

Speed of diffusion
Easier to replace damaged cells (damage of a smaller cell is less significant)
Surface area to volume ratio (SA/Volume Ratio)

SA/Volume Ratio

Nutrients, waste, and other materials enter/exit the cell via the plasma membrane
Larger cells require more material to maintain metabolic needs
Surface area and volume do not increase proportionally.

Components Common to All Cells

Ribosomes
Cytoplasm and cytosol
DNA (and the central dogma)
Plasma membrane
Cytoskeleton

DNA and the Central Dogma

All cells contain DNA
Contains genetic instructions encoded in genes
The central dogma is: DNA --> RNA --> protein

Prokaryotic vs Eukaryotic Cells- DNA and Central Dogma

Prokaryotic: single circular chromosome in the nucleoid region
Eukaryotic: Multiple linear chromosomes in the nucleus

Plasma Membrane

Forms a semi-permeable barrier
Composed of a phospholipid bilayer with embedded proteins
Phospholipids are amphipathic
Can be described using the fluid mosaic model.

Plasma Membrane - Prokaryotes vs Eukaryotes

Similar structure in prokaryotes and eukaryotes
Slight differences in membrane composition and regulation of fluidity

Ribosomes

Machinery for protein synthesis.
Formed from rRNA and proteins; large and small subunits.
Read genetic instructions (mRNA) and produce proteins
Translation (process of protein building)

Ribosomes - Prokaryotes vs Eukaryotes

Prokaryotic ribosomes are smaller and freely suspended.
Eukaryotic ribosomes are larger and sometimes attached to the endoplasmic reticulum.

Cytoplasm and Cytosol

Cytoplasm is everything inside the plasma membrane.
Cytosol is liquid part of the cytoplasm containing molecules (ions, organic molecules)
Prokaryotic cells primarily consist of cytosol without many organelles
Eukaryotic cells have cytoplasm divided into compartments by internal membranes

Cytoskeleton

Network of proteins supporting, shaping, and moving cells
Functions to support and protect the cell, assist in cellular movement/response to stimuli, anchor organelles, aid in cell division;

Cytoskeleton - Prokaryotes vs Eukaryotes

Prokaryotic cytoskeleton is simpler.
Eukaryotic cytoskeleton serves additional functions, including anchoring organelles and aiding in cell division.

Prokaryotic Cells (Overview)

Two kingdoms: bacteria and archaea
Unicellular organisms
Capable of thriving in extreme conditions.
Each cell performs all life functions without specialization

Prokaryotic Cells - Other Features

Nucleoid region: Stores DNA.
Circular Chromosome: Single circular DNA molecule
Cell wall: Supporting structure
Glycocalyx: Carbohydrate coating; capsule or slime layer
Flagella: Used for movement
Pili: Used for attaching to surfaces
Plasmids: Extra pieces of self-replicating DNA

Eukaryotic Cells (Overview)

Four kingdoms: Plants, Animals, Protista, Fungi
Most are multicellular but some are unicellular

Eukaryotic Cells - Summary

Nucleus: Stores DNA (in linear chromosomes)
Organelles : Perform specific processes
Cell wall (some eukaryotes)

Summary

Life forms are made of macromolecules
Microscopes enabled understanding cell types
Cells are divided into prokaryotic and eukaryotic categories; eukaryotic cells are larger and have more elaborate structures. Some features are shared by both cells

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Description

Test your understanding of cell theory, the characteristics of prokaryotic and eukaryotic cells, and microscopy concepts. This quiz covers essential topics that are crucial for any biology student. Challenge yourself with questions regarding cellular structures and processes.