Cell Biology: Prokaryotes and Inclusions

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Questions and Answers

What distinguishes eukaryotic cells from prokaryotic cells?

Eukaryotic cells have a single, circular chromosome.

Eukaryotic cells do not have a nucleus.

Eukaryotic cells have no genetic material.

Eukaryotic cells possess membrane-bound organelles. (correct)

Which of the following structures is typically found in plant cells but absent in animal cells?

Cytoskeleton

Glycogen granules

Cell walls (correct)

Centrioles

Inclusion bodies in prokaryotic cells primarily serve what function?

Locomotion

Storage of reserve materials (correct)

Energy production

Genetic material organization

Which type of bacteria contains gas vacuoles?

Photosynthetic bacteria Signup and view all the answers

What feature is characteristic of animal cells but not typically found in plant cells?

Centrioles Signup and view all the answers

What is a characteristic feature of prokaryotes?

Mesosome structure Signup and view all the answers

Which layer of the prokaryotic cell envelope provides structural support?

Cell wall Signup and view all the answers

How are prokaryotic bacteria classified based on their cell envelope?

According to their response to Gram staining Signup and view all the answers

What distinguishes the glycocalyx in different bacterial types?

It differs in composition and thickness. Signup and view all the answers

What is the function of the plasma membrane in prokaryotic cells?

It selectively regulates material exchange. Signup and view all the answers

Which statement is true regarding the structure of prokaryotic cell envelopes?

They have a three-layered structure. Signup and view all the answers

What type of glycocalyx is characterized as a loose sheath?

Slime layer Signup and view all the answers

What similarity exists between the plasma membrane of prokaryotes and eukaryotes?

Both are selectively permeable. Signup and view all the answers

What is the primary function of chloroplasts in plants?

Trapping light energy for photosynthesis Signup and view all the answers

Which type of plastid is responsible for storing carbohydrates?

Amyloplasts Signup and view all the answers

Which pigment is contained in chloroplasts that aids in photosynthesis?

Chlorophyll Signup and view all the answers

What distinguishes chromoplasts from chloroplasts?

Presence of carotenoid pigments Signup and view all the answers

What shape are chloroplasts typically?

Lens-shaped, oval, or discoid Signup and view all the answers

In which part of the plant are chloroplasts most commonly found?

Mesophyll cells of leaves Signup and view all the answers

What is the main role of leucoplasts?

Storing various nutrients Signup and view all the answers

How many chloroplasts can typically be found in the mesophyll cells of a plant?

20-40 Signup and view all the answers

What primarily allows the lateral movement of proteins within the lipid bilayer?

Quasi-fluid nature of lipids Signup and view all the answers

Which process describes the movement of water across a membrane?

Osmosis Signup and view all the answers

Which type of transport requires energy to move molecules against their concentration gradient?

Active transport Signup and view all the answers

Which structure protects plant and fungal cells from mechanical damage?

Cell wall Signup and view all the answers

How do polar molecules typically cross the lipid bilayer?

Using carrier proteins Signup and view all the answers

What is essential for the formation of intercellular junctions according to the fluid nature of the membrane?

Membrane fluidity Signup and view all the answers

What common feature do both passive and active transport share?

Both may involve carrier proteins Signup and view all the answers

The Na+/K+ pump is an example of which type of transport?

Active transport Signup and view all the answers

What is the primary function of mitochondria within the cell?

Aerobic respiration Signup and view all the answers

What structure inside the mitochondrion increases its surface area?

Cristae Signup and view all the answers

What components are found in the mitochondrial matrix?

Single circular DNA Signup and view all the answers

What type of cellular division do mitochondria undergo?

Fission Signup and view all the answers

Which of the following statements about mitochondria is incorrect?

Mitochondria are visible under the microscope without staining. Signup and view all the answers

What is the diameter range of a typical mitochondrion?

0.2-1.0µm Signup and view all the answers

Where are mitochondria located within the cell?

Cytoplasm Signup and view all the answers

In which type of cells are plastids typically found?

All plant cells and euglenoides Signup and view all the answers

Study Notes

Prokaryotic Cells

Prokaryotes possess inclusions as unique features for storage.
Mesosomes, specialized infoldings of the cell membrane, are characteristic of prokaryotes.
Prokaryotic cell envelopes are complex and consist of three layers: glycocalyx, cell wall, and plasma membrane.
The glycocalyx can vary in composition; a loose slime layer or a thick capsule provides protection.
The cell wall maintains cell shape and structural integrity, preventing lysis or collapse.
The plasma membrane is selectively permeable and interacts with the external environment.
Inclusion bodies within prokaryotic cells store reserve materials and lack a membrane.
Examples of inclusion bodies include phosphate granules, cyanophycean granules, and glycogen granules.
Gas vacuoles are present in photosynthetic bacteria, aiding in buoyancy.

Eukaryotic Cells

Eukaryotes include diverse organisms: protists, plants, animals, and fungi.
These cells feature extensive compartmentalization via membrane-bound organelles.
Eukaryotic cells have an organized nucleus enclosed by a nuclear envelope.
Genetic material is organized into chromosomes, allowing for complex genetic regulation.
Plant cells possess cell walls, plastids, and large central vacuoles, while animal cells contain centrioles.
The fluidity of the lipid membrane allows protein mobility within the bilayer, impacting cell functions like growth and transport.

Plasma Membrane Functions

The plasma membrane is selectively permeable, regulating molecule transport.
Passive transport involves the movement of molecules along their concentration gradient without energy, such as simple diffusion and osmosis for water.
Active transport requires energy (ATP) for moving substances against their concentration gradient, exemplified by the Na+/K+ pump.

Cell Wall

The cell wall is a rigid structure surrounding the plasma membrane in fungi and plants.
It provides shape, mechanical protection, and acts as a barrier to undesirable substances.

Mitochondria

Mitochondria are double membrane-bound organelles, varying in number and shape (0.2-1.0µm in diameter, 1.0-4.1µm in length).
Inner compartments (matrix) contain enzymes, ribosomes (70S), and circular DNA, and are sites of aerobic respiration, producing ATP as energy.
The inner membrane features infoldings called cristae, increasing the surface area for metabolic reactions.

Plastids

Plastids are prominent in plant cells and euglenoids, classified into chloroplasts, chromoplasts, and leucoplasts.
Chloroplasts contain chlorophyll, essential for photosynthesis, while chromoplasts store carotenoid pigments, imparting colors.
Leucoplasts are colorless plastids that store nutrients such as carbohydrates (amyloplasts), oils (elaioplasts), and proteins (aleuroplasts).
Chloroplasts vary in number from one in Chlamydomonas to 20-40 in mesophyll cells; they are also double membrane-bound.

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Description

This quiz focuses on the unique characteristics of prokaryotes, including their specialized structures like inclusions and mesosomes. Explore the differences in cell membranes and envelopes found in bacterial cells. Test your knowledge on the essential features that define prokaryotic organisms.