Cell Biology Basics Quiz

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Questions and Answers

What is the primary function of the nuclear pores?

To initiate DNA replication

To regulate the movement of molecules into and out of the nucleus. (correct)

To maintain the shape of the nucleus.

To secure the nucleus within the cytoplasm

Which cellular component is NOT found in prokaryotic cells?

Ribosomes

Membrane-bound organelles (correct)

DNA

Cytoplasm

What technique is used to separate cell components by size and density?

Confocal microscopy

X-ray crystallography

Immunofluorescence

Cell fractionation using centrifugation (correct)

What is the role of the nuclear lamina?

Maintaining the shape of the nucleus Signup and view all the answers

What primarily distinguishes eukaryotic cells from prokaryotic cells?

The presence of a membrane-bound nucleus and organelles Signup and view all the answers

Which characteristic is unique to plant cells, compared to animal cells?

Chloroplasts and cell walls Signup and view all the answers

In which region of a prokaryotic cell is DNA located?

Nucleoid Signup and view all the answers

What is the nuclear envelope composed of?

A double membrane consisting of two lipid bilayers Signup and view all the answers

Which structure is NOT directly associated with the mitochondrion?

Stroma Signup and view all the answers

What is the primary function of the enzyme catalase found in peroxisomes?

To convert hydrogen peroxide to water Signup and view all the answers

Which of the following best describes the function of the cytoskeleton?

To anchor organelles and facilitate cell movement Signup and view all the answers

In animal cells, which structure contains a pair of centrioles?

The centrosome Signup and view all the answers

What is the internal soluble compartment found within the inner membrane of a chloroplast called?

Stroma Signup and view all the answers

Which of the following best describes the location of chlorophyll in a chloroplast?

Within the thylakoid membranes Signup and view all the answers

What is the role of the centrosome during cell division?

Organizing chromosome separation Signup and view all the answers

Which of the following is NOT a component of the cytoskeleton?

Centrioles Signup and view all the answers

What is the main purpose of vacuoles within a cell?

To remove damaged components, prevent build-up of toxic materials, and store water. Signup and view all the answers

What is the primary function of the nucleolus?

Synthesizing ribosomal RNA (rRNA) Signup and view all the answers

What is the key function of the plasma membrane?

To act as a selective barrier, controlling substance passage into and out of the cell. Signup and view all the answers

Which of these is NOT a component of the endomembrane system?

Mitochondria Signup and view all the answers

Why is a high surface area to volume ratio important for a cell?

It ensures efficient exchange of materials with the environment. Signup and view all the answers

What is the primary function of the rough endoplasmic reticulum?

Synthesizing glycoproteins and proteins for the endomembrane system Signup and view all the answers

What process mainly takes place in the mitochondria?

Cellular respiration Signup and view all the answers

What specific function do chloroplasts perform, that mitochondria do not?

Fixation of carbon using sunlight Signup and view all the answers

How does the smooth endoplasmic reticulum differ from the rough endoplasmic reticulum?

It synthesizes lipids and steroids. Signup and view all the answers

What is the role of the Golgi apparatus in the endomembrane system?

Modifying, sorting, and packaging proteins. Signup and view all the answers

According to the endosymbiotic theory, what is the origin of mitochondria and chloroplasts?

They are derived from engulfed prokaryotic cells Signup and view all the answers

Which of the following is NOT a structural characteristic of mitochondria?

Presence of a single membrane that is folded into cristae Signup and view all the answers

What type of enzymes are found within a lysosome and what environment do they require to function?

Hydrolytic enzymes; acidic environment Signup and view all the answers

What is the process of autophagy?

The recycling of the cell's own organelles and macro-molecules Signup and view all the answers

What structures are responsible for increasing the mitochondrial membrane surface area?

Cristae Signup and view all the answers

What is the name of the material formed inside the nucleus which is made up of DNA and proteins?

Chromatin Signup and view all the answers

What is the primary function of dynein in cilia and flagella?

Driving the bending motion through microtubule interaction Signup and view all the answers

Which protein is primarily responsible for muscle contraction and cell motility, working in conjunction with actin?

Myosin Signup and view all the answers

What is the role of pseudopodia in cell movement?

To extend and contract through actin-myosin assembly and contraction. Signup and view all the answers

What is cytoplasmic streaming and what is its primary function?

The circular flow of cytoplasm, speeding up the distribution of materials within the cell. Signup and view all the answers

What distinguishes plant cells from animal cells in terms of extracellular structures?

Plant cells have a cell wall; animal cells do not. Signup and view all the answers

What are plasmodesmata and what function do they perform?

They are channels between plant cells that allow for the passage of water, small solutes, proteins and RNA. Signup and view all the answers

What are integrins and what is their role in cells?

They are receptor proteins within the plasma membrane that bind to the ECM. Signup and view all the answers

What is the extracellular matrix (ECM), and what are its main functions?

It is an elaborate matrix found in animal cells that provides support, adhesion, movement, and regulation. Signup and view all the answers

Study Notes

Cell Structure and Function

Biologists use microscopes and biochemical tools to study cells.
Eukaryotic cells have internal membranes that separate their functions into compartments.
Eukaryotic genetic instructions are stored in the nucleus and carried out by ribosomes.
The endomembrane system regulates protein movement and metabolic processes within the cell.
Mitochondria and chloroplasts convert energy from one form to another.
The cytoskeleton organizes cell structures and activities using a network of fibers.
Extracellular components and connections between cells coordinate cellular activities.

Prokaryotic and Eukaryotic Cells

Cells are the fundamental units of all living organisms.
Two main types of cells exist: prokaryotic and eukaryotic.
Prokaryotic cells lack a nucleus and membrane-bound organelles, while eukaryotic cells have both.
Prokaryotic cells include bacteria and archaea.
Eukaryotic cells include protists, fungi, plants, and animals.

Cells and Microscopes

Microscopes are essential tools for visualizing cells.
Different types of microscopes offer varying magnification and resolution.

Cell Fractionation

Cell fractionation separates cell components by differential centrifugation.
This technique isolates organelles for study and understanding their functions.
Biochemistry and cytology study cellular structures and their functions.

Prokaryotic Cells

Prokaryotic cells lack a nucleus and membrane-bound organelles.
Their DNA is concentrated in a region called the nucleoid.
Structures like ribosomes, cell walls, and membranes are present in prokaryotic cells.

Eukaryotic Cells

Eukaryotic cells are characterized by a nucleus and membrane-bound organelles.
Their DNA is organized into chromosomes within the nucleus.
The cytoplasm houses various organelles, each with a specific function.
Examples include mitochondria, chloroplasts, the endoplasmic reticulum, the Golgi apparatus, and lysosomes.

Animal and Plant Cells

Plant and animal cells share many organelles but have some unique features.
Plant cells have cell walls, chloroplasts, and large central vacuoles; animal cells do not.

Examples of Eukaryotic Cells

Various eukaryotic cells exhibit distinct structures and functions categorized by organism.

Cellular Structures

The nucleus contains most of a cell's genetic material.
The nuclear envelope encloses the nucleus, separating it from the cytoplasm.
The nuclear envelope features pores that regulate molecular entry and exit.
Nuclear lamina maintains the shape of the nucleus.

Inside the Nucleus

DNA in the nucleus is organized into chromosomes.
Chromatin consists of DNA combined with proteins.
The nucleolus is the site of ribosome subunit assembly and rRNA synthesis.

The Endomembrane System

The endomembrane system consists of interconnected organelles and membranes.
The system includes the nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, and vacuoles.
It regulates protein traffic and performs metabolic functions.

The Endoplasmic Reticulum

The endoplasmic reticulum (ER) is a widespread membrane network within the cytoplasm.
There are two distinct ER regions: rough ER (studded with ribosomes) and smooth ER (lacking ribosomes).
Rough ER synthesizes proteins for the endomembrane system and secretion.
Smooth ER synthesizes lipids, metabolizes carbohydrates, detoxifies drugs and poisons, and stores calcium ions.

Golgi Apparatus

The Golgi apparatus modifies, sorts, and packages proteins and other molecules for secretion or delivery to other locations in the cell.
It has cis and trans faces, reflecting the direction of vesicle flow.

Lysosome

Lysosomes are membrane-bound organelles containing hydrolytic enzymes.
They break down macromolecules and are involved in intracellular digestion.
Autophagy is the process of lysosome-mediated recycling of cellular components.

Vacuoles

Vacuoles are membrane-bound sacs with varied functions depending on cell type.
Food vacuoles form through phagocytosis.
Contractile vacuoles regulate water balance in protists.
Central vacuoles store water, organic compounds, and ions in plant cells.

Plasma Membrane

The plasma membrane is a selective barrier that regulates the passage of molecules into and out of the cell.
It is mostly composed of a phospholipid bilayer with embedded proteins.
Surface area to volume ratio is important for cellular function and limits cell size to maintain efficiency.

Organelles for Energy Processing

Mitochondria are the site of cellular respiration.
They generate ATP, the cell's primary energy currency.
Chloroplasts are found in plants and algae, carrying out photosynthesis.
Chloroplasts convert light energy into chemical energy.

Endosymbiotic Theory

Mitochondria and chloroplasts arose from prokaryotic cells engulfed by ancestral eukaryotic cells.

Mitochondria

Mitochondria are encased by two membranes and contain their own DNA.
Their inner membranes form cristae, which increase the surface area for ATP synthesis.
Cellular respiration occurs within the mitochondrial matrix.

Chloroplasts

Chloroplasts are surrounded by two membranes and contain their own DNA.
Thylakoid membranes form grana, increasing surface area for photosynthesis.

Peroxisomes

Peroxisomes are oxidative organelles involved in various metabolic processes, including fat metabolism.
They contain an enzyme called catalase, which breaks down hydrogen peroxide, a reactive oxygen species.

Cytoskeletal Structures

The cytoskeleton is a network of protein fibers that provides structural support and facilitates movement within the cell.
Microfilaments (actin filaments) form a network just inside the plasma membrane and are involved in cell shape, muscle contraction, and cytoplasmic streaming.
Microtubules are hollow tubes made of tubulin subunits that maintain cell shape, act as tracks for intracellular transport, and are crucial in cell division and organelle positioning.
Intermediate filaments provide structural support and connect the nucleus and other organelles.

Centrosomes

Centrosomes are microtubule-organizing centers.
In animal cells, centrosomes contain centrioles.
Centrioles are involved in cell division.

Cilia and Flagella

Cilia and flagella are microtubule-based appendages that enable cell motility.
Microtubules and motor proteins control their beating patterns.

Microtubular Anatomy of Cell Appendages

Cilia and flagella have a common core structure composed of microtubules encased by the plasma membrane.
The basal body anchors cilia or flagella and has a similar microtubule structure as the appendage itself.

Microfilaments

Microfilaments are thin, solid rods built from actin subunits.
They form a network called the cortex beneath the cell membrane for shape maintenance and cell motility.
Microfilaments are responsible for movement and contraction, including muscle contraction, and cytoplasmic streaming.

Muscle Contraction and Cell Motility

Actin filaments interact with the motor protein myosin to enable muscle contraction.
Myosin interacts with actin in other processes to enable cell motility.

Cytoplasmic Streaming

Cytoplasmic streaming is a circular flow of cytoplasm.
It facilitates the distribution of materials within plant cells.

Intermediate Filaments

Intermediate filaments are tough, insoluble fibers.
They reinforce cell shape and anchor organelles.
They are more permanent than microfilaments or microtubules

Extracellular Components

Cell walls are external structures, distinguishing plant from animal cells and other eukaryotic cells.

Cell Walls

Cell walls are rigid structures consisting mainly of cellulose.
They function in shaping and protecting the cell, as well as defending against excessive water uptake.
Primary and secondary cell walls differ in composition and structure.

Extracellular Matrix (ECM)

Animal cells lack cell walls but possess a complex extracellular matrix (ECM), a gel-like substance.
ECM composed of various proteins forms a surrounding network.

Cell Junctions

Intercellular junctions connect and coordinate neighboring cells in tissues.
Tight junctions seal cells together.
Desmosomes fasten cells in strong sheets.
Gap junctions provide channels between adjacent cells.

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Description

Test your knowledge of fundamental cell biology concepts, focusing on the differences between prokaryotic and eukaryotic cells, the structure and function of cellular components, and key cellular processes. This quiz covers topics essential for understanding cell structure and function.