Cell Organelles Overview

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Questions and Answers

What is the primary function of the nucleus in a cell?

Synthesize proteins

Store collagen

Coordinate cell activities and contain DNA (correct)

Provide mechanical support

What distinguishes the rough endoplasmic reticulum from other organelles?

It provides mechanical support to the cell

It is responsible for cellular movement

It is involved in protein synthesis due to the presence of ribosomes (correct)

It contains DNA

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

It binds adjacent cells and provides energy

It synthesizes and stores proteins

It contains the cell's genetic material

It maintains cell shape and facilitates movement (correct)

What is the primary component of the extracellular matrix mentioned?

Collagen Signup and view all the answers

Which of the following organelles plays a role in both protein synthesis and storage?

Rough endoplasmic reticulum Signup and view all the answers

What is the primary function of the Smooth Endoplasmic Reticulum?

To synthesize lipids and steroid hormones Signup and view all the answers

Which structure is responsible for synthesizing ribosomal RNA?

Nucleolus Signup and view all the answers

What role do centrioles play in the cell?

Develop spindle fibers for cell division Signup and view all the answers

What is the primary purpose of cell walls in plants?

Provide structural support Signup and view all the answers

Which structure is described as a fluid-filled area where metabolic activities occur?

Cytoplasm Signup and view all the answers

What type of DNA is found within mitochondria?

Double stranded circular DNA Signup and view all the answers

What is the main function of mitochondria?

ATP production and fatty acid catabolism Signup and view all the answers

Which components are ribosomes composed of?

30S and 50S subunits Signup and view all the answers

What is the primary function of microfilaments in a cell?

Cell motility Signup and view all the answers

What is a key characteristic of the cell walls mentioned in the content?

Consist of peptidoglycan Signup and view all the answers

Which of the following is NOT a function of mitochondria?

Photosynthetic activities Signup and view all the answers

How is mitochondrial DNA categorized?

Circular and naked Signup and view all the answers

What is the structural composition of microfilaments?

Actin filaments Signup and view all the answers

What do mitochondria do in relation to fatty acids?

Break down fatty acids Signup and view all the answers

What are ribosomes' roles related to proteins?

Synthesize proteins Signup and view all the answers

Study Notes

Cell Organelles

Nucleus: Contains the cell's DNA, coordinates activities like protein synthesis and reproduction. In prokaryotes, the nucleoid contains the genetic material.
Nucleolus: Site of rRNA synthesis, for ribosome production.
Cytoplasm: Fluid-filled area where metabolic activity occurs, including the organelles.
Mitochondria: Double-layered, produces ATP (energy), a site for fatty acid breakdown. Contains its own circular DNA and ribosomes.
Ribosomes: Made of rRNA, responsible for protein synthesis.
Rough Endoplasmic Reticulum (RER): Has ribosomes attached, synthesizes and stores proteins.
Smooth Endoplasmic Reticulum (SER): Synthesizes lipids and steroid hormones.
Golgi Apparatus: Modifies and packages proteins, including glycosylating polypeptides.
Lysosomes: Made by Golgi, breaks down nutrients, bacteria, and cell debris, used in apoptosis.
Peroxisomes: Common in liver and kidneys, break down substances.
Vacuoles: Vesicles that move cell materials, membrane bound.
Cytoskeleton: Maintains cell shape and movement. Includes microtubules (support and mobility), filaments (cell shape), centrioles (spindle fiber development).
Vesicles: Membrane-bound structures that transport materials.
Chloroplasts: (Plant cells) Contain chlorophyll, crucial for photosynthesis.
Cell Walls: (Plant cells), provide support, made of various materials (peptidoglycan in bacteria, various polysaccharides in archaea).
Cell Membrane: Controls what enters and exits the cell; selectively permeable, composed of phospholipids, proteins and cholesterol.

Cell Membrane Properties

Phospholipid Bilayer: Allows small, uncharged, hydrophobic molecules to freely pass; others (large, polar, charged) require transporters.
Permeability: Regulates cell membrane fluidity.
Cholesterol: Regulates membrane fluidity.
Membrane Proteins: Channel proteins (voltage-, ligand-, mechanically-gated); Porins (ions, polar molecules); Carrier and transport proteins (active transport like sodium-potassium pump).

Substance Movement

Passive Transport: No ATP needed (down concentration gradient). Includes simple diffusion, osmosis, dialysis, plasmolysis, facilitated diffusion, and countercurrent exchange
Active Transport: Uses ATP (against concentration gradient).
Endocytosis: Phagocytosis (solid material), Pinocytosis (liquid), Receptor-mediated endocytosis (ligands binding to receptors).

Water Balance of Cells

Hypertonic: Higher solute concentration than the surrounding environment.
Hypotonic: Lower solute concentration than the surrounding environment.
Isotonic: Equal solute concentration.
Hypertonic Solution: Cell shrinks
Hypotonic Solution: Cell swells
Isotonic Solution: Cell remains the same size

Cell Junctions

Anchoring Junctions: Connects cells.
Tight Junctions: Forms a seal; prevents passage between cells. (e.g., digestive tract cells).
Gap Junctions: Creates tunnels between animal cells for ion and small molecule passage.

Prokaryotes

No nucleus.
Single, circular, naked, double-stranded DNA.
Ribosomes (70S).
Cell walls (peptidoglycan or polysaccharides).
Capsule/s may be present
Flagella consist of flagellin (not microtubules)

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Description

This quiz covers essential details about various cell organelles, including their functions and significance in cellular processes. Test your knowledge on components such as the nucleus, mitochondria, and Golgi apparatus. Ideal for biology students aiming to understand cell structure and function.