Cell Biology: Organelles and Functions

Study Notes

Nucleus Appearance

Large organelle located in the center of the cell
Stains darkly with DNA stains

Nucleus Function

Contains chromosomes which are made up of genes
Genes contain instructions to make proteins

Nucleolus Appearance

Dark spots within the nucleus

Nucleolus Function

Site of ribosome production

Nuclear Membrane/Envelope Appearance

Membrane that surrounds the nucleus

### Nuclear Membrane/Envelope Function

Separates the nucleus from the cytoplasm
Protects DNA
Contains pores that allow molecules to pass in and out of the nucleus

Rough Endoplasmic Reticulum Appearance

Interconnected network of flattened sacs
Ribosomes attached to the surface of the membrane

### Rough Endoplasmic Reticulum Function

Protein synthesis

Smooth Endoplasmic Reticulum Appearance

Interconnected network of membranes, not flattened sacs
No ribosomes attached

Smooth Endoplasmic Reticulum Function

Lipid and carbohydrate synthesis

Ribosomes Appearance

Contains ribosomal (rRNA) and protein
Hamburger-like structure

Ribosomes Function

Protein synthesis using mRNA as an instruction
Forms a complete ribosome from a small and large subunit

Transport Vehicles/Vesicles Appearance

Membrane components

### Transport Vehicles/Vesicles Function

Transport molecules from one organelle to another or to the cell membrane
Types:
- Transport vehicles
- Secretory vesicles

Golgi Apparatus/Body Appearance

Flattened sacs, not interconnected

Golgi Apparatus/Body Function

Modifies and packages proteins received from the rough ER
Packaged into a secretory vesicle for export to another organelle or to the cell membrane

Cytoskeleton

Network of fibers that provides structure and support to the cell

Microtubules Appearance

Long, rigid fibers made of tubulin protein

Microtubules Function

Form various structures:
- Cilia
- Flagella
- Centrioles
- Network for intracellular transport

Cilia Function

Motile cilia move fluid over the surface of the cell (e.g., respiratory system)
Sensory cilia detect vibrations (e.g., in the inner ear)

Flagella Function

Move the cell (e.g., sperm cells)

Centrioles Function

Form spindle fibers during cell division (mitosis and meiosis)

Microtubule Network Function

Transport organelles within the cell

### Microfilaments Appearance

Very thin fibers

### Microfilaments Function

Change the shape of the cell
- Cell movement (e.g., white blood cell movement)
- Cytokinesis (division of the cytoplasm)

Intermediate Filaments Appearance

Intermediate size fibers, between microtubules and microfilaments

Intermediate Filaments Function

Provide structural integrity and support to the cell

Cell Wall Appearance (Plants, Fungi, Prokaryotes)

Structure surrounding the cell membrane

Cell Wall Function

Provide strength and support

Cell Wall Composition

Cellulose in plants
Chitin in fungi
Peptidoglycan in prokaryotes (bacteria)

Cell Membrane/Plasma Membrane Appearance

Phospholipid bilayer with embedded proteins

Cell Membrane/Plasma Membrane Function

Separate the cell interior from the exterior

Mitochondria Appearance

Large organelle with an outer membrane and an inner membrane with folds called cristae

Mitochondria Function

Aerobic respiration
ATP production

Chloroplasts Appearance

Large organelle with an outer membrane and an inner membrane enclosing a fluid called stroma
Thylakoids (folded membrane structures) within the stroma

Chloroplasts Function

Photosynthesis

Eukaryotes vs Prokaryotes

DNA Structure:
- Eukaryotes: Linear DNA in a nucleus, associated with histones
- Prokaryotes: Circular DNA located in cytoplasm, considered naked
Organelles:
- Eukaryotes: Membrane-bound organelles (e.g., Golgi apparatus, ER)
- Prokaryotes: No membrane-bound organelles
Ribosome Size:
- Eukaryotes: 80s ribosomes
- Prokaryotes: 70s ribosomes
Cell Wall:
- Eukaryotes: Present in plants, fungi
- Prokaryotes: Peptidoglycan cell wall
Cell Membrane:
- Eukaryotes: Outermost layer in animal cells, with different lipids than prokaryotes
- Prokaryotes: Cell membrane is not the outermost structure, cell wall surrounds the membrane

Essential Retrieval Questions

How do organelles work together in protein synthesis?
What are the structures and functions of organelles in protein synthesis?
What are the similarities and differences between prokaryotic and eukaryotic cells?

Description

This quiz covers key concepts related to cell organelles, including their appearances and functions. It focuses on the nucleus, nucleolus, and endoplasmic reticulum, providing critical insights into the cellular structures essential for life processes. Test your knowledge on how these organelles contribute to cellular functions!

Cell Biology: Organelles and Functions

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Questions and Answers

Which of the following structures is responsible for modifying and packaging proteins?

Which of the following is NOT a function of microtubules?

Which of the following structures is found only in eukaryotic cells?

What is the main function of the cell wall in plant cells?

Which of the following statements correctly describes the relationship between the rough endoplasmic reticulum and ribosomes?

Which of the following is NOT a difference between eukaryotic and prokaryotic cells?

Which of the following organelles is responsible for the production of ATP?

What is the primary function of cilia?

Which of the following is the correct sequence of events in protein synthesis?

What is the function of the nuclear membrane?