BIO MODULE 2: Set 2 — Nucleus, Ribosomes & Organelles

What is an organelle?

A specialized cellular structure that performs a particular function.

Why are membrane-bound organelles important in eukaryotic cells?

They create separate compartments with specialized environments and functions.

What is the nucleus?

A membrane-bound compartment containing most of a eukaryotic cell's DNA.

Why is the nucleus called the genetic library of the cell?

It stores most of the cell's hereditary information.

What is the nuclear envelope?

A double membrane that separates the nucleus from the cytoplasm.

What is the nuclear pore complex?

A structure that regulates the movement of proteins and RNA between the nucleus and cytoplasm.

What is the nuclear lamina?

A dense network of protein fibres associated with the inner nuclear membrane.

What is a eukaryotic chromosome?

A DNA molecule associated with proteins.

What is the nucleolus?

A structure within the nucleus involved in assembling ribosomes.

What are ribosomes made of?

Ribosomal RNA (rRNA) and proteins.

What is the main function of ribosomes?

Protein synthesis.

What two subunits make up a ribosome?

A large subunit and a small subunit.

Where are ribosomes located in eukaryotic cells?

Free in the cytosol or attached to the endoplasmic reticulum or nuclear envelope.

How do ribosomes produce proteins?

They decode mRNA and form peptide bonds between amino acids.

What is the endomembrane system?

A system of membranes that divides eukaryotic cells into specialized compartments.

What structures are included in the endomembrane system?

Nuclear envelope, endoplasmic reticulum, Golgi complex, lysosomes, vesicles, and plasma membrane.

What is the endoplasmic reticulum (ER)?

An interconnected network of membranous channels and sacs involved in biosynthesis.

What are cisternae?

Membrane-enclosed flattened sacs or compartments.

What is the ER lumen?

The enclosed space inside the endoplasmic reticulum.

Why is rough ER called rough?

Ribosomes are attached to its outer surface.

What are the main functions of rough ER?

Protein synthesis, folding, modification, and transport.

What is a glycoprotein?

A protein with carbohydrate groups attached.

What are the main functions of smooth ER?

Lipid synthesis and processing drugs, poisons, and toxins.

What is the Golgi complex?

A stack of flattened membrane sacs that modifies, sorts, and packages proteins for transport.