Introduction to the Endomembrane System and Cell Membrane Functions

This set of flashcards covers key terms and concepts related to the endomembrane system, cell structure, and functions discussed in the lecture.

Endomembrane System

A collection of membrane-based organelles that work together to create and distribute cell products like proteins and lipids.

Rough Endoplasmic Reticulum (Rough ER)

A type of endoplasmic reticulum studded with ribosomes, responsible for synthesizing proteins.

Smooth Endoplasmic Reticulum (Smooth ER)

A type of endoplasmic reticulum that lacks ribosomes and is primarily involved in the detoxification of harmful chemicals and lipid production.

Golgi Apparatus

A cellular organelle that modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.

Secretory Vesicle

A membrane-bound vesicle that carries materials destined for secretion from the cell.

Amphiphilic Molecule

A molecule that has both a hydrophilic (water-attracting) and a hydrophobic (water-repelling) part.

Lysosome

An organelle that contains digestive enzymes to break down waste materials and cellular debris.

Protein Synthesis

The process of translating messenger RNA (mRNA) to form polypeptides and proteins in ribosomes.

Vesicle

A small, membrane-bound sac that carries materials within a cell.

Hydrophobic Effect

The tendency of nonpolar substances to aggregate in aqueous solutions to minimize their exposure to water.

Euchromatin

The less condensed form of chromatin that allows for active transcription of genes.

Heterochromatin

The densely packed form of chromatin that is generally transcriptionally inactive.

ATP Synthase

An enzyme that catalyzes the production of ATP from ADP and inorganic phosphate, utilizing a proton gradient.

NADH

A coenzyme that carries electrons during cellular respiration; produced in the Krebs cycle.

Reactive Oxygen Species (ROS)

Highly reactive molecules that contain oxygen, which can damage cellular components if not regulated.

Mitochondrion

An organelle responsible for generating most of the cell's supply of ATP, used as a source of chemical energy, through cellular respiration.

Nucleus

A membrane-bound organelle that contains the cell's genetic material (DNA) and controls cell growth, metabolism, and reproduction.

Plasma Membrane

The cell membrane that separates the interior of all cells from the outside environment, regulating the passage of substances into and out of the cell.

Cytoplasm

The entire contents within the cell membrane, excluding the nucleus, consisting of the cytosol and cellular organelles.

Step 1: mRNA Production

Messenger RNA (mRNA) is synthesized from DNA in the nucleus using RNA polymerase.

Step 2: mRNA Exit

The newly synthesized mRNA exits the nucleus and moves into the cytoplasm through nuclear pores.

Step 3: Protein Synthesis (Cytoplasm)

Protein synthesis begins in the cytoplasm on free ribosomes for proteins destined to remain in the cytoplasm.

Step 4: Protein Synthesis (ER)

Proteins destined for the endomembrane system, secretion, or integration into membranes are synthesized on ribosomes attached to the Rough Endoplasmic Reticulum (RER), entering the ER lumen for further processing.

Step 5: Vesicle Transport to Golgi

Proteins move from the ER to the Golgi apparatus via transport vesicles.

Step 6: Golgi Processing and Packaging

The Golgi apparatus modifies, sorts, and packages proteins for their final destinations, such as secretion, integration into membranes, or delivery to lysosomes.