Biology Q2 Quiz 1: The Endomembrane System

Endomembrane System

A group of connected or interacting membranes inside a eukaryotic cell that modify, package, and transport lipids and proteins

Central Dogma of Biology

The flow of genetic information in cells: DNA → RNA → Protein.

DNA

The molecule that stores an organism’s genetic information and contains instructions for making proteins.

RNA

A single-stranded molecule that helps convert DNA instructions into proteins.

Protein

A large, complex molecule made of amino acids that performs many functions in cells (structure, enzymes, transport, etc.).

Gene

A segment of DNA that codes for a specific protein or functional RNA molecule.

Nucleus

The membrane-bound organelle in eukaryotic cells that contains the cell’s DNA.

Nuclear Membrane

membrane surrounding the nucleus that controls what enters and leaves it.

Membrane-Bound

Organelles enclosed by a membrane (e.g., nucleus, ER, Golgi).

Non-Membrane Bound

Cell structures not surrounded by membranes (e.g., ribosomes).

Phospholipid Bilayer

The double layer of phospholipids that makes up cell membranes and forms a barrier between inside and outside of the cell

Hydrophilic

attracted to water.

Hydrophobic

repels water.

Transcription

Process in the nucleus where DNA is copied into mRNA.

mRNA

Carries the genetic message from DNA to ribosomes for protein synthesis.

Translation

The process at the ribosome where mRNA is decoded to build a protein.

Polypeptide Chain

A chain of amino acids that folds into a functional protein.

Ribosome

The cellular machine that reads mRNA and assembles proteins; can be free or attached to the rough ER.

rRNA

RNA component of the ribosome that helps catalyze protein synthesis.

Large Subunit (of Ribosome)

The top part of the ribosome that joins amino acids together.

Small Subunit (of Ribosome)

The bottom part of the ribosome that reads the mRNA code.

RER

ER with ribosomes; helps fold and modify newly made proteins.

SER

ER without ribosomes that produces lipids and works with drugs like alcohol.

Secretory Vesicle

A vesicle made of the golgi that merges with the membrane as proteins leave out of it.

Transport Vesicle

Moves proteins to the golgi body that is made of the RER

Golgi Body

Stack of membranes that modifies and packages proteins

Cell Membrane

A phospholipid bilayer that controls what enters and exits the cell.

Prokaryotic Cell

Simple cell without a nucleus or membrane-bound organelles (e.g., bacteria)

Eukaryotic Cell

Complex cell with a nucleus and membrane-bound organelles (e.g., plant and animal cells).

Exocytosis

Process where vesicles fuse with the cell membrane to release materials outside the cell.

Lactase

Enzyme that breaks down lactose into glucose and galactose.

Lactose

The sugar found in milk.

Lactase Persistent

Continues to produce lactase as an adult; can digest lactose.

Lactase Non-Persistent

Stops producing lactase after childhood; may cause lactose intolerance.

Lactose Intolerant

Cannot digest lactose well due to low lactase enzyme levels.

Lactose Tolerant

Can digest lactose normally because lactase production continues into adulthood.