Bio 181 SI Session Notes

This set of flashcards covers key vocabulary terms and concepts related to cell biology, including properties of molecules in relation to cell membranes and differences between prokaryotic and eukaryotic cells.

Hydrophobic

Describes a substance that does not mix well with water; acts as a barrier against hydrophilic molecules.

Hydrophilic

Describes a substance that mixes well with water; attracted to water.

Oxygen (O2)

A nonpolar molecule that can easily pass through the lipid bilayer.

Carbon Dioxide (CO2)

A nonpolar molecule composed of one carbon and two oxygen atoms; can pass through the lipid bilayer.

Water (H2O)

A polar molecule that, despite being unable to pass through the lipid bilayer easily, can move through via osmosis.

Sodium Chloride (NaCl)

An ionic compound that dissolves in water and does not pass through the lipid bilayer; considered hydrophilic.

Glucose

A large, polar molecule that cannot pass through the lipid bilayer due to its size and polarity.

Prokaryotes

Simple, unicellular organisms that lack a nucleus and membrane-bound organelles; include bacteria and archaea.

Eukaryotes

Complex organisms with cells containing a nucleus and membrane-bound organelles; include plants and animals.

Nucleoid

The region in prokaryotic cells where DNA is located; it is not bounded by a membrane.

Peptidoglycan

A polymer that makes up the cell wall of bacteria; absent in archaea.

Plasma Membrane

Also known as the phospholipid bilayer; a barrier surrounding all cells that regulates what enters and exits.

Cytoplasm

The contents within a cell, excluding the nucleus; includes cytosol and organelles.

Cytosol

The fluid portion of the cytoplasm, primarily composed of water.

Ribosomes

Molecular machines in cells responsible for protein synthesis.

Endosymbiotic Theory

The theory proposing that mitochondria and chloroplasts originated from engulfed prokaryotic cells.

Osmosis

The movement of water across a semipermeable membrane from a region of lower solute concentration to a region of higher solute concentration.

Membrane-Bound Organelles

Organelles that are enclosed by membranes within eukaryotic cells.

Flagella

Long, tail-like structures that help some cells to move; found in both prokaryotic and some eukaryotic cells.