Cytology Lecture Notes Flashcards

Vocabulary flashcards generated from the Cytology lecture notes covering membrane structure, membrane transport, tonicity, and protein synthesis.

Cytology

The study of cells.

Plasma Membrane

An extremely pliable cell membrane composed of two adjacent layers of phospholipids that serves as an active barrier separating intracellular fluid (ICF) from extracellular fluid (ECF) and controls what enters and leaves the cell.

Phosphate Group (Head)

The polar and hydrophilic end of a phospholipid that is attracted to water.

Lipid Tails

Two side-by-side chains of fatty acids on a phospholipid that are nonpolar and hydrophobic.

Integral Proteins

Membrane proteins that are embedded directly in the plasma membrane.

Channel Proteins

Membrane proteins that allow substances to pass into or out of the cell.

Cell Recognition Proteins

Membrane proteins that serve to mark a cell's identity so it can be recognized by other cells.

Peripheral Proteins

Proteins found on the inner or outer surface of the lipid bilayer that can be loosely attached to integral proteins and typically perform a specific function for the cell.

Passive Transport

Membrane transport that relies on the movement of molecules down their concentration or pressure gradient (from high to low concentration/pressure) with no energy expended.

Filtration

A type of passive transport involving the movement of molecules down a pressure gradient across capillary walls with no energy expended.

Simple Diffusion

A form of passive transport where hydrophobic substances (such as oxygen, carbon dioxide, and fat-soluble vitamins) diffuse directly through the phospholipid bilayer.

Facilitated Diffusion

A form of passive transport restricted to protein channels in the membrane, used for hydrophilic molecules and substances that cannot directly cross the lipid bilayer due to size, charge, and/or polarity (such as glucose, amino acids, and ions).

Isotonic Solution

A solution that contains the same concentration of solutes as inside the cell, resulting in unchanged cell volume.

Hypertonic Solution

A solution containing a higher solute concentration than inside the cell, causing water to flow out of the cell and resulting in cell shrinking.

Hypotonic Solution

A solution containing a lower solute concentration than inside the cell, causing water to flow into the cell, resulting in cell swelling and potential bursting.

DNA

The nucleic acid molecule that holds the code for protein.

RNA

The 'go between' molecule that links DNA to proteins.

mRNA

Single-stranded RNA copied from DNA that contains the triplet code (codon).

tRNA

A type of RNA that carries amino acids.

Triplet

A section of 3 DNA bases coding for amino acids.

Transcription

The first step of protein synthesis, involving the synthesis of a strand of mRNA that is complementary to the gene's DNA code.

Initiation (Transcription)

The first phase of transcription where RNA binds to the promoter region and separates DNA strands.

Elongation (Transcription)

The second phase of transcription where RNA adds complementary nucleotides to the mRNA strand.

Termination (Transcription)

The final phase at the end of a gene where RNA releases the new mRNA and stops.

Spliceosomes

Special proteins that modify mRNA before it leaves by removing non-coding DNA regions called introns.

Introns

Non-coding DNA regions that are removed from mRNA during processing by spliceosomes.

Exons

The remaining coding DNA regions that are joined together during mRNA processing.