Foundations of Biology Chapter 4

Prokaryotic cell

Cell lacking a membrane enclosed nucleus and cell compartmentalizaiton

Bacteria

Small prokaryotic cells that lack internal compartmentalization; possess a single chromosome

Archaea

Diverse group of prokaryotic microorganisms; more complex than bacteria

Eukaryotic cell

Cell that is compartmentalized with a nucleus enclosed in a membrane

Plasma membrane

A boundary between the cell and the extracellular matrix that is embedded with proteins

Phospholipid bilayer

Basic framework of the cellular membrane consisting of two layers of lipids where hydrophobic tails face inwards

Nucleus

The organelle found in eukaryotic cells that contains most of the genetic material; functions to protect, organize, replicate, and express genetic information

Nucleolus

Region of the nucleus where ribosome assembly occurs

Nucleoid

Irregularly shaped region within the cell of a prokaryote that contains all or most of the genetic material

Cytoplasm

Everything within the plasma membrane including organelles

Cytosol

The region of a eukaryotic cell that is inside the plasma membrane but outside of the organelles

Ribosome

Organelle which synthesizes proteins consisting of two subunits composed of RNA and proteins

Flagella

Long, cellular appendages that allow more cellular movement

Bacterial: Move in a propeller-like motion

Eukaryotic: Membrane bound; move in a whip-like motion

Pilli

Threat like surface appendages that allow bacterium to attach to one another or move across a surface

Cell wall

Rigid, porous structure located outside of the plasma membrane of prokaryotic, plant, fungal, and protist cells that provides support and protection

Centrosome

Structure near the cell nucleus that forms a nucleating site for the growth of microtubules

Cytoskeleton

A network of protein filaments in the cytosol

Microtubules

Long, hollow, cylindrical structures composed of protein α and β tubulin subunits which oscillate between growing and shortening; formed in centrosomes

Actin

The thinnest cytoskeletal filament which grows and shortens continuously and is concentrated near the plasma membrane

Myosin

A fibrous protein that forms the contractile filaments of muscle cells

Intermediate filaments

Tension bearing, relatively permanent fibers that maintain cell shape and rigidity; bind to form twisted, rope like structures

ER

Network of membranes which form cisternae, flattened, fluid filled tubules

Rough ER

ER studded by ribosomes involved in the synthesis and sorting of proteins into vesicles

Smooth ER

ER lacking ribosomes involved in lipid synthesis and storage and calcium ion storage

Golgi apparatus

A stack of flattened membrane bound compartments which secrete, process, and sort proteins

Mitochondria

Organelle in eukaryotic cells that supplies ATP

Chloroplast

Organelle that captures light energy and concerts it to glucose via photosynthesis

Peroxisome

Small organelles that catalyze detoxifying reactions; found in high concentrations in liver cells; break down toxins into H2O2 and breaks down fats and amino acids

Lysosome

Small organelle in animal cells which break down macromolecules via an acidic interior maintained by proton pumps

Vacuole

Prominent organelle in plant, fungal, and protist cells which store fluids and solids and regulate cell volume

Chromatin

A composition of DNA and proteins

Chromosome

Condensed genetic material

Nuclear membrane

Double membrane structure that encloses the cell's nucleus

Nuclear pore

Passageway for the movement of molecules and macromolecules into and out of the nucleus formed where the inner and outer membranes meet

Nuclear matrix

A filamentous network of proteins found in the nucleus and inner nuclear membrane which organizes chromosomes

Genome

The entire complement of a species genetic material

Proteome

The complete protein composition of a cell or organism

Transcription

Process of copying DNA into RNA

Translation

Process of turning RNA into polypeptides

Polypeptide

A string of amino acids

Protein

A folded mass of polypeptides

tRNA

RNA that brings amino acids to ribosomes during translation

rRNA

RNA that forms ribosomes

mRNA

RNA that carries transcribed DNA

Endosymbiosis

Symbiotic relationship where the smaller species lives inside the larger species; explains presence of mitochondria and chloroplasts in eukaryotic cells