Bio chapter 4 definitions

Cell theory

Cells are the basic unit of life; cells come from preexisting cells.

Prokaryotic cell

Cell without a nucleus; DNA is in a nucleoid.

Eukaryotic cell

Cell with a nucleus and membrane-bound organelles.

Bacteria

Prokaryotes.

Archaea

Prokaryotes.

Animals

Eukaryotes.

Plants

Eukaryotes with cell walls; photosynthetic cells have chloroplasts.

Fungi

Eukaryotes with chitin-containing cell walls.

Protists

Eukaryotes.

Nucleoid

Region containing prokaryotic DNA.

Plasma membrane

Phospholipid bilayer controlling movement in and out of cells.

Cytoplasm

Cell contents inside the plasma membrane.

Compartmentalization

Division of cell functions among specialized organelles.

Surface area-to-volume ratio

Limits cell size; decreases as a cell gets larger.

Magnification

How much larger an image appears.

Resolution

Ability to distinguish nearby points as separate.

Light microscopy

Uses visible light; useful for cells and tissues.

Fluorescence microscopy

Uses fluorescent labels to identify specific structures.

Confocal microscopy

Produces sharp optical sections and 3D images.

TEM

Electron microscopy showing internal structures in thin sections.

SEM

Electron microscopy showing detailed surfaces.

Cell fractionation

Separates cellular components by centrifugation.

Nucleus

Contains DNA and regulates gene expression.

Nuclear envelope

Membrane surrounding the nucleus.

Nuclear pores

Openings allowing materials to move through the nuclear envelope.

Chromosome

Organized linear DNA in eukaryotic cells.

Chromatin

DNA associated with proteins.

Nucleolus

Produces and assembles ribosomal subunits.

Ribosome

Synthesizes proteins from mRNA.

Free ribosome

Makes proteins mainly used in the cytosol.

Bound ribosome

Ribosome on rough ER making secreted or membrane proteins.

Endomembrane system

Membranes and organelles that process and transport proteins and lipids.

Rough ER

Protein synthesis, folding, and modification.

ER lumen

Internal space of the ER.

Smooth ER

Lipid synthesis and detoxification.

Cisternae

Flattened membrane sacs in ER or Golgi.

Golgi apparatus

Modifies, sorts, and ships cell products.

Cis Golgi

Receiving side of Golgi.

Trans Golgi

Shipping side of Golgi.

Transport vesicle

Membrane sac that carries cellular cargo.

Secretory pathway

Rough ER → Golgi → vesicle → plasma membrane.

Lysosome

Acidic organelle for digestion and recycling.

Hydrolytic enzymes

Digestive enzymes inside lysosomes.

Vacuole

Membrane sac for storage and digestion.

Central vacuole

Large plant vacuole that maintains turgor pressure.

Turgor pressure

Pressure supporting plant cell shape.

Peroxisome

Breaks down fatty acids and detoxifies harmful compounds.

Mitochondrion

Organelle for cellular respiration and ATP production.

Cellular respiration

Process that captures energy from food in ATP.

ATP

Main usable energy molecule of cells.

Cristae

Folds of the inner mitochondrial membrane.

Mitochondrial matrix

Inner mitochondrial space containing enzymes, DNA, and ribosomes.

Endosymbiotic theory

Mitochondria and chloroplasts originated from ancient prokaryotes.

Chloroplast

Organelle that performs photosynthesis.

Photosynthesis

Converts light energy into chemical energy.

Stroma

Fluid-filled internal space of chloroplast.

Thylakoid

Flattened chloroplast membrane sac.

Granum

Stack of thylakoids.

Chlorophyll

Light-absorbing pigment in thylakoid membranes.

Cytoskeleton

Protein network supporting shape, transport, movement, and division.

Microtubule

Tubulin-based cytoskeletal tube used for transport and chromosome movement.

Tubulin

Protein subunit of microtubules.

Centrosome

Major microtubule-organizing center.

Intermediate filament

Cytoskeletal fiber providing tensile strength and support.

Microfilament

Actin-based cytoskeletal fiber involved in shape and movement.

Actin

Protein subunit of microfilaments.

Motor protein

Protein that uses ATP to produce movement.

Kinesin

Motor protein moving along microtubules.

Dynein

Motor protein moving along microtubules.

Myosin

Motor protein moving along actin.

Cilia

Short, numerous structures that move material across a cell surface.

Flagella

Longer structures that propel cells.

Cell wall

Rigid external structure supporting and protecting cells.

Cellulose

Major structural material of plant cell walls.

Primary cell wall

Thin, flexible plant cell wall.

Secondary cell wall

Strong, rigid wall added in some mature plant cells.

Lignin

Material that can strengthen secondary plant cell walls.

Plasmodesmata

Channels connecting neighboring plant cells.

Chitin

Structural material in fungal cell walls.

Peptidoglycan

Typical structural material in bacterial cell walls.

Cell adhesion molecules

Help cells attach to other cells and the extracellular matrix.

Anchoring junctions

Mechanically attach animal cells.

Tight junctions

Seal spaces between animal cells.

Gap junctions

Channels connecting neighboring animal cells.

Extracellular matrix (ECM)

Material around animal cells providing support, attachment, and signaling.

Collagen

Major structural protein of the extracellular matrix.

Integrin

Cell-surface protein connecting cells with the extracellular matrix.

Fibronectin

Extracellular matrix protein involved in cell attachment.