cell organelles and their functions

Nucleus

Contains DNA and controls gene expression.

Nucleolus

Produces rRNA and assembles ribosome subunits.

Ribosomes

Synthesize proteins by translating mRNA.

Rough endoplasmic reticulum (Rough ER)

Processes proteins destined for secretion or membranes.

Smooth endoplasmic reticulum (Smooth ER)

Synthesizes lipids, detoxifies substances, and stores calcium.

Golgi apparatus

Modifies, sorts, and packages proteins and lipids.

Mitochondria

Produce most cellular ATP through cellular respiration.

Chloroplasts

Carry out photosynthesis in plants and algae.

Lysosomes

Digest and recycle cellular materials using enzymes.

Central vacuole

Stores substances and maintains turgor pressure in plant cells.

Vesicles

Transport and store materials inside cells.

Cytoskeleton

Maintains cell shape and helps with movement and internal transport.

Plasma membrane

Selectively controls what enters and leaves the cell.

Cell wall

Provides structural support and protection.

Cytoplasm

Includes the cytosol and structures inside the plasma membrane.

Cytosol

The fluid portion inside the cell where many reactions occur.

Peroxisomes

Break down fatty acids and help detoxify hydrogen peroxide.

Centrosome

Organizes microtubules and helps form the mitotic spindle in animal cells.

Centrioles

Help organize microtubules in the centrosomes of many animal cells.

Cilia

Short, hairlike structures that move cells or substances across cell surfaces.

Flagella

Long, whip-like structures that help some cells move.

Nuclear envelope

Double membrane surrounding the nucleus; nuclear pores regulate exchange.

Nuclear pores

Control movement of substances between the nucleus and cytoplasm.

Nuclear DNA

Stores genetic instructions used to direct cell activities.

Chromatin

DNA and associated proteins that make up chromosomes.

Rough ER ribosomes

Build proteins that enter the rough ER for processing.

Free ribosomes

Build proteins mainly used in the cytosol.

Transport proteins

Help specific substances cross the plasma membrane.

Channel proteins

Provide passageways for specific ions or molecules across membranes.

Carrier proteins

Bind substances and change shape to transport them across membranes.

Receptor proteins

Bind signaling molecules and trigger cellular responses.

Phospholipids

Form the bilayer; hydrophilic heads face water and hydrophobic tails face inward.

Cholesterol

Helps regulate membrane fluidity in animal cells.

Membrane carbohydrates

Help cells recognize and communicate with other cells.

Mitochondrial DNA

Provides evidence supporting the endosymbiotic theory.

Chloroplast DNA

Provides evidence supporting the endosymbiotic theory.

Thylakoids

Chloroplast membrane sacs where light-dependent reactions occur.

Grana

Stacks of thylakoids inside chloroplasts.

Stroma

Fluid inside chloroplasts where the Calvin cycle occurs.

Cristae

Folds of the inner mitochondrial membrane that increase surface area for ATP production.

Mitochondrial matrix

Inner mitochondrial compartment where pyruvate oxidation and the citric acid cycle occur.

Cell junctions

Connect neighboring cells or help form seals and communication pathways.

Plasmodesmata

Channels connecting neighboring plant cells through their cell walls.

Gap junctions

Channels allowing direct communication between neighboring animal cells.

Tight junctions

Seal spaces between neighboring cells.

Desmosomes

Anchor neighboring cells together for mechanical strength.

Extracellular matrix

Provides support and signaling outside animal cells.

Endomembrane system

Coordinates synthesis, modification, transport, and breakdown of cellular materials.

Secretory vesicles

Carry materials to the plasma membrane for release by exocytosis.