Cell Parts and Functions

Cell Theory

All living things are made up of cells, which are the smallest functional units of life that arise from preexisting cells. The chemical constituents and metabolic functions of cells share many similarities.

Prokaryotic Cells

Cells that lack a distinct nucleus and membrane-bound organelles, characterized by structures like cell walls and ribosomes. Single piece of circular DNA, usually single-celled, and may need oxygen for metabolism.

Eukaryotic Cells

Cells that have a membrane-bound nucleus and contain organelles surrounded by membranes, and chromosomes; found in most living organisms. Often multicellular and require oxygen for metabolism.

Cell Membrane

The outer layer of the cell, double layer, and is described by the fluid mosaic model. Composed of a phospholipid bilayer with embedded proteins. Allows food to enter the cell and wastes to leave the cell but keeps organelles in and invaders out. Allows the cell to communicate with other cells.

Cell Wall

Found commonly in plant cells and some bacteria. Composed of cellulose (celery is mostly cell wall). Protect and support plants, provide rigidity. Have pores to allow nutrients and wastes to pass through.

Nucleus

The organelle that directs cell activities and contains genetic material (DNA), separated from the cytoplasm by the nuclear membrane.

Nuclear Membrane

Surrounds nucleus, made of two layers, and openings allow material to enter and leave nucleus.

Cytoplasm/Cytosol

Gel-like mixture surrounded by cell membrane that contains all of the other organelles suspended in it. Creates room for work and space.

Chloroplast

An organelle found in plant cells that has a double membrane, and contains green chlorophyll and is the site of photosynthesis.

Mitochondria

Organelles that produce easily usable energy frm stored energy through cell resp by breaking down fats and carbohydrates. Its DNA is called mDNA.

Mitochondrion

Composed of outer membrane, inner membrane that creates folds called cristae, and a liquid matrix.

Ribosomes

Synthesize proteins and found on the rough ER and floating through the cell. Each cell contains thousands.

Endoplasmic Reticulum

A series of canals that transport materials within the cell.

Rough ER

Covered in ribosomes and connects with the nucleus. Proteins are made here and transported.

Smooth ER

Makes lipids and stores Calcium ions.

Lysosomes

Organelles that contain enzymes for digesting proteins, fats, and carbohydrates. Transports undigested material to cell membrane for removal and digests old, worn out cell parts.

Vacuoles

Membrane-bound sacs used for storage of water, food and waste; one large in plant cells and multiple smaller in animal cells. Helps plants maintain shape.

Golgi Bodies/Apparatus

Protein 'packaging plant', which produces transport vesicles that move materials within and out the cell. Secretes mucus.

Nucleolus

A structure within the nucleus, made from material such as chromosomes, responsible for the production of ribosomes. Contains RNA to build proteins.

Peroxisomes

Organelles that contain enzymes for breaking down fatty acids and toxins. Smaller than lysosomes.

Cytoskeleton

Protein filaments and tubules in cytoplasm, gives shape and coherence.

Centriole

Found in animals, helps with cell division.

Flagellum

Found in animals, projection of cell that helps with locomotion.

Starch Granule

Primary carb storage reserve