How Cells Work
Endoplasmic Reticulum
A complex network of tubular passageways leading out of the nuclear membrane used in transporting proteins.
Deoxyribonucleic Acid (DNA)
A long chemical shaped like a twisted ladder. The plans for running and reproducing cells are chemically stored in the DNA. DNA is found mostly in the nucleus but small amounts have also been found in the mitochondria and chloroplasts.
Chloroplasts
Organelles in plant and algae cells that contain the green pigment chlorophyll that captures the sun's energy. Chloroplasts are the place where plants make sugar.
Lysosomes
Organelles rarely found in plants that contain digestive enzymes which break down food and digest worn out cell parts.
Enzymes
Proteins that control the rates of chemical reactions in cells. Digestive enzymes such as pepsin and trypsin are produced by specialized cells to break down food in the digestive tract.
Nuclear
Refers to the nucleus.
Adenosine Triphosphate (ATP)
The major source of readily available energy in cells. ATP is produced in the mitochondria when sugar and oxygen are chemically combined. The energy released is transferred to a chemical known as ADP to make ATP.
Mitochondria (singular: Mitochondrion)
The organelles where chemically stored energy is released. Known as the "power houses of the Cell".
Ribosomes
The organelles where proteins are made from amino acids.
Cell Membrane
The outer layer of the cell that helps control what comes into and what goes out of the cell. Also called the plasma membrane.
Cell Division
The process that results in two cells being formed from one cell.
Microtubules
The structural parts that make up the "skeleton" of the cell and that also help move certain organelles in the cell.
Cell Wall
The tough layer outside the cell membrane in plants and bacteria. Wood is little more than the cell walls of trees.
Phagocytosis
"Cell Eating", occurs when the cell membrane surrounds food material producing a food vacuole.
Nucleolus
"Little Nucleus", the area of the nucleus where ribosomes are made. Cells can have more than one nucleolus.
Organelles
"Little Organs", certain structures in the cytoplasm where specific tasks are carried out.
Chromosomes
Chromosomes are worm-shaped structures that "condense" from chromatin before cells divide. Chromosomes contain DNA and protein. Human body cells have two full sets of 23 different chromosomes.
Nucleus (plural: Nuclei)
A rounded structure located in the cytoplasm tthat acts as the control center for the entire cell.
Food Vacuole
A small sac created when the cell membrane surrounds a food particle.
Amoeba
A type of unicellular organism that has no definite outer shape.
Cytoplasm
All the protoplasm located outside the nucleus.
Golgi Complex
An organelle made up of stacks of membranes that help process, package and deliver proteins from the endoplasmic reticulum.
Plasma Membrane
Another name for the cell membrane.
Chromatin
Chromatin is made up of the tangled, threadlike, coils of chromosomes. Chromatin contains DNA plus certain proteins.
Prokaryotic Cells
Cells of very primitive organisms such as bacteria and blue-green algae that lack nuclei.
Eukaryotic Cells
Cells that possess nuclei.
Proteins
Chemicals made up of long chains for amino acids. Proteins build living material, help carry out chemical reactions, fight disease, and help transport tings out of the cell.
Centrioles
Cytoplasmic structures in animal cells that play a role in cell division by aiding spindle formation.
Vacuole
In plant cells the vacuole is a large sac that contains liquid.
Chlorophyll
The chemical found in chloroplasts that transfers light energy to chemical energy. Plants get their green color from chlorophyll.
Genetic Code
The chemical language of the cell. DNA stores its plans in the genetic code language.
Protoplasm
The living jelly-like substance of cells.
