Unit 7 - Cells: Structures & Functions (7th Grade Science)

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cell
in biology, the smallest unit that can perform all life processes; they are covered by a membrane and have DNA and cytoplasm
The Cell Theory
all organisms are made of one or more cells; the cell is the basic unit of all living things; all cells come from existing cells
cytoplasm
the part of a cell that contains its organelles and the fluid surrounding them
cell membrane
a phospholipid (composed of phosphoric and fatty acids) layer that covers a cell's surface; it acts as a barrier between the inside of a cell and the cell's environment
organelle
one of the small bodies in a cell's cytoplasm that are specialized to perform a specific function
nucleus
in a eukaryotic cell, an organelle bound by a membrane that contains the cell's DNA and that has a role in processes such as growth, metabolism, and reproduction
prokaryotes
an organism that contains a single that does not have a nucleus or or membrane-bound organelles (examples: bacteria and archaea)
eukaryote
an organism made up of cells that have a nucleus enclosed by a membrane and other membrane-bound organelles (examples: animals, plants, and fungi)
cell wall
a rigid structure that surrounds the cell membrane and provides support to the cell (found in plant cells but not animal cells)
cytoskeleton
part of a cell that is made of protein fibers, helps the cell retain its shape, move its organelles, and move in its environment
ribosome
the smallest cell organelle but the one that cells have the most of; composed of RNA and protein; makes protein; is not covered by a membrane and all cells have them
endoplasmic reticulum (ER)
a system of membranes found in a cell's cytoplasm that assists in the production, processing, and transport of proteins and in the production of lipids (fatty acids); can be rough or smooth
mitochondria
in eukaryotic cells, it is the site of cellular respiration; it is the powerhouse of the cell that breaks down sugar into energy and stores it in ATP (adenosine triphosphate)
Golgi complex
cell organelle that helps make and package materials to be transported out of the cell such as the lipids and proteins it receives from the endoplasmic reticlulum (ER)
vesicle
a small cavity or sac that surrounds materials to be moved into or out of a eukaryotic cell
lysosome
a cell organelle containing digestive enzymes to destroy worn-out cells, get rid of waste materials, and protect the cell from foreign invaders
vacuole
organelle that stores water and digestive enzymes aiding in digestion within the cell; plant cells have a large central one of these that stores water and other liquids; animal cells have several smaller ones
function
the job an organ or part performs
photosynthesis
the chemical process by which plants, algae, and some bacteria use sunlight, carbon dioxide, and water to make food (a simple sugar called glucose)
cellular respiration
the chemical process by which cells use oxygen to produce energy from food (in prokaryotic cells this takes place in the cell membrane; in eukaryotic cells it occurs mostly in the mitochondria)
fermentation
the breakdown of food without oxygen
chorophyll
the main pigment that absorbs sunlight and gives plants their green color; it is contained in a plant's chloroplasts and allows plants to convert light energy from the sun into chemical energy during photosynthesis
chloroplast
an organelle found in plant and algae cells where photosynthesis occurs
glucose
a simple sugar (C6 H12 O6) which is a carbohydrate, that is one of the products of photosynthesis. It is broken down by organisms during cellular respiration and turned into energy