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13 terms

Cell Structure & Function

STUDY
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Plasma Membrane
-Regulates what enters and leaves a cell
-Selectively Permeable- cell membrane controls what enters and exits the cell.
-Composed of lipids, proteins, and carbohydrates
-Phospholipid bilayer- hydrophobic tails and hydrophilic heads
-Integral Proteins- imbedded in bilayer
-Peripheral Proteins- sit on top of the bilayer
-Transport Proteins- allow cell to be selectively permeable
-Carbohydrates on outer surface of membrane act as signals for other cells, chemical messages, or viruses to attach.
-Fluid Mosaic Model- constant change and fluid movement of lipids and proteins in cell membrane
ex. bouncer at a night club, parents because they have a say about who you can date, border control, hockey goalie, etc.
Ribosome
-Structure responsible for protein synthesis
-Most numerous organelle in cell
-Doesn't have membrane
-Made of RNA and proteins
-Free ribosomes contain proteins to be used in the cytosol
-Proteins to be used outside the cell or in membranes are attached to the ER
ex. workers in a factory, ants in a colony, bees in a hive, etc.
Nucleus
-Houses the cell's DNA
-Carries genetic information and where RNA is copied from DNA
-Surrounded by a double membrane called the nuclear envelope with nuclear pores as exit sites

ex. brain of the cell, motherboard of a computer, president, mayor, city hall, boss, general, etc.
Nucleolus
Dense area of the nucleus
-Spherical ball inside nucleus which is the site for ribosome synthesis and assembly before they pass through the nuclear pores
Microtubule
-Hollow tubes made of proteins call tubulin; they maintain cell shape, cell motility (in cilia and flagella), chromosome movement, organelle movement
-Acts like a track
Mitochondria
-Site of chemical reactions that transfer energy from organic compounds to ATP
-Contains double membranes (outer & inner)
-Has folds called cistae, increasing the surface area and allowing more chemical reactions
-Have own DNA (coming from the mother)
ex. power house of the cell, coffee, heart, sun, core of earth, etc.
Endoplasmic Reticulum
-System of membranous tubules and sacs, inside the sacs are called the lumen
-Intracellular highway, path which molecules use to travel from one part of the cell to another
ex. US mail system, Fedex, Kinkos, Staples, gift wrappers, etc.
Rough ER
-Covered in ribosomes, which aid in the export of proteins into membranes or out of the cell
Smooth ER
-Aids in the synthesis of lipids and chemical modification of proteins
Lysosome
-Single membrane, small, spherical organelles that are filled with hydrolytic enzymes that digest proteins, lipids, DNA, RNA, carbohydrates, and old organelles.
-Aid in the early embryonic development to eat away tissue between fingers
ex. garbage men of the cell, mafia waste management
Golgi Apparatus
-System of flattened membranous sacs that aid in processing, packaging, and secretion of proteins for export by the cell
-Works closely with the ER in preparing materials for release by the cell.
ex. Fedex, Kinkos
Nucleolus
-A spherical ball inside the nucleus which is the site for ribosome synthesis and assembly before they pass through the nuclear pores
Microfilaments
-Finer than microtubules, long threads of beadlike protein called actin that are attached end to end and wrapped like a strand of rope. Work in maintenance and changing of cell shape; muscle contraction; movement of cytoplasm; cell motility; cell division