Cell theory
3 essential parts:
-all living organisms are composed of one or more cells
-cells are the basic units of structure and function in an organism
-cells come only from the reproduction of existing cells
Plasma membrane
Cell's outer boundary, covers a cell's surface and acts as a barrier between inside and outside of cell
-all materials enter or exit thru plasma membrane
Eukaryote
Organisms made up of one or more cells that have a nucleus and membrane-bound organelles
-have a variety of sub cellular structures called organelles
-eukaryotic cells generally much larger than prokaryotic
-white blood cells
Prokaryote
Organisms that lack a membrane-bound nucleus and membrane-bound organelles
-although lack nucleus, their genetic info-in form of DNA- is often concentrated in a part of cell called nucleoid
-prokaryotes divided into 2 domains: Bacteria and Archaea
�bacter
Ribosome
Organelles made of protein and RNA that direct protein synthesis in the cytoplasm
-smallest organelle in cell
Mitochondrion
Tiny organelles that transfer energy from organic molecules to adenosine triphosphate (ATP)
-ATP ultimately powers most of the cell's chemical reactions
-highly active cells, muscle cells, can have hundreds of mitochondria
-cells not very active, fat-stor
Nuclear envelope
Double membrane that surrounds the nucleus
-made up of two phospholipid bilayers
-covering surface of nuclear envelope are nuclear pores
Nucleolus
The site where DNA is concentrated when it is in the process of making ribosomal RNA
-one denser area in nuclei
Golgi apparatus
Flattened membranous sacs nearest nucleus that receive vesicles from ER containing newly made proteins or lipids
-vesicles travel from one part of Golgi to next and transport substances as they go
Thylakoids
A system of flattened, membranous sacs
-inside chloroplasts
-only in plant cells
Cell well
A rigid later that lies outside the cell's plasma membrane
-only in plant cells
-cell wall contains carb "cellulose"
-pores in cell wall allow water, ions and some molecules to enter and exit cell
Central vacuole
A large, fluid-filled organelle that stores not only water but also enzymes, metabolic wastes, and other materials
-can make up 90% of plant cells volume and can push all other organelles into thin layer against plasma membrane
-only in plant cells
Chlorophyll
-green pigment inside thylakoids
-main molecule that absorbs light and captures light energy for cell
-only in plant cells