ANAT NOTES 2 PART 1 Flashcards
(39 cards)
Cells are…
the smallest living units in the body
What do cells do?
- obtain nutrients
- make molecules needed to survive
- dispose of wastes
- maintain shape of cell
- replicate
Organelles
subunits of cells with specific functions
What are the 3 main components of the cell?
plasma membrane-the outer boundary
cytoplasm-contains most organelles
nucleus-controls cellular activities
Plasma membrane
separates the intracellular fluid within cell from extracellular fluid outside and between cells
*selectively permeable membrane
Integral proteins
firmly embedded in, or attached to lipid bilayer
peripheral proteins
attached to membrane surface
What does the plasma membrane do?
- provides barrier against substances outside cell
- some plasma membranes act as receptors
- determine which substance enter or leave the cell
Simple diffusion
tendency of molecules to move down their concentration gradient
Osmosis
diffusion of water molecules across a membrane
Facilitated diffusion
movement of molecules down their concentration gradient through an integral protein
Active transport
integral proteins move molecules across the plasma membrane against their concentration gradient
Endocytosis
mechanism by which particles enter cells
Phagocytosis
“cell eating”
Pinocytosis
“cell drinking”
Receptor-mediated endocytosis
Plasma proteins bind to certain molecules
Exocytosis
A mechanism that moves substances out of the cell
Mitochondria is surrounded by a…
double-walled membrane
Mitochondria
- Generate most of the cell’s energy “powerhouse of the cell”
- Release energy stored in chemical bonds and transfer energy to produce ATP
Centrosome
a spherical structure in the cytoplasm
Composed of centrosome matrix and centrioles
Centrioles
paired cylindrical bodies;
- Consists of 27 short microtubules
- Act in forming cilia
- Necessary for karyokinesis (nuclear division)
Peroxisomes “toxic waste removal system”
Membrane-walled sacs of oxidase enzymes
that neutralize free radicals and break down poisons.
Also break down longs chains of fatty acids.
Nuclear envelope
two parallel membranes separated by fluid-filled space
Nuclear pores…
penetrate the envelope enabling large molecules to pass in and out of the nucleus
