Chapter 3: Cells Flashcards
Nerve Cells: special features
Long extensions allow these cells to quickly transmit electrical impulses from one part of the body to another.
Muscle Cells: special features
Elongated, thread-like fibers can shorten to allow body parts to move.
Red Blood Cells: special features
Concave shape allows these cells to bend and squeeze through tiny blood vessels.
Gland Cells: special features
Intracellular sacs store and release substances, such as hormones, enzymes, mucus, and sweat.
Immune Cells: special features
These cells can recognize and destroy foreign invaders(such as viruses, fungi, and bacteria) some engulf or destroy foreign cells directly; others manufacture antibodies.
Plasma Membrane
The boundary of the cell
Nucleus
The center of the cell
Cytoplasm
A gel-like substance surrounding the nucleus and packed with various organelles and molecules each of which serves a specific function.
Selective Permeability
meaning some substances, such as lipid-soluble molecules, pass through easily, while others do not.
Nuclear Envelope
Double-layered membrane surrounding the nucleus
Nuclear Pores
Perforating the nuclear envelope, these pores regulate the passage of molecules into the nucleus, as well as out of the nucleus.
Chromatin
Thread-like structures composed of DNA and protein extending throughout the nucleoplasm
Nucleolus
in the center of the nucleus
Passive Transport
Mechanisms that don’t require the cell to expend energy (diffusion, osmosis, filtration, and facilitated diffusion)
Diffusion
Involves the movement of particles from an area of higher concentration to lower concentration.
Osmosis
involves the diffusion of water down the concentration gradient through a selectively permeable membrane.
Filtration
occurs because of differences in pressure. water and dissolved particles are forced across a membrane from an area of higher to lower hydrostatic pressure.
Facilitated diffusion
some molecules need other molecules to help, or facilitate, their movement across a membrane, higher to lower concentration gradient.
Active Transport
solutes move up the concentration gradient-from areas of lesser to greater concentration. Requires energy which is provided in the form of ATP.
Sodium-Potassium Pump
regulates the volume of fluid within cells, provides the electrical potential necessary for the nervous system activity, and helps heat production.
Endocytosis
The form of vesicular transport that brings substances into the cell
Exocytosis
uses vesicles to release substances outside of the cell.
Phagocytosis
occurs when the cell engulfs a solid particle and brings it into the cell.
Pinocytosis
Occurs when tiny vacuoles bring droplets of extracellular fluid containing dissolved substances into the cell. The cell then uses the engulfed fluid and nutrients.
