Chapter 3 -- The Cell Flashcards
List General Parts of a Cell
1- plasma membrane
2- cytoplasm– contains organelles
3- nucleus
Relate and explain the 4 main functions of cells
- Cell metabolism and energy use
- Synthesis of molecules (proteins, lipids, etc.)
- Communication: produce and receive electrical and chemical signals
- Reproduction and Inheritance: each cell contains DNA. Some cells called gametes transmit DNA during sexual intercourse.
Aquaporins
Water channel proteins
Osmotic Pressure
Force required to prevent water from moving by osmosis across a selectively permeable membrane
Hydrostatic Pressure
Prevents net movement of water into the tube
Osmotic vs. Hydrostatic
Pressures
Osmotic has to do with concentration gradient
Hydrostatic has to do with weight –>pressure that the water
Endocytosis and Exocytosis are included in what broader transport category?
Vesicular transport
Endocytosis
The uptake of material through the plasma membrane by the formation of a vesicle.
(Ingested)
Three types of endocytosis:
- phagocytosis
- pinocytosis
- mediated endocytosis
Phagocytosis
“Cell eating”–> solid particles are ingested and phagocytic vesicles are formed
(Important to eliminate harmful substances from body. Ex. White blood cells phagocytize bacteria)
Pinocytosis
“Cell drinking”–> smaller vesicles form and contain molecules dissolved in liquid rather than particles
(Pinocytotic vesicles form on the internal side of a capillary, are transported across the cell, and open by exocytosis outside the capillary)
Receptor-mediated endocytosis
The receptors combine only with certain molecules (ex. Cholesterol)
Hypercholesterolemia
Common genetic disorder characterized by the reduction or absence of low-density lipoprotein (LDL) receptors on cell surfaces resulting in inadequate cholesterol uptake, cholesterol synthesis within these cells is not regulated, and too much cholesterol is produced. The excess cholesterol accumulates in blood vessels, resulting in atherosclerosis which can cause hart attacks or strokes
Exocytosis
Secretions are expelled from the cell
Ex. Digestive enzymes, mucous by salivary gland, milk by mammary glands
Cytoplasm
Material outside nucleus but inside cell
AFM
ATOMIC FORCE MICROSCOPE
Combined SEM and TEM
Measures atomic force
TEM
TRANSMISSION ELECTRIC MICROSCOPE
T=through
SEM
SCANNING ELECTRON MICROSCOPE
S= surface
Cytosol
Fluid portion of the cytoplasm
Contains cytoskeleton, and cytoplasmic inclusions
Two basic types of microscopes
Light microscopes and
electron microscopes
Light microscope
Allows us to visualize the general features of cells
Use light to produce image
Electron Microscope
Enables the study of fine structure of cell
Uses beams of electrons to produce an image
Cytoskeleton
Supports cell and holds nucleus and other organelles in place
Colloid
Viscous solution containing dissolved ions and molecules and suspended molecules (Especially Proteins)
3 types included in Cytoskeleton
Microtubules
Intermediate filaments
Actin filaments
Microtubules
Hollow tubes composed primarily of protein units called TUBULIN
Functions:
- Provide support and structure
- Involved in cell division
- Involved in transport of extracellular material
Intermediate filaments
Protein fibers (about 10nm in diameter) that provide mechanical support
Actin filaments (or microfilaments)
Small fibrils (abt 8nm diameter) that form bundles tht look like spider webs
Provide :
- structure to cell,
- mechanical support to microvilli,
- support plasma membrane,
- define shape of cell
