Chapter 3 Flashcards
What 3 parts can a cell be divided to:
1) plasma membrane or plasmalemma
2) cytoplasm → cytosol (intracellular fluid) and organelles
3) nucleus
• chromatin
What is chromatin and where is it found
It is the condensed form of DNA in the nucleus.
It is found in the nucleus
The most condensed form of DNA is
Chromosomes
What are the 2 types of membrane proteins
1) integral proteins: permanently attached to biological membrane
2) peripheral proteins: Attached to the surface
Plasma membrane
flexible yet sturdy barrier that surrounds and contains the cytoplasm of a cell
Carbohydrates purpose in plasma membrane
are only located on the extracellular face of the cell and it is used for identification
Cholesterol purpose in cells
makes the cell membranes more solid and reduces fluidity of the membrane
What are the two types of transport proteins and their purpose
Channel proteins and carrier proteins that help transport specific substances across the membrane
Channel proteins (integral)
forms a pore through which a specific ion can flow to get across the membranes. example: NA+
Carrier proteins (integral)
transports a specific substance across the membrane by undergoing a change in shape. For example: amino acids
Receptor (integral)
recognizes specific bonds, and alters the cells function in some way. example: ADH hormone binds to receptors in the kidneys and changes the water permeability of certain plasma membranes.
Enzyme (integral and peripheral)
catalyzes a reaction inside or outside your cells.
Linker (integral and peripheral)
connects cells to cells
What can directly go through a membrane
small, nonpolar molecules such as O2, CO2 and H2O can go through without transport proteins
Membrane fluidity
membrane lipids and proteins are mobile in their own half of the bilayer and can move easily
Plasma membranes allow small, non polar uncharged molecules and not charged molecules and therefore are
selectively permeable
What is a concentration gradient
difference in the concentration gradient of a chemical between one side of the plasma membrane and the other
What is an electrical gradient
difference in concentration of ions between one side of the plasma membrane and the other
Transport processes that move substances across a cell membrane are…
passive processes (diffusion and osmosis) and active processes ( primary, secondary and vesicular transport)
Passive transport never requires…
energy
Active transport requires…
energy
Diffusion is influenced by these 5 factors:
- steepness of the concentration gradient
- Temperature: the higher the temp, the more movement
- Mass of diffusing substance: lower the mass, the faster the diffusion
- Surface area
- Diffusion distance: longer distance = longer time
Simple diffusion
Does not require transport proteins, and moves particles from an area of higher concentration to lower until equilibrium . Normally moves particles that are nonpolar and uncharges.
Facilitated diffusion
transmembrane proteins help solutes that are too polar or too highly charged move through the lipid bilayer
What are the two types of proteins involved in facilitated transport
channel and carrier
Sodium potassium pump; channel mediated facilitated diffusion
inward movement of NA+ and outward movement of K+ (important for nerve function)
Glucose transporter (carrier protein)
insulin tells cells to put more glucose transporters to allow for more glucose to enter the cells to prevent high blood sugar levels
Osmosis
net movement of a solvent (water) through a selectively permeable membrane from an area of higher concentration to an area of lower concentration. –> water always follows solutes
Tonicity
relates to how the solution influences the shape of body cells
Isotonic solution
the same concentration
Hypotonic solution
more water (solvent) in solution than cells. causes cells to swell