Chapter 3: Cells - The Living Units
Glycocalyx
Definite changes in the __________ of the cell membrane can be seen in a cell that is becoming cancerous.
Osmosis
Diffusion of a solvent, such as water, through a specific channel protein(aquaporin) or through lipid bilayer
secondary active transport
Driven indirectly by energy stored in concentration gradients of ions
membrane proteins
Make up half of the plasma membrane, all cell communication with environment, and most have specialized membrane proteins
desmosome
Mechanical couplings scattered like rivets along the sides of adjacent cells to prevent their separation
- lipid soluble and nonpolar substances - very small molecules that can pass through membrane or membrane channels - larger molecules assisted by carrier proteins
Molecules able to passively diffuse through membrane:
Fluid Mosaic
Specialized membrane proteins float through the plasma membrane, resulting in constantly changing patterns
Glycocalyx
Surface sugars form
Integral proteins
...
Peripheral proteins
...
hypotonic
A cell would plump with water and possibly lyse in which of the following solutions:
isotonic
A patient arrives in the hospital dehydrated. In order to fill his cells with fluid relatively quickly and no over-hydrate, what type of intravenous drip should he receive:
hypotonic
A solution that contains fewer solutes than the cell is:
Active processes
A way a substance crosses the membrane, energy(ATP) required
Passive processes
A way a substance crosses the membrane, with no energy(ATP) required
Gap Junctions
Adjacent cells held together by connexon proteins that form cylinders allowing ion flow between the cells' cytoplasm
receptor-mediated endocytosis
Cells of the body mainly use __________ for the selective endocytosis of most macromolecules.
mitochondria
The organelle that produces ATP from glucose is the __________.
Plasma membranes
These stop diffusion and create concentration gradients by acting as selectively permeable barriers
Generalized cell
This contains a plasma membrane, cytoplasm, and nucleus
phagocytosis and pinocytosis
Two types of endocytosis are:
nonpolar, hydrophobic lipid core of plasma membrane
What blocks most diffusion?
The pump must be phosphorylated
What critical event must occur before the sodium-potassium pump can transport sodium and potassium ions across the plasma membrane?
Cell size, shape, and subcellular components
What leads to differences in functions?
there is a transport maximum because transport proteins are required
When a molecule is transported via facilitated diffusion, ____________________.
filtration
Which of the following do NOT involve the movement of molecules from an area of greater concentration to an area of lower concentration:
facilitated diffusion and solute pumping
Which of the following processes require the use of protein carrier molecules:
Secondary active transport requires an input of energy, while facilitated diffusion does not.
Which of the following statements best describes the difference between facilitated diffusion and secondary active transport?
Osmosis leads to a volume change across the plasma membrane, while simple diffusion of a solute does not.
Which of the following statements best describes the difference between the simple diffusion of a solute and osmosis?
it allows water soluble molecules to pass through easily
Which one of the following is NOT true about the plasma membrane:
phagocytosis
Which transport process allows for the movement of solid particles across the plasma membrane?
Primary active transport
Which type of membrane transport process uses ATP as a source of energy?
cellular excretions
a class of extracellular fluid ex. saliva
integral protein
a membrane protein that functions in cell recognition
Plasma(cell) membrane
acts as an active barrier separating intracellular fluid from extracellular fluid - selectively permeable
Interstitial fluid
cells are submerged in this
Pinocytosis
endocytosis of a tiny quantity of extracellular fluid containing solute molecules
cerebrospinal fluid
fluid surrounding nervous system organs
Osmolarity
measure of total concentration of solute particles
cell junctions
membrane structures help to hold cells together through
Extracellular fluid
substances found outside cells Ex. blood plasma
Extracellular matrix
substances that act as glue to hold cells together
Exocytosis
the fusion of a vesicle with the plasma membrane to move substances out of the cell
tonicity
water concentration varies with # of solute particles because solute particles displace water molecules
gap junctions
Nutrients and ions can pass directly from cell to cell through special membrane junctions known as:
aquaporins
Osmosis transports water across membranes using:
require no ATP
Passive processes that move substances across membranes: