Mastering A&P Chapters 1-3
Type of active process in which the cell engulfs extracellular substances by phagocytosis or pinocytosis
Endocytosis
What is the basic difference between simple diffusion and facilitated diffusion across a cell membrane?
In facilitated diffusion, molecules only move with the aid of a protein in the membrane.
Which of the following is most likely to move through the cell membrane by facilitated diffusion?
Na+ Ions move easily through water, which is polar, but cannot pass directly through the lipid (nonpolar) part of the cell membrane.
Type of active transport in which sodium and potassium are pumped across a membrane using ATP
Solute pumping
A cell is isotonic to the surrounding 4% dextrose solution. If the cell is moved to a 6% dextrose solution, then predict what will happen to the cell.
The cell will shrink.
If a person is severely dehydrated, their extracellular fluids will become hypertonic to the intracellular fluid. What do you predict will happen to the person's cells?
The cells will lose water and shrink. The hypertonic extracellular fluid will draw water out of the hypotonic intracellular fluid, so the cells will shrink. This is called crenulation.
What happens when body cells are placed in a hypertonic solution?
Water leaves the cells and the cells shrink.
What transport process can create a concentration gradient for sodium across the plasma membrane?
active transport
What is required for osmosis to occur?
aquaporins
Which of the following is not required for osmosis to occur?
cellular energy
What is required for diffusion to occur?
concentration gradient
Type of passive process in which molecules move across the plasma membrane down a concentration gradient
diffusion
Passive processes that move substances across membranes ________.
do not require ATP
A vesicle fuses with the plasma membrane and releases its contents to the extracellular fluid. This statement describes _____.
exocytosis
Some transport processes use transport proteins in the plasma membrane, but do not require ATP. This type of transport is known as _____.
facilitated diffusion
The majority of water molecules moving across plasma membranes by osmosis do so via a process that is most similar to ____.
facilitated diffusion
What process permits absorption of glucose into cells?
facilitated diffusion
Which of the following processes require the use of protein carrier molecules?
facilitated diffusion and solute pumping
Which of the following is not a major function of proteins in the cell membrane?
forming the entire glycocalyx
What type of membrane junction allows ions to pass directly from the cytoplasm of one cell to the cytoplasm of the adjacent cell?
gap junction
Which of the following substances must travel across a membrane via facilitated diffusion?
glucose
The phospholipid tails are ________, which make the plasma membrane impermeable to water.
hydrophobic
Which of the following solutions contains the most solute?
hypertonic "Hyper" means "high," so a hypertonic solution has a higher solute concentration than the solution to which it is being compared.
A solution that contains fewer solutes than the cell is ________ to the cell.
hypotonic
In general, to maintain homeostasis the relationship between our intracellular and extracellular fluids should be which of the following?
isotonic to each other In order to prevent the cells from either swelling or shrinking, the body fluids should be isotonic, meaning that they are at equilibrium.
A primary active transport process is one in which __________.
molecules move through transport proteins that have been activated by ATP
Which of the following best explains diffusion?
movement of molecules from an area of high concentration to an area of low concentration
The passive process that involves the movement of water through aquaporins is ________.
osmosis
Type of passive process in which water is moved through aquaporins
osmosis
What process does water use to move across the plasma membrane?
osmosis
By what endocytosis process do some white blood cells engulf bacteria?
phagocytosis
What are two types of endocytosis?
phagocytosis and pinocytosis
What part of a cell membrane is usually in contact with the interstitial fluid?
phosphate heads of phospholipids
What part of the plasma membrane is hydrophobic?
phospholipid tails
Which of the following is the main component of the cell membrane?
phospholipids
What separates the intracellular fluid from the extracellular fluid?
plasma membrane
What is required for filtration to occur?
pressure gradient
The sodium-potassium pump uses ATP to move sodium and potassium ions across the plasma membrane. This statement describes _____.
primary active transport
What assists the movement of substances by facilitated diffusion?
protein carrier or channel
Which of these components add specialized functions to the plasma membrane?
proteins
Which of the following is a characteristic of the cell membrane?
semipermeable
Which of the following is least likely to increase the rate of diffusion?
small concentration gradient
The membrane connections that prevent the leaking of fluid between cells are called ________.
tight junctions
Which cell junctions prevent substances from passing between adjacent cells?
tight junctions