The slowest rate of diffusion of dye particles in water will occur at: - Answers 10 C
Which type of cell would you expect to burst when placed in a hypotonic solution? - Answers red
blood cell
Which of the following requires adenosine triphosphate? - Answers active transport
Cells use exocytosis to: - Answers release substances from the cell.
The diffusion of water molecules across a selectively permeable membrane is called: - Answers
osmosis.
Which of the following transport processes require(s) energy? - Answers endocytosis
The bacterium Vibrio cholerae releases a toxin that blocks a channel protein in the membranes
of cells that line the intestine. This toxin prevents the movement of positively charged sodium
ions out of the intestine and into these cells. If the sodium ions could not move into the cells,
how would this affect the movement of water? - Answers Water would leave the cells and enter
the intestines by osmosis.
A cell is placed in a hypotonic solution. What will happen? - Answers Water will move into the
cell.
A hormone circulating in the bloodstream would most likely bind to __________. - Answers a
receptor protein
The secretion of excess water via the contractive vacuole of a Paramecium cell is an example
of: - Answers exocytosis.
The point at which a substance is evenly dispersed within a fluid __________. - Answers is
referred to as dynamic equilibrium and happens when net diffusion is zero
What happens when diffusion moves molecules across the plasma membrane? - Answers The
process is relatively slow and is driven by concentration gradients
ISO membranes are inside-out membrane vesicles used by researchers in membrane studies.
As a molecule diffuses into the vesicle, it will encounter the layers of the membrane in the
following order: - Answers head-tail-tail-head.
The main lipids found in cell membranes are: - Answers phospholipids.
Each substance needs a different type of transport to get into a cell. Pick the answer choices
that accurately match the type of transport needed to convey each of the following substances
into a cell.oxygen, water, sodium ions, potassium ions, bacteria (Note that sodium ions are more
concentrated outside cells than inside; potassium ions are more concentrated inside cells than
,outside.) - Answers simple diffusion, osmosis, facilitated diffusion, active transport, endocytosis
Specialized cell junctions include all of the following EXCEPT: - Answers phospholipases.
Which process accounts for the movement of solids into some animal cells? - Answers
phagocytosis
The concentration of sodium ions is lower in the cytoplasm of a heart muscle cell than it is in
the extracellular fluid. By what mechanism does the cell maintain this difference? - Answers
active transport
Which cell junctions function to make the connections between cells leakproof? - Answers tight
junctions
In osmosis, water diffuses from the side of the membrane with a higher concentration of water
to the side with a lower concentration of water. What determines the concentration of water in a
solution? - Answers the amount of molecules other than water dissolved in the solution
Glucose is a six-carbon sugar that diffuses slowly through artificial phospholipid bilayers. The
cells lining the small intestine, however, rapidly move large quantities of glucose from the
glucose-rich food into their glucose-poor cytoplasm. Given this information, which transport
mechanism is most probably functioning in the intestinal cells? - Answers facilitated diffusion
Many metabolic poisons work by inhibiting ATP production. Which type of transport would be
most affected? - Answers active transport
In reference to diffusion, "passive" really means: - Answers no energy required.
Which of the following processes does a cell use to take up molecules against their
concentration gradient? - Answers both active transport and endocytosis
According to the fluid mosaic model of cell membranes, which of the following is a TRUE
statement about membrane phospholipids? - Answers They form a viscous fluid through which
proteins shift and flow.
Cystic fibrosis is a genetic disease that leads to the production of excessive, thick mucus in the
respiratory tract, causing frequent and serious respiratory infections. The defect is due to the
production of a faulty membrane protein for the transport of the chloride ion. The protein exists
in membranes, but it doesn't function normally.Based on this scenario, what is occurring at the
molecular level in a person with cystic fibrosis? - Answers A channel protein is being adversely
affected.
Osmosis is the diffusion of water molecules across selectively water-permeable membranes.
True or False? - Answers True
When a drop of food coloring is placed in a glass of water, the spreading out of the molecules of
, food dye is caused by __________. - Answers the random movement of molecules
Facilitated diffusion requires __________. - Answers a membrane transport protein and a
concentration gradient
If there is a high concentration of oxygen on one side of a biological membrane, what will
happen? - Answers The oxygen will diffuse across the membrane until the concentration of
oxygen on each side is the same.
The cytoplasm of a certain cell, such as a neuron, already has a high concentration of K+ ions.
How can K+ ions continue to enter the cell? - Answers active transport
Active transport requires all of the following EXCEPT: - Answers aquaporins.
The gases O2 and CO2 enter or leave a plant cell by: - Answers simple diffusion.
________ is used by cells to consume large particles such as bacteria. - Answers Phagocytosis
The movement of molecules across a cell membrane in which no energy is required (i.e.,
diffusion) is called ________ transport, and the movement of molecules across a cell membrane
in which energy (i.e., ATP) is required is called ________ transport. - Answers Active, Passive
Which of the following occurs as an enzyme produced by a cell is secreted from the cell? -
Answers exocytosis
In biological membranes, the phospholipids are arranged in a: - Answers bilayer with the fatty
acids pointing toward one another.
During endocytosis, the contents of the endocytic vesicle __________. - Answers enter the cell
The ________ portion of the cell membrane is responsible for the isolating function of the
membrane, while the ________ portion regulates exchange and communication with the
environment. - Answers lipid; protein
Which of the following types of membrane proteins are responsible for connecting cells to one
another? - Answers attachment proteins
Protein channels that provide passage for hormones and nutrients between animal cells are
termed: - Answers gap junctions.
The compounds in biological membranes that form a barrier to the movement of materials
across the membrane are: - Answers lipids.
Bacterial cells have only one DNA molecule, which is double stranded and is replicated in
essentially the same fashion as in eukaryotes. Imagine that, following the techniques of other
scientists studying DNA, you created a bacterial cell that contains only radioactive nitrogen in its
DNA. You then place the cell in a culture medium containing only "regular" (nonradioactive)