Transcript Document

Which component of the cell membrane is
primarily responsible for the membrane’s ability
to form a physical barrier between the cell’s
internal and external environments?
1.
2.
3.
4.
Phospholipid bilayer
Glycocalyx
Peripheral proteins
Proteoglycans
Which type of integral protein allows
water and small ions to pass
through the cell membrane?
1.
2.
3.
4.
Receptor proteins
Carrier proteins
Channel proteins
Recognition proteins
Which statement(s) correctly distinguish
between cytoplasm and cytosol?
1.
2.
3.
4.
Cytosol has a higher concentration of
suspended proteins than cytoplasm.
Cytosol is the intracellular fluid and is composed
of nutrients, ions, proteins, and wastes and
cytoplasm is the term for all material located
between the cell membrane and nucleus.
Potassium ion concentration is higher in
cytoplasm than in cytosol.
Cytosol and cytoplasm refer to the same
substance.
What is/are the major difference(s)
between cytosol and extracellular fluid?
1. Cytosol has a higher concentration of
sodium ions
2. ECF is a transport medium only, whereas
cytosol has some carbohydrates and
amino acids
3. Cytosol has a higher concentration of
potassium ions
4. 2 and 3
Which of the listed organelles is nonmembranous and correctly paired with its
function?
1. Microvilli/movement of materials over cell
surface
2. Ribosomes/protein synthesis
3. Mitochondria/produces ATP required by cell
4. Microtubules/increase surface area for
absorption
What does the presence of many
mitochondria imply about a cell’s energy
requirements?
1. A high demand for energy
2. A low demand for energy
3. Fluctuating energy needs requiring
flexibility
4. Number of mitochondria provides no
implication of energy needs
Certain cells in the ovaries and testes contain
large amounts of smooth endoplasmic
reticulum (SER). Why?
1.
2.
3.
4.
To produce large amounts of proteins
To digest materials quickly
To store large amounts of hormones
To produce large amounts of steroid
hormones
Cells lining the small intestine have numerous
fingerlike projections on their free surface. What
are these structures, and what is their function?
1.
2.
3.
4.
Microvilli; move substances across cell
surface
Microvilli; increase cell’s surface area and
absorptive ability
Cilia; increase cell’s surface area and
absorptive ability
Cilia; move substances across cell surface
What is the genetic code?
1.
2.
3.
4.
It is the method by which proteins code for
amino acids.
It is the “language” the cell uses in the form of
triplet codons, which specify individual amino
acids.
It is the portion of DNA that contains instructions
for the synthesis of tRNA.
It is the strand of DNA containing
complementary triplets used for mRNA
production.
What process would be affected by the lack
of the enzyme RNA polymerase?
1. Nothing would be affected; DNA
polymerase would take over
2. Cell’s ability to duplicate DNA
3. Cell’s ability to translate DNA
4. Cell’s ability to transcribe RNA
What are two reasons that mRNA
transcription so vital?
1.
2.
3.
4.
Protein synthesis occurs through transcription/it
occurs very quickly
DNA cannot leave the nucleus/transcription
ensures that mRNA exactly matches the coding
strand of the gene
It allows formation of chains of amino acids/the
same information is presented in a different
language
None of these is correct
Define “selectively permeable” as it applies
to the cell membrane.
1.
2.
3.
4.
It is a membrane through which nothing can pass.
It is a membrane that allows the free passage of
some molecules, but restricts the passage of
others.
It is a membrane through which any substance
can pass without restriction.
It is a membrane that only allows substances
through by active transport.
How would a decrease in the concentration of
oxygen in the lungs affect the diffusion of oxygen
into the blood?
1.
2.
3.
4.
Decrease in molecule size results in
decreased diffusion
Decrease in distance results in increased
diffusion
Increase in electrical forces results in
increased diffusion
Decrease in gradient size results in
decreased speed of diffusion
What is so special about osmosis,
compared with diffusion?
1.
2.
3.
4.
Osmosis allows free passage of alcohol, fatty
acids, and steroids through the plasma
membrane.
Osmosis is the movement of water rather than
solute.
In osmosis, water flows across a membrane
toward the solution that has a higher
concentration of solutes, because that is where
water concentration is lower.
2 and 3 are correct.
Some Pediatricians recommend the use of a
10% salt solution to relieve congestion for infants
with stuffy noses.
What effect would such a solution have on the
cells lining the nasal cavity, and why?
1.
2.
3.
4.
Cells will lose water because this is a
hypertonic solution.
Cells will lose water because this is a
hypotonic solution.
Cells will gain water because this is a
hypertonic solution.
Cells will gain water because this is a
hypotonic solution.
All methods of carrier-mediated transport
have the following characteristics ___.
1.
2.
3.
4.
Concentration gradients, transmembrane
potential, and resting potential
Specificity, saturation limits, and regulation
Endocytosis, exocytosis, and pinocytosis
Isotonic, hypertonic, and hypotonic solutions
Which of the following methods of carriermediated transport is paired with its function?
1.
2.
3.
4.
Active transport/it is dependent on a
concentration gradient
Facilitated diffusion/substances are bound to a
receptor and passed across the cell membrane by
carrier proteins
Sodium-potassium pump/moves Na outside the
cell and K inside the cell
2 and 3 are correct
During digestion in the stomach, the
concentration of hydrogen ions (H+) rises to
many times that of cells in the stomach. Which
transport process must be operating?
1.
2.
3.
4.
Facilitated diffusion
Osmosis
Active transport
Endocytosis
When they encounter bacteria, certain types
of white blood cells engulf the bacteria and
bring them into the cell. What is this process
called?
1.
2.
3.
4.
Pseudocytosis
Exocytosis
Pinocytosis
Phagocytosis
Each type of cell has a characteristic resting
potential. Which is correct?
1.
2.
3.
4.
Fat cells (−40 mV)
Neurons (−70 mV)
Cardiac muscle cells (−90 mV)
All of the above are correct
If the cell membrane were freely permeable to
sodium ions (Na+), how would the
transmembrane potential be affected?
1.
2.
3.
4.
It would not change
It would become more positive
It would become more negative
It would become unstable
During the S phase, which of the following
occur(s)?
1.
2.
3.
4.
DNA polymerase binds to exposed
nitrogenous bases
DNA replication
Synthesis of histone proteins in the nucleus
All of the above are correct
A cell is actively manufacturing enough
organelles to serve two functional cells.
This cell is probably in which phase of its
life cycle?
1.
2.
3.
4.
S
G1
G2
M
During DNA replication, a nucleotide is deleted
from a sequence that normally codes for a
polypeptide. What effect will this deletion have
on the amino acid sequence of the
polypeptide?
1. No effect, deletion will be skipped
2. No effect, deletion will be automatically
repaired
3. Amino acid sequence will disintegrate
4. Amino acid sequence would be altered
What would happen if spindle fibers
failed to form in a cell during mitosis?
1. Centromeres would not appear
2. Nuclear membrane would not
disintegrate
3. Chromosomes would not separate
4. Chromatin would not condense
Which of the following stages of mitosis is
correctly paired with the events of that stage?
1.
2.
3.
4.
Anaphase/centromeres of chromatid pairs
separate and daughter chromosomes are
pulled to opposite ends of the cell
Prophase/chromatids are aligned along center
of the cell
Telophase/chromosomes condense and
nuclear membrane fragments
All of the above are correct