The amino acid lysine has an amino
group in its side chain. In a protein, a
scientist replaced every lysine with
serine (side chain -CH2OH). The
alteration made the protein's folding ...
less sensitive
to pH
To make a disulfide
bridge, it's necessary
to _____
remove two H
atoms
Why don't cells rely more on
disulfide bridges to stabilize
the folding of proteins?
They make the protein rigid.
Many proteins change their
shape as they work
A certain protein is not very
sensitive to pH. It may have
many side chains with
________ groups
CH2OH
Which of the following
factors does not affect
membrane permeability?
The polarity of
membrane
phospholipids
How can a lipid be
distinguished from a
sugar?
Lipids are
mostly nonpolar
True or false?
Osmosis is a type of
diffusion.
TRUE
What property of dishwashing
liquid (detergent) makes it
useful to wash grease from
pans?
Amphipathic
nature
Which of the following particles could
diffuse easily through a cell
membrane? Oxygen (O2) Glucose
Sodium ion (Na+) Hydrogen ion (H+)
Oxygen (O2)
True or false? The water-soluble
portion of a phospholipid is the polar
head, which generally consists of a
glycerol molecule linked to a
phosphate group
True
If a red blood cell is placed in a
salt solution and bursts, what is
the tonicity of the solution relative
to the interior of the cell?
Hypotonic
Which statement best describes the
electrochemical gradient for chloride
ions in the figure, assuming the
chloride concentrations are equal on
both sides of the membrane?
It favors the movement of
chloride ions from the inside
to the outside of the cell.
Cells in a live organism
differ from cells in a
dead organism. Why?
Live cells acquire energy, dead cells
do not. Live cells process genetic
information, dead cells do not. Live
cells replicate by division, dead cells
do not.
Which of the following accurately
summarizes sources of evidence that
support the pattern and process
components of the cell theory?
Pattern: Hooke's microscopic
examination of cork; Process:
Pasteur's experiment
To answer questions about life, biologists
use the scientific method, which involves
hypotheses, predictions and experiments.
Which statement most accurately
summarizes the relationship among these
three elements?
A hypothesis is a proposed answer to
a tightly focused question; a prediction
is a specific claim that follows from a
hypothesis and can be tested in an
experiment.
In a natural population of a grass species, the
average protein content of seeds would increase over
time if seeds with higher protein content survive better
and grow into individuals that produce many seeds
with high protein content when they mature. Which
statement best explains why?
Seeds with higher protein content
become more common in the
population because this characteristic
is heritable and increases survival.
Which of these is NOT a
lipid? wax steroids
phospholipid cholesterol RNA
RNA
Which of these is rich in
unsaturated fats? butter beef
fat lard olive oil a fat that is
solid at room temperature
olive oil
A function of cholesterol
that does not harm health
is its role _____.
as a component of
animal cell
membranes
The presence of many C-C
and C-H bonds causes fats to
be _____ in energy and
______ in water
Rich in energy &
insoluble in water.
In fat synthesis,________and
fatty acids combine to make
fats plus________.
glycerol;
water
In the reaction that builds a
fat,________ groups react
with ________ groups
hydroxyl;
carboxyl
Triglycerides vary
with respect to the
number of ...
C atoms in the tails &
double bonds in the
tails.
A food company
hydrogenated a barrel
of fat. The treatment ...
made the fat
less fluid
The most
unsaturated fats
have ...
the most
double bonds
What do DNA,
proteins, and fats
have in common?
They contain
carbonyl groups
Phospholipids are
most important for ...
preventing leakage
from cells
To find the best source
of phospholipids, look
at ...
membranes
What do
phosphoglycerides and
fats have in common?
Ester linkages
Which statement is
true of
phospholipids?
ALL TRUE (a) Their synthesis
uses fatty acids. (b) Some of
their tails have double bonds.
(c) They all ionize.
Which fact is most important
in causing phospholipids to
behave as they do in water?
Water molecules
make hydrogen
bonds
In a membrane, the________of the
phospholipids in one monolayer face
the________of the phospholipids in
the other monolayer
tails; tails
It is difficult for molecules to
pass through the
phospholipid bilayer because
...
polar molecules
attract one another
Which lipid is most
amphipathic? Triglyceride,
Wax, Phospholipid, Fat,
Cholesterol
Phospholipid