The best reference source for the atomic number and mass number of elements is
the periodic table.
A β pleated sheet organization in a polypeptide chain is an example of _______ structure.
The "backbone" of a nucleic acid molecule is made of
alternating sugars and phosphate groups.
Large molecules that contain carbon and are held together by covalent bonds are categorized as
Which of the following is not a macromolecule?
Lactose, or milk sugar, which is composed of one glucose unit and one galactose unit, can be classified as a
What determines if a molecule is polar, nonpolar, or ionic?
The differences in the electronegativities of the atoms
A human hair is found to have a high ratio of 18O to 16O. From this information it can be assumed that
CorrectE. the person lives in a region where "heavy" water is consumed.
A nucleotide contains a pentose sugar, a phosphate group, and
CorrectE. a nitrogen-containing base.
Two atoms are held together in four covalent bonds because of forces between the
Ice is used in beverages primarily because
CorrectB. it absorbs a lot of heat when it melts.
The Miller-Urey experiment showed that in any environment with conditions similar to those of Earth,
CorrectE. inorganic molecules would react to form organic molecules.
DNA and RNA both include
A prerequisite for the survival of life on land was the accumulation of
O3 in the atmosphere
When sodium hydroxide (NaOH) is added to water, it ionizes, releasing OH- and Na+ ions. The resulting solution is
Which of the following was not a component of Earth's early atmosphere?
What accounts for the stability of the DNA molecule?
CorrectC. The bonds between purines and pyrimidines
A type of molecule very often drawn with a single six-sided ring structure is
A molecule that has an important role in long-term storage of energy is
All of the following bases are found in DNA except
Which of the following statements about atoms is true?
When the number of protons equals the number of electrons, an atom has a neutral charge.
Which of the following is responsible for making every amino acid unique?
R group
Particles having a net negative charge are called
The difference between α- and β-glucose is
placement of OH and H atoms
An essential functional group involved in cellular energy transfer is the _______ group.
Two carbon atoms held together in a double covalent bond share _______ electron(s).
Maltose and lactose are similar in that they both are
The diversity in DNA molecules is due to
base sequence differences in the DNA molecule.
The branching patterns of the evolutionary tree of life are based on a rich array of evidence from
CorrectD. All of the above
Starch and glycogen, which are both polysaccharides, differ structurally in that glycogen _______, whereas starch _______.
CorrectE. is highly branched; is moderately branched
Examination of meteorites suggests that
life is not limited on earth
In a hydrogen molecule, the two atoms are held together by
shared pair of electrons
The monomers that make up polymeric carbohydrates like starch are called
All living organisms acquire _______ from their environment.
Which of the following questions cannot be answered by means of the hypothetico-deductive method?
CorrectB. Are red roses more beautiful than yellow roses?
The amino and carboxyl functional groups tend to form bases and acids by attracting or dropping
Which of the following statements about proteins is true?
CorrectA. Some function as enzymes.
An atom with _______ has an atomic mass of 14.
CorrectB. 6 protons and 8 neutrons
Which of the following is not a function in which lipids play an important role?
storing genetic information
If tight junctions were replaced by desmosomes in cells lining the bladder,
CorrectA. dissolved substances would move freely through the extracellular matrix.
In some prokaryotic organisms, the plasma membrane folds to form an internal membrane system that is able to
CorrectA. carry out photosynthesis.
How do the cell membranes of a hibernating animal change in colder temperatures?
CorrectA. Unsaturated fatty acids make up more of the lipid composition.
The function of the nuclear pores is to
CorrectA. regulate movement of materials across the nuclear membrane.
In the mitochondria, energy storage molecules are converted to ATP by a process known as
cell respiration
In the intestine, Na+ and an amino acid bind to the same transport protein that moves the two substances in the same direction. This type of active transport is called
Chromatin is a series of entangled threads composed of
DNA and protein
An important difference between phagocytosis and receptor-mediated endocytosis is that
CorrectA. receptor-mediated endocytosis is more specific in terms of what it brings into the cell.
Which of the following organelles is found only in plant cells?
A ribosome is a specialized structure but is not considered an organelle because it
lacks a lipid bilayer.
Which of the following organelles were once independent prokaryote organisms?
mitochond and chloroplast
A general function of all cellular membranes is to
CorrectA. regulate which materials can enter or leave the cell.
In facilitated diffusion, the diffusion rate of a specific molecule across a membrane does not continue to increase as the concentration difference of the molecule across the membrane increases. The reason is that
carriers become saturated
Two membrane components that serve as cell recognition sites are
CorrectC. glycolipids and glycoproteins.
When vesicles from the Golgi apparatus deliver their contents to the exterior of the cell, they add their membranes to the existing plasma membrane. This is made possible by the
CorrectA. capacity of lipids to associate with one another.
Prokaryotes and eukaryotes must transform energy from the environment into energy that can be used. Which of the following is not one of the processes by which energy is transformed by these organisms?
all the above
Phagocytosis, pinocytosis, and receptor-mediated endocytosis all involve
CorrectD. invagination of the plasma membrane.
Active transport usually moves molecules
direction opposite of diffusion moves them
A specialized structure surrounding the cell wall in some prokaryotes is the
Receptor-mediated endocytosis is the mechanism for the import of
Which type of membrane protein would likely be removed most easily from a cell membrane in a laboratory experiment?
An unknown organism is discovered and found to lack a membrane-bound nucleus in its cell. This unknown organism is most likely
Proteins packaged by the Golgi apparatus are delivered to the correct location by means of
. identifying carbohydrate groups covalently bound to the packaged proteins.
Which of the following molecules will cross a plasma membrane most easily?
In a mixture of ground-up plant cells, one structure containing a membrane stains positive for hydrogen peroxide. This structure is a
Steroids are synthesized by
Smooth ER
Starch molecules are stored inside
A particle of food encounters a series of cellular structures upon digestion by a cell. In what order does this encounter occur, starting from the exterior of the cell?
Plasma membrane → phagosome → primary lysosome → secondary lysosome
In which of the following locations would you not expect to find RNA?
What is the major distinction between a prokaryotic and a eukaryotic cell?
the DNA in a prokaryotic cell is not separated from the ribosomes.
The hydrophilic regions of a membrane protein would most likely be found
on the surface of membrane exposed
Transport of cytoplasmic materials in plants is facilitated by
membrane-lined channels called plasmodesmata.
The cytoskeleton is composed of three major components, each with distinct functions. Which of the following represents the correct order of these components, from smallest to largest size?
micro fil, intermediate fil, microtubles
For each molecule of ATP consumed during active transport of sodium and potassium, there is an import of _______ ion(s) and an export of _______ ion(s).
2 K+, and 2 NA+
A group of transmembrane proteins involved in maintaining cell structure via their interactions with the cytoskeleton are known as
Which of the following is not a component of the endomembrane system?
Proteins produced by ribosomes pass through several cellular structures before reaching their targeted destination. Which of the following represents the structures, in the correct order, that will be encountered by a newly synthesized protein targeted for outside the cell?
RER → vesicle → cis Golgi → trans Golgi → vesicle → plasma membrane
The compounds in a biological membrane that form a barrier to the movement of hydrophilic materials across the membrane are
Cells arrange themselves into tissues through
cell recognition and adhesion
Ion channels are formed by a particular kind of membrane protein that allows the passage of a specific ion under certain conditions. This type of protein is most likely a(n)
integral protein with a transmembrane domain.