Which of the following is responsible for the cohesive property of water?
Hydrogen bonds between the oxygen atoms of two adjacent water molecules
Covalent bonds between the hydrogen atoms of two adjacent water molecules
Hydrogen bonds between the oxygen atom of one water molecule and a hydrogen atom of another water molecule
Covalent bonds between the oxygen atom of one water molecule and a hydrogen atom of another water molecule
Hydrogen bonds between water molecules and other types of molecules
Which of the following is most directly responsible for water’s unique properties?
It contains oxygen atoms.
It contains hydrogen atoms.
It is an ionic compound.
It forms hydrogen bonds.
It is nonpolar.
Which of the following best explains why surface tension is created on the surface of bodies of water?
Water molecules are attracted to each other because the hydrogen atoms donate electrons to oxygen atoms
Water molecules are attracted to each other because the sharing of electrons between hydrogen and oxygen is unequal.
Water molecules are attracted to substances dissolved in the waterbecause most dissolved substances are positive charged
Water molecules are attracted to substances dissolved in the waterbecause most dissolved substances are negative charged
A feature of organic compounds NOT found in inorganic compounds is the presence of
ionizing chemical groups
electrons
carbon atoms covalently bonded to each other
oxygen
hydrogen bonds
Which of the following best matches the fertilizer component with the molecule in which it will be incorporated by organisms in the area?
Nitrogen will be incorporated into nucleic acids.
Phosphorus will be incorporated into amino acids.
Potassium will be incorporated into lipids.
Magnesium will be incorporated into carbohydrates.
Which of the following best explains how higher concentrations of nitrogen and phosphorus contribute to eutrophication?
Increase in the population of algae results in more nitrogen and phosphorus in the water, causing severe eutrophication.
Both bacteria and algae require nitrogen and phosphorus, so the algae must grow faster to compete with bacteria
Nitrogen and phosphorus stimulate oxidative phosphorylation, which consumes the available oxygen in the water
Algae require nitrogen and phosphorus build macromolecule, so higher concentration of nutrient can result in algal bloom
Which of the following best describes the process by which gas from the atmosphere is obtained by plants and used to build lipids?
Gas is fixed by plants as part of the sulfur cycle
Gas is fixed by plants as part of the nitrogen cycle
Gas is directly obtained by plants as part of the carbon cycle
Gas is directly obtained by plants as part of the magnesium cycle
Cholinesterase is an enzyme that catalyzes the hydrolysis of acetylcholine. Which of the following best explains how cholinesterase carries out its function?
Cholinesterase breaks covalent bonds within acetylcholine by the addition of a water molecule.
Cholinesterase breaks covalent bonds within acetylcholine by removing a water molecule
Cholinesterase forms covalent bonds between acetylcholine and another molecule by the addition of a water molecule
Cholinesterase forms covalent bonds between acetylcholine and another molecule by removing a water molecule
Which of the following best describes the hydrolysis of carbohydrates?
The removal of a water molecule breaks a covalent bond between sugar monomers.
The removal of a water molecule forms a covalent bond between sugar monomers.
The addition of a water molecule breaks a covalent bond between sugar monomers.
The addition of a water molecule forms a covalent bond between sugar monomers.
The synthesis of protein or carbohydrate polymers always produces which of the following as a byproduct?
ATP
Oxygen
Carbon dioxide
Urea
Water
Which of the following most likely explains how the amino acid substitution has resulted in decreased catalytic activity by the mutated enzyme?
The substitution decreased the mass of the enzyme so mutated enzyme binds more weakly to the substrate.
The substitution altered the secondary and tertiary structure of the enzyme so mutated enzyme folds into different shape
The substitution caused many copies of the mutated enzyme to cluster together and compete for substrate to bind.
The substitution caused the directionality of the enzyme to change such that amino terminus has become carboxy terminus
Used to carry the genetic code
Proteins
Carobon hydrates
Nucleic Acids
Lipids
Steroids
Which part of the amino acid most likely contributes to the hydrophobic behavior of this region of the polypeptide?
Amine (NH2) group
Carboxyl (COOH) group
Methyl (CH3) group
Hydrogen (H) atom
Which of the following best describes the structures of carbohydrates?
They only occur as disaccharides.
They occur as monomers, chains of monomers, and branched structures.
They only occur as long and branched structures.
They occur as chains of monomers that hydrogen bond with complementary chains of monomers.
Which of the following best describes how amino acids affect the tertiary structure of a protein?
The number of amino acids determines the tertiary structure of the protein.
The interactions of the different R-groups and with their environment determine the tertiary structure of the protein.
The R-group of last amino acid that is added to growing polypeptide determines the next amino acid added to the chain.
The sequence of amino acids determines the protein’s primary structure but has no effect on the tertiary structure
If of the nucleotides in a single-stranded molecule are adenine, then what percent are expected to be thymine?
0%
20%
30%
70%
Which of the following best describes a structural difference between and ?
DNA contains four types of nitrogenous bases, whereas RNA contains only two types of nitrogenous bases.
The backbone of DNA contains deoxyribose, whereas the backbone of RNA contains ribose.
DNA is composed of two parallel strands with 5' to 3' direction, RNA molecule is composed of only one 5' to 3' strand.
Phosphate groups provide rigidity to DNA, but RNA is flexible and contains no phosphate groups.
Ultraviolet (UV) radiation can damage DNA by breaking weak bonds. Which of the following best explains how this occurs?
UV radiation disrupts the double helix structure by breaking the covalent bonds between the nitrogenous base pairs.
UV radiation disrupts the double helix structure by breaking the hydrogen bonds between the nitrogenous base pairs.
radiation is able to break DNA strands in two by breaking covalent bonds between the sugarphosphate backbone molecules.
radiation is able to break DNA strands in two by breaking hydrogen bonds between the sugarphosphate backbone molecules.