Online Quiz Questions Flashcards
The chemical behavior of an atom is primarily due to
the number of electrons in the highest energy shell.
If the intracellular pH of a cell would increase from normal pH 7.2 to pH 9.0, what would you expect to happen to the carboxyl groups on all the proteins?
Mosts of the carboxyl groups would gain a H+ and have a net positive charge.
What unit of length would you generally use to measure a typical plant or animal cell?
micrometer
If two atoms that form a covalent bond have electronegativity numbers of 2.0 and 1.9, what can you predict about the nature of this covalent bond?
It will be a nonpolar covalent bond
The diversity of cell types (their shape, function, etc) in a particular organism is due primarily to
Differential gene expression and unique proteins types being made in each cell type.
Which of the following characteristics would be expected for hydrophobic molecules? a)They are polar molecules. b)They contain C-H covalent bonds. c)They usually hydrogen bond with water. d) Hydrophobic molecules tend to interact with one another in water.
They contain C-H covalent bonds. Hydrophobic molecules tend to interact with one another in water.
T or F: The hydrogen atom involved in the hydrogen bond is negatively charged.
False
Which of the following is found in BOTH an animal and plant cell? a)endoplasmic reticulum b)chloroplast c)cell wall d)mitochondria
endoplasmic reticulum mitochondria
T or F: Electrostatic interactions are relatively strong interactions that can not easily be broken
False
T or F: Electrostatic or ionic interactions involve actual attraction of a negative to a positive charge.
True
T or F: Hydrogen bonding within a polypeptide chain can take place between molecules in a peptide bond and the R group of another amino acid.
True
T or F: Two polypeptides with the exact same numbers and types of amino acids can have very different structures.
True
In a nucleotide (or nucleoside) the bond between the ribose sugar and the organic base always involves what atom in the organic base?
nitrogen
The correct name for the nucleotide dCDP is what?
deoxycytidine diphosphate
How do the nonpolar amino acids in the polypeptide chain contribute to the tertiary (3-D) structure of the polypeptide?
The nonpolar R groups of these amino acids move to the interior of the polypeptide as it folds up.
Consider the amino acid shown below. Which of the following interactions is likely to be involved between the R group of this amino acid and other molecules?
covalent
hydrophobic
ionic
wan der Waals
disulfide
ionic
After formation of a peptide bond, what molecule is given off in the reaction?
water
T or F: The flexibility of the polypeptide is due to the free rotation of the peptide bond.
False
T or F: If a lysine is numbered 57 and a glycine is numbered 157 in the polypeptide chain, then the glycine is nearer to the carboxyl (or C) terminus of the polypeptide.
True
T or F: The AA sequence TAQKDPSN is likely to be found on the outside of a polypeptide tertiary (3-D) structure
True
Free energy or ∆G is a measure of the change in a chemical conversion that includes the
a. change in potential energy or useable energy in chemical bonds
b. change in disorder
The standard ∆G° of a chemical reaction can be altered by a number of factors. Which one of the following is used to alter the ∆G° in a cell?
a. change pH
b. change temperature
c. change concentration of reactant and products
d. add an enzyme
e. change pressure
change concentration of reactant and products
The role of enzymes in biological chemical reaction is to
reduce the activation energy.
Proteins function by binding specific molecules called “ligands.” These can be other proteins, small organic molecules, or even DNA. What ultimately determines why protein-ligand binding is very specific. That is, why do proteins only recognize and bind one other molecule?
Because of the protein’s primary structure, which determines its overall tertiary structure and possibly quaternary interactions.
At first glance, it may seem that living systems are able to defy the second law of thermodynamics. However, on closer examination, it becomes clear that although cells create organization from raw materials in the environment, they also contribute to disorder in the environment by releasing _____________.
heat
Enzymes function similar to all proteins. The ligand binding to an enzyme is called the _____________________ and it binds to the ____________________ of the enzyme.
substrate; active site
