General Flashcards
The bonding of two amino acid molecules to form a larger molecule requires:
A. The release of a water molecule B. An increase in activation energy C. The release of a carbon dioxide molecule D. The addition of a nitrogen atom E. The addition of a water molecule
A. The release of a water molecule.
A common feature of starch and glycogen is that molecules of both:
A. Contain repeated monomers of glucose and galactose
B. Are water soluble disaccharides
C. Are important structural components of plant cell walls
D. Form microfibrils that give support to connective tissue fibers
E. Are polymers of glucose
E. Are polymers of glucose.
All of the following statements about enzymes are true EXCEPT:
A. Enzymes can operate only in living cells
B. Enzymes are reusable
C. Some enzymes contain coenzymes
D. Enzymes are specific
E. High temperatures usually denature enzymes
A. Enzymes can operate only in living cells.
Which of the following is TRUE about an enzyme?
A. An enzyme is stable at high temperatures.
B. An enzyme combines chemically with a substrate to form a temporary enzyme-substrate complex.
C. An enzyme catalyzes a reaction that is theoretically impossible otherwise.
D. An enzyme is a vitamin.
E. An enzyme increases the activation energy of a substrate and hence accelerates reactions.
B. An enzyme combines chemically with a substrate to form a temporary enzyme-substrate complex.
The nitrogenous base, adenine, is found in which three of the following?
A. Proteins, chlorophyll and vitamin A B. Proteins, carbohydrates and ATP C. Proteins, ATP and DNA D. Chlorophyll, ATP and DNA E. ATP, DNA and RNA
E. ATP, DNA and RNA
Which of the following is an example of a hydrogen bond?
A. The peptide bond between amino acids in a protein.
B. The attraction between a hydrogen of one water molecule and the oxygen of another water molecule.
C. The bond between an oxygen atom and a hydrogen atom in the carboxyl group of a fatty acid.
D. The bond between carbon and hydrogen in methane.
E. The bond between Na+ and Cl- in salt.
B. The attraction between a hydrogen of one water molecule and the oxygen of another water molecule.
Which of the following macromolecules is primarily responsible for the insolubility of cell membranes in water?
A. Glycogen D. Phospholipid
B. Cellulose E. Protein
C. Starch
D. Phospholipid
A substrate molecule may be bound to the active site of an enzyme by all of the following EXCEPT:
A. van der Waals interactions D. Peptide bonds
B. Hydrogen bonds E. Ionic bonds
C. Hydrophobic interactions
D. Peptide bonds
A complex polysaccharide that forms the exoskeleton if insects, crustaceans and other invertebrates is:
A. Pectin D. Glycogen
B. Cellulose E. Starch
C. Chitin
C. Chitin
Unsaturated and saturated fatty acids differ in that the former have:
A. More oxygen atoms B. Carbon to Carbon double bonds C. Fewer carboxyl groups D. More hydrogen atoms E. Amino acids
B. Carbon to Carbon double bonds
Some enzymes have secondary sites that when filled change the shape of the primary site. The enzyme is thus prevented from binding to its usual substrate and negative feedback occurs. The secondary site is called:
A. Cyclic D. Hydrophobic
B. Isomorphic E. Enzymatic
C. Allosteric
C. Allosteric
During the synthesis of a polypeptide chain from 40 amino acids, the number of water molecules released is:
A. 25 B. 42 C. 40 D. 80 E. 39
E. 39
The number of possible amino acid sequences in a protein chain composed of 200 amino acids would be:
A. 20^200 D. 10^20
B. 200^1 E. 200^20
C. 10^200
A. 20^200
Penicillin works on some bacteria because it:
A. Poisons the cell B. Inhibits the enzyme necessary to make cell walls C. Catalyzes the cell D. Raises the temperature E. Just does
B. Inhibits the enzyme necessary to make cell walls
If energy is needed to start a reaction, then the reaction is said to be:
A. Spontaneous D. Endergonic
B. Exergonic E. Phosphorylated
C. Exothermic
D. Endergonic
