Biochemistry - Exam 1 Practice Questions

Biochemistry - Exam 1 Practice Questions In a bacterial cell, the DNA is in the: A) cell envelope. B) cell membrane. C) nucleoid. D) nucleus. E) ribosomes. - ANSWER nucleoid A major change occurring in the evolution of eukaryotes from prokaryotes was the development of: A) DNA. B) photosynthetic capability. C) plasma membranes. D) ribosomes. E) the nucleus - ANSWER the nucleus In eukaryotes, the nucleus is enclosed by a double membrane called the: A) cell membrane. B) nuclear envelope. C) nucleolus. D) nucleoplasm. E) nucleosome. - ANSWER nuclear envelope The dimensions of living cells are limited, on the lower end by the minimum number of biomolecules necessary for function, and on the upper end by the rate of diffusion of solutes such as oxygen. Except for highly elongated cells, they usually have lengths and diameters in the range of: A) 0.1 µm to 10 µm. B) 0.3 µm to 30 µm. C) 0.3 µm to 100 µm. D) 1 µm to 100 µm. E) 1 µm to 300 µm - ANSWER 0.3 µm to 100 µm The bacterium E. coli requires simple organic molecules for growth and energy—it is therefore a: A) chemoautotroph. B) chemoheterotroph. C) lithotroph. D) photoautotroph. E) photoheterotroph - ANSWER chemoheterotroph Which one of the following has the cellular components arranged in order of increasing size? A) Amino acid < protein < mitochondrion < ribosome B) Amino acid < protein < ribosome < mitochondrion C) Amino acid < ribosome < protein < mitochondrion D) Protein < amino acid < mitochondrion < ribosome E) Protein < ribosome < mitochondrion < amino acid - ANSWER Amino acid < protein < ribosome < mitochondrion The three-dimensional structure of macromolecules is formed and maintained primarily through noncovalent interactions. Which one of the following is not considered a noncovalent interaction? A) carbon-carbon bonds B) hydrogen bonds C) hydrophobic interactions D) ionic interactions E) van der Waals interactions - ANSWER carbon-carbon bonds Which one of the following is not among the four most abundant elements in living organisms? A) Carbon B) Hydrogen C) Nitrogen D) Oxygen E) Phosphorus - ANSWER Phosphorus The four covalent bonds in methane (CH4) are arranged around carbon to give which one of the following geometries? A) linear B) tetrahedral C) trigonal bipyramidal D) trigonal planar E) trigonal pyramidal - ANSWER tetrahedral The macromolecules that serve in the storage and transmission of genetic information are: A) carbohydrates. B) lipids. C) membranes. D) nucleic acids. E) proteins - ANSWER nucleic acids Stereoisomers that are nonsuperimposable mirror images of each other are known as: A) anomers. B) cis-trans isomers. C) diastereoisomers. D) enantiomers. E) geometric isomers - ANSWER enantiomers The enzyme fumarase catalyzes the reversible hydration of fumaric acid to l-malate, but it will not catalyze the hydration of maleic acid, the cis isomer of fumaric acid. This is an example of: A) biological activity. B) chiral activity. C) racemization. D) stereoisomerization. E) stereospecificity. - ANSWER stereospecificity Humans maintain a nearly constant level of hemoglobin by continually synthesizing and degrading it. This is an example of a(n): A) dynamic steady state. B) equilibrium state. C) exergonic change. D) free-energy change. E) waste of energy - ANSWER dynamic steady stat