Lehninger Biochemistry Chapter 1 – Flashcards

In a bacterial cell, the DNA is in the: A) cell envelope. B) cell membrane. C) nucleoid. D) nucleus. E) ribosomes.

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.

In eukaryotes, the nucleus is enclosed by a double membrane called the: A) cell membrane. B) nuclear envelope. C) nucleolus. D) nucleoplasm. E) nucleosome.

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.

Which group of single-celled micro-organisms has many members found growing in extreme environments? A) bacteria. B) archaea. C) eukaryotes. D) heterotrophs. E) none of the above.

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.

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

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

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

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

What functional groups are present on this molecule? A) ether and aldehyde B) hydroxyl and aldehyde C) hydroxyl and carboxylic acid D) hydroxyl and ester E) hydroxyl and ketone

The macromolecules that serve in the storage and transmission of genetic information are: A) carbohydrates. B) lipids. C) membranes. D) nucleic acids. E) proteins.

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.

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.

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.

If heat energy is absorbed by the system during a chemical reaction, the reaction is said to be: A) at equilibrium. B) endergonic. C) endothermic. D) exergonic. E) exothermic.

If the free energy change ΔG for a reaction is -46.11 kJ/mol, the reaction is: A) at equilibrium. B) endergonic. C) endothermic. D) exergonic. E) exothermic.

The major carrier of chemical energy in all cells is: A) acetyl triphosphate. B) adenosine monophosphate. C) adenosine triphosphate. D) cytosine tetraphosphate. E) uridine diphosphate.

Enzymes are biological catalysts that enhance the rate of a reaction by: A) decreasing the activation energy. B) decreasing the amount of free energy released. C) increasing the activation energy. D) increasing the amount of free energy released. E) increasing the energy of the transition state.

Energy requiring metabolic pathways that yield complex molecules from simpler precursors are: A) amphibolic. B) anabolic. C) autotrophic. D) catabolic. E) heterotrophic.

Hereditary information (with the exception of some viruses) is preserved in: A) deoxyribonucleic acid. B) membrane structures. C) nuclei. D) polysaccharides. E) ribonucleic acid.

When a region of DNA must be repaired by removing and replacing some of the nucleotides, what ensures that the new nucleotides are in the correct sequence? A) DNA cannot be repaired and this explains why mutations occur. B) Specific enzymes bind the correct nucleotides. C) The new nucleotides basepair accurately with those on the complementary strand. D) The repair enzyme recognizes the removed nucleotide and brings in an identical one to replace it. E) The three-dimensional structure determines the order of nucleotides.

The three-dimensional structure of a protein is determined primarily by: A) electrostatic guidance from nucleic acid structure. B) how many amino acids are in the protein. C) hydrophobic interaction with lipids that provide a folding framework. D) modification during interactions with ribosomes. E) the sequence of amino acids in the protein.

According to Oparin's theory for the origin of life, the prebiotic atmosphere: A) already contained some primitive RNA molecules. B) basically was very similar to the atmosphere of today. C) contained many amino acids. D) had an abundance of methane, ammonia, and water. E) was rich in oxygen.