Question 1

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

Accepted Answer

Bacterial cells do not have a true nucleus, but instead have a region known as the nucleoid. This is where the single, circular chromosome of bacterial DNA is located.

Question 2

Which is a list of organelles?
A) mitochondria, chromatin, endoplasmic reticulum
B) peroxisomes, lysosomes, plasma membrane
C) proteasomes, peroxisomes, lysosomes
D) mitochondria, endoplasmic reticulum, peroxisomes
E) All of the answers are correct.

Accepted Answer

The only list that includes organelles is D, which lists mitochondria, endoplasmic reticulum, and peroxisomes. The other options list various cellular components, but not specific organelles.

Question 3

Which list 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

Accepted Answer

Amino acids are smaller building blocks of proteins, so they are the smallest. Proteins are made of many amino acids and are bigger than individual amino acids. Ribosomes are larger than proteins because they are the site where proteins are actually made. Mitochondria, as organelles that generate energy for the cell, are the largest of these options. Therefore, the correct order of increasing size is amino acid < protein < ribosome < mitochondrion, which is represented by option B.

Question 4

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.

Accepted Answer

A dynamic steady state refers to a system in which there is a constant flow of materials and energy, maintaining a stable overall condition. In this case, the continual synthesis and degradation of hemoglobin keeps its concentration within a certain range, but the process itself is not in equilibrium as there is a constant exchange of molecules between different states (i.e. newly synthesized hemoglobin molecules replacing degraded ones). The other choices do not accurately describe this process.

Question 5

Which group of single-celled microorganisms has many members found growing in extreme environments?
A) bacteria
B) archaea
C) eukaryotes
D) heterotrophs
E) None of the answers is correct.

Accepted Answer

Many members of the archaea group of single-celled microorganisms are found growing in extreme environments, such as hot springs, deep-sea hydrothermal vents, and highly acidic or alkaline environments.

Question 6

Which element is NOT among the four most abundant in living organisms?
A) carbon
B) hydrogen
C) nitrogen
D) oxygen
E) phosphorus

Accepted Answer

The four most abundant elements in living organisms are carbon, hydrogen, nitrogen, and oxygen. Phosphorus is an important element for life, but it is much less abundant than the other four.

Question 7

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.

Accepted Answer

The development of the nucleus was a major change occurring in the evolution of eukaryotes from prokaryotes. Eukaryotes have a distinct nucleus, which houses the cell's genetic material in the form of chromosomes. Prokaryotes, on the other hand, lack a nucleus and have their DNA dispersed throughout the cytoplasm. This development allowed for more complexity and regulation of DNA replication, transcription and translation processes.

Question 8

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.

Accepted Answer

Non-superimposable mirror images are known as enantiomers.

Question 9

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

Accepted Answer

The nucleus is enclosed by a double membrane called the nuclear envelope, which separates the contents of the nucleus from the cytoplasm. The nuclear envelope is made up of two lipid bilayers that are perforated by nuclear pores, which allow selective transport of molecules between the nucleus and the cytoplasm.

Question 10

The catalog of all proteins functioning in a cell is the:
A) metabolome.
B) proteasome.
C) lysosome.
D) proteome.
E) genome.

Accepted Answer

The term "proteome" refers to the complete set of proteins expressed by an organism, cell, tissue, or system at a given time. Therefore, the catalog of all proteins functioning in a cell is its proteome. A is incorrect because the metabolome includes all of the small molecule metabolites present in a cell. B is incorrect because the proteasome is a complex of proteins responsible for degrading damaged or unwanted proteins. C is incorrect because the lysosome is a membrane-bound organelle that breaks down cellular waste and debris through hydrolysis. E is incorrect because the genome refers to the complete set of genetic material (DNA or RNA) in an organism, which includes the genes that encode the proteins of the proteome.

Question 11

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.

Accepted Answer

Endothermic reactions absorb heat energy, while exothermic reactions release heat energy. At equilibrium, the reaction rates of the forward and reverse reactions are equal, so there is no net absorption or release of heat energy. Endergonic and exergonic reactions refer to the overall change in free energy of a reaction, not the absorption or release of heat energy.

Question 12

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 $\mu$m to 10 $\mu$m.
B) 0.3 $\mu$m to 30 $\mu$m.
C) 0.3 $\mu$m to 100 $\mu$m.
D) 1 $\mu$m to 100$\mu$m.
E) 1 $\mu$m to 300 $\mu$m.

Accepted Answer

According to the passage, living cells have lengths and diameters in the range of 0.3 µm to 100 µm. Choice C falls within this range. Choices A, B, D, and E either have dimensions too small or too large compared to the range given in the passage.

Question 13

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

Accepted Answer

Carbon-carbon bonds are covalent bonds, not noncovalent interactions.

Question 14

Use the terms a) chemoautotrophs, b) chemoheterotrophs, c) photoautotrophs, and d) photoheterotrophs and identify the answer that CORRECTLY finishes the statement: Carnivores are _____ and herbivores are _____.
A) b; c
B) b; d
C) b; b
D) a; b
E) a; a

Accepted Answer

Carnivores and herbivores are both chemoheterotrophs because they obtain energy by consuming organic compounds from other organisms.

Question 15

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.

Accepted Answer

The enzyme fumarase has stereospecific activity, meaning it can only catalyze the hydration of one stereoisomer (fumaric acid) and not its cis isomer (maleic acid). It is not an example of biological activity, chiral activity, racemization, or stereoisomerization.

Question 16

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

Accepted Answer

A negative free energy change indicates that the reaction is exergonic, meaning it releases energy.

Question 17

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

Accepted Answer

The molecule has a hydroxyl (OH) group and an aldehyde (CHO) group.

Question 18

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

Accepted Answer

Nucleic acids, specifically DNA and RNA, are macromolecules that store and transmit genetic information. Carbohydrates, lipids, membranes, and proteins have various other functions in living organisms, but do not serve this specific role in genetic information.

Question 19

The four covalent bonds in methane (CH₄) are arranged around carbon to give which geometry? A) linear B) tetrahedral C) trigonal bipyramidal D) trigonal planar E) trigonal pyramidal

Accepted Answer

Methane has four bonding pairs of electrons around carbon, which results in a tetrahedral geometry.

Question 20

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.

Accepted Answer

E. coli is a chemoheterotroph because it obtains its energy and organic molecules from other sources.

Quiz 1: The Foundations of Biochemistry

In a bacterial cell, the DNA is in the:

Which is a list of organelles?

Which list has the cellular components arranged in order of INCREASING size?

Humans maintain a nearly constant level of hemoglobin by continually synthesizing and degrading it. This is an example of a(n) :

Which group of single-celled microorganisms has many members found growing in extreme environments?

Which element is NOT among the four most abundant in living organisms?

A major change occurring in the evolution of eukaryotes from prokaryotes was the development of:

Stereoisomers that are nonsuperimposable mirror images of each other are known as:

In eukaryotes, the nucleus is enclosed by a double membrane called the:

The catalog of all proteins functioning in a cell is the:

If heat energy is absorbed by the system during a chemical reaction, the reaction is said to be:

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:

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?

Use the terms a) chemoautotrophs, b) chemoheterotrophs, c) photoautotrophs, and d) photoheterotrophs and identify the answer that CORRECTLY finishes the statement: Carnivores are _ and herbivores are _.

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:

If the free energy change $\Delta$ G for a reaction is -46.11 kJ/mol, the reaction is:

What functional groups are present on this molecule?

The macromolecules that serve in the storage and transmission of genetic information are:

The four covalent bonds in methane (CH₄) are arranged around carbon to give which geometry?

The bacterium E. coli requires simple organic molecules for growth and energy-it is therefore a: