BIOS 1700 Chapter 2

Which one of the following pH values of a solution represents the highest concentration of hydrogen ions? 9.1 1.0 7.0 4.5 11.5

1.0

How many hydrogen atoms are present in a hydrocarbon chain of eight carbon atoms with three double bonds and the rest single bonds? 16 10 14 12

12

The atomic number of the regular magnesium atom is ( ), and its atomic mass is ( ). Consult the periodic table in Figure 2.3 if necessary. 11; 11 12; 24 11; 22 12; 12

12; 24

How many hydrogen atoms are present in a ring of six carbon atoms held together by alternating single and double bonds? 8 12 10 6

6

14C is an isotope of carbon that possesses: 6 protons, 2 neutrons, and 6 electrons. 6 protons, 8 neutrons, and 6 electrons. 6 protons, 8 neutrons, and 2 electrons. 6 protons, 6 neutrons, and 2 electrons. 8 protons, 6 neutrons, and 2 electrons

6 protons, 8 neutrons, and 6 electrons

Molecules made primarily of carbon and hydrogen are called hydrocarbons. How many carbon and hydrogen atoms are present in this molecule, respectively? \/\/\/ a)7, 14 b)8, 14 c)7, 16 d)8, 16

7, 16

How many hydrogen atoms are present in a hydrocarbon chain of five carbon atoms with two double bonds and two single bonds? 8 12 10 6

8

The neon atom has ( ) electrons in the most outer orbital. Thus, the neon atom alone is very stable. Consult the periodic table in Figure 2.3 if necessary. 7 10 6 8

8

The outermost orbital of atoms used in this class has a capacity of ( ) electrons. Exclude the hydrogen and the neon atoms from this question. 8 10 9 7

8

Three carbon atoms are linked by single covalent bonds such that they form the shape of a V. All of the unshared electrons form covalent bonds with hydrogen. How many hydrogen atoms does this molecule contain? 6 2 8 4 10

8

What is the chemical basis for water's role as the universal solvent? Because water is polar, it disrupts both hydrogen and ionic bonds. Because water is polar, it disrupts ionic bonds. Because water is polar, it disrupts both covalent and hydrogen bonds. Because water is polar, it disrupts most covalent bonds. Because water is polar, it disrupts hydrogen bonds.

Because water is polar, it disrupts both hydrogen and ionic bonds

Because of hydrogen bonding, water is uniquely suited for its central role in life. Many hydrophilic molecules interact freely with water, but a number of hydrophobic molecules are important for life, too. How does the interaction between water and hydrophobic molecules help to organize biological systems? The ionic bonds between water molecules cause hydrophobic molecules to associate with each other and not with water molecules. None of the other answer options is correct. Because water molecules preferentially associate with each other, they force hydrophobic molecules to associate with each other and not with water molecules. Because cells are not pure water (they have many substances dissolved within them), the hydrophilic/hydrophobic effect has a limited role in biological organization.

Because water molecules preferentially associate with each other, they force hydrophobic molecules to associate with each other and not with water molecules

Which one of the following statements about a carbon-carbon double bond is CORRECT? The double bond is longer than a corresponding carbon-carbon single bond. Double bonds are often found in cyclical structures. None of the other answer options is correct. Each of the two carbons is capable of bonding to three other atoms. The double bond allows free rotation of the molecule at the bond position.

Double bonds are often found in cyclical structures

Consider the structure and function of DNA. Which of the following statements is TRUE? If the sequence of one DNA strand is known, then the sequence of the other strand can be determined. The phosphodiester bonds that stabilize the association of the two strands are easily broken and reformed. Because DNA is made of phosphate groups that are ionized, it could easily pass through a cell membrane. Because DNA contains carbohydrates, it provides structural support to the cells.

If the sequence of one DNA strand is known, then the sequence of the other strand can be determined

Refer to the periodic table, and decide which of the following molecules is held together by ionic bonds. NH3 KCl CO2

KCl

Which of the following statements is TRUE regarding carbon? Carbon atoms can only form single covalent bonds with other carbon atoms. Double bonds that form between carbon atoms are only found in "ring" molecules. None of the other answer options is correct. When a carbon atom forms a molecule, it acquires four dumbbell-shaped orbitals. Isomers of carbon-containing compounds always have the same structure but different chemical formulas.

None of the answer options is correct

In A-T paring of nucleic acid, hydrogen, nitrogen, and oxygen atoms are involved in hydrogen bonds. Hydrogen atoms are positively charged, and nitrogen and oxygen atoms are negatively charged. What explains negative charge of oxygen atom? The electronegativity of oxygen is greater than carbon atom. Oxygen atom is always negatively charged. The atomic number of oxygen is 8. The electronegativity of oxygen is greater than hydrogen atom.

The electronegativity of oxygen is greater than carbon atom

A phosphodiester bond in RNA is formed between: a)a 5' phosphate and a 3' hydroxyl group b) two amino acids. c) a 3' phosphate and a 5' hydroxyl group. d) a 5' phosphate and a 2' hydroxyl group. e) a fatty acid and a glycerol molecule.

a 5' phosphate and a 3' hydroxyl group

For an atom that is NOT an ion, which of the following must be TRUE? The number of electrons equals the number of neutrons. The number of electrons equals the number of protons. The number of protons equals the number of neutrons.

The number of electrons equals the number of protons

In an atom that is NOT an ion, which of the following must be true? a)The number of electrons equals the number of neutrons. b)The number of electrons equals the number of protons. c)The number of protons equals the number of neutrons

The number of electrons equals the number of protons

A woman's doctor tells her to gargle with salt water. She stirs a tablespoon of salt into a cup of warm water and watches it dissolve. Why does the salt dissolve in water? The positive hydrogen atoms in water molecules are attracted to chlorine ions. The negative oxygen atoms in water molecules are attracted to sodium ions. The negative oxygen atoms in water molecules are attracted to chlorine ions. The positive hydrogen atoms in water molecules are attracted to sodium ions. The positive hydrogen atoms in water molecules are attracted to chlorine ions, and the negative oxygen atoms in water molecules are attracted to sodium ions.

The positive hydrogen atoms in water molecules are attracted to chlorine ions, and the negative oxygen atoms in water molecules are attracted to sodium ions

You are employed by a company that makes artificial sweeteners. Your job is to taste different synthesized compounds for sweetness. One day at work, the control sample, which was supposed to be glucose (C6H12O6), tasted sweeter than usual. You analyzed this control sample and the previous week's control sample. Chemical analysis showed that they have exactly the same chemical formula (C6H12O6). What might explain the difference in the control samples? This week's control sample is glucose, but the sample was old and degraded. This week's control sample is fructose (a 6-carbon ketose) instead of glucose (a 6-carbon aldose). Your tongue has become more sensitive to sweetness. This week's control sample is the disaccharide sucrose instead of glucose (a 6-carbon aldose).

This weeks control sample is a fructose (a 6-carbon ketose) instead of glucose (a 6-carbon aldose)

You are given two double stranded (ds) DNA fragments. You are told that fragment A contains 70% C-G pairs, and fragment B contains 75% A-T pairs, but you are not told the length of each fragment. Which fragment is more stable at high temperatures? Both fragments are similarly stable at any given temperature. Fragment B is more stable than Fragment A. Fragment A is more stable than Fragment B. We cannot answer this question with the given information.

We cannot answer this question with the given information

Which one of the following is NOT a component of an amino acid? a carboxyl group an R group a phosphate group an amino group an alpha carbon

a phosphate group

Which of the following are covalent bonds? peptide bonds All of the above glycosidic bonds phosphodiester bonds

all of the above

The atom: All of these choices are correct. is the basic unit of matter. is the unit of composition for elements. contains protons, neutrons, and electrons. has negatively charged particles circling around a positively charged nucleus.

all of these choices are correct

Which of the following statements about water is CORRECT? All of these choices are correct. Water is the most abundant molecule in living cells. Water molecules form hydrogen bonds with other polar molecules. Water has good solvent properties. Water is a polar molecule.

all of these choices are correct

Which one of the following elements is found in every organic molecule? phosphorus carbon nitrogen sulfur oxygen

carbon

In ( ) bonds, atoms share valence electrons in the outer most orbitals (or shells) to keep two (H atom) or eight (most other atoms) electrons. ionic Glue covalent hydrogen

covalent

A pair of shared valence electrons is referred to as a(n): covalent bond. van der Waals interaction. hydrogen bond. ionic bond. hydrophobic effect.

covalent bond

Among all chemical bonds you learned in class, ( ) is the strongest, and ( ) is the weakest. hydrogen bond; van der Waals force ionic bond; hydrogen bond covalent bond; ionic bond ionic bond; van der Waals force covalent bond; van der Waals force

covalent bond; van der Waals force

Isotopes are the same element that carries the ( ) numbers of neutrons. same different

different

If you isolate a single nucleotide from a nucleic acid chain and determine that the nitrogenous ring structure is cytosine, you could say with certainty that the nucleotide may have come from: RNA but not DNA. either DNA or RNA. DNA but not RNA. neither DNA nor RNA. double-stranded DNA but not single-stranded DNA.

either DNA or RNA

The ability of atoms to attract electrons is referred to as: a)potential energy. b)hydrophobicity. c)van der Waals attraction. d)electronegativity. e)cohesion.

electronegativity

The ability of atoms to attract electrons is referred to as: van der Waals attraction. hydrophobicity. cohesion. electronegativity. potential energy.

electronegativity

Triacylglycerols are used primarily for: information storage. movement. cell membrane biosynthesis. biological catalysis. energy storage.

energy storage

Regular atoms has the ( ) numbers of protons and neutrons. variable unequal different equal

equal

An ionic interaction, such as the interaction between Na+ and Cl-, is considered a covalent bond. True False

false

An atom with three electrons ____ a)has one orbital with three electrons b)has three energy shells, each of which contains one electron c)has three orbitals, each of which contains one electron d)has two orbitals, one of which has two electrons, the other has one

has two orbitals, one of which has two electrons, the other has one

Since water molecules are polar, they form ( ) bonds among themselves. magnetic hydrogen covalent ionic

hydrogen

Cells change the composition of their plasma membranes as a response to changing environments. In general, colder temperatures reduce the fluidity of the membrane, so cells will produce different molecules to bring the fluidity back to normal. How would the cell change the membrane in response to colder temperatures? increase the amount of saturated triacylglycerols increase the amount of unsaturated fatty acids increase the length of the fatty acid side chains in the phospholipids

increase the amount of unsaturated fatty acids

The potassium atom (K) can form a (or an) ( ) bond with the chlorine atom (Cl) like sodium chloride (NaCl). Consult the periodic table in Figure 2.3 if necessary. ionic tight hydrogen covalent

ionic

Exposure of purified phospholipids to water results in the spontaneous formation of: lipid bilayers. carbohydrates. triacylglycerols. polypeptides. steroids.

lipid bilayers

Which one of the following biological polymers is defined by a physical property instead of a chemical structure? proteins polysaccharides lipids monosaccharides nucleic acids

lipids

The designation of a magnesium ion as Mg2+ indicates an atom that has: lost two electrons and is negatively charged. gained two protons and is negatively charged. two more protons than neutrons. gained two protons and is positively charged. lost two electrons and is positively charged.

lost two electrons and is positively charged

Isomers are defined as: a) atoms with the same number of protons but different numbers of neutrons b) molecules with the same number of carbon atoms but potentially different numbers of other atoms c) molecules with different chemical formulas but similar biological functions d) molecules with the same general three-dimensional structures but different chemical formulas e) molecules with the same chemical formula but different structures

molecules with the same chemical formula but different structures

The ( ) of a given atom contains ( ) and neutrons. nucleus; electrons nucleus; protons core; electrons core; protons

nucleus; protons

The hydrogen atom has ( ) energy level(s) of orbital(s), but the oxygen atom has ( ) energy level(s) of orbital(s). one; three one; two two; one two; two

one; two

A molecule of water is polar because the ( ) atom attracts electrons resulting in the unequal sharing of electrons between the oxygen and the hydrogen atoms. sodium hydrogen oxygen nitrogen

oxygen

The linkage of one amino acid to another amino acid in a protein is referred to as a(n): R group. glycosidic bond. ionic bond. phosphodiester bond. peptide bond.

peptide bond

Which one of the following elements would most likely have bonding properties similar to nitrogen (N)? Consult the periodic table in Figure 2.3 if necessary. oxygen (O) phosphorus (P) sulfur (S) silicon (Si) carbon (C)

phosphorus (P)

Which of the following CORRECTLY pairs the particles of an atom with their physical properties? proton-uncharged; neutron-negatively charged; electron-positively charged proton-positively charged; neutron-uncharged; electron-negatively charged proton-positively charged; neutron-negatively charged; electron-uncharged proton-negatively charged; neutron-uncharged; electron-positively charged

proton-positively charged; neutron-uncharged; electron-negatively charged

In a chemical reaction, we usually write ( ) on the left side of an arrow (?) and ( ) on the right side. products; reagents products; reactants reactants; products reagents; products

reactants; products

Which side of the periodic table of the element show atoms with higher electronegativity? Left side Middle Right side

right side

Most nitrogen atoms on the earth have ( ) protons and ( ) neutrons. But a very small percentage of nitrogen atoms have one additional neutron for an atomic mass of 15. six; seven seven; six seven; seven seven; eight

seven; seven

Which one of the following types of fatty acids would be likely to have the lowest melting temperature? a)long tails and low saturation b)short tails and low saturation c)short tails and high saturation d)All fatty acids have the same melting temperature regardless of tail length or level of saturation. e)long tails and high saturation

short tails and low saturation

The carbon atom's atomic number is ( ), and has ( ) energy level(s) of orbital(s). Consult the periodic table in Figure 2.3 if necessary. seven; one six; two six; one seven; two

six; two

Which one of the following elements would most likely have bonding properties similar to oxygen (O)? Consult the periodic table in Figure 2.3 if necessary. phosphorous (P) silicon (Si) carbon (C) sulfur (S)

sulfur (S)

Which of the following is an example of a hydrogen bond? the bond that forms between two oxygen atoms within different water molecules the bond that forms between two hydrogen atoms within the same water molecule the bond that forms between a hydrogen and oxygen atom within the same water molecule the bond that forms between hydrogen and oxygen atoms within different water molecules the bond that forms between two hydrogen atoms within different water molecules

the bond that forms between hydrogen and oxygen atoms within different water molecules

The structural diversity of carbon-based molecules is based upon which of the following properties a) the ability of carbon to form four covalent bonds b) the ability of those bonds to rotate freely c) None of these choices is correct. d) All of these choices are correct. e) the orientation of those bonds in the form of a tetrahedron

the orientation of those bonds in the form of a tetrahedron

In regular atoms, not isotopes, the numbers of protons and electron are ( ). different the same

the same

Which one of the following components of an amino acid differs from one amino acid to another? the hydrogen atom opposite the R group the amino group the side chain the α-carbon atom the carboxyl group

the side chain

Several chemical properties make water uniquely suited for its role as a central "molecule of life." Which of the following is FALSE? Water is a good solvent of polar molecules and ions. The structure of a water molecule is stabilized by hydrogen bonds. Hydrogen bonding leads to high cohesiveness between water molecules. Water resists temperature changes. Water molecules are always polar.

the structure of a water molecule is stabilized by hydrogen bonds

Which one of the following is a pyrimidine found in DNA? thymine None of the other answer options is correct adenine uracil guanine

thymine

Although monosaccharides can exist in linear form, virtually all cellular monosaccharides are found in circular form. True False

true

Hydrogen gas shares (or has) ( ) electrons in their orbitals (or shells). one four two three

two

The atoms in the second row in the periodic table of the elements has ( ) energy levels or ( ). Consult the periodic table in Figure 2.3 if necessary. two; orbits two; circles three; shells two; shells

two; shells

The ability of atoms to form bonds is due largely to electrons farthest from the nucleus. These electrons are called ______ electrons

valence

What are electrons in the outermost orbital called? Valencia electrons Valence electrons Valentine electrons Victoria electrons

valence electrons