exam 1 study set

Can the atomic mass of an element vary?

Yes. Adding or losing neutrons will change the atomic mass without forming a different element.

What is the maximum number of covalent bonds that an oxygen atom with atomic number 8 can make with hydrogen?

2

In the term trace element, what does the adjective trace mean?

The element is required in very small amounts.

An ion with six protons, seven neutrons, and a charge of 2+ has what atomic number?

six

Which pairs of base sequences could form a short stretch of a normal double helix of DNA?

5'-AGCT-3' with 5'-TCGA-3'

Why does ice float in liquid water?

Stable hydrogen bonds keep water molecules of ice farther apart than water molecules of liquid water.

Which of the following questions is considered a thought-provoking scientific query?

Does the amount of solute in water affect the boiling point of the solution?

Which of the following is a hydrophobic material?

wax

How many molecules of water are released during the polymerization of a 20 monomer-long cellulose molecule?

19

Which of the following is not a polymer?

glucose

Based on your knowledge of the polarity of water molecules, the solute molecule depicted is most likely what?

without charge

The two molecules shown in the figures are best described as what?

structural isomers

Which molecule has both hydrophilic and hydrophobic properties and is found in plasma membranes?

14

Which of the following is true of unsaturated fats?

They have double bonds in their fatty acid chains.

Differences among organisms are caused by differences in what?

the types and relative amounts of organic molecules synthesized by each organism

If one strand of a DNA molecule has the sequence of bases 5'-ATTGCA-3', the mRNA synthesized following the template will be what?

5'-UGCAAU-3'

Which molecule shown above contains a functional group that is a part of the molecule known as the "energy currency of living organisms"?

B

Which of the following is an example of qualitative data?

The fish swam in a zigzag motion.

Which of the following order is correct in terms of the hierarchy of the organization?

Biosphere -> Ecosystem ->Community -> Population -> Organism

A glycosidic linkage is analogous to which of the following in proteins?

a peptide bond

Research indicates that ibuprofen, a drug used to relieve inflammation and pain, is a mixture of two enantiomers; that is, molecules that what?

are mirror images of each other

What element does not prefer to react with other elements?

helium

A solution with a pH of 2 has how many more protons in it than a solution with a pH of 4?

100 times more

Which of the following statements is true about buffer solutions?

They maintain a relatively constant pH when either acids or bases are added to them.

When are atoms most stable?

when all of the electron orbitals in the valence shell are filled

Why does a partial negative charge occur in a molecule of water?

Electrons shared between oxygen and hydrogen spend more time around the oxygen atom nucleus.

What accounts for the complexity and variety of organic molecules?

The chemical versatility of carbon atoms.

Which pair of elements would likely have similar valency and thus similar chemical behavior?

Nitrogen and phosphorus.

What best describes nucleotides?

A nitrogenous base, a phosphate group, and a sugar.

Why is a steam burn more severe than a hot water burn?

Steam contains more energy than water.

Which functional group is NOT present in the molecule HO-H-C-C-OH-NH-H?

Sulfhydryl.

What kind of bonds exist between two atoms that are equally electronegative?

Nonpolar covalent bonds.

What provides evidence of the common ancestry of all life?

Near universality of the genetic code.

What kind of attraction occurs when the partial negative charge at one end of a water molecule is attracted to the partial positive charge of another water molecule?

A hydrogen bond.

What is a rare property of water among compounds?

Solid water is less dense than liquid water.

What polysaccharide is an important component in the structure of many animals and fungi?

Chitin.

What is one of the primary functions of RNA molecules?

To function in the synthesis of proteins.

What best summarizes the relationship between dehydration reactions and hydrolysis?

Dehydration reactions assemble polymers; hydrolysis reactions break polymers apart.

What is the major difference between covalent bonds and ionic bonds?

Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between charged atoms.

What component of amino acid structure varies among different amino acids?

The components of the R group.

Why does Minneapolis have more extreme temperatures than Portland, Oregon?

The ocean near Portland moderates the temperature.

Why does Nitrogen-15 have a greater mass number than nitrogen-14?

The atomic nucleus of nitrogen-15 contains 8 neutrons.

How many electrons does one atom of carbon share to complete its valence shell?

4

What are cells characteristic of?

Prokaryotic and eukaryotic organisms.

What is an example of negative feedback regulation?

Evaporation of sweat leading to cooling of the body surface when body temperature rises.

Which two functional groups are always found in amino acids?

Carboxyl and amino groups.

Which of these is an example of inductive reasoning?

Hundreds of individuals of a species have been observed and all are photosynthetic; therefore , the species is photosynthetic.

What kind of chemical reaction results in a peptide bond?

The chemical reaction illustrated results in a peptide bond.

Which of the following molecules is the pentose sugar found in RNA?

Molecule 6

How do phospholipids interact with water molecules?

The polar heads interact with water; the nonpolar tails do not.