Quizzes

When an ionic compound such as sodium chloride (NaCl) is placed in water, the component atoms of the NaCl crystal dissociate into individual sodium ions (Na+) and chloride ions (Cl-). In contrast, the atoms of covalently bonded molecules (e.g., glucose, sucrose, glycerol) do not generally dissociate when placed in aqueous solution. Which of the following solutions would be expected to contain the greatest number of solute particles (molecules or ions)?

1 Liter of 1.0 M NaCl

What will be the most likely change in pH when the H+ ions in the solution is increased to twice its original concentration?

1.6 to 1.3

Measurements show that the pH of a particular lake is 4.0. What is the hydroxide ion concentration of the lake?

10^-10 M

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

12: OH-H H---OH / / O-----------------H---OH HOCH2--H

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

3- UAACGU-5

How many grams of the compound in the figure are required to make 1 liter of a 0.5 M solution? (Note: The atomic masses, in daltons, are approximately 12 for carbon, 1 for hydrogen.)

39

Homo sapiens have 23 pairs of chromosomes. What does the number '23' represent here?

46 double- stranded DNA molecules in each somatic cell

Which molecule is a saturated fatty acid?

9: O=C-c-c-c-c-c-c-c- HO

Select the statement that best describes a buffer.

A buffer resists change in pH by accepting hydrogen ions when acids are added to the solution and donating hydrogen ions when bases are added

Considering that the reactants have no charge, what are the products of the reaction shown above?

A cation with a net charge of +1 and an anion with a net charge of -1

Which of the following statements about genetic information is correct?

All forms of life employ the same genetic code

Maltose is a disaccharide that can easily be digested into glucose molecules. Which type of glycosidic linkage connects glucose molecules in maltose?

Alpha 1-4

3H2 + N2 ↔↔ 2NH3 Which of the following is true for the above reaction?

Ammonia is being formed and decomposed simultaneously

Which of the following best describes a controlled experiment?

An experiment includes at least two groups, one of which does not receive the experimental treatment

Which of the following statements about cells is correct?

Both prokaryotic and eukaryotic organisms are made up of cells

How are the hydrogen bonds formed between water molecules?

By the attraction between the positive end of one water molecule with the negative end of the other

Which functional group shown in the figure can accept protons and raise the pH of the surrounding solution?

C: -NH2

About 25 of the 92 natural elements are known to be essential to life. Four of these 25 elements make up approximately 96% of living matter. Which of the following elements account for most of the remaining 4% of an organism's mass?

Calcium, potassium, phosphorus, sulfur

Which of the following functional groups gives amino acids their acidic character?

Carboxyl

Which two functional groups are always found in amino acids?

Carboxyl and amino groups

Which molecule shown above contains a functional group that is a part of the principal molecule that stores and transfers energy in cells?

D: H O H-C-O-P-O- H O-

Which of the following best compares dehydration reactions and hydrolysis?

Dehydration reactions assemble polymers; hydrolysis reactions break polymers apart

Cotton-topped tamarins are small primates with tufts of long white hair on their heads. While studying these creatures, researchers noticed that males with longer hair get more opportunities to mate and father more offspring. Which of the following research questions would best test the hypothesis that having longer hair is adaptive in these males?

Determine if hair length is heritable

How many electrons must one carbon atom share with other atom or atoms to complete its valence shell?

Four

Is the thermal energy of a full bathtub higher or lower than the thermal energy of a pot of freshly brewed coffee (even though the coffee has a higher temperature than the bathwater)? Why?

Higher; greater volume

Why can humans digest starch but not cellulose?

Humans have enzymes that can hydrolyze the A glycosidic linkages of starch but not the B glycosidic linkages of cellulose

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

Which of the following types of bond is broken when water evaporates?

Hydrogen Bonds

Melting of ice and thus reduced feeding opportunities for polar bears is occurring because of the ________.

Increase in CO2 and other greenhouse gases in the atmosphere

Which of the following statements is true for water in its liquid state?

It has a heat vaporization higher than most other substances

If an atom has a charge of +1, which of the following must be true?

It has two more protons than neutrons

A compound contains hydroxyl groups as its predominant functional group. Which of the following properties of the molecule can be predicted with the information provided?

It should dissolve in water

Compared to a hydrocarbon chain where all the carbon atoms are linked by single bonds, which of the following statements best describe a hydrocarbon chain with the same number of carbon atoms but with one or more double bonds?

It will be more constrained in structure

1. Tertiary structure is achieved when a protein folds into a compact, three-dimensional shape stabilized by interactions between side-chain R groups of amino acids. 2. Secondary structure describes the alpha-helices and beta-sheets that are formed by hydrogen bonding between backbone atoms located near each other in the polypeptide chain. 3. Quaternary structure is the result of two or more protein subunits assembling to form a larger, biologically active protein complex. 4. Primary structure is the sequence of amino acids in a protein.

Level of structure of protein

Which of the following statements about lipids is true?

Lipids mix poorly with water

Which of the following is one of Charles Darwin's observations?

Many of the traits in an individual are heritable

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

Molecules that are mirror images of each other

Which of these provides evidence of the common ancestry of all life?

Near universality of the genetic code

A solution contains 0.0000001 (10-7) moles of hydrogen ions [H+] per liter. Which of the following best describes this solution?

Neutral

Which of the following statements correctly describes the property of hydrophobic substances such as vegetable oil?

Nonpolar substances that repel water molecules

What kind of bond is formed between the two hydrogen atoms and the single oxygen atom?

Polar covalent bonds

Apple on tree ripens ripe apple produces ethylene ethylene signals neighboring apples to ripen neighbor apples produce more ethylene more apples ripen. The above process is an example of which of the following?

Positive feedback regulation

Which pair of elements is most likely to react if bought together?

Sodium and chlorine

Which answer best describes why does ice float in liquid water?

Stable hydrogens bonds keep water molecules of ice farther apart than water molecules of liquid water

Based on electron configuration, which of the elements would exhibit a chemical behavior similar to oxygen?

Sulfur

Which of the following characteristics is responsible for the complexity and variety of organic molecules?

The chemical versatility of carbon atoms

Which part of an amino acid gives it its unique identity?

The components of its side chain

The partial negative charge in a molecule of water occurs because ________.

The electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom nucleus than around the hydrogen atom nucleus

Which of the following statements describes the interaction of water molecules with phospholipids?

The polar heads interact with water, the nonpolar tails do not

Which of the following factors contribute to the tetrahedral shape of the above molecule?

The shape of the sp^3 hybrid orbitals of the electrons shared between the carbon and hydrogen atoms

Which of the following identifies the chemical relationship between glucose and fructose?

They are structural isomers

Which of the following statements correctly describes "saturated fats"?

They contain more hydrogen than unsaturated fats that consist of the same number of carbon atoms

Which of the following features of cooking oil and gasoline (hydrocarbons) identifies why the molecules are NOT amphipathic?

They do not have polar or charged region

Which of the following statements is incorrect?

Water can form intramolecular hydrogen bonds

Which property of water allows dogs to cool themselves by panting?

Water's high heat vaporization

What is the pH of a solution with a hydroxyl ion (OH-) concentration of 10-10 M?

pH4