Unit 2: Chemistry of Biology

Compared to a solution of pH 9, a solution of pH 7 is _______.

100 times more acidic

What is the maximum number of electrons in the first energy shell of an atom?

2

What would be the valence number of electrons in the sulfur (S) atom? Its atomic number is 16.

6

What is the maximum number of electrons in the second energy shell of an atom?

8

Which of the term-34 following represents a synthesis reaction?

A + B → AB

Which of the following represents a reversible reaction?

AB + XY ↔ AY +XB

Which of the following is not a pyrimidine?

Adenine

Characteristics shared by all cells include _______.

All of the choices are correct.

One nucleotide contains one _______.

All of the choices are correct.

NASA has published a list of criteria for identifying fossil bacteria in samples from Mars, as part of a search for evidence of life. Which of the following is good evidence for the presence of bacterial cells?

Cell size of 0.5 to 2 microns

Which pertains to DNA but not to RNA?

Contains thymine

Which of the following is not true about enzymes?

Enzymes have high-energy bonds between phosphates.

A covalent bond is formed between an anion and a cation.

False

A new organism was identified that contained arsenic in place of phosphate in its DNA double helix structure. Based upon this information alone, it can be determined that this change will greatly alter the information encoded by this genetic material.

False

All proteins are enzymes.

False

Electrons that participate in chemical bonding are typically located closest to the nucleus.

False

Nucleic acids have primary, secondary, tertiary, and quaternary levels of organization.

False

The concentration of a solution expresses the amount of solvent present.

False

Water molecules are nonpolar molecules.

False

What part of a phospholipid comprises the hydrophobic tail?

Fatty acids

Select the statement that most accurately reflects the process of plant material digestion in humans.

It is a process that is dependent upon enzyme (cellulase) production by gut microbiota.

One technique for staining bacteria for viewing under the microscope is called the Gram stain. In this technique, alcohol is used as a decolorizer because it degrades the outer membrane found in some bacteria. What chemical component of the cell does alcohol affect?

Lipid

A student forgot to label a beaker containing a DNA solution and a beaker containing a glucose solution. If chemical analysis was performed to identify the contents of each beaker, which of the following would be found in the beaker of DNA but not in the beaker with glucose?

Nitrogen and phosphorus

What type of bond is formed by dehydration synthesis between two amino acids?

Peptide

Which of the following functional groups is mismatched to the organic compound in which it is typically found?

Phosphate - carbohydrates

Which of the following would have glycosidic bonds?

Polysaccharides

Which of the following is a correct description of a component of the ATP molecule?

Sugar: ribose

Which of the following statements is incorrect regarding protein structure?

The interaction between various R groups of amino acids determines the primary structure of a protein.

In what way would life be different if the element carbon was absent?

There would be no organic compounds.

If solution A has a lower pH compared to solution B, then solution A is more acidic than solution B.

True

Polar molecules have more reactivity compared to nonpolar molecules.

True

The most important outcome of polypeptide intrachain bonding and folding is the unique shape of the protein.

True

The only part of an amino acid that differs from other amino acids is its R group.

True

Burning coal produces sulfur dioxide in the atmosphere. When combined with rain that falls into bodies of water, this leads to _______.

a decrease in the pH level of the water

C 6H 12O 6 + C 6H 12O 6 → C 12 H 22O 11 + H 2O represents _______.

a dehydration synthesis

A capillary tube is used to acquire a small blood sample for CBC (complete blood count) analysis. Suction is not required to transfer the blood from the fingertip prick to the tube in part due to _______.

adhesive forces between the water molecules and the glass particles of the tube

The electrons of an atom are _______.

always equal to the number of protons

The building blocks of an enzyme are ______.

amino acids

Starch is the primary storage food for all of the following except ______.

animals

Ionic compounds _______.

are hydrophilic

Polar molecules are composed of covalently bonded _______.

atoms of different electronegativity

Cations are _______.

capable of forming ionic bonds with anions

Organic chemicals always have a basic framework of the element _____ bonded to other atoms.

carbon

Substances that release ions when dissolved in water and conduct electricity are ______.

electrolytes

The subatomic particles that surround the nucleus are the ______.

electrons

All of the following are monosaccharides except ______.

glycogen

The purine ______always hydrogen bonds with the pyrimidine ______ in double-stranded DNA.

guanine;cytosine

All of the following pertain to the atom Carbon-14 except it _______.

has 14 neutrons

Compared to a solution of pH 9, a solution of pH 7 _______.

has more H+ ions

Polar molecules _______.

have an unequal charge distribution

Atoms that gain or lose electrons become charged particles called ______.

ions

Anything that occupies space and has mass is called ______.

matter

Two or more atoms bonded together are called a(n) ______.

molecule

The electrons of an atom are _______.

moving in pathways called orbitals

Purines and pyrimidines are components in the building block units of all ______.

nucleic acids

Protons and neutrons make up the atom's central core, which is referred to as its ______.

nucleus

The valence number is the _______.

number of electrons in the outermost orbital

A culture of an organism believed to cause intestinal symptoms is viewed under the microscope, and the microbiologist observes a cell membrane, flagella, mitochondria, and some dark unrecognizable structures within each cell. The microbiologist notes that the cells are eukaryotic because _______.

only eukaryotic cells have mitochondria

A reaction where an electron is lost is called ______.

oxidation

An amino acid contains all of the following except a/an ______.

phosphate

An example of an amphipathic molecule found in living cells is ______.

phospholipid

The lipid group that is the major component of cell membranes is the ______.

phospholipids

An atom has gained an electron; it has been ______.

reduced

Most biochemical macromolecules are polymers, which are chains of ______.

repeating monomers

Hydrogen bonds _______.

result from attractive forces between molecules with polar covalent bonds

Covalent bonds _______.

result from sharing electrons

Ionic bonds _______.

result from transferring electrons

All cells contain _______.

ribosomes for protein synthesis

A fat is called _______ if all carbons of the fatty acid chain are single-bonded to 2 other carbons and 2 hydrogens.

saturated

The alpha (α)helix is a type of _____ protein structure.

secondary

In the cell cytoplasm, molecules of ATP are a ______.

solute

All of the following are lipids except ______.

starch

All of the following are polysaccharides except ______.

sterols in cell membranes

ATP differs from the nucleotides found in DNA in the _______.

sugar portion of the molecule

ATP is best described as _______.

the energy molecule of cells

The lipid group that serves as energy storage molecules is the ______.

triglycerides

The important solvent associated with living things is ______.

water