Microbiology Chapter 2

Consider the reaction AB A + B. What is the product of this reaction?

A and B

Which statement does not describe a catalyst?

A catalyst will decrease the rate of a reaction.

Which term is incorrectly matched to its description?

Amphipathic: Has properties that are neither hydrophilic nor hydrophobic

Which of the following is incorrectly matched?

Salt: Formed by the combination of hydrogen ions (H+) and hydroxide ions (OH-)

Which statement is true about valence electrons?

Valence electrons participate in chemical reactions, and interactions between valence electrons in reacting atoms determine what kind of chemical bond is formed.

A compound which stabilizes pH by absorbing or releasing H+ ions is called a(n)

buffer

Electrolytes

include acids, bases, and salts, are ionic compounds dissolved in solution and are involved in regulating the nervous system, heartbeat, blood volume and water balance in the body.

The pictured molecules both contain six carbon atoms, twelve hydrogen atoms, and six oxygen atoms (C6H12O6). However, these atoms are arranged differently in each molecule. What are these molecules called?

isomers

An atom is best described as

the smallest unit of an element

Which is an ionic bond?

the two atoms not touching

Which reaction is incorrectly matched with its name?

Hydrolysis: A + B AB + H2O

Plasma membranes, the key boundary layer of cells, are composed of amphipathic molecules called phospholipids. Why would neither purely hydrophilic nor purely hydrophobic molecules be a suitable molecule for plasma membranes?

Hydrophilic molecules would dissolve in the aqueous environment in which cells live, disrupting the structural integrity of the cell, and hydrophobic molecules would be unable to interact with the aqueous environment in which cells live.

Isotopes are atoms of the same element that differ in

Isotopes are atoms of the same element that differ in

7, Nitrogen (N) 14.007

The atomic number for nitrogen is 7.

A feature of many of the isotopes that are used in the field of medicine is that the isotopes are radioactive. What does this mean?

The nucleus of the isotope is unstable and breaks down over time.

Which reaction has X and Y as reactants?

X + Y XY

Pure water is defined by

a neutral pH of 7 and an equal number of H+ and OH- ions.

A micelle is formed of

amphipathic molecules where the hydrophobic portion faces toward the center.

An anion is formed when

an atom gains one or more negatively-charged electrons.

what does the dotted line represent?

an electrostatic interaction between the partially-positive hydrogen and the partially-negative nitrogen

Ionic bonds

are electrostatic forces of attraction between oppositely charged ions and form when electrons are transferred from atom to another.

Hydrogen bonds

are responsible for the unique properties of water and are involved in stabilizing the structure of proteins and nucleic acids.

in a polar covalent bond

electrons are shared unequally between two atoms.

Which of the following is an organic compound?

ethanol (C2H6O) and methane (CH4)

Which functional group is incorrectly matched with its structure?

ether: R-CH3

Proton: Found in shells orbiting the nucleus

false

which atom(s) will have a partial negative charge?

nitrogen and oxygen

Van der Waals interactions

occur when temporary disposes within molecules form that are not the result of hydrogen bond to O,N or F atoms

Compared to a solution with a pH value of 4, a solution with a pH value of 2 has ________ H+ ions.

one hundred times as many

In a dehydration synthesis reaction, macromolecules are built when ________ is removed to form a covalent bond.

water