Review Questions I Got Wrong

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

The ionic bonds between the molecules in ice prevent the ice from sinking.

The crystalline lattice of ice causes it to be denser than liquid water.

The high surface tension of liquid water keeps the ice on top.

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

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

Which of the following best describes cis-trans isomers?

they differ in their spatial arrangement around inflexible double bonds

they are mirror images of each other

they have the same number of atoms of the same elements, but different structures

they differ in the arrangement of covalent bonds and in covalent partners

they are long chains of hydrogen and carbon atoms

they differ in their spatial arrangement around inflexible double bonds

The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are in the α form. Which of the following could amylase break down?

glycogen, starch, and amylopectin

starch, chitin, and cellulose

cellulose and chitin

glycogen and cellulose

glycogen, starch, and amylopectin

The difference between an aldose sugar and a ketose sugar is ________.

the position of the hydroxyl groups

the ring form and the linear chain

the number of carbon atoms

the position of the carbonyl group

the position of the carbonyl group

The structural level of a protein least affected by a disruption in hydrogen bonding is the

secondary level.

primary level.

quaternary level.

tertiary level.

primary level.

There are four levels of protein structure. These figures show primary, secondary, tertiary, and quaternary protein structure. Which level(s) of protein structure may be stabilized by covalent bonds?

Secondary level of protein structure

Primary, tertiary and quaternary levels of protein structure

None of the levels of protein structure is stabilized by covalent bonds

Primary, tertiary and quaternary levels of protein structure

The primary structure of a protein is the specific linear sequence of amino acids forming the protein. The amino acids are joined by covalent peptide bonds.

Tertiary structure, producing the unique structure of a protein, is stabilized by interactions among the R groups on each amino acid in the protein. Tertiary structure may be stabilized by covalent bonds, called disulfide bridges, that form between the sulfhydryl groups (SH) of two cysteine monomers. Tertiary structure may also be stabilized by weaker interactions, including hydrogen bonds between polar and/or charged areas, ionic bonds between charged R groups, and hydrophobic interactions and van der Waals interactions among hydrophobic R groups.

Many globular proteins are made up of several polypeptide chains called subunits stuck to each other by a variety of attractive forces but rarely by covalent bonds. Protein chemists describe this as quaternary structure.

Which of the following is similar between RNA and DNA?

type of pyrimidine base

type of purine base

number of strands

type of sugar

type of purine base

Purine - Adenine (Both), Guanine (Both)

Pyrimidines - Thymine (DNA), Uracil (RNA), Cytosine (Both)

The liver is involved in detoxification of many poisons and drugs. Which of the following structures is abundant in liver cells and primarily responsible for detoxification processes?

nuclear envelope

smooth endoplasmic reticulum

rough endoplasmic reticulum

Golgi apparatus

smooth endoplasmic reticulum

Which of the following is a common trait of chloroplasts and mitochondria?

both contain their own DNA

both are found in plant and animal cells

both reproduce by meiosis

both are surrounded by a single membrane

proteins for both are synthesized on ribosomes in the rough ER

Neither mitochondria nor chloroplasts are part of the endomembrane system. They both make some of their own proteins, the rest are synthesized by free cytoplasmic ribosomes

both contain their own DNA

Mitochondria and chloroplasts contain their own DNA and ribosomes.

Which of the following molecules would likely diffuse through the lipid bilayer of a plasma membrane most rapidly?

an amino acid

sucrose

Na+

O2

Previous Answers

O₂

What will happen to a red blood cell (RBC), which has an internal ion content of about 0.9%, if it is placed into a beaker of pure water?

The cell will remain the same size because the solution outside the cell is isotonic.

The cell will shrink because the water in the beaker is hypotonic relative to the cytoplasm of the RBC.

The cell will shrink because the water in the beaker is hypertonic relative to the cytoplasm of the RBC.

The cell will swell because the water in the beaker is hypotonic relative to the cytoplasm of the RBC.

The cell will swell because the water in the beaker is hypotonic relative to the cytoplasm of the RBC.

An animal cell that lacks carbohydrates on the external surface of its plasma membrane would likely be impaired in which of the following functions?

attaching the plasma membrane to the cytoskeleton

transporting ions against an electrochemical gradient

establishing a diffusion barrier to charged molecules

cell-cell recognition

cell-cell recognition