Biochemistry: Cells, Bonds & Reactions

A salt (NaCl) crystal is sitting in a glass of water at room temperature.Its shape is changing, but not its volume. Which of the following are true?

a. The salt is dissolving from and crystallizing onto the crystal at the same rate.

b. Sodium and chloride ions are constantly attaching to and detaching from the crystal.

c. Sodium and chloride ions in the salt crystal are jiggling in accordance with the temperature of the crystal.

d. Because the volume of the salt crystal is not changing, it must be in equilibrium.

e. The atoms (ions) in a crystal of salt hovering in no gravity in a vacuum at room temperature would be jiggling, even though they are not interacting with anything else.

f. The water in the glass would taste salty

a. true

b. true

c. true

d. true

e. true

f. true

The most rigid part of a cell.

-endoplasmic reticulum

-cytoplasm

-cytoskeleton

-plasma membrane

-nucleus

cytoskeleton

According to the "central dogma":

-information flows from DNA to RNA to protein

-information flows from DNA to RNA

-DNA can be replicated

-information flows from RNA to protein

-ALL OF THESE are true

ALL OF THESE are true

Site where genetic information becomes a protein.

-smooth endoplasmic reticulum

-nucleus

-ribosome

-DNA

ribosome

Which of the following is NOT semipermeable?

-endoplasmic reticulum

-nuclear membrane

-mitochondrial membrane

-plasma membrane

-ALL OF THESE are semipermeable

ALL OF THESE are semipermeable

The hydrophobic effect is directly responsible for which of the following?

-functional groups

-membrane formation

-polypeptide synthesis

-NONE OF THESE

-ALL OF THESE

membrane formation

Which of the following is not a common carbohydrate?

-fat

-starch

-glycogen

-sucrose

-glucose

fat

Substances that affect energetic balance are most likely to target which of the following?

-golgi apparatus

-endoplasmic reticulum

-nucleus

-cytoskeleton

-mitochondrion

mitochondrion

10 angstroms equals _________ nanometer(s).

.01

0

10

.1

1

1

Which of the following is important for breaking things into smaller pieces?

-Golgi complex

-endoplasmic reticulum

-secretory granule

-nucleus

-lysosome

lysosome

Which of the following is usually found as a single-stranded polymer with phosphodiester-linked monomers?

-carbohydrate

-RNA

-DNA

-protein

-NONE OF THESE

-ALL OF THESE

RNA

Which of the following is inside the cell, but is not an "intracellular structure"?

-cytoskeleton

-endoplasmic reticulum

-nucleus

-cytoplasm

cytoplasm

An essential part of EVERY CELL

-mitochondria

-plasma membrane

-nucleus

-cell wall

-ALL OF THESE are essential

-NONE OF THESE are essential

plasma membrane

Faster-moving atoms are ___________ atoms.

-less reactive

-hotter

-greener

-colder

hotter

Contains pores large enough to accommodate folded proteins.

-secretory granule

-plasma membrane

-nucleus

-endoplasmic reticulum

-endosome

nucleus

Which of the following organelles is enclosed by a single membrane?

-lysosome

-Golgi apparatus

-mitochondrion

-nucleus

-ALL OF THESE

-NONE OF THESE

lysosome

If a drop of water were floating in the vacuum of outer space, molecules that leave the drop due to evaporation would have ___________ the average amount of energy as the molecules that stay in the drop.

-more than

-Molecules would not be leaving the drop because it would be frozen.

-less than

-the same as

more than

The basic unit of life.

-DNA

-protein

-cell

-nucleic acid

-carbohydrate

cell

Which of these atoms are often hydrogen-bond acceptors?

-carbon

-oxygen

-hydrogen

-ALL OF THESE

-NONE OF THESE

oxygen

Which of the following is usually found as a single-stranded polymer with peptide-bond-linked monomers?

-carbohydrate

-DNA

-protein

-RNA

-ALL OF THESE

-NONE OF THESE

protein

The part of a lipid that can interact with water is said to be _______________.

- hydrophobic

- hydrophilic

- molecular

- amphipathic

- molar

hydrophilic

Which of the following are responsible for the repulsive force between two identically charged atoms?

- electrostatic interactions

- van der Waals interactions

- hydrogen bonds

- covalent bonds

- hydrophobic interactions

electrostatic interactions

____________ molecules in solution are driven together by entropy.

- hydrophilic

- ionic

- hydrophobic

- water

- polar

- ALL OF THESE

- NONE OF THESE

hydrophobic

Which of the following best describes the "atomic hypothesis"?

- when matter gets hot enough, it turns into a gas

- atoms move faster when they are hotter

- atoms are composed of smaller (subatomic) particles

- atoms combine to form molecules

- matter is composed of tiny particles called atoms

matter is composed of tiny particles called atoms

Contiguous with the nuclear membrane.

- mitochondrion

- endosome

- lysosome

- endoplasmic reticulum

- ALL OF THESE

- NONE OF THESE

endoplasmic reticulum

Which of the following interactions are considered "weak"?

- van der Waals interactions

- hydrogen bonds

- electrostatic interactions

- ALL OF THESE

- NONE OF THESE

ALL OF THESE

Which of the following is often found as a highly branched polymer?

- RNA

- protein

- DNA

- carbohydrate

- ALL OF THESE

- NONE OF THESE

carbohydrate

Present in eukaryotes but not prokaryotes.

- cytoplasm

- cytoskeleton

- plasma membrane

- mitochondria

- ALL OF THESE

- NONE OF THESE

mitochondria

Water can't form hydrogen bonds with ___________.

- aromatic rings

- carbonyl groups

- amine groups

- alcohol groups

- water can form hydrogen bonds with all of these

aromatic rings

Which of these is the "main ingredient" in proteins?

- carbohydrates

- amino acids

- nucleic acids

- hydrocarbons

- NONE OF THESE

amino acids

Formed when the plasma membrane buds off into the cytoplasm.

- endosome

- lysosome

- endoplasmic reticulum

- Golgi complex

- daughter cell

endosome

A sort of "intermediate processing center" for proteins.

- lysosome

- plasma membrane

- Golgi complex

- mitochondria

- nucleus

Golgi complex

Defines the boundary of a cell.

- cytoplasm

- cytoskeleton

- nucleus

- plasma membrane

plasma membrane

Which of the following is the least important role of proteins in biological systems?

- signal molecules

- catalysts

- structural elements

- long-term information storage

- receptors for signal molecules

- ALL OF THESE

- NONE OF THESE

long-term information storage

After hydrogen and oxygen, the next most common element in seawater is _______________.

- carbon

- chlorine

- sulfur

- phosphorous

- nitrogen

chlorine

Performs the opposite of endocytosis.

- Golgi complex

- nucleus

- secretory granule

- lysosome

- endoplasmic reticulum

secretory granule

Material enters cells via ___________ .

- endocytosis

- phagocytosis

- passage though membrane proteins

- ALL OF THESE

- NONE OF THESE

ALL OF THESE

Which of the following is FALSE?

- Burning is a chemical reaction.

- In a chemical reaction, atoms change partners.

- All chemical reactions generate some amount of light.

- Some chemical reactions release a large amount of energy.

- A chemical reaction always forms new molecules.

- ALL OF THESE

- NONE OF THESE

All chemical reactions generate some amount of light.