Question 1

Which property of the carbon atom is primarily responsible for the diversity of organic molecules found in living organisms?

Accepted Answer

Its tetravalence, allowing four covalent bonds with other atoms

Question 2

Why is the energy of visible light not sufficient to break the covalent bonds in biological molecules such as those between carbon atoms?

Accepted Answer

Visible light has a longer wavelength and therefore lower energy than the bond energy of C–C bonds

Question 3

Which of the following functional groups is most likely to be found ionized and negatively charged at the near-neutral pH of a cell?

Accepted Answer

Carboxyl group

Question 4

A molecule with the formula $$C_2H_2 is $$shown in the study materials. What type of bond connects the two carbon atoms in this molecule?

Accepted Answer

Triple bond

Question 5

Which of the following best explains why water has a high specific heat capacity?

Accepted Answer

Hydrogen bonds between water molecules absorb heat energy before breaking

Question 6

Which of the following statements about the permeability of biological membranes is correct?

Accepted Answer

Small, nonpolar molecules like $$O_2$$ and $$CO_2$$ can diffuse rapidly across the membrane

Question 7

Which of the following is a direct consequence of the amphipathic nature of phospholipids in biological membranes?

Accepted Answer

Phospholipids form a bilayer with hydrophobic tails facing inward and hydrophilic heads facing outward

Question 8

Which of the following best describes a condensation reaction in the synthesis of biological macromolecules?

Accepted Answer

A reaction in which two monomers are joined and a water molecule is released

Question 9

A protein is denatured by heat and then slowly cooled. What is most likely to happen if the protein is capable of self-assembly?

Accepted Answer

The protein will spontaneously refold into its native, functional conformation

Question 10

Which of the following interactions is primarily responsible for the secondary and tertiary structure of proteins?

Accepted Answer

Noncovalent interactions such as hydrogen bonds, ionic bonds, van der Waals forces, and hydrophobic interactions

Question 11

Which of the following best explains why hydrocarbons are generally insoluble in water?

Accepted Answer

They are nonpolar and cannot form hydrogen bonds with water

Question 12

Which of the following statements about stereoisomers is correct?

Accepted Answer

Stereoisomers are mirror images of each other and cannot be superimposed

Question 13

Which of the following is a real-world example of the importance of water’s high heat of vaporization for living organisms?

Accepted Answer

The cooling effect of sweating in humans

Question 14

Which of the following best describes the role of molecular chaperones in protein folding?

Accepted Answer

They prevent incorrect interactions during folding but do not dictate the final structure

Question 15

Which of the following is a key advantage of hierarchical assembly in cellular structures?

Accepted Answer

It enables quality control at each level, allowing defective components to be discarded early

Question 16

Which of the following best explains why sodium chloride ($$NaCl) $$dissolves readily in water?

Accepted Answer

Water molecules form spheres of hydration around $$Na^+$$ and $$Cl^-$$ ions, neutralizing their attraction for each other

Question 17

Which of the following is NOT a property of water that is critical for life?

Accepted Answer

Low polarity

Question 18

Which of the following statements about the synthesis of biological macromolecules is correct?

Accepted Answer

Monomers must be activated, usually by coupling to a carrier molecule, before polymerization

Question 19

Which of the following is an example of a biological process that relies on the selective permeability of membranes?

Accepted Answer

The regulated uptake of glucose via specific transport proteins

Question 20

Which of the following best describes the process of self-assembly in the formation of the tobacco mosaic virus (TMV)?

Accepted Answer

TMV RNA and protein subunits spontaneously assemble into a functional virus particle without external information

The Chemistry of the Cell: Carbon, Water, Membranes, and Macromolecular Assembly

Guida di studio - Domande di pratica