Question 1

Which of the following best explains why ice floats on liquid water?

Accepted Answer

Ice is less dense than liquid water because hydrogen bonds form a stable lattice during freezing.

Question 2

A scientist is studying a molecule with the following properties: it is nonpolar, hydrophobic, and does not dissolve in water. Which type of molecule is this most likely to be?

Accepted Answer

A lipid

Question 3

Which functional group is responsible for acting as an acid by donating an $$\mathrm{H^+}$$ ion and is found on every amino acid?

Accepted Answer

Carboxyl group

Question 4

Which of the following statements about covalent bonds is correct?

Accepted Answer

Covalent bonds involve the sharing of electrons between atoms.

Question 5

A patient is suffering from a fever that causes their body temperature to rise above normal. Which of the following best describes what might happen to their proteins?

Accepted Answer

The proteins may denature, losing their three-dimensional shape and function.

Question 6

Which of the following best describes the difference between saturated and unsaturated fatty acids?

Accepted Answer

Saturated fatty acids have only single bonds in their hydrocarbon tails, making them solid at room temperature.

Question 7

Which type of bond connects the monomers in a protein?

Accepted Answer

Peptide bond

Question 8

A solution has a pH of 4. Which of the following statements is true about this solution?

Accepted Answer

It is acidic and has a higher concentration of $$\mathrm{H^+}$$ ions than pure water.

Question 9

Which property of water allows it to move up the roots of plants against gravity?

Accepted Answer

Capillary action, which results from both cohesion and adhesion.

Question 10

Which of the following best explains why water is an excellent solvent for ionic and polar substances?

Accepted Answer

Water is polar, so it can surround and interact with charged and polar molecules.

Question 11

Which of the following is a correct pairing of a macromolecule, its monomer, and the bond that connects them?

Accepted Answer

Nucleic acid – nucleotide – phosphodiester bond

Question 12

Which of the following best describes the secondary structure of a protein?

Accepted Answer

It is formed by hydrogen bonds between the backbone of the polypeptide, resulting in alpha helices and beta sheets.

Question 13

Which of the following functional groups is nonpolar and can bind to DNA, affecting gene expression?

Accepted Answer

Methyl group

Question 14

A DNA molecule is held together by two types of bonds. Which bonds hold the nitrogenous bases together, and which bonds connect the sugar-phosphate backbone?

Accepted Answer

Hydrogen bonds hold the bases together; phosphodiester bonds connect the backbone.

Question 15

Which of the following best describes dehydration synthesis?

Accepted Answer

It is a process where an enzyme removes a hydroxyl group from one molecule and a hydrogen atom from another, forming a covalent bond and releasing water.

Question 16

Which of the following is true about DNA's antiparallel structure?

Accepted Answer

The two strands run in opposite directions, such as 5’ to 3’ and 3’ to 5’.

Question 17

Which of the following best explains why carbon is so important in biological molecules?

Accepted Answer

Carbon can form up to four covalent bonds, allowing for a variety of structures such as rings and chains.

Question 18

Which of the following is a property of water that helps moderate Earth's climate?

Accepted Answer

High specific heat, which allows water to absorb large amounts of heat before changing temperature.

Question 19

Which of the following best describes the role of enzymes in biological systems?

Accepted Answer

Enzymes speed up chemical reactions by lowering the activation energy required.

Question 20

A molecule contains a long hydrocarbon tail and a carboxyl group. Which type of molecule is this, and what property does the hydrocarbon tail confer?

Accepted Answer

It is a fatty acid; the hydrocarbon tail makes it hydrophobic.

Chemistry of Life: Foundations for General Biology

Guida di studio - Domande di pratica

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