Biochemistry

Water is a _ molecule.

• nonpolar

• polar

Answer explanation

Water is a polar molecule because it has a bent shape and a difference in electronegativity between oxygen and hydrogen, leading to a partial positive charge on hydrogen and a partial negative charge on oxygen.

Tags

NGSS.HS-PS1-3

Water _ heat when it evaporates.

• absorbs

• releases

Answer explanation

Water absorbs heat when it evaporates, which is why evaporation is a cooling process. This means that as water changes from liquid to vapor, it takes in energy from its surroundings.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Water molecules are

• cohesive

• adhesive

• nonpolar

• fatty

Answer explanation

Water molecules are cohesive due to hydrogen bonding, allowing them to stick to each other. They are also adhesive, meaning they can stick to other substances, which is crucial for processes like capillary action.

Tags

NGSS.HS-ESS2-5

Which pair is incorrect?

• carbohydrates - provide energy

• lipids - provide insulation

• nucleic acids - store hereditary information

• proteins - provide energy

Answer explanation

The pair 'proteins - provide energy' is incorrect because while proteins can provide energy, their primary roles are in structure and function, unlike carbohydrates and lipids which are more direct energy sources.

Which is the strongest acid?

• ph of 1

• ph of 4

• ph of 7

• ph of 9

Answer explanation

The pH scale measures acidity, with lower values indicating stronger acids. A pH of 1 is much more acidic than pH 4, 7, or 9, making it the strongest acid among the choices.

Which is false?

• Enzymes bind to a substrate.

• Enzymes slow down chemical reactions.

• Enzymes lower the activation energy.

• Enzymes are affected by temperature and pH.

Answer explanation

The false statement is that enzymes slow down chemical reactions. In fact, enzymes speed up reactions by lowering the activation energy required, while also binding to substrates and being influenced by temperature and pH.

Tags

NGSS.HS-PS1-5

Enzymes _ activation energy

• raise

• lower

Answer explanation

Enzymes lower activation energy, making it easier for reactions to occur. This is crucial for biological processes, as it allows reactions to proceed at a faster rate under physiological conditions.

Because enzymes speed up chemical reactions, they are called

• catalysts

• metabolism

• viruses

• living

Answer explanation

Enzymes are biological molecules that act as catalysts, meaning they accelerate chemical reactions without being consumed in the process. This is why they are referred to as catalysts.

Tags

NGSS.HS-PS1-5

Which is the wrong polymer/monomer pair?

• nucleic acids : nucleotides

• lipids: monosaccharides

• carbohydrates: monosaccharides

• proteins : amino acids

Answer explanation

The pair 'lipids: monosaccharides' is incorrect because lipids are not made from monosaccharides; they are primarily composed of fatty acids and glycerol. The other pairs correctly match their respective polymers and monomers.

Which of the following is not a function of proteins

• provide energy

• transport O₂

• movment

• catalyze chemical reactions

Answer explanation

While proteins can provide energy, this is not their primary function. Their main roles include transporting O2, facilitating movement, and catalyzing chemical reactions, making 'provide energy' the correct choice.