Chemistry of life

Which elements are correctly paired with their atomic symbol? Select all that apply.

• He - Hydrogen

• C - Carbon

• N - Nitrogen

• O - Oxygen

A cation has a ____ charge.

What is an enzyme?

• A catalyst made of protein

• A catalyst made of DNA or RNA

• A catalyst made of metals only

The four main types of carbon-based molecules in organisms are carbohydrates, lipids, nucleic acids, and

• starches.

• fatty acids.

• monosaccharides.

• proteins.

By which process does water vapor become a cloud?

• evaporation

• transpiration

• condensation

• precipitation

What is true about hydrogen bonds?

• They are relatively weak

• They are involved in the structure of DNA

• They occur between hydrogen and more electronegative atoms like oxygen

• All of the above

A(n) ____________________ is two or more atoms held together by covalent bonds.

• molecule

• compound

• atom

• ion

Where does a peptide bond form?

• between the five-carbon sugar of one nucleotide and the phosphate group of another nucleotide

• between the R group of one amino acid and the carboxyl group of another amino acid

• between the amino group of one amino acid and the carboxyl group of another amino acid

• between the nitrogenous base of one nucleotide and the phosphate group of another nucleotide

Why is carbon able to form a large number of different molecules?

• carbon only forms ionic bonds

• carbon only forms ring structures

• carbon can form four covalent bonds

• carbon forms small simple structures

A sample of the element potassium has 19 protons and 18 electrons, making it a...

• Positive Ion

• Neutral Atom

• Negative Ion