AP Bio Insta-Review Topic 1.2*: Elements of Life

A macromolecule is found to have C, H, O, N, and S. Identify?

• Carbohydrate

• Lipid

• Nucleic Acid

• Protein

Answer explanation

All of the macromolecules have carbon (C), hydrogen (H), and oxygen (O). Nitrogen is found in proteins and nucleic acids. Sulfur is found in the R group of some amino acids. Proteins are the only macromolecule with C, H, O, N, and S.

Tags

NGSS.HS-LS1-6

A macromolecule is found to have C, H, O, N, and P. Identify?

• Carbohydrate

• Lipid

• Nucleic Acid

• Protein

Answer explanation

All of the macromolecules have carbon (C), hydrogen (H), and oxygen (O). Nitrogen is found in proteins and nucleic acids. Phosphorous is found in nucleotides (and phospholipids) which is found in nucleic acids. Nucleic acids are the only macromolecule with C, H, O, N, and P.

Tags

NGSS.HS-LS1-6

What macromolecule also has phosphate?

Answer explanation

Phospholipids

Note: lipids wasn't the answer earlier because they don't have a Nitrogen (and all the members don't have Phosphate)

Two students are attempting to recreate the Hershey and Chase experiment to identify the genetic information for a cell. They use radioactive Nitrogen to track the material of interest. 

Why can't they identify the genetic material? 

Answer explanation

Nitrogen is found in both Nucleic Acids and Proteins. So, by using radioactive Nitrogen you marked both macromolecules and were unable to track the material of interest. 

Where is the Nitrogen in proteins?

Answer explanation

The Nitrogen is found in the Amine group (NH₃) on the central carbon in each amino acid. 

Tags

NGSS.HS-LS1-6

Where is the Nitrogen in nucleic acids?

Answer explanation

The Nitrogen is in the nitrogenous bases (A, T, C, G, U) that branch from the pentose sugar in each nucleotide (specifically the 1' BUT THAT’S NOT IMPORTANT)

How many valence electrons does Carbon have?

• 2

• 3

• 4

• 5

Answer explanation

Valence electrons are the electrons found in the outermost energy level. The first energy level can hold 2 electrons and the second energy level can hold 8 electrons. If you look at the periodic table, carbon has 6 electrons. There are 2 in the first level leaving 4 for the outermost energy level.

Tags

NGSS.HS-PS1-1

What type of bond does Carbon make other atoms?

• Covalent

• Hydrogen

• Ionic

• Van der Waals

Answer explanation

Carbon has four valence electrons (so it is equidistant from a complete valence shell). Due to this, carbon will share its valence electrons. Sharing valence electrons is due to covalent bonding.

Tags

NGSS.HS-LS1-6

Why is the carbon/carbon bond non-polar but with carbon/oxygen polar?

Answer explanation

Carbon/Carbon have the same electronegativity, so equal pull of electron (nonpolar)

Carbon/Oxygen have different electronegativity, so unequal pull of electron (polar)

Tags

NGSS.HS-PS1-1

Which of the following macromolecules include nitrogen?

• Carbohydrates & Lipids

• Lipids & Nucleic Acids

• Nucleic Acids & Proteins

• Proteins & Carbohydrates

Answer explanation

Nitrogen is

› found in the amine group of amino acids (which is protein’s monomer)

› found in the nitrogenous base of nucleotides (which is nucleic acid’s monomer)

Tags

NGSS.HS-LS1-1