2.4 IB Amino Acids & Proteins

What are polypeptides?

• chains of carbohydrates

• chains of amino acids

• chains of fatty acids

• chains of nucleic acids

Answer explanation

poly = lots of

peptide = the bond between amino acids

Tags

NGSS.HS-LS1-6

The reaction which occurs when a polypeptide is formed is called .....

• a condensation reaction

• a hydrolysis reaction

• a hydration reaction

• a peptide reaction

Answer explanation

Because it gives out / creates water

Tags

NGSS.HS-PS1-2

Which parts of the amino acid react with another amino acid to form a peptide bond?

• The carboxyl group and the R group

• The carboxyl group and the amino group

• The amine group and the R group

• The R group and carbon backbone

Answer explanation

What is the name of the bond that is formed when a polypeptide is made?

• Ester bond

• Glycosidic bond

• Peptide bond

• Amine bond

Answer explanation

Hence you get a polypeptide formed.

Amino acids are different from one another due to .......

• their differing carboxyl group

• their differing amine group

• their differing R group

• their differing carbon backbone

Answer explanation

The 'R' group is also known as the 'variable side chain' too. See in the diagram how they all have the same structure with the exception of the R group.

Tags

NGSS.HS-LS1-6

How many amino acids can be in a polypeptide?

• 20

• 200

• 2,000

• 20,000+

Answer explanation

Yep, they can be enormous!

Tags

NGSS.HS-LS1-6

Due to organisms having 20 amino acids that can be sequenced in any order and in any chain length, the number of possible combinations in a polypeptide is almost infinite.

• True

• False

Answer explanation

Do the math. If polypeptides can have anywhere up to 20,000+ amino acids in their chain, the possible combinations are 20^20,000+ which is a pretty big number!

Tags

NGSS.HS-LS1-1

Where does a cell get the information it needs to determine which order the amino acids should be in a polypeptide?

• Ribosomes

• DNA

• RNA

• The sequence is random

Answer explanation

DNA codes for proteins, specifically the order of amino acids in the polypeptide chain.

Tags

NGSS.HS-LS1-1

Can more than one polypeptide chain link together?

• Yes

• No

Answer explanation

That's how we get such crazy folding and unique shapes.

How many bases are required in a genetic sequence to code for one amino acid?

• one

• two

• three

• four

Answer explanation

Remember back to codons? They are triplicate bases. We will go into this in more detail in a couple of units.