W16 L2 - Proteins and Amino Acids

Flashcards for Proteins and Amino Acids

What is the ultimate product generated in the cell from DNA and messenger RNA?

Proteins.

What critical feature of proteins dictates their function?

Their three-dimensional shape.

What are the building blocks of proteins?

20 different amino acids (proteinogenic or biogenic).

What are the four components connected to the alpha carbon in a typical amino acid?

A carboxylic acid, a hydrogen, an amino group, and an R-group.

What does the 'R' in the structure of an amino acid stand for?

A residue that can vary between different amino acids.

What type of isomers can amino acids form due to the chiral nature of the alpha carbon?

Stereo isomers.

Are the amino acids found in proteins L or D configuration?

L amino acids only.

Can ribosomes use D amino acids?

No, ribosomes can only use L amino acids.

Which amino acid does not have a stereo isomer?

Glycine.

Which amino acids have a positive charge?

Lysine, arginine, and histidine.

Which amino acids have a negative charge?

Aspartate and glutamate.

What can aromatic amino acids be used for?

To measure the concentration of proteins because they can absorb electromagnetic energy.

What is a codon?

A triplet of three bases that tell us what amino acid should be in a protein.

How many reading frames can be found in a DNA sequence?

Six (three on each strand).

How many different amino acids can be encoded using triplets?

64.

What is the function of the genetic code?

To convert DNA sequences (triplets) into proteins.

Why is the genetic code said to be redundant or degenerated?

Because some amino acids are encoded by more than one codon.

What is the start codon, and what amino acid does it encode?

ATG, which encodes methionine (M).

What are the three stop codons?

TAA, TAG, and TGA.

What does it mean that the genetic code is non-overlapping?

Once the reading frame begins, the bases are read in successive triplets without sharing bases.

What does universal genetic code mean?

Every organism uses the same genetic code.

What is Tryptophan's one letter code?

W.