Protein Structure and the Genetic Code (G)

Question 1

What is a polypeptide?

Answer 1

A chain of covalently linked amino acids

Question 2

What does each mRNA specify?

Answer 2

It specifies a particular amino acid sequence of a particular polypeptide

Question 3

What is a protein in comparison to a polypeptide?

Answer 3

It is a structure made of one or more polypeptides that has a distinct function within an organism

Question 4

What is E. coli RNA polymerase?

Answer 4

It is a protein made of six interacting polypeptides

Question 5

What is the function of RNA polymerase?

Answer 5

To synthesize RNA

Question 6

What are amino acids?

Answer 6

They are individual monomers that make up a polypeptide

Question 7

What is the basic structure of all amino acids?

Answer 7

There is a central carbon atom that is covalently bonded to a hydrogen atom, an amino group, a carboxyl group, and a side chain/R group

Question 8

What is the purpose of a side chain/R group?

Answer 8

The side chain is variable in the composition of amino acids
This variation distinguishes one amino acid from another

Question 9

How many different amino acids are there?

Answer 9

20 amino acids, all with a different side chain

Question 10

Certain side chains share similar chemical properties. What are the four broad groups amino acids are separated into?

Answer 10

1. Acidic side chains
2. Basic side chains
3. Uncharged polar (hydrophilic)
4. Nonpolar (hydrophobic)

Question 11

How are amino acids linked together?

Answer 11

Peptide bonds

Question 12

How is a peptide bond formed?

Answer 12

By linking the carboxyl group of one amino acid to the amino group of another

Question 13

How many peptide bonds can each amino acid make? Why?

Answer 13

Two peptide bonds
This is because each amino acid has one carboxyl and one amino group

Question 14

What is the orientation of all amino acids and polypeptides?

Answer 14

The amino groups are directed toward one end of the polypeptide and the carboxyl groups are directed toward the other end

Question 15

What is found at the ends of a polypeptide?

Answer 15

There is an amino acid with a free amino group in one end
There is an amino acid with a free carboxyl group at the other end

Question 16

What is the end with a free amino group called?

Answer 16

Amino terminus
N terminus

Question 17

What is the end with a free carboxyl group called?

Answer 17

Carboxyl group
C terminus

Question 18

What is a polypeptide’s conformation?

Answer 18

It acquires a unique 3D shape after being synthesized (i worded this weird mb)

Question 19

How are conformations formed in polypeptides?

Answer 19

By interactions between different functional groups within the amino acids

Question 20

What is the conformation of polypeptides dependent on?

Answer 20

On the amino acid sequence of the polypeptide

Question 21

What is considered the primary structure of a polypeptide? Why?

Answer 21

The amino acid is considered the primary structure because conformation is dependent on it

Question 22

What are the different levels of conformation?

Answer 22

Secondary
Tertiary
Quarternary

Question 23

What is secondary structure?

Answer 23

The conformation within a particular area of one polypeptide

Question 24

What is tertiary structure?

Answer 24

The overall conformation of one polypeptide

Question 25

What is quarternary structure?

Answer 25

The overall conformation of a protein that contains two or more polypeptides

Question 26

What kind of structures are found on a protein consisting of one polypeptide?

Answer 26

Primary Secondary Tertiary (NO quarternary)

Question 27

Where is a protein's function acquired?

Answer 27

From its conformation

Question 28

What happens to a protein's function if its conformation is lost?

Answer 28

The function will also be lost

Question 29

How is each amino acid specified?

Answer 29

It is specified by a group of three bases called a codon

Question 30

What are the other names for codons?

Answer 30

Triplet codons Triplets

Question 31

Why is the order of bases in codons important?

Answer 31

Each codon specifies a different amino acid EX: The codon CCA specifies a different amino acid than CAC or ACC

Question 32

If codons are a genetic language, what are the bases in the gene/mRNA and what are the codons?

Answer 32

The bases would be considered the alphabet and the codons would be the words

Question 33

What do codons (the "words") make up?

Answer 33

The genetic code

Question 34

What does translation do to the genetic code?

Answer 34

It turns it into the amino acid sequence of a polypeptide

Question 35

How mano possible codons exist?

Answer 35

64 codons

Question 36

How many codons code for amino acids?

Answer 36

61 codons

Question 37

There are 61 codons for amino acids but only 20 amino acids. What does that mean?

Answer 37

That means most amino acids are encoded by more than one codon

Question 38

Which amino acids are encoded by a single codon?

Answer 38

Methionine and tryptophan

Question 39

Why is the genetic code considered to be degenerate?

Answer 39

Because an amino acid may be encoded by more than one codon

Question 40

Which codons do not encode amino acids?

Answer 40

UGA UAA UAG

Question 41

What is the function of the three codons that do not encode amino acids?

Answer 41

They function as translation termination signals STOP codons

Question 42

What does the codon AUG labeled as?

Answer 42

Methionine Start

Question 43

What is the rule for the codon AUG?

Answer 43

All AUG codons specify methionine, but not all AUG codons are translation start signals

Question 44

Which AUG codon is considered the START codon?

Answer 44

Only the first AUG in an mRNA can be the start codon Any other AUG is considered to be methionine

Question 45

What is the genetic code sometimes referred to as? Why?

Answer 45

The universal code This is because the genetic code is almost identical in all organisms

Question 46

What are some exceptions to the universal code?

Answer 46

Variations have been found in the mitochondrial DNA of many eukaryotes, and in some bacterial and protists species