module 7 part 1

Question 1

What is the starting point of the central dogma?

Answer 1

he starting point is DNA.

Question 2

What happens to DNA in the central dogma?

Answer 2

DNA undergoes transcription to produce an RNA transcript.

Question 3

What are the three types of RNA that can be produced?

Answer 3

The three types of RNA are messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA).

Question 4

What happens to mRNA after transcription?

Answer 4

mRNA is processed and then translated to produce a polypeptide.

Question 5

What is the final product of translation?

Answer 5

The final product of translation is a polypeptide.

Question 6

What is the genetic code?

Answer 6

The genetic code is the set of rules by which the nucleotide sequence in DNA or RNA is translated into a sequence of amino acids in a protein.

Question 7

How does the genetic code specify a string of amino acids?

Answer 7

The nucleotide sequence in DNA or RNA is read in codons (sets of three nucleotides), each of which codes for a specific amino acid.

Question 8

How many nucleotides are in one “word” of the genetic code?

Answer 8

One “word” of the genetic code consists of three nucleotides, called a codon.

Question 9

How can we distinguish different “words” (codons) in the genetic code?

Answer 9

Each codon corresponds to a specific amino acid or a stop signal, distinguishing the “words” by their unique three-nucleotide sequence.

Question 10

Where does a gene start and where does it end?

Answer 10

A gene starts with a start codon (usually AUG) and ends with a stop codon (e.g., UAA, UAG, or UGA).

Question 11

Are there punctuation marks in the genetic code?

Answer 11

Yes, the genetic code has punctuation marks: start and stop codons act as signals to begin and end translation.

Question 12

How many amino acids are encoded by the genetic code?

Answer 12

There are 20 amino acids encoded by the genetic code.

Question 13

How many nucleotides are used to code for amino acids?

Answer 13

4 nucleotides (A, T, C, G in DNA, or A, U, C, G in RNA) are used to code for amino acids.

Question 14

How many possibilities would there be for codons if 1 nucleotide coded for 1 amino acid?

Answer 14

If 1 nucleotide coded for an amino acid, there would be 4 possibilities (4¹).

Question 16

How many possibilities would there be if 2 nucleotides coded for 1 amino acid?

Answer 16

If 2 nucleotides coded for an amino acid, there would be 16 possibilities (4²).

Question 17

Why do we need 3 nucleotides to code for each amino acid?

Answer 17

With 3 nucleotides (a triplet codon), there are 64 possible combinations (4³), which is enough to code for all 20 amino acids and still allow for redundancy (more than one codon for some amino acids).

Question 18

How many triplet codons are there in the genetic code?

Answer 18

There are 64 triplet codons in the genetic code.

Question 19

How many amino acids are encoded by the genetic code?

Answer 19

The genetic code encodes 20 amino acids.

Question 20

What is the role of the codon AUG?

Answer 20

AUG is the initiation codon, signaling the start of translation.

Question 21

How many codons signal the end of translation?

Answer 21

3 codons (UAA, UAG, UGA) act as stop codons, signaling the end of translation.

Question 22

What does it mean that the genetic code is “degenerate”?

Answer 22

The genetic code is degenerate, meaning that multiple codons can code for the same amino acid.

Question 23

What did Charles Yanofsky’s experiment demonstrate?

Answer 23

Yanofsky’s experiment showed that a gene’s nucleotide sequence is collinear with the amino acid sequence of the encoded polypeptide.

Question 24

What organism did Yanofsky use in his experiment?

Answer 24

He used Escherichia coli (E. coli) in his study.

Question 25

What gene did Yanofsky study in E. coli?

Answer 25

He studied the trpA gene, which encodes a subunit of tryptophan synthetase.

Question 26

What was the focus of Yanofsky’s experiment?

Answer 26

He compared mutations in the trpA gene to specific amino acid substitutions in the tryptophan synthetase enzyme.

Question 27

What did Yanofsky examine to understand the relationship between DNA mutations and protein changes?

Answer 27

He looked at the order of DNA mutations and the order of amino acid sequence changes in the tryptophan synthetase protein.

Question 28

What did Yanofsky’s experiment demonstrate about the relationship between a gene and the encoded protein?

Answer 28

Yanofsky’s experiment demonstrated that a gene’s nucleotide sequence is collinear with the amino acid sequence of the encoded polyp

Question 29

What is meant by “collinear” in Yanofsky’s experiment?

Answer 29

“Collinear” means that the order of nucleotides in the gene directly corresponds to the order of amino acids in the protein.

Question 30

What gene did Charles Yanofsky study in his experiment?

Answer 30

He studied the trpA gene in Escherichia coli, which codes for a subunit of tryptophan synthetase.

Question 31

What method did Yanofsky use to connect mutations in the gene to amino acid changes?

Answer 31

: He compared mutations in the trpA gene to specific amino acid substitutions in the tryptophan synthetase enzyme.

Question 32

What did Yanofsky’s experiment reveal about codons?

Answer 32

Yanofsky’s experiment showed that a codon is composed of more than one nucleotide.

Question 33

Can different point mutations affect the same amino acid?

Answer 33

Yes, different point mutations can affect the same amino acid due to the degeneracy of the genetic code.

Question 34

How are codons related to nucleotides in the genetic code?

Answer 34

Each nucleotide is part of only one codon, and codons for amino acids do not overlap.

Question 35

What did Yanofsky observe about point mutations and their effects?

Answer 35

Yanofsky found that each point mutation altered only one amino acid in the encoded protein.

Question 36

How many nucleotides are in a codon?

Answer 36

A codon is composed of three nucleotides.

Question 37

What determines the reading frame for a gene?

Answer 37

The starting point of the gene establishes the reading frame.

Question 38

Why is the reading frame important in translation?

Answer 38

The reading frame is important because it determines how the codons are grouped and read during translation to ensure the correct amino acids are added to the polypeptide chain.

Question 39

What happens if the reading frame is shifted?

Answer 39

A frameshift mutation (adding or deleting nucleotides) can shift the reading frame, potentially altering the entire amino acid sequence after the mutation.

Question 40

different sets of mutations generate either a ____ or a _____

Answer 40

mutant;normal phenotype

Question 41

What determines the phenotypic effect of a frameshift mutation?

Answer 41

It depends on whether the reading frame is restored.

Question 42

Do most amino acids have more than one codon?

Answer 42

Yes, most amino acids are encoded by more than one codon.

Question 43

What happens in a deletion mutation? cat ate the rat

Answer 43

One or more nucleotides are removed from the sequence.
Example: “The cat ate the rat.” becomes “Thc ata tet her

Question 44

What happens in an insertion mutation? cat ate the rat

Answer 44

One or more nucleotides are added to the sequence.
Example: “The cat ate the rat.” becomes “The cat tat eth era t…”

Question 45

What happens in a deletion and insertion mutation? the cat ate the rat

Answer 45

Both nucleotides are removed and added, shifting the sequence.
Example: “The cat ate the rat.” becomes “Thc att ate the rat.”