How Genes Work

Question 1

What is the definition of Transcription?

Answer 1

Synthesis of RNA using the information in the DNA

Question 2

What is the definition of translation?

Answer 2

Synthesis of a polypeptide using the information in the RNA message

Question 3

What is the term used to describe the instructions for building polypeptides that are written in non-overlapping triplets?

Answer 3

Codons

Question 4

Fill in the blanks: Genetic code is ____ but not ____

Answer 4

redundant (multiple codons code for same aa) ; ambiguous (no codon codes for more than 1 aa)

Question 5

Define mutation as it relates to genes

Answer 5

Permanent change in an organism’s DNA (creates new alleles)

Question 6

What can change as a result of a change in DNA?

Answer 6

The final protein can change

Question 7

Is a chromosomal rearrangement a large scale or small scale mutation?

Answer 7

Large scale

Question 8

Are a couple changes in a few nucleotides a large scale or a small scale mutation?

Answer 8

Small scale

Question 9

What are point mutations?

Answer 9

A change in a single or small number of base pairs

Question 10

What is a substitution as it relates to mutation of genes?

Answer 10

Replacement of one base pair with another

Question 11

What kind of mutation results in the coding for the same amino acid?

Answer 11

Silent mutation (could be caused by redundancy of the genetic code)

Question 12

What kind of mutation results in the coding for a different amino acid?

Answer 12

Missense mutation (Can range from little effect to completely destroying the protein’s function)

Question 13

What kind of mutation codes for a stop codon?

Answer 13

Nonsense mutation (causes translation to stop early and usually creates a nonfunctional protein)

Question 14

What is an example of a point, missense mutation?

Answer 14

Sickle cell anemia

Question 15

What is an example of a silent mutation?

Answer 15

Progeria (creates a cryptic splice site that leads to incorrect splicing;Also creates shortened protein that is unable to be modified)

Question 16

What causes frameshift mutations?

Answer 16

Can be caused by either insertions or deletions

Question 17

What happens if the number of base pairs that are inserted or deleted is not a multiple of 3?

Answer 17

Every codon from that point on will be altered and this will usually end in a premature stop codon.

Question 18

What is more severe, a point mutation or a frameshift mutation? Why?

Answer 18

Frameshift mutation because it almost always produces a nonfunctional protein.

Question 19

What are a couple reasons as to why mutations happen?

Answer 19

1) Can be due to errors in replication (spontaneous mutations).
2) Can be caused by exposure to certain physical or chemical agents called mutagens. (most mutagens are carcinogenic-cause cancer)

Question 20

What are chromosome mutations?

Answer 20

Changes in the number of chromosomes

Question 21

What is the difference between polyploidy and aneuploidy?

Answer 21

Polyploidy means having more than 2 paired sets of chromosomes and aneuploidy means having missing or extra chromosomes.

Question 22

What is the current definition of a gene?

Answer 22

A region of DNA that can be expressed to produce a final functional product that is either a polypeptide or an RNA molecule.