Exam 2- Genetics

Question 1

What is the genome?

Answer 1

all of the genetic material in a cell

Question 2

What does the sequence of bases in DNA represent?

Answer 2

information & is organized into genes

Question 3

What is a gene?

Answer 3

a locus (region) of DNA that encodes a protein or functional RNA product

Question 4

What is most of the DNA in a cell organized into?

Answer 4

chromosomes, where the DNA is coiled & packed with associated proteins

Question 5

What are plasmids?

Answer 5

small, extrachromosomal, self-replicating pieces of double-stranded DNA

Question 6

What is transcription?

Answer 6

the process of copying a gene from DNA to into mRNA

Question 7

What is transcription?

Answer 7

begins at the promoter sequence & stops at the terminator sequence

Question 8

Exlpain initiation (transcription).

Answer 8

RNA polymerase binds to the promoter

Question 9

Explain elongation (transcription).

Answer 9

RNA chain is extended (~45 bases/sec)

Question 10

Explain termination (transcription).

Answer 10

RNA polymerase detaches from the DNA at the terminator sequence

Question 11

What is translation?

Answer 11

the synthesis of protein (amino acid) guided by the template mRNA (nucleotides)

Question 12

What is mRNA translated to?

Answer 12

codons

Question 13

What does messenger RNA do (mRNA)?

Answer 13

encodes proteins

Question 14

what does ribosomal RNA (rRNA) do?

Answer 14

forms ribosomes

Question 15

What does transfer RNA (tRNA) do?

Answer 15

shuttles amino acids

Question 16

What is anticodon in tRNA?

Answer 16

complementary to codon in mRNA & directs addition of specific amino acid

Question 17

Where ate transcription & translation physically separated?

Answer 17

in eukaryotes

Question 18

Explain transcription.

Answer 18

RNA polymerase binds to the promoter & reading the template strand, begins RNA transcription at nucleotide +1, stops at the transcription terminator region

Question 19

What does transcription produce?

Answer 19

mRNA

Question 20

Explain translation.

Answer 20

the mRNA has an untranslated region of variable length & then a ribosome-binding site

Question 21

What is a mutation?

Answer 21

any permanent, heritable alteration in a DNA sequence

Question 22

What are the two basic requirements to produce a heritable mutation?

Answer 22

base sequence is changed & a change in DNA sequence is not repaired before the next round of replication

Question 23

What is point mutation or base substitution?

Answer 23

single nucleotide is changed in a DNA sequence

Question 24

What is a silent mutation?

Answer 24

when theres no change in the amino acid sequence

Question 25

What is a missense mutation?

Answer 25

results in one changed amino acid in the protein sequence

Question 26

What is a nonsense mutation?

Answer 26

codon is changed to a STOP codon resulting in a truncated protein

Question 27

Explain frameshift mutation.

Answer 27

it alters the reading frame of the message & thus changes the entire protein sequence after the site of the mutation

Question 28

What is a framework mutation?

Answer 28

insertion or deletion of 1 or more nucleotide pairs