Lecture 8c: Molecular Biology- Gene Expression

Question 1

Gene expression

Answer 1

the flows of genetic information from the genotype to the phenotype
DNA—>RNA—>Protein

Question 2

transcription

Answer 2

is the process by which the information encoded in DNA is made into a complementary RNA.

Question 3

the Central Dogma is

Answer 3

DNA –(Transcription)-> RNA–(Translation)-> Protein

Question 4

Gene

Answer 4

an organized unit of DNA sequences that enables a segment of DNA to be transcribed into RNA and ultimately results in the formation of a function of a functional product

Question 5

what is a gene composed of?

Answer 5

the promoter, the regulatory sequence, the transcribed region and the terminator

Question 6

promoter

Answer 6

the site in the DNA where RNA polymerase binds to begin transcription

Question 7

regulatory sequences

Answer 7

the sites binding to regulatory proteins control whether a gene is turned on or off

Question 8

Transcribed region

Answer 8

a region of a DNA that is transcribed into an RNA molecule

Question 9

terminator

Answer 9

a sequence that causes the RNA strand to be released from the transcription complex

Question 10

Transcription molecular processes

Answer 10

transcription initiation
transcription elongation
transcription termination

Question 11

exon

Answer 11

a coding portion of the gene

Question 12

intron

Answer 12

a non-coding portion of a gene that is excised from the RNA transcript

Question 13

RNA splicing

Answer 13

the removal of introns and joining of exons in eukaryotic RNA, forming an mRNA molecule with a continuous coding sequence

Question 14

Capping

Answer 14

a 7-methylguanosine attached to the mature eukaryotic mRNAs at the 5’ end

Question 15

tailing

Answer 15

a poly A tail is added to the most mature eukaryotic mRNAs at the 3’ end

Question 16

the genetic code (simple def)

Answer 16

Genetic code refers to the instructions contained in a gene that tell a cell how to make a specific protein.

Question 17

mutation

Answer 17

a mutation is the permanent alteration of the nucleotide sequence of the genome of an organism (2 common forms)

Question 18

common gene mutations occur in which 2 ways

Answer 18

1. a base substitution
2. an insertion or deletion

Question 19

Common forms of mutations

Answer 19

• Base-pair substitution
• Missense mutation
• Silent mutation
• Nonsense mutation
• Frameshift mutation

Question 20

Base-pair Substitution:

Answer 20

Also called point mutation- the replacement of one nucleotide and its partner in the complementary DNA strand with another pair of nucleotides

Question 21

Missense mutation

Answer 21

A point mutation in which single nucleotide change results in a codon that codes for a different amino acid

Question 22

Silent Mutation

Answer 22

A mutation where a change in a DNA codon does not result in a change in amino acid specified by the gene

Question 23

Nonsense mutation

Answer 23

a mutation in which a sense codon that corresponds to one of the 20 amino acids specified by the genetic code is changed to a chain-terminating codon

Question 24

Frameshift mutation

Answer 24

a mutation caused by insertions or deletions of a number of nucleotides in a DNA sequence that is not divisible by 3

Question 25

The translation process requires

Answer 25

-Amino acids (20AA)
- ATP and GTP
- Enzymes and proteins
- RNAs (mRNA, tRNA, rRNA)
- Ribosomes (small and large subunits)

Question 26

Anticodon

Answer 26

the 3-nucleotide segment that base-pairs with a codon in mRNA