Chapter 17: Gene Expression - From Gene To Protein

Question 1

Gene expression

Answer 1

The process by which information encoded in DNA directs the synthesis of proteins or, in some cases, RNA that are not translated into proteins and instead function as RNAs

Question 2

Transcription

Answer 2

The synthesis of RNA using a DNA template

Question 3

Messenger RNA

Answer 3

A type of RNA, synthesized using a DNA template, that attaches to ribosomes in the cytoplasm and specifies the primary structure of a protein

Question 4

Translation

Answer 4

the synthesis of a polypeptide using the genetic information encoded in an mRNA molecule. There is a change of language from nucleotides to amino acids

Question 5

Transfer RNA

Answer 5

An RNA molecule that functions as a translator between nucleic acid and protein languages by picking up a specific amino acid and carrying it to the ribosome, where the rRNA recognized the appropriate codon in mRNA.

Question 6

Anticodon

Answer 6

A nucleotide triplet at one end of a tRNA molecule that base pairs with a particular complementary codon on an mRNA molecule

Question 7

Aminoactyl tRNA synthase

Answer 7

An enzyme that joins each amino acid to the appropriate tRNA

Question 8

Wobble

Answer 8

Flexibility in the base-pair rule in which the nucleotide at the 5 end of a tRNA codon can form hydrogen pairs with more than one kind of base in the third position of a codon

Question 9

ribosomal RNA

Answer 9

RNA molecules that, together with proteins, make up ribosomes; the most abundant type of RNA

Question 10

P site

Answer 10

One of a ribosome’s three binding sites for tRNA during translation. The P site holds the tRNA carrying the growth polypeptide chain

Question 11

A site

Answer 11

One of a ribosomes three binding sites for tRNA during translation. The A site holds the tRNA carrying the next amino acid to be added to the polypeptide chain

Question 12

E site

Answer 12

One of a ribosomes three binding sites for tRNA during translation. The E site is the place where discharged tRNAs leave the ribosome

Question 13

Primary Transcript

Answer 13

An initial RNA transcript from any gene; also called pre-mRNA when transcribed from a protein-coding gene

Question 14

Triplet Code

Answer 14

A genetic information system in which a series of three-nucleotide-long words specifies a sequence of amino acids for a polypeptide chain

Question 15

Template strand

Answer 15

The DNA strand that provides the pattern or template, for ordering, by complementary base pairing, the sequence of nucleotides in an RNA transcript

Question 16

Codons

Answer 16

A three-nucleotide sequence of DNA or mRNA that specifies a particular amino acid or termination signal; the basic unit of the genetic code

Question 17

Coding strand

Answer 17

Nontemplate strand of DNA, which has the same sequence as the mRNA except it has thymine instead of uracil

Question 18

Reading Frame

Answer 18

On an mRNA, the triplet grouping of ribonucleotides used by the translation machinery during polypeptide synthesis

Question 19

RNA polymerase

Answer 19

An enzyme that links ribonucleotides into a growing RNA chain during transcription based on complementary binding of nucleotides on a DNA template strand

Question 20

Promoter

Answer 20

A specific nucleotide sequence in the DNA of a gene that bind RNA polymerase positioning it to start transcribing RNA at the appropriate place

Question 21

terminator

Answer 21

In bacteria, a sequence of nucleotides in DNA that marks the end of a gene and signals RNA polymerase to release the newly made RNA molecules and detach from DNA

Question 22

Transcription Unit

Answer 22

A region of DNA that is transcribed into an RNA molecule

Question 23

Start Point

Answer 23

In transcription, the nucleotide position on the promoter where RNA polymerase begins synthesis of RNA

Question 24

Transcription factors

Answer 24

A regulatory protein that binds to DNA and affects transcription of specific genes

Question 25

TATA box

Answer 25

A DNA sequence in eukaryotic promoters crucial in forming the transcription initiation complex

Question 26

RNA processing

Answer 26

Modification of RNA primary transcripts, including the splicing out of introns, joining together of exons, and alteration of the 5 and 3 ends

Question 27

5’ Cap

Answer 27

A modified form of guanine nucleotides added onto the 5’end of a pre-mRNA molecule

Question 28

Poly-A tail

Answer 28

A sequence of 50-250 adenine added onto the 3’ end of a pre-mRNA molecule

Question 29

RNA splicing

Answer 29

After synthesis of eukaryotic primary RNA transcript, the removal of portions of transcript, introns, that will not be included in the mRNA and the joining together of the remaining portions, exons.

Question 30

Introns

Answer 30

A non coding, intervening sequence within a primary transcript that is removed from the transcript during RNA processing; also refers to the region of DNA from which this sequence was transcribed

Question 31

Exons

Answer 31

A sequence within a primary transcript that remains in the RNA after RNA processing; also refers to the region of DNA from this sequence was transcribed

Question 32

Spliceosome

Answer 32

A large complex made up of proteins and RNA molecules that splices RNA by interacting with the ends of an RNA intron, releasing the intron and joining the two adjacent exons

Question 33

Ribozyme

Answer 33

An RNA molecule that functions as an enzyme, such as an intron that catalyzes its own removal during RNA splicing

Question 34

Alternative RNA splicing

Answer 34

A type of eukaryotic gene regulation at the RNA-processing level in which different mRNA molecules are produced from the same primary transcript, depending on which RNA segments are treated as exons and which as introns

Question 35

Domains

Answer 35

A discrete structural and functional region of a protein

Question 36

Mutations

Answer 36

A change in the nucleotide sequence of an organism’s DNA or in the DNA or RNA of a virus

Question 37

Point Mutation

Answer 37

A change in a single nucleotide pair of a gene

Question 38

Nucleotide-pair substitution

Answer 38

A type of point mutation in which one nucleotide in a DNA strand and its partner in the complementary strand are replaced by another pair of nucleotides

Question 39

Silent mutation

Answer 39

A nucleotide pair substitution that has no observable effect on the phenotype

For example, Within a gene a mutation that results in a codon that codes for the same amino acid

Question 40

Missense mutation

Answer 40

A nucleotide pair substitution that results in a codon that codes for a different amino acid

Question 41

Nonsense mutation

Answer 41

A mutation that changes an amino acid codon to one of the three stop codons, resulting in a shorter and usually nonfunctional protein

Question 42

Insertions

Answer 42

A mutation involving the addition of one or more nucleotide pairs to a gene

Question 43

Deletion

Answer 43

A mutational loss of one or more nucleotide pairs from a gene

Question 44

Frame shift mutation

Answer 44

A mutation occurring when nucleotides are inserted in or deleted from a gene and the number inserted or deleted is not a multiple of three, resulting in the improper grouping of the subsequent nucleotides into codons.

Question 45

Mutagens

Answer 45

A chemical or physical agent that interacts with DNA and can cause a mutation

Question 46

Polyribosome

Answer 46

A group of several ribosomes attached to, and translating the same messenger RNA molecule.