Chap 7- Gene Expression of Bacteria

Question 1

What does “expression” of DNA in Bacteria mean?

Answer 1

the formation of a functional product of DNA

Question 2

process where info encoded in DNA is copied into RNA

Answer 2

transcription

Question 3

complete set of genetic info in a cell/ virus

Answer 3

genome/ chromosome

Question 4

functional unit of GENOME that encodes for a product (product is typically a protein)

Answer 4

gene

Question 5

In order for cells to multiply, two things must be accomplished: ______

Answer 5

DNA replication and gene expression (transcription & translation)

Question 6

Transcribing and then translating the information in DNA to produce the encoded protein

Answer 6

gene expression

Question 7

process where info carried by mRNA is used to synthesize protein

Answer 7

translation

Question 8

enzyme that synthesizes single strand of RNA from DNA template

Answer 8

RNA Polymerase

Question 9

RNA made during transcription is _______ and __________ to its DNA template

Answer 9

complementary and antiparallel

Question 10

Minus strand of DNA is the _________ for RNA , while RNA is complementary to the ______ of DNA

Answer 10

template; plus (Thymine is replaced by Uracil)

Question 11

RNA transcript that carries one gene; mRNA molecule that carries the information for more than one gene.

Answer 11

monocistronic; polycistronic …. cistron = gene

Question 12

Nucleotide sequence where RNA polymerase binds to start transcription.

Answer 12

promoter

Question 13

DNA sequence that stops transcription

Answer 13

terminator

Question 14

RNA Polymerase can only add nucleotides to what end and synthesize RNA in what direction?

Answer 14

3prime end; 5’ to 3’

Question 15

Do RNA polymerases need primers to start working?

Answer 15

NOPE

Question 16

part of RNA polymerase that recognizes and binds to promoters

Answer 16

sigma factor

Question 17

When does transcription start?

Answer 17

Once RNA polymerase binds to a promoter

Question 18

Why is it important that a cell can produce various sigma factors?

Answer 18

The various sigma factors recognize different promoters, allowing cells to transcribe specialized sets of genes as needed

Question 19

How does RNA polymerase recognize promoters in Eukarya and archaea?

Answer 19

Transcription factors

Question 20

Orientation (position of promoter) dictates

Answer 20

direction of RNA transcription and which DNA strand will be used as template (RNA needs to be transcribed in the 5’ to 3’ direction)

Question 21

Transcription simplified (initiation, elongation, termination)

Answer 21

RNA Pol binds to promoter to start transcription –>sigma factor dips and allows RNA Pol to transcribe –> RNA synthesized in 5’ to 3’ direction, adding nucleotides to 3’ end —->Once RNA Pol reaches terminator, it falls off and releases the newly synthesized RNA strand

Question 22

process of synthesizing proteins from mRNA template (turning nucleic acids to amino acids)

Answer 22

translation

Question 23

RNA molecule that contains genetic info decoded during translation

Answer 23

mRNA

Question 24

language of mRNA is in the form of

Answer 24

codons

Question 25

series of 3 nucleotides that code for a specific amino acid

Answer 25

codon

Question 26

sequence of three nucleotides in a tRNA molecule that is complementary to a codon in mRNA.

Answer 26

anticodon

Question 27

complementary anticodon is carried by

Answer 27

tRNA

Question 28

there are _____ possible codon combos but only _____ amino acids

Answer 28

64; 20

Question 29

redundant codons that code for same amino acids

Answer 29

degenerates

Question 30

can be translated and code for Amino Acids

Answer 30

sense codons

Question 31

Translation of mRNA begins at ______ codon , which is

Answer 31

start; AUG

Question 32

Translation ends at nonsense codons aka _____ which are ; DO NOT encode for amino acid

Answer 32

stop codons; UAA, UAG, UGA

Question 33

structure where translation takes place; composed of rRNA and proteins

Answer 33

ribosome

Question 34

Roles of ribosomes in translation

Answer 34

locate sequences on mRNA molecule; maintains correct reading frame

Question 35

Role of tRNA in translation

Answer 35

delivers correct A.A , has specific anticodon to pair with specific codon, can be recycled once anticodon+A.A is delivered

Question 36

Translation Process- Initiation

Answer 36

Ribosomal subunit binds to mRNA ; initator tRNA binds to start codon (AUG)

Question 37

Translation Process- Elongation

Answer 37

tRNA enters with Amino acid, reads codon and pairs its complementary anticodon. *ribosome facilitates this pairing and moves along the mRNA as the tRNAs read for codons* tRNA then leaves and cycle is repeated while Amino Acids are held together by peptide bonds in a growing polypeptide chain

Question 38

Translation Process- Termination

Answer 38

Elongation process continues ribosome reaches STOP codons that CANNOT BE READ by tRNA; component disassembles and release newly formed polypeptide

Question 39

How is termination conducted in translation?

Answer 39

Enzymes free newly composed polypeptide chain by breaking the covalent bond with the tRNA. Ribosome falls off mRNA and splits back into 30S and 50S which can later be reused to start translation at other sites

Question 40

EPA sites (located on ribosome)

Answer 40

1st binding site (A- acceptors) accept tRNA , 2nd binding site (P-Peptide) holds tRNA, 3rd E site (E-Exit) tRNA leaves ribosome