Translation and Transciption

Question 1

What does tRNA stand for and what is its purpose?

Answer 1

Transfer RNA. Its purpose is to deliver amino acids to the ribosome during protein synthesis.

Question 2

What prime end does an amino acid attach to for tRNA?

Answer 2

3 prime end

Question 3

What is the definition of an anti-codon?

Answer 3

complementary/anti-parallel sequence to a codon

Question 4

Use the coding strand to find the codons: 5’ ACTGCCCAT 3’

Answer 4

ACU GCC CAU

Question 5

Give a molecular definition for a gene

Answer 5

Functional segment of DNA coding for a heritable structure or function

Question 6

What is the function of the promoter region?

Answer 6

Initiation of transcription. Binding site for RNA polymerase. Strong promoters= a higher level of gene expression

Question 7

What is the function of the terminator region in transcription?

Answer 7

Termination of transcription. Located at the end of the gene. RNA polymerase leaves the DNA template strand.

Question 8

Explain the difference between the coding, non-coding, template, and non-template strand.

Answer 8

Coding strand= Non-template strand
Template strand= Non-coding strand

Question 9

What is the role of the template and non-template strand during transcription?

Answer 9

Coding strand- carries information to make proteins
Template- compliment to the coding strand

Question 10

Provide examples of the three characteristics of the genetic code.

Answer 10

Redundant- More than 1 codon specifies for the same amino acid

Unambiguous- A single codon never codes for more than one amino acid

Conservative- The first two bases of a codon that specify for the same amino acid are almost always the same

Question 11

What makes the genetic code universal?

Answer 11

All living organisms, alive and extinct, rely on the genetic code.

Question 12

Describe the 3 modifications in RNA processing that take place in eukaryotic cells.

Answer 12

Nucleotide Cap added to the 5 prime end of pre mRNA to protect from degradation.
Splicing (Connects Exons, Removes Introns- mature RNA)
Poly-A-Tail- added to the 3 prime ends to protect from degradation.

Question 13

Outline the first of the three stages of transcription in E.Coli and the role of RNA polymerase in this process.

Answer 13

Initiation: The promoter functions as a recognition site for the sigma factor. RNA polymerase binds to the sigma factor causing it to bind to the promoter. After binding, the DNA is unwound to form an open complex.

Question 14

Outline the second of the three stages of transcription in E.Coli and the role of RNA polymerase in this process.

Answer 14

Elongation: Sigma factor is released and the RNA polymerase slides along the DNA in an open complex to synthesize RNA.

Question 15

Outline the third of the three stages of transcription in E.Coli and the role of RNA polymerase in this process.

Answer 15

Termination: When the RNA polymerase reaches the terminator, it and the RNA transcript dissociate from the DNA

Question 16

Outline the first of the three stages of translation

Answer 16

Initiation:
1. mRNA binds to the small subunit
2. Initiator tRNA binds to the start codon
3. Large ribosomal joins the complex forming functional ribosome ready for protein synthesis

Question 17

Outline the second of the three stages of translation

Answer 17

Elongation Step One:
1. tRNA binds to the A site
2. Peptide bond forms
3. large subunit translocation
4. small unit translocation

Elongation Step Two:
1. C end of polypeptide released from tRNA of P site and joins the free group (N) of tRNA sitting in A site

Question 18

Outline the third of the three stages of translation

Answer 18

Termination: Stop codon enters the A site of the ribosome

Question 19

What is the purpose of the small subunit in bacterial ribosomes?

Answer 19

Read genetic code in mRNA

Question 20

What is the purpose of the large subunit in bacterial ribosomes?

Answer 20

Link amino acids together to make a protein

Question 21

Outline the general steps of the Central Dogma.

Answer 21

DNA->RNA->Polypeptide->Protein

Question 22

Relate the steps of the Central Dogma to gene expression

Answer 22

Gene expression starts at the polypeptide. Gene expression explains how a gene becomes a protein.

One gene= One protein.

DNA->mRNA (Transcription)
mRNA->Protein (Translation)

Question 23

How is the mRNA sequence of nucleotides “cut” into groups?

Answer 23

“Cut” into groups of 3 nucleotides each.
3 nucleotides = codons.
1 codon = 1 amino aicd

Question 24

Where are codons and anti-codons located?

Answer 24

Codons are in mRNA
Anti-codons are in tRNA

Question 25

How many codons are in use?

Answer 25

There are 64 codons, but only 61 are in use.

Question 26

How many anti- codons are in use?

Answer 26

There are 64 anti-codons, but only 54 are in use.

Question 27

What helps to make DNA into mRNA?

Answer 27

RNA polymerase

Question 28

Where and when do these steps occur in eukaryotes and prokaryotes? Step 1. DNA->mRNA Step 2. mRNA->Polypeptide

Answer 28

Eukaryotes- Steps are separated in space and time. Step 1- Nucleus Step 2- Cytosol Prokaryotes- Both steps occur the same time Step 1 and 2- cytoplasm

Question 29

What helps to make mRNA into a polypeptide?

Answer 29

tRNA and ribosomes

Question 30

Understand how to draw and label the structure of tRNA.

Answer 30

Draw it.

Question 31

Understand how to draw and label a bacterial ribosome.

Answer 31

Draw it.

Question 32

True or False: Mature mRNA has a 3’ cap, 5’ poly-a tail, and has undergone splicing.

Answer 32

False.

Question 33

Which of the following statements are false? a. The template strand is identical to the RNA strand except for uracil and thymine b. The non-coding strand is what codes for RNA using complementary base pairing c. The coding strand is identical to the RNA strand except for uracil and thymine d. The non-template strand is what codes for RNA using complementary base pairing

Answer 33

a. The template strand is identical to the RNA strand except for uracil and thymine d. The non-template strand is what codes for RNA using complementary base pairing

Question 34

Mark True or False for the following statements. ●The promoter region signals the beginning of transcription ● A gene is a segment of genetic material on DNA that determines a characteristic ● The terminator region turns a gene “on” or “off” ● The promoter region is found at the end of a gene

Answer 34

● __T__ The promoter region signals the beginning of transcription ● __T__ A gene is a segment of genetic material on DNA that determines a characteristic ● __F__ The terminator region turns a gene “on” or “off” ● __F__ The promoter region is found at the end of a gene

Question 35

Select the true statement(s). a. The transcribed region of DNA is translated to produce mRNA b. tRNA brings amino acids into RNA polymerase c. Sigma factor has to bind to DNA polymerase in order for transcription to begin d. None of the above statements are true

Answer 35

d. None of the above statements are true

Question 36

Which of the following occurs in the termination stage of transcription in E. coli? a. Sigma factor releases b. DNA polymerase, mRNA, and DNA disassociate c. The terminator region is reached by DNA polymerase d. A hairpin forms in RNA

Answer 36

d. A hairpin forms in RNA

Question 37

What is true regarding the three stages of translation? a. The stop codon codes for an amino acid b. The sigma factor is released in elongation c. tRNA enters the ribosome at the P-binding site d. tRNA exits the ribosome at the E-binding site

Answer 37

d. tRNA exits the ribosome at the E-binding site

Question 38

True or False: The template strand of DNA contains instructions to make a polypeptide.

Answer 38

False.

Question 39

Which of the following is not true regarding codon characteristics? a. Codons are redundant, meaning each codon specifies one amino acid b. Codons are unambiguous, meaning several codons can code for a single amino acid c. Codons are conservative, meaning the first two bases are the same in codons that code for the same amino acid d. Codons are redundant, meaning several codons can code for a single amino acid

Answer 39

a. Codons are redundant, meaning each codon specifies one amino acid b. Codons are unambiguous, meaning several codons can code for a single amino acid

Question 40

Which of the following mRNA strands was transcribed from DNA containing this non-template strand? 5’ ATAGCCGTA 3’

Answer 40

c. 5’ AUAGCCGUA 3’

Question 41

What holds together a polypeptide? a. Phosphodiester bonds b. Peptide bonds c. Hydrogen bonds

Answer 41

b. Peptide bonds

Question 42

True or False: Codons are a set of three nucleotide bases used to code for amino acids.

Answer 42

True

Question 43

What takes place in RNA processing? a. Capping on the 3' end b. Removal of exons c. Tailing on the 3' end d. Splicing

Answer 43

c. Tailing on the 3' end d. Splicing

Question 44

Match the components with the process(s) they are involved in. Transcription Translation RNA Modification Options: Ribosomes rRNA DNA Splicing 3’ poly-A tail RNA Polymerase mRNA RNA Modification Sigma Factor 5’ Cap Spliceosome tRNA

Answer 44

Ribosomes- translation rRNA- translation DNA- transcription Splicing- RNA modification 3’ poly-A tail- RNA modification RNA Polymerase- Transcription mRNA- Transcription RNA Modification- Translation Sigma Factor- Transription 5’ Cap- RNA modification Spliceosome- RNA modification tRNA- Translation