RNA Structure, Transcription And Translation

Question 1

What differentiates a heart cell from a liver cell or any other cell?

Answer 1

Gene expression

Question 2

Every somatic cell in the body has the same genetic information. True or false?

Answer 2

True

Question 3

How do cells use genetic information?

Answer 3

Cells use the same genetic information in different ways to have different shapes and functions

Question 4

What is transcription?

Answer 4

This is the process of copying one strand of dna into rna

Question 5

Where does transcription occur?

Answer 5

In the nucleus

Question 6

During what phase of cell division does transcription occur mostly?

Answer 6

Interphase

Question 7

What are the three major ways in which rna differs from dna?

Answer 7

RNA has ribose as sugar
Uracil replaces thymine as a base in rna
Rna is single stranded in structure

Question 8

In what structure can rna fold and bind onto itself taking on double stranded characteristics?

Answer 8

Secondary structure

Question 9

What structure is important for rna integrity and function?

Answer 9

Secondary structure.

Question 10

(Messenger) MRNA comes about as a result of?

Answer 10

Transcription.

Question 11

What is mRNA?

Answer 11

It is messenger rna, a template for translation of protein

Question 12

What RNA type is part of the ribosomal complex?

Answer 12

rRNA

Question 13

What is rRNA?

Answer 13

It is RNA that controls recognition between mRNA codon and tRNA anticodon during translation

Question 14

This RNA’s function is to control recognition between codon of mRNA and anticodon of tRNA

Answer 14

rRNA

Question 15

What is tRNA’s structure?

Answer 15

tRNAhas a cloverleaf secondary structure

Question 16

What is the function of tRNA?

Answer 16

It carries amino acid to correct location on mRNA template to form protein

Question 17

This RNA carries amino acid to correct location on mRNA template to form a protein

Answer 17

tRNA

Question 18

In what direction does transcription occur?

Answer 18

5’ - 3’

Question 19

What is the term given to RNA synthesis?

Answer 19

Transcription

Question 20

What is RNA polymerase?

Answer 20

This is the enzyme that catalyzes RNA synthesis

Question 21

What are the things required for RNA synthesis? (Transcription)

Answer 21

RNA polymerase
DNA template (anti-sense strand)
Ribonucleoside triphosphates
Transcription factors

Question 22

What is DNA template?

Answer 22

Antisense of DNA

Question 23

What is the sense strand?

Answer 23

The DNA coding strand

Question 24

In terms of what is DNA sequence always written?

Answer 24

In terms of sense strand (5’ - 3’)

Question 25

Why is the sense strand also called the coding strand?

Answer 25

Because you can predict the amino acid sequence directly from it

Question 26

What is the mRNA sequence?

Answer 26

It is the same sequence as the DNA sense strand except thymine replaced with uracil

Question 27

What is the antisense strand?

Answer 27

It is the strand that is complementary and antiparallel to the sense strand (3’ - 5’), which serves as the template for mRNA synthesis

Question 28

What is another name for the antisense strand?

Answer 28

Template strand

Question 29

This strand serves as the template for mRNA synthesis.

Answer 29

Antisense strand

Question 30

What is the upstream and downstream part of a sequence?

Answer 30

5’ and 3’ end respectively in reference to a sense strand

Question 31

What is the transcription start site designated?

Answer 31

+1

Question 32

What numbers are the bases upstream given?

Answer 32

Negative numbers

Question 33

What are the three phases of transcription?

Answer 33

Initiation Elongation Termination

Question 34

What us found upstream of the coding region of a gene?

Answer 34

A promoter region

Question 35

What are promoters?

Answer 35

They’re short consensus sequences

Question 36

List the DNA sequences collectively known as promoters?

Answer 36

``` TATA box (TATAA) -30 to -100 GC box (GGGCGG) -40 to -150 CAAT box (CCAAT) -40 to -150 ```

Question 37

What do transcription factors bind to in order to initiate transcription?

Answer 37

Promoters

Question 38

How do promoters help in initiating transcription?

Answer 38

Through binding with transcription factors (proteins)

Question 39

What other sequence elements can direct transcription?

Answer 39

Enhancers Silencers Hormone response elements

Question 40

What initiates transcription?

Answer 40

The binding of RNA polymerase and transcription factors to promoters

Question 41

What happens after initiation?

Answer 41

Elongation

Question 42

What happens during elongation?

Answer 42

RNA polymerase moves along the DNA and incorporates rNTPs in the growing RNA chain in the 5’ to 3’ direction

Question 43

What happens in transcription termination?

Answer 43

Transcription of the growing RNA chain continues in the 5’ to 3’direction until RNA polymerase recognizes a sequence signal that signals the end

Question 44

What is the termination sequence?

Answer 44

AAUAAA

Question 45

Where is the termination signal located?

Answer 45

In the 3’ UTR (untranslated region) of the gene

Question 46

What happens after RN polymerase recognizes the termination sequence AAUAAA in the 3’ UTR?

Answer 46

The immature mRNA goes through processing

Question 47

What are the three steps of mRNA processing?

Answer 47

Capping Polyadenylation RNA splicing

Question 48

For what reasons is the 5’ end of the growing primary transcript capped?

Answer 48

For functional and protective reasons

Question 49

What ends are joined during capping of mRNA?

Answer 49

7-methylguanine is joined to the 5’ nucleotide

Question 50

Termination of transcription upon the recognition of the sequence AAUAAAresukts in what?

Answer 50

In the cleavage of the 3’ end of the primary transcript

Question 51

What is then added on the 3’ end after cleavage?

Answer 51

The enzyme poly(A)polymerase adds a repeated sequence of Aden,ate (A) residues on the 3’ end

Question 52

What purpose does the repeated sequence of adenylate (A) residues added by the poly(A)polymerase on the 3’ end serve?

Answer 52

To protect the mRNA and designate it as mature mRNA which can be recognized by ribosomes for translation

Question 53

What two areas are found on DNA?

Answer 53

Exxon’s and introns

Question 54

The coding region of most eukaryotic genes contains what two regions?

Answer 54

Translated and untranslated regions

Question 55

What are introns?

Answer 55

These are regions that interrupt the coding sequence, do not code for protein, and are not part of the mature mRNA

Question 56

What are Exons?

Answer 56

Exons include the coding sequence (open reading frame) and some untranslated, regulatory regions (UTR)

Question 57

This part of DNA interrupts coding sequence, does not code for protein and is not part of a mature mRNA.

Answer 57

Intrins

Question 58

This part of DNA includes the coding sequence and some untranslated regulatory regions

Answer 58

Exons

Question 59

What is RNA splicing?

Answer 59

Thus us a series of reactions where the intron sequences are snipped out and the exon sequences are joined from end-to-end (spliced)

Question 60

What is the term given to removal of introns?

Answer 60

Splicing

Question 61

What designates the intron-exon boundaries?

Answer 61

Some conserved sequences

Question 62

Where does splicing out occur?

Answer 62

In the spliceosome

Question 63

What is the spliceosome?

Answer 63

Thus is a unit of proteins and small nuclear RNA where splicing occurs

Question 64

What is alternative splicing?

Answer 64

This is when one gene results in several different proteins because of different Exon combinations that resulted after splicing

Question 65

List the things found on a mature mRNA after splicing.

Answer 65

5’ cap Exons joined Poly(A) train on 3’ end

Question 66

What two exons are not translated?

Answer 66

5’ UTR | 3’ UTR

Question 67

What happens to the mature mRNA when transcription terminates?

Answer 67

It is exported out of the nucleus into the cytoplasm in preparation for translation.

Question 68

What is translation?

Answer 68

This is the conversion of mRNA message into protein

Question 69

Where does translation take place?

Answer 69

On ribosomes

Question 70

What serves as an adaptor molecule for converting the mRNA message into an amino acid (protein) sequence?

Answer 70

tRNA

Question 71

All the information necessary to synthesize a cell’s protein is contained in?

Answer 71

The DNA

Question 72

What is protein made of?

Answer 72

A series of amino acids

Question 73

How many bases and amino acids are there?

Answer 73

There are only 4 bases but 20 amino acids

Question 74

A sequence of how many bases is used during translation?

Answer 74

A sequence of 3 bases

Question 75

How many combinations of triplicate bases are possible?

Answer 75

64 possible combinations

Question 76

What is the codon?

Answer 76

This is the triplicate of bases

Question 77

What us the term given to the the triplicate of bases formed for translation?

Answer 77

Codon

Question 78

Each codon specifies what two things?

Answer 78

Either an amino acid or a stop signal

Question 79

How many codons are designated in an amino acid?

Answer 79

Most amino acids are designated by more than one codon

Question 80

How is a protein’s primary sequence read on the mRNA?

Answer 80

5’ to 3’

Question 81

What is the size of a tRNA?

Answer 81

They’re small molecules of about 70-95 nt

Question 82

What does one loop of a tRNA contain?

Answer 82

Anticodon which is complement to the codon on the mRNA

Question 83

What does the other end of a tRNA contain?

Answer 83

A CCA sequence which binds and carries the appropriate amino acids

Question 84

Where does translation occur in eukaryotes?

Answer 84

In the cytoplasm on the ribosomes

Question 85

What are ribosomes?

Answer 85

They’re complexes of proteins and RNA

Question 86

How many ribosomal proteins are found in the Large 60Ssubunit?

Answer 86

~50 ribosomal proteins

Question 87

How many ribosomal proteins are found in the Smaller 40S subunit?

Answer 87

~30 ribosomal proteins

Question 88

How does translation start?

Answer 88

Special proteins recognize the 5’ cap and poly-A tail of mRNA so they recruit ribosomal subunits

Question 89

What happens after special proteins recognize the 5’ cap and poly(A) tail of the mRNA?

Answer 89

Pre-initiation complex scans for AUG start codon

Question 90

What us the AUG start codon?

Answer 90

Methionine

Question 91

Describe the structure of the ribosome.

Answer 91

The ribosome has 2 functional sites; the P-site (peptidyl) and A-site (aminoacyl), and a third E-site (exit)

Question 92

Pre initiation complex scans for what in the mRNA?

Answer 92

AUG start codon (methionine)

Question 93

What happens during elongation and termination in translation?

Answer 93

Peptide bond is formed between adjacent amino acids, process which continues until stop codon is reached, and release factors detach polypeptide from tRNA, and ribosome disassembles.