Nuclei Acid Part 2

Question 1

What are the three steps during Translation(Codon) and Transcription

Answer 1

1. initiation
2. Elongation
3. Termination
4. Processing (Transcription)

Question 2

What happens during Translation in Initiation ?

Answer 2

Initiation :
Small subunits bind to the AUG start codon of the mRNA.

2. A specific initiation (tRNA) carrying a methionine bind to the AUG start codon.
3. Large subunits of a ribosome binds to this complex in which the tRNA occupying the P site

Question 3

What happens during Elongation ? Translation

Answer 3

1. A tRNA with the complementary anti codon bonds to the mRNA occupying the A site in the ribosome A bond between the two forms a peptide bond.
2. A ribosome moves one codon further away long the mRNAA translocation in the 5”3 direction A-P site .
3. Empty tRNA moves from the P site to the E site
4. A site is empty ready for another tRNA.
5. tRNA is released from the E site

Question 4

What happens during Termination ? Translation

Answer 4

1. Ribsome reaches the stop codon (UAG, UAA and UGA )
2. Polypeptide is realised from the ribosome.
3. tRNA is released from the ribosome .

Question 5

What is the Translation process summary ?

Answer 5

mRNA used as a template to assemble a series of amino acids to produce polypeptide with a specific amino acid sequence.

Question 6

What is Transcription in summary >

Answer 6

Process of RNA synthesis ,controlled by the interaction of promoters and enhancers.

Question 7

What happens during the Trancription in Initation ?

Answer 7

1. DNA molecule unwinds , seperates to form a small open complex.RNA polymerase binds to the promoter.

Question 8

What happens in in Elongation (Transcription)?

Answer 8

RNA polymerase move along the template strand 5-3 synthesis on mRNA molecule

In Eukaryotes, there are three RNA polymerase 1, 2, 3,
including proofing mechanism PRE mRNA is spliced and modified to produce mRNA which moves from the nucleus to the cytoplasm.

Using the ribonucleoside triphosptes .They synthesis complementary in 5-3 direction .

Newly synthesis mRNA detaches after transcription behind transcription , the DNA helix resembles.

Question 9

What happens in Termination (Transcription )?

Answer 9

RNA polymerase reaches the terminator sequence , transcription stops messenger rNA mRna is realised as a results

Polymerase detaches from the DNA.

Question 10

What happens during processing in Transcription ?

Answer 10

The rNA molecule is processed in a number of ways .
Introns are removed ,
Exons are spliced together to form a mature mRNA moleules consisting of a single proteins
Thymine is replaced with Uracil.

Question 11

How is Protein formed in Translation ?

Answer 11

In the process of translation, a cell reads information from a molecule called a messenger RNA (mRNA) and uses this information to build a protein.

Question 12

What is the role of the RNA polymerase ?

Answer 12

The rNA polymerase is used to create a sequence that will become messenger .
RNA polymerase are enzymes which transcribe DNA into RNA .

Using a DNA template, RNA polymerase builds a new RNA molecule through base pairing .

If there is a G in the DNA template , the Rna polymerase will add a C to the new growing RNA strand.

RNA polymerase always builds a new RNA strand in the 5’ to 3’ direction. That is, it can only add RNA nucleotides (A, U, C, or G) to the 3’ end of the strand.

Question 13

What do we mean by the 5 to 3 ?

Answer 13

The two ends of a strand of DNA or RNA strand are different from each other. That is, a DNA or RNA strand has directionality.

At the 5’ end of the chain, the phosphate group of the first nucleotide in the chain sticks out. The phosphate group is attached to the 5’ carbon of the sugar ring, which is why this is called the 5’ end.

At the other end, called the 3’ end, the hydroxyl of the last nucleotide added to the chain is exposed. The hydroxyl group is attached to the 3’ carbon of the sugar ring, which is why this is called the 3’ end.

Question 14

How do you know which direction the DNA 5-3 strand ?

Answer 14

During Transcription, the mRNA sequence will regularly be the same as the coding strand when both are read in the 5′ to 3′ direction.

However, it is important to note that the mRNA sequence will be shorter since introns will be spliced out by snRNPs to leave only the coding exons

. The same is also true for the polypeptide sequence generated from the mRNA. Its amino acids will be arranged in the same order as the codons (tri-nucleotides) of the mRNA also in the 5′ to 3′ direction.

Question 15

What do Purines and pyrimidines serve as ?

Answer 15

Purines and pyrimidines serve as a basis for the building blocks of DNA and RNA.

Question 16

What type of strand does bacteria have ?

Answer 16

Bacteria has a single type of RNA polymerase that synthesises not only the mRNA but other types of RNA that function in protein synthesis such as RNA

Question 17

How many strands of RNA does eukaryotes have ?

Answer 17

They have three types
Pre-Mrna which is known as RNA polymerase 11
Other transcribes RNA molecules that are not translated into proteins

Question 18

What happens in a Eukaryotic Promoter due to the initiation of transcription

Answer 18

A TATA box including nucleotide sequence about 25 nucleotides upstream from the transcriptional start point.

Several Transcription factors one recognising the TATA box binds to the DNA before the RNA polymerase 11 can bind.

Additional factors bind to the the DNA along with the RNA polymerase 11 forming an transcription unutiation .

The RNA polymerase 11 unwinds the DNA double helix and RNA synthesis begins at the start point on the template strand.

Question 19

What happens during RNA processing ?

Answer 19

RNA splicing occurs where large portion of RNA molecules are removed .Leaving the others to reconnect

Pre -mRNA is spliced because the removal of introns is accomplished by large complex of proteins and small RNAs called spliceosome .

The introns are realised.

RNA splicing can occur without protein or additional mRNA .

RNA Splicing is one reason why human get along with the same gene as round worms.

The benefit of RNA splicing is that one gene can produce many different proteins as a result of what segments are treated as introns and exons.

Question 20

Why do some RNA function as enzymes ?

Answer 20

RNA is single stranded
Contain functional groups that participate
the ability for RNA to hydrogen to bond with other nuclei acids .

Question 21

What is one important thing in the presence of introns ?

Answer 21

That a single gene can encode for more than one kind of polypeptide .

Question 22

What is translation the synthesis of ?

Answer 22

Is the synthesis of polypeptide whose amino acid sequence is specified by the mRNA.

Move through the A, E site and P site .

Question 23

What is the ribosome made of ?

Answer 23

rNAS and proteins which facilitate this coupling with binding sites for mRNA and tRNA

Question 24

What is Primary Transcript ?

Answer 24

the single-stranded ribonucleic acid product synthesized by transcription of DNA, and processed to yield various mature RNA products such as mRNAs, tRNAs, and rRNAs.

The primary transcripts designated to be mRNAs are modified in preparation for translation

The primary transcript of mRNA is then processed to remove the introns and join the remaining exons together. A mature transcript of mRNA is formed.

Question 25

When does the amino acid activation occur ?

Answer 25

after its been spliced

Each amino acid attached to tRNA with the help of specific enzyme and ATP

Question 26

Difference between the Prokaryotes and Eukaryotes in translation/transcription ?

Answer 26

Transcription and Translation in Cells.

In a prokaryotic cell, transcription and translation are coupled; that is, translation begins while the mRNA is still being synthesized.

In a eukaryotic cell, transcription occurs in the nucleus, and translation occurs in the cytoplasm.