Question

Question 19 (3 points) Saved Choose all of the modifications to mRNA in eukaryotes. 5' methyl G cap splicing endonuclease 3' poly A tail exonuclease

Answer 1

Ans 19) Option (a) , (b) and (d) are correct.

Eukaryotic mRNA undergo various post transcriptional modifications so that they are exported to cytoplasm so that mRNA can synthesise protein. It includes
1. 5' capping
At the 5'end of mRNA the cap is added which is made of 7 methyl guanosine
2. Splicing
It is the process of removal of introns and joining of exons togther
3. 3' Tailing
In this the tail made of poly A tail is added to 3'end of mRNA.

Ans 21) 1. Smaller subunit of ribosome binds to mRNA.

2. Larger subunit of ribosome binds to mRNA

3. tRNA with anticodon UAC binds to mRNA codon AUG

4. A site is open

Translation is synthesizing protein from the molecule of mRNA
The process is initiated
With the recognition of start codon that is AUG is recognized and tRNA binds to it then the smaller ribosomal subunit binds to mRNA following the larger subunit which also binds to mRNA and the A site is acceptor site that will accept tRNA and is open.

Ans) Option (a) , (d) and (e) are correct.

Transcription is the process of synthesis of mRNA from DNA template by enzyme RNA polymerase
DNA is used as a template for mRNA synthesis
Nucleotides are made of 3 components
They are- 1. Pentose sugar, nitrogeneous bases and phosphate group it can be DNA and RNA thus from molecule of DNA the mRNA synthesis take place
RNA polymerase is the enzyme which will basically synthesize mRNA.

Ans) 1. Binds to calcium and activates other proteins : Calmodulin.

Calmodulin is a protein which is calcium modulated is present in cytoplasm. It serves as a regulator.

2. Stored in the smooth ER and binds to proteins to change their conformation : Calcium.

The SER present it in in the muscle cell is the storage of calcium ions.

3. Splits PIP2 into IP3 and DAG : Phospholipase kinase (PLC).

Phospholipase C is used to breakdown PIP2 and produces IP3 along with DAG. The second message is inositol triphosphate that transmits chemical signal.

4. Activity is regulated by GTP and GDP : G-protein.

G-protein are regulated by the regulators known as GTP-binding protein in different ways.

5. Activates protein kinase C and is a part of PIP2 : Diacylgylceral (DAG).

DAG activates the enzyme protein kinase C which will further phosphorylate The Other proteins.

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