Question

1. Where does translation happen? What are the differences between ribosome and ribosomal subunit of prokaryote and eukaryote?

2. What is codon? Who carry the codon and anticodon?

3. What is mutation? What are the type and causes of mutations?

4. Know everything about the gene transfer.

Answer 1

1. Translation occurs in the cytoplasm.

Eukaryotic ribosome	Eukaryotic ribosome
Larger	Smaller
80S Consists of 2 subunits, 60S and 40S.	70SConsists of 2 subunits, 50S and 30S.
The 80S ribosomes are composed of 40% RNA and 60% proteins.	The 70S ribosomes are composed of 60% RNA and 40% proteins.
The 60S subunit contains three rRNAs (28S, 5.8S and 5S) complexed with ~49 proteins	The 50S subunit contains two rRNAs (23S and 5S) complexed with ~34 proteins
The 40S subunit contains 18S rRNAs complexed with ~33 proteins.	The 30S subunit contains 16S rRNAs complexed with ~21 proteins.

2. Codon

A sequence of three nucleotides which together form a unit of genetic code in a DNA or RNA molecule.

• mRNA carries the codon.
• tRNA carries the anticodon.

3. Mutation

A mutation is an alteration in the nucleotide sequence of the genome of an organism, virus, or extrachromosomal DNA.

Types of mutation

There are three types of DNA Mutations:

• Base substitutions

1. Transition
2. Transversion
3. Point mutation (silent, missence, nonsense)

• Deletions
• Insertions

Causes of mutation

• Errors in DNA Replication
• Errors in DNA Recombination
• Chemical damage to DNA
• Radiation

4. Gene transfer

Horizontal gene transfer or lateral gene transfer is the movement of genetic material between unicellular and multicellular organisms other than by the transmission of DNA from parent to offspring. HGT is an important factor in the evolution of many organisms.

Process

• Isolation of gene and vector (by PCR)
• Digestion of gene and vector (by restriction endonuclease)
• Ligation of gene and vector (by DNA ligase)
• Selection and expression of transgenic construct.