DNA translation

Question 1

The reason there are 64 possible codons

Answer 1

Codons are three letter genetic words: and the language of genes use 4 letters (=nitrogenous bases). hence there is only 64 possible combination of 4 bases to form different codons. Hence 64 words are there in genetic dictionary. And only 61 code for amino acid.

Question 2

how do 64 codons code for 20 amino acid only?

Answer 2

1. low of degeneracy. more than one codons can code for same amino acid.

Question 3

role of Mg2+ in translation, transcription and replication

Answer 3

1. in translation Mg2+ ions are essential for both structure and function of the ribosome.
2. in transcription Magnesium is an essential cofactor for the synthesis and salvage of purine and pyrimidine nucleotides.
3. in replication, DNA polymerases catalyze the incorporation of deoxynucleoside triphosphates into a growing DNA chain using a pair of Mg2+ ions,

Question 4

The concentration of mRNA in the cell is necessarily proportional to its rate of transcription

Answer 4

folse

Question 5

technique used to identify specific DNA sequence in the bacteria colonies in ……………………..

Answer 5

colony hybridization

Question 6

what is colony hybridization ?

Answer 6

Colony hybridization is a method of selecting bacterial colonies with desired genes through a straightforward cloning and transfer process

Question 7

what is in situ hybridization?

Answer 7

a technique that allows for precise localization of a specific segment of nucleic acid within a histologic section

Question 8

the technique used to locate specific gene in chromosome is? a. colony hybridization b. in situ hybridization c. dot blot technique d. western blotting

Answer 8

b

Question 9

what is The lactose operon (also known as the lac operon)

Answer 9

is a set of genes that are specific for uptake and metabolism of lactose and is found in E. coli and other bacteria.

Question 10

which of the following statements are true regarding lac operon? a. the repressor binds to promoter element b. lac operon is subjected to catabolite repression. C. the promoter element is not essential for operon transcription d. lacZ, lac Y, lac A gene products are synthesized at low levels in the in induced state

Answer 10

b

Question 11

deletion mutation would cause frameshift mutations. In which of the following would their effect be the most? a. during DNA replication b. during transcription c. during translation d. during RNA processing

Answer 11

c

Question 12

All of the following processes involve hydrogen bonding except: A. DNA replication B. Formation of ice crystals C. Binding of enzyme and substrate D. Protein folding E. All of the above

Answer 12

e

Question 13

An amphipathic molecule is a molecule that has [a] 2 different forms that are mirror images of each other [b] An amino group [c] A hydrophilic end and a hydrophobic end [d] A positively charged end and a negatively charged end

Answer 13

c