To form a nucleoside, a nitrogenous base is linked to a pentose sugar:

(1) Through a P-Glycosidic linkage at carbon atom number 1

(2) Through a P-Glycosidic linkage at carbon atom number 5

(3) Through a N-Glycosidic linkage at carbon atom number 1

(4) Through a N-Glycosidic linkage at carbon atom number 5

 

Identify the incorrectly matched pair:

The amino acid acceptor arm of the tRNA is at its:

(1) DHU loop

(2) TψC loop

(3) 5' end

(4) 3' end

Which of the following codons has a dual role in the genetic code?

(1) AUG

(2) GUG

(3) CUG

(4) UUG

What is the major difference between the lagging and leading strands during DNA replication ?

1. On the leading strand, DNA synthesis occurs from 5' to 3', while DNA synthesis occurs from 3' to 5' on the lagging strand.

2. DNA polymerase is able to continuously add new nucleotides on the leading strand while it must keep 'starting over' on the lagging strand.

3. The lagging strand requires only a single primer while the leading strand requires many.

4. Helicase opens the leading stran at a faster rate than the lagging strand.

The inducer of lac operon is :

1. Beta galactosidase

2. Galactose

3. Lactose

4. Glucose

regulatory domains of most activators interact with

1. the transcription factor complex

2. RNA polymerase

3. repressors

4. the DNA binding domain

DNA chemically is less reactive and structurally more stable than RNA. Therefore,

1. DNA has evolved from the RNA

2. RNA can directly code for proteins

3. DNA is the better genetic material than RNA

4. The protein synthesizing machinery has evolved around RNA

A transcription unit does not contain:

1. A promoter

2. The structural gene

3. A terminator

4. An operator

Regulation of lac operon by repressor is referred to as:

1. Inducible regulation

2. Repressible regulation

3. Negative regulation

4. Positive regulation