Biology Answers

With the help of an example explain the role of cyclic AMP in carrying out signalling mediated by a cell - surface receptor .

Describe the role of each of the following in protein synthesis :

(1) Ribosome

(2) tRNA

(3) Aminoacyl - tRNA synthetase

(4) Release factor

Explain the role of antibodies in the detection of biomolecules .

Describe the process of cellular locomotion brought about by pseudopodia .

With the help of of an example , explain the control of catalytic activity by feedback regulation .

Give the schematic account of the glycolytic pathway .

Explain the role of the hormone glucagone in the regulation of the level of glycogen in mammals .

Fill in the blanks :-

1. Linking of Two biomolecules at the expense of ATP is brought about the enzymes categorised as _________ .

2. The CFo CF₁ ATPase complex, present in __________ helps in the transport of protons.

3. _________ Are the base sequences in the eukaryotic genes that are not transcribed .

4. The cytoplasmic channels that connect the neighbouring cells in higher plants are called __________ .

5. The type of blood cell that does not contain a nucleus is __________ .

Choose the correct :-

1. A cell is lysed when placed in a (hypotonic / hypertonic) solution.

2. The polynucleotide chain which contains ribose sugar is (DNA /RNA) .

3. Surface features of the specimens can be examined in detail by (SEM / TEM) .

4. Structurally , (monosaccharides / fatty acid) can exist either as an open form or ring form in a solution .

5. Cellulose is a polymer of (glucose / galactose).

180 µL of medium containing (200 µg/mL) Ampicillin were treated with 20 µL of ꞵ-lactamase enzyme to give finial concentrations ranging from 1:1 to 1:10 ratio of ampicillin to B-lactamase enzyme. The ꞵ-lactamase activity is 400 Unit/mg (Unit = 1 µmol / min hydrolysis of benzylpenicillin at pH 7 at 25C). The Ampicillin mass = 349.406 g/mol. Explain how to prepare the ꞵ-lactamase stock solution concentrations that can be used to give a final concentration ratio from 1:1 to 1:10 (ampicillin to enzyme) in the medium?