MCQsOnline - Online Collection of MCQs of Medical PG Entrance Exams.

MCQ stands for Multiple Choice Questions sometimes called as Objective type questions. Here we discuss the Old Question Papers, High Yield Points and Strategies with respect to the Indian Medical Post Graduate PG Entrance Exams like AIIMS,AIPG, JIPMER, CMC Vellore, PGI Chandigarh, UPSC, TNPSC, State PG Exams like Tamil Nadu PG (TN PG), Delhi PG, UPPG, Tamilnadu PG (TNPG), Karnataka PG, MAHE, COMED-K etc.

Target PG

PG Preparation

Related Portals

Search This Site

If you cannot locate what you want to find, please search using the box given below

Wednesday, January 09, 2008

Valine can be a homologous substitution for isoleucine in a protein sequence

047. Which one of the following can be a homologous substitution for isoleucine in a protein sequence?

1. Methionine

2. Aspartic acid

3. Valine

4. Arginine

Answer

3. Valine

Reference:

Harper 26th Edition Page 15

Quality

Thinker

Status
Repeat

QTDF

Most books

Discussion

Homologous substitutions are those which don’t affect the function. Valine is an amino acid with aliphatic side chain and isoleucine also has aliphatic side chain

Explanation

1. Methionine is a sulphur containing aminoacid and will not be a homologous substitution for isoleucine

2. Aspartic acid has a acidic side chain and will not be a homologous substitution for isoleucine

3. Valine has aliphatic side chain and will be a homologous substitution for isoleucine

4. Arginine has a basic side chain and will not be a homologous substitution for isoleucine

Comments

Some time back we used to have questions directly from the Classification of Amino Acids such as “The basic amino acid is” All of the following has aliphatic side chains except” Now questions gyrating around the same topic are asked in an indirect way.

Tips

Hemoglobinopathies as well as classification of proteins are important topics. For an overview about the Hemoglobinopathies, refer to Q.No 30 in RxPG AIPG 2003 book

No comments:

Post a Comment