A. They are substituted methanes.
B. Serine is an aromatic amino acid.
C. Valine is a neutral amino acid.
D. Lysine is an acidic amino acid.
Choose the correct answer from the options given below :
Amino Acids: Statement Analysis
Let's evaluate each statement regarding amino acids:
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Statement A: They are substituted methanes.
Amino acids possess a central alpha-carbon atom bonded to an amino group ($-NH_2$), a carboxyl group ($-COOH$), a hydrogen atom ($-H$), and a variable side chain (R-group). Methane is $CH_4$. By replacing hydrogen atoms on methane with these functional groups, we obtain the basic amino acid structure. Therefore, amino acids are indeed substituted methanes. This statement is correct.
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Statement B: Serine is an aromatic amino acid.
Aromatic amino acids contain a ring structure in their side chain (e.g., Phenylalanine, Tyrosine). Serine's side chain is $-CH_2OH$, which contains a hydroxyl group, not an aromatic ring. Thus, Serine is an alcohol-containing amino acid, not an aromatic one. This statement is incorrect.
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Statement C: Valine is a neutral amino acid.
Valine has an isopropyl side chain ($-CH(CH_3)_2$). This is a nonpolar alkyl group, meaning it does not carry a charge at physiological pH. Amino acids with such side chains are classified as neutral. This statement is correct.
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Statement D: Lysine is an acidic amino acid.
Acidic amino acids have carboxyl groups in their side chains (e.g., Aspartic acid, Glutamic acid), resulting in a negative charge. Lysine has an additional amino group ($-NH_2$) in its side chain, making it positively charged and classifying it as a basic amino acid. This statement is incorrect.
Conclusion on Correct Statements
Based on the analysis, statements A and C are correct.
The correct option is the one that includes only A and C.
Correct Option: 2. A and C only
Similar Questions
- Match List I with List II :
List I List II A. Trypsin I. Intercellular ground substance B. Morphine II. Lectin C. Concanavalin A III. Enzyme D. Collagen IV. Alkaloid
Choose the correct answer from the options given below : - Identify the correct statements about biomolecules.
A. Lipids are generally water soluble.
B. Proteins are polypeptides.
C. Polysaccharides are long chains of sugars.
D. Adenine and guanine are substituted pyrimidines.
E. Almost all enzymes are proteins.
Choose the correct answer from the options given below : - Alpha-helix is found in which level of protein structure ?
Non-membrane bound cell organelles found in both prokaryotic and eukaryotic cells are : ____________________
- Match List I with List II :
List I (Phase of cell cycle) List II (Activity) A. $G_1$ phase I. Actual cell division occurs B. S phase II. Cell is metabolically active and continuously grows but does not replicate its DNA C. $G_2$ phase III. Synthesis of DNA occurs and the amount of DNA per cell doubles D. M phase IV. Proteins are synthesized while cell growth continues
Choose the correct answer from the options given below : - Select the correct statements regarding cell membrane in eukaryotic cell.
A. Membrane of human RBCs has approximately 52% protein.
B. The phospholipids are arranged in a bilayer.
C. Extensions of the plasma membrane into the cell form mesosomes.
D. Tails towards the inner part of lipids are hydrophobic and thus protected from aqueous medium.
E. Glycocalyx is present on the outer surface of the plasma membrane.
Choose the correct answer from the options given below : - Choose the correct statements regarding cell organelles and their inclusions.
A. The endomembrane system includes Golgi complex, endoplasmic reticulum and mitochondria.
B. Rough endoplasmic reticulum bears ribosomes on its surface.
C. Both mitochondria and plastids have circular DNA.
D. A network of microtubules, microfilaments and intermediate filaments present in the cytoplasm is called cytoskeleton.
E. Mitochondrion is a single membrane-bound structure.
Choose the correct answer from the options given below : - The following reaction depicts the activity of a particular class of enzymes :
$$ \begin{array}{cc} \text{X} & \text{Y} \\ | & | \\ \text{C} - & \text{C} \end{array} \xrightarrow{E} \text{X} - \text{Y} + \text{C} = \text{C} $$
(Substrate) $\quad$ (Product) (Product)
Identify the enzyme class 'E' from the following options :
Important Questions from Structure and Function of Cell
- Match List I with List II :
List I List II A. Trypsin I. Intercellular ground substance B. Morphine II. Lectin C. Concanavalin A III. Enzyme D. Collagen IV. Alkaloid
Choose the correct answer from the options given below : - Identify the correct statements about biomolecules.
A. Lipids are generally water soluble.
B. Proteins are polypeptides.
C. Polysaccharides are long chains of sugars.
D. Adenine and guanine are substituted pyrimidines.
E. Almost all enzymes are proteins.
Choose the correct answer from the options given below : - Alpha-helix is found in which level of protein structure ?
Non-membrane bound cell organelles found in both prokaryotic and eukaryotic cells are : ____________________
- Match List I with List II :
List I (Phase of cell cycle) List II (Activity) A. $G_1$ phase I. Actual cell division occurs B. S phase II. Cell is metabolically active and continuously grows but does not replicate its DNA C. $G_2$ phase III. Synthesis of DNA occurs and the amount of DNA per cell doubles D. M phase IV. Proteins are synthesized while cell growth continues
Choose the correct answer from the options given below :
