Draw the structure of the following amino acids, dipeptides, and tripeptides at low pH (pH 1) and high pH (pH 14). At each pH, assume that all functional groups that might do so are ionized.
a. Val

검증된 단계별 안내

Step 1: Understand the structure of valine (Val). Valine is an amino acid with the following structure: an amino group (-NH₂), a carboxyl group (-COOH), and a side chain (R group) that is isopropyl (-CH(CH₃)₂). At neutral pH, the amino group is protonated (-NH₃⁺), and the carboxyl group is deprotonated (-COO⁻).

Step 2: Analyze the behavior of valine at low pH (pH 1). At low pH, the environment is highly acidic, so all ionizable groups will be protonated. The amino group will remain as -NH₃⁺, and the carboxyl group will be protonated to -COOH. The side chain of valine does not ionize, so it remains unchanged.

Step 3: Draw the structure of valine at low pH. Represent the amino group as -NH₃⁺, the carboxyl group as -COOH, and the side chain as -CH(CH₃)₂. Ensure the correct connectivity of the groups to the central carbon (α-carbon).

Step 4: Analyze the behavior of valine at high pH (pH 14). At high pH, the environment is highly basic, so all ionizable groups will lose protons. The amino group will deprotonate to -NH₂, and the carboxyl group will remain deprotonated as -COO⁻. The side chain of valine does not ionize, so it remains unchanged.

Step 5: Draw the structure of valine at high pH. Represent the amino group as -NH₂, the carboxyl group as -COO⁻, and the side chain as -CH(CH₃)₂. Again, ensure the correct connectivity of the groups to the central carbon (α-carbon).

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Amino Acid Structure

Amino acids are organic compounds that serve as the building blocks of proteins. Each amino acid consists of a central carbon atom, an amino group (–NH2), a carboxyl group (–COOH), a hydrogen atom, and a variable R group that determines the specific properties of the amino acid. Understanding the structure of amino acids is crucial for analyzing their behavior at different pH levels.

Ionization at Different pH Levels

The ionization state of amino acids and peptides changes with pH due to the protonation and deprotonation of functional groups. At low pH (acidic conditions), amino groups are typically protonated, while carboxyl groups are also protonated, leading to a positively charged species. Conversely, at high pH (basic conditions), carboxyl groups lose protons and become negatively charged, while amino groups may become neutral, affecting the overall charge and structure of the molecule.

Peptide Bond Formation

Peptide bonds are covalent bonds that link amino acids together to form dipeptides and tripeptides. This bond forms through a condensation reaction, where the carboxyl group of one amino acid reacts with the amino group of another, releasing a molecule of water. Understanding peptide bond formation is essential for drawing the structures of dipeptides and tripeptides, especially when considering their ionization states at varying pH levels.

Draw the structure of the following amino acids, dipeptides, and tripeptides at low pH (pH 1) and high pH (pH 14). At each pH, assume that all functional groups that might do so are ionized.a. Val