Biology: Polypeptides and Proteins

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What is the structure of haemoglobin according to the text?

Haemoglobin consists of two polypeptides of two different kinds

Haemoglobin consists of four polypeptides of the same kind

Haemoglobin consists of two polypeptides of the same kind

Haemoglobin consists of four polypeptides of two different kinds (correct)

What is the preferred method of amino acid composition analysis for proteins according to the text?

Alkaline hydrolysis

Acid hydrolysis at 110°C for 72 hours

Acid hydrolysis at 110°C for 24 hours (correct)

Acid hydrolysis at 110°C for 48 hours

Which amino acid is destroyed by acid hydrolysis and must be estimated by other means?

Threonine

Serine

Tryptophan (correct)

Arginine

What is the purpose of performing acid hydrolysis of proteins at different time points (24, 48, and 72 hours)?

To ensure complete hydrolysis of the peptide bonds Signup and view all the answers

Which of the following amino acids are less destroyed by acid hydrolysis compared to alkaline treatment?

Serine, Threonine, Arginine, and Cysteine Signup and view all the answers

What is the term used for peptide chains with more than 12 but less than 20 residues?

Oligopeptides Signup and view all the answers

How is the term 'polypeptide' used in discussing single polypeptide chains?

Interchangeably with protein Signup and view all the answers

What type of proteins have more than one kind of polypeptide chains?

Heteromultimeric Signup and view all the answers

How are multimeric proteins denoted in terms of composition?

By Greek letters and subscripts Signup and view all the answers

What does an 'α2-type protein' indicate?

Homodimeric structure Signup and view all the answers

Which of the following enzymes is considered relatively nonspecific in cleaving peptide bonds?

Pepsin Signup and view all the answers

Which enzyme is highly specific and cleaves at methionine residues?

Cyanogen bromide Signup and view all the answers

Which enzyme cleaves at arginine residues?

Clostripain Signup and view all the answers

Which of the following enzymes is specific for cleaving at lysine residues?

Endopeptidase Lys-C Signup and view all the answers

Which enzyme cleaves at aspartic acid and glutamic acid residues?

Staphylococcal protease Signup and view all the answers

Which of the following enzymes is found in papaya and causes the hydrolysis of gelatin?

Papain Signup and view all the answers

Which of the following statements is true about the challenges of synthesizing a specific peptide?

All of the above. Signup and view all the answers

What is the purpose of blocking groups in peptide synthesis?

To protect functional groups not involved in the current coupling reaction. Signup and view all the answers

What is a requirement for the blocking groups used in peptide synthesis?

They must be removable under conditions where the newly formed peptide bonds are stable. Signup and view all the answers

What does the text imply about the process of adding each amino acid during peptide synthesis?

It requires several steps involving blocking and deblocking of functional groups. Signup and view all the answers

Which of the following statements is NOT mentioned in the text?

Peptide synthesis can be carried out without any special considerations. Signup and view all the answers

Which of the following is a structural protein that forms inelastic fibrils?

Collagen Signup and view all the answers

What type of proteins are α-Keratins?

Insoluble fibrous proteins Signup and view all the answers

Which of the following is an essential component of ligaments?

Elastin Signup and view all the answers

What type of modules in scaffold proteins bind to proteins with tyrosine residues phosphorylated on its phenolic –OH?

SH2 modules Signup and view all the answers

Which of the following proteins are produced by the lymphocytes of vertebrates?

Immunoglobulins or antibodies Signup and view all the answers

What is the purpose of antifreeze proteins in Arctic and Antarctic fishes?

To protect their blood against freezing in below-zero temperatures Signup and view all the answers

Which of the following is an example of an exploitive protein?

Ricin Signup and view all the answers

What is the function of resilin?

To have exceptional elastic properties Signup and view all the answers

Which of the following proteins is considered an artificial sweetener for human consumption?

Monellin Signup and view all the answers

What type of proteins do certain marine organisms, such as mussels, secrete?

Glue proteins Signup and view all the answers