Podcast
Questions and Answers
What type of bonds connect amino acids in a protein?
What type of bonds connect amino acids in a protein?
- Peptide bonds (correct)
- Ionic bonds
- Hydrogen bonds
- Disulfide bonds
What percentage of the dry weight of cells do proteins constitute?
What percentage of the dry weight of cells do proteins constitute?
- 30%
- 60%
- 20%
- 50% (correct)
What is unique about glycine among the 20 common amino acids?
What is unique about glycine among the 20 common amino acids?
- It is the largest amino acid
- It is the simplest amino acid (correct)
- It is an imino acid
- It is the only D-isomer
What is the term for the process by which amino acids are connected to form a protein?
What is the term for the process by which amino acids are connected to form a protein?
What type of amino acids are the most common?
What type of amino acids are the most common?
What is the meaning of the Greek word 'proteios', from which the term 'protein' is derived?
What is the meaning of the Greek word 'proteios', from which the term 'protein' is derived?
What is the characteristic feature of chiral carbon centers in amino acids?
What is the characteristic feature of chiral carbon centers in amino acids?
What is the characteristic of L-amino acids found in the body?
What is the characteristic of L-amino acids found in the body?
What type of proteins are derived from simple or conjugated proteins through physical or chemical means?
What type of proteins are derived from simple or conjugated proteins through physical or chemical means?
What is the primary difference between complete and incomplete proteins?
What is the primary difference between complete and incomplete proteins?
What is the process called when peptide bonds are broken by treatment with aqueous acid, base, or certain enzymes?
What is the process called when peptide bonds are broken by treatment with aqueous acid, base, or certain enzymes?
What is the term for proteins that lack one or more essential amino acids in correct proportion?
What is the term for proteins that lack one or more essential amino acids in correct proportion?
What is the effect of heat on protein structure?
What is the effect of heat on protein structure?
What is the purpose of combining two or more incomplete proteins?
What is the purpose of combining two or more incomplete proteins?
What is the primary structure of a protein that remains intact during denaturation?
What is the primary structure of a protein that remains intact during denaturation?
What is the effect of reducing agents on protein structure?
What is the effect of reducing agents on protein structure?
What is the primary role of the amino acid leucine in the body?
What is the primary role of the amino acid leucine in the body?
Which amino acid is involved in calcium absorption and tissue repair?
Which amino acid is involved in calcium absorption and tissue repair?
What is the term for the amino acid that is in shortest supply in relation to need?
What is the term for the amino acid that is in shortest supply in relation to need?
Which of the following amino acids has hepatoprotective properties?
Which of the following amino acids has hepatoprotective properties?
What is the primary function of proteins in the body?
What is the primary function of proteins in the body?
Which of the following foods is a rich source of the limiting amino acid lysine?
Which of the following foods is a rich source of the limiting amino acid lysine?
What is the consequence of a shortage of a limiting amino acid?
What is the consequence of a shortage of a limiting amino acid?
Which amino acid is involved in neuronal function and immunity?
Which amino acid is involved in neuronal function and immunity?
Flashcards are hidden until you start studying
Study Notes
Proteins
- Complex organic macromolecules containing carbon, hydrogen, oxygen, nitrogen, and usually sulfur
- Linear polymers of amino acids connected by peptide bonds
- Diverse and abundant class of biomolecules, making up about 50% of the dry weight of cells
- Not stored in the body, so they must be consumed daily
Amino Acids
- Organic compounds containing an amino group (NH2) and a carboxylic acid group (COOH)
- Building blocks of proteins
- 20 common amino acids, with most being chiral molecules
- Most amino acids are α-amino acids, and all amino acids in the body are L-isomers
- Exceptions: Glycine (simplest amino acid, achiral) and Proline (imino acid)
Classification of Proteins
- According to composition: derived proteins (e.g. denatured proteins and peptides)
- According to nutritional basis:
- Complete proteins: contain all essential amino acids in correct proportion (e.g. meat, fish, dairy, egg)
- Incomplete proteins: lack one or more essential amino acids in correct proportion (e.g. grains, nuts, beans, seeds, peas, corn)
- Complementary proteins: combining two or more incomplete proteins to create a complete protein
Properties of Proteins
- Denaturation: loss of secondary, tertiary, and quaternary structures, but primary structure remains intact
- Factors that cause protein denaturation: heat, detergents, acids and bases, salts, reducing agents, heavy metal ions, alcohol, and mechanical stress
Protein Hydrolysis
- Breaking peptide bonds by treatment with aqueous acid, base, or certain enzymes
- Primary structure of protein is cleaved by the addition of water
- Involved in the development of antibodies and has important antiviral properties
Specific Amino Acids
- Leucine: helps maintain nitrogen balance and energy supply, supports muscle building, and lowers cholesterol and LDL levels
- Limiting amino acids: amino acids in shortest supply in relation to need, inhibits protein synthesis, and usually found in incomplete proteins
Examples of Limiting Amino Acids
- Lysine: involved in growth, tissue repair, and collagen synthesis
- Threonine: involved in lipid metabolism and intestinal health
- Methionine: involved in detoxification, antioxidant functions, and liver health
- Tryptophan: involved in neuronal function, immunity, and gut homeostasis
Functions of Proteins
- Structure: provides strength to cells and tissue, chief constituents of skin, bones, hair, and nails
- Other functions: enzymatic, transport, storage, and defense-related functions
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
