Podcast
Questions and Answers
Which characteristic is true of fibrous proteins?
Which characteristic is true of fibrous proteins?
What defines globular proteins?
What defines globular proteins?
Which of the following statements differentiates keratin from collagen?
Which of the following statements differentiates keratin from collagen?
Which protein category includes molecules other than amino acids?
Which protein category includes molecules other than amino acids?
Signup and view all the answers
What function does myoglobin primarily serve?
What function does myoglobin primarily serve?
Signup and view all the answers
What is the primary characteristic of fibrous proteins?
What is the primary characteristic of fibrous proteins?
Signup and view all the answers
Which of the following proteins is classified as mesenchymal?
Which of the following proteins is classified as mesenchymal?
Signup and view all the answers
What role do disulfide bonds play in keratin?
What role do disulfide bonds play in keratin?
Signup and view all the answers
How does the cysteine content in hair keratin affect its properties?
How does the cysteine content in hair keratin affect its properties?
Signup and view all the answers
What percentage of total protein does collagen constitute in the human body?
What percentage of total protein does collagen constitute in the human body?
Signup and view all the answers
What primary function does myoglobin serve in the human body?
What primary function does myoglobin serve in the human body?
Signup and view all the answers
What structural feature allows hemoglobin to bind up to four molecules of oxygen?
What structural feature allows hemoglobin to bind up to four molecules of oxygen?
Signup and view all the answers
Which characteristic distinguishes globulins from albumins?
Which characteristic distinguishes globulins from albumins?
Signup and view all the answers
What role does the heme pocket in hemoglobin play?
What role does the heme pocket in hemoglobin play?
Signup and view all the answers
Which function is least associated with the albumin protein family?
Which function is least associated with the albumin protein family?
Signup and view all the answers
What is the composition of adult hemoglobin HbA?
What is the composition of adult hemoglobin HbA?
Signup and view all the answers
In which state does hemoglobin have a low affinity for oxygen?
In which state does hemoglobin have a low affinity for oxygen?
Signup and view all the answers
Which of the following hemoglobins is associated with fetal development?
Which of the following hemoglobins is associated with fetal development?
Signup and view all the answers
How does the glycosylation ratio of hemoglobin relate to glucose concentration?
How does the glycosylation ratio of hemoglobin relate to glucose concentration?
Signup and view all the answers
What happens when O2 is released from hemoglobin?
What happens when O2 is released from hemoglobin?
Signup and view all the answers
What type of cross-links are present in elastin?
What type of cross-links are present in elastin?
Signup and view all the answers
How does collagen differ structurally from elastin?
How does collagen differ structurally from elastin?
Signup and view all the answers
Which of the following is NOT a characteristic of silk fibroin?
Which of the following is NOT a characteristic of silk fibroin?
Signup and view all the answers
What is a common feature of globular proteins?
What is a common feature of globular proteins?
Signup and view all the answers
What is the presence of hydroxylysine in collagen indicative of?
What is the presence of hydroxylysine in collagen indicative of?
Signup and view all the answers
In the context of elastin, what does the term 'random coils' refer to?
In the context of elastin, what does the term 'random coils' refer to?
Signup and view all the answers
Which type of modification is present in elastin but absent in collagen?
Which type of modification is present in elastin but absent in collagen?
Signup and view all the answers
What governs the stability of silk fibroin?
What governs the stability of silk fibroin?
Signup and view all the answers
Which of the following is a feature of collagen?
Which of the following is a feature of collagen?
Signup and view all the answers
Which amino acid is in high concentration in silk fibroin?
Which amino acid is in high concentration in silk fibroin?
Signup and view all the answers
What causes the decrease in oxygen affinity in hemoglobin in response to increased carbon dioxide concentration?
What causes the decrease in oxygen affinity in hemoglobin in response to increased carbon dioxide concentration?
Signup and view all the answers
What role does 2,3-BPG play in the oxygen transport process?
What role does 2,3-BPG play in the oxygen transport process?
Signup and view all the answers
Why is 2,3-BPG important for transfused blood?
Why is 2,3-BPG important for transfused blood?
Signup and view all the answers
What is one consequence of a decrease in pH on the hemoglobin dissociation curve?
What is one consequence of a decrease in pH on the hemoglobin dissociation curve?
Signup and view all the answers
What happens to 2,3-BPG during the storage of blood for transfusion?
What happens to 2,3-BPG during the storage of blood for transfusion?
Signup and view all the answers
Which of the following explains the chloride shift in relation to carbon dioxide transport?
Which of the following explains the chloride shift in relation to carbon dioxide transport?
Signup and view all the answers
What is the primary consequence of carbon monoxide exposure on hemoglobin?
What is the primary consequence of carbon monoxide exposure on hemoglobin?
Signup and view all the answers
In the presence of 2,3-BPG, how does hemoglobin's affinity for oxygen change?
In the presence of 2,3-BPG, how does hemoglobin's affinity for oxygen change?
Signup and view all the answers
Study Notes
Protein Classification and Function
- Proteins are classified based on shape (structural) and composition.
- Structural proteins have shapes determined by their amino acid sequence.
- Fibrous proteins provide structural support, shape, and mechanical properties. Examples include keratin, collagen, elastin, silk fibroin, and muscle proteins (tropomyosin, myosin).
- Globular proteins are typically round and soluble in water. Functions include regulation, catalytic activity, transport, and form hormones and receptors.
- Compositional classification divides proteins into simple and conjugated.
- Simple proteins are composed solely of amino acids (homoproteins).
- Conjugated proteins contain non-amino acid components (heteroproteins). These components include metals (metalloproteins), lipids (lipoproteins), carbohydrates (glycoproteins), etc.
- Some conjugated proteins have prosthetic groups; these are non-amino acid parts.
Learning Objectives
- Classify proteins based on shape and composition.
- Describe the structural properties of fibrous proteins.
- Explain the structural differences among keratin, collagen, and elastin.
- Define globular proteins and their structural properties.
- Explain the structure and function of myoglobin and its oxygen saturation.
- Explain the structure and function of hemoglobin and its oxygen saturation.
Fibrous Proteins
- Scleroproteins are insoluble in water, not digestible, and resistant to heat (thermostable).
- They provide mechanical strength, like in hair, nails, horns, and connective tissues. Keratin, collagen, and elastin are examples.
- Collagen forms the triple helix structure, giving strength and flexibility to connective tissues.
- Elastin is crucial in tissues that need elasticity, providing recovery after being stretched.
- Silk fibroin contains amino acids glycine and alanine, forming a β-sheet structure. It provides flexibility and strength.
- Muscle proteins like tropomyosin and myosin are fibrous proteins supporting movement.
Classification of Proteins
- Structural (shape): Fibrous (supports cell shape, protective roles, mechanical properties) vs. Globular (regulation, catalytic activity, transport, hormones, receptors).
- Composition: Simple (only amino acids) vs. Conjugated (non-amino acid components).
Keratin
- Keratin structure consists of α-helices, coiled to form fibers.
- Cysteine content affects keratin's properties (e.g., hardness).
- Disulfide bonds contribute to keratin's insolubility.
- Cysteine is lower in skin keratin compared to hair or nails.
Collagen
- Collagen is ~30% of total body protein and 6% of body weight.
- There are varying types with different functions.
- Physical properties (elasticity, hardness) depend on the collagen type.
- Collagen's structure includes a triple helix and hydroxyproline (Hyp).
- Collagen is a critical component of connective tissues.
Elastin
- Elastin provides durability and flexibility, found in skin, blood vessels, and lungs.
- Elastin is a hydrophobic protein, rich in glycine, alanine, and lysine, and has small amounts of hydroxyproline, but no hydroxylysine.
- Cross-linking is crucial for elastin's elasticity, via Lysyl oxidase.
Silk Fibroin
- Silk fibroin forms a β-sheet structure made from amino acids glycine and alanine.
- The β-sheet structure contributes to its strength and flexibility.
- Many weak bonds (hydrogen and van der Waals) contribute to silk's stability.
Globular Proteins
- High solubility in water.
- Mostly conjugated (bound with different molecules besides amino acids).
- Diverse functions (catalysis, transport, storage, gene regulation, immunity).
- Examples include albumins and globulins, myoglobin, and hemoglobin.
Albumins
- Common in blood, ~50% of the plasma proteins.
- Transport substances like hormones, fatty acids, and ions.
- They connect between substances and send signals.
Globulins
- Larger than albumins, less soluble in water.
- Three major classes: alpha, beta, and gamma globulins.
- Gamma globulins include antibodies, critical for the immune system.
Globin (Globulin subclass)
- Contains a heme group—a ferrous iron atom connected to a porphyrin ring.
- Has oxygen-binding properties.
- Examples: Myoglobin and Hemoglobin.
Myoglobin
- Single polypeptide, stores oxygen in muscles.
- Binds oxygen even at low concentrations.
- Single polypeptide chain.
Hemoglobin
- Four polypeptide chains (2 alpha, 2 beta), carries oxygen in the blood.
- Binds oxygen at high concentrations and releases it at low concentrations.
- Can bind CO2 and hydrogen.
- 4 heme groups can bind 4 oxygen molecules.
Hemoglobin Types
- Different types of hemoglobin exist including HbA, HbA2, HbF. These exist in different concentrations at different stages of life.
Glycosylated Hemoglobin (HbA1c)
- Glycosylation ratio is dependent on blood glucose concentration.
- Indicator of diabetes control
2,3-BPG binding to Hemoglobin
- 2,3-BPG is a side product of glycolysis.
- It binds to hemoglobin and decreases its affinity for oxygen, promoting oxygen release in tissues.
- Affects the Hb oxygen dissociation curve.
Carbon Monoxide
- A toxicant, binds to heme's iron, reducing blood's oxygen-carrying capacity.
- The binding is highly reversible, which allows for treatments to restore the oxygen-binding capacity of hemoglobin
Bohr Effect
- CO2 and H+ levels affect hemoglobin's oxygen-binding affinity.
- When CO2 increases, the affinity decreases (Bohr effect).
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz explores the classification of proteins based on their shape and composition. You'll learn about structural and globular proteins, as well as the differences between simple and conjugated proteins. Test your knowledge on examples and functions of various protein types.
