Fibrous Proteins and Muscle Proteins Quiz
38 Questions
1 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which of the following statements about fibrous proteins is true?

  • They can be digested easily.
  • They are soluble in water.
  • They are not thermostable.
  • They possess mechanical strength. (correct)

Collagen constitutes about 30% of total protein in the human body.

True (A)

What are the main types of muscle proteins mentioned?

Tropomyosin and Myosin

The hardness of keratin increases with the amount of ______ present in its structure.

<p>cysteine</p> Signup and view all the answers

Match the types of keratin with their sources:

<p>Keratin = Ectodermal Collagen = Mesenchymal Elastin = Mesenchymal Silk Fibroin = Silk-producing organisms</p> Signup and view all the answers

What property of collagen is primarily responsible for the pulling power in tendons and ligaments?

<p>Pulling power (D)</p> Signup and view all the answers

Elastin contains significant amounts of hydroxylysine.

<p>False (B)</p> Signup and view all the answers

What vitamin deficiency can lead to a failure in the formation of Tropocollagen?

<p>Vitamin C</p> Signup and view all the answers

____ is a symptom associated with Ehlers-Danlos syndromes.

<p>Dislocated joints</p> Signup and view all the answers

Match the disease with its associated collagen defect:

<p>Scorbutus = Hydroxyproline deficiency Ehlers-Danlos Syndromes = Type III Collagen defect Osteogenesis imperfecta = Type I Collagen synthesis deficiency None = No collagen defect</p> Signup and view all the answers

What is the primary function of myoglobin?

<p>Store oxygen in muscles (D)</p> Signup and view all the answers

Human Serum Albumin constitutes nearly 50% of all plasma proteins.

<p>True (A)</p> Signup and view all the answers

What is the significance of the heme group in hemoglobin?

<p>It binds oxygen reversibly due to the ferrous iron atom.</p> Signup and view all the answers

Globulins are generally _____ than albumins and less soluble in water.

<p>bigger</p> Signup and view all the answers

Match the protein type to its characteristic:

<p>Albumins = Carries ions, hormones, and fatty acids Alpha globulins = Class of globulins Gamma globulins = Comprising immunoglobulins Myoglobin = Single polypeptide with one heme group</p> Signup and view all the answers

Which type of hemoglobin is primarily associated with adults?

<p>HbA (A)</p> Signup and view all the answers

Deoxyhemoglobin can bind to carbon dioxide and hydrogen.

<p>True (A)</p> Signup and view all the answers

What are the two states of hemoglobin and their affinities for oxygen?

<p>T State (low affinity), R State (high affinity)</p> Signup and view all the answers

HbF is made up of ______ and ______ subunits.

<p>α, γ</p> Signup and view all the answers

Match the types of hemoglobin with their description:

<p>Hb Gower 1 = Embryonic yolk sac hemoglobin HbF = Fetal hemoglobin HbA = Main adult hemoglobin HbA2 = Minor adult hemoglobin</p> Signup and view all the answers

Which of the following cross-links are found in elastin?

<p>Desmosine (D)</p> Signup and view all the answers

Elastin is formed from multiple genetic types.

<p>False (B)</p> Signup and view all the answers

What structural feature differentiates collagen from elastin regarding their helices?

<p>Collagen has a triple helix, while elastin has random coils.</p> Signup and view all the answers

In silk fibroin, nearly half of the amino acids are __________.

<p>glycine</p> Signup and view all the answers

Match the following features with the correct protein: Collagen, Elastin, Silk Fibroin.

<p>Single genetic type = Elastin Triple helix structure = Collagen High content of glycine = Silk Fibroin</p> Signup and view all the answers

Which property is NOT associated with globular proteins?

<p>Mostly fibrous proteins (B)</p> Signup and view all the answers

Hydroxylysine is present in elastin.

<p>False (B)</p> Signup and view all the answers

Name two types of cross-links found in elastin.

<p>Desmosine and lysine-norleucine.</p> Signup and view all the answers

Silk fibroin has a ___________ sheet structure.

<p>β-pleated</p> Signup and view all the answers

Which modification is NOT present in elastin?

<p>Carbohydrate modification (A)</p> Signup and view all the answers

What is the Bohr effect primarily associated with?

<p>Decreased affinity of hemoglobin for oxygen due to pH changes (D)</p> Signup and view all the answers

The binding of 2,3-BPG to hemoglobin increases its affinity for oxygen.

<p>False (B)</p> Signup and view all the answers

What is the primary role of carbonic anhydrase in the blood?

<p>Catalyze the conversion of carbon dioxide and water into carbonic acid.</p> Signup and view all the answers

The shift of the HbO2 dissociation curve to the right occurs in ______ pH conditions.

<p>lower</p> Signup and view all the answers

Match the following terms with their definitions:

<p>Bohr Effect = Decreased affinity of oxygen due to increased CO2 and acidity 2,3-BPG = Compound that facilitates oxygen release from hemoglobin Carbonic Anhydrase = Enzyme that converts CO2 and H2O into H2CO3 Chloride Shift = Movement of chloride ions into red blood cells during CO2 transport</p> Signup and view all the answers

Why is 2,3-BPG important for transfused blood?

<p>It is essential for facilitating oxygen release to tissues. (D)</p> Signup and view all the answers

Carbon monoxide is a beneficial gas released during respiration.

<p>False (B)</p> Signup and view all the answers

What happens to oxygen release when blood is transfused without 2,3-BPG?

<p>Oxygen cannot be effectively released to tissues.</p> Signup and view all the answers

Flashcards

Fibrous Proteins

Insoluble in water, not easily digested, and resistant to heat. They give mechanical strength to tissues.

Keratin

A fibrous protein found in hair, nails, and skin. Its strength depends on cysteine content; higher cysteine means harder.

Collagen

A fibrous protein, a major component of connective tissues like skin and tendons. High content in body (30% total protein).

Cysteine in Keratin

Cysteine content affects keratin's hardness. Higher cysteine leads to harder keratin (like nails).

Signup and view all the flashcards

Protein Classification (Composition)

Proteins are categorized into simple (only amino acids) and conjugated (contain non-amino acid components).

Signup and view all the flashcards

Collagen Properties

Collagen's physical properties (elasticity, hardness, pulling power) depend on location in the body (skin, veins, bones, teeth, tendons, ligaments).

Signup and view all the flashcards

Collagen Cross-linking

Covalent cross-links stabilize collagen structure, formed by lysyl oxidase.

Signup and view all the flashcards

Collagen Deficiency (Scorbutus)

Hydroxyproline deficiency impairs collagen cross-linking, leading to delayed wound healing and fragile capillaries.

Signup and view all the flashcards

Ehlers-Danlos Syndrome

Genetic defect in type III collagen structure leads to joint problems, skin abnormalities and other problems.

Signup and view all the flashcards

Elastin Function

Elastin provides flexibility and durability to skin, blood vessels, and lungs. It is rich in Glycine, Alanine and Lysine. It lacks hydroxyproline and hydroxylysine.

Signup and view all the flashcards

Cross-links in Elastin

Chemical bridges that connect elastin molecules, providing elasticity.

Signup and view all the flashcards

Desmosine

A type of crosslink found in elastin, crucial for its elasticity.

Signup and view all the flashcards

Collagen vs. Elastin

Collagen forms strong, fibrous structures; Elastin provides elasticity.

Signup and view all the flashcards

Collagen Structure

Triple helix structure with repeating Gly-X-Y sequences.

Signup and view all the flashcards

Elastin Structure

Random coils, lacking repetitive sequences, enabling elasticity.

Signup and view all the flashcards

Silk Fibroin

A protein forming silk, characterized by β-pleated sheet structure.

Signup and view all the flashcards

Globular Proteins

Proteins with high solubility, often conjugated with other molecules.

Signup and view all the flashcards

β-pleated sheet

A common secondary structure in proteins, characterized by a folded sheet.

Signup and view all the flashcards

Glycine in Silk Fibroin

A frequent amino acid in silk fibroin, placing R groups opposite each other.

Signup and view all the flashcards

Protein Conjugation

Globular proteins often bond with non-amino acid molecules (prosthetic group).

Signup and view all the flashcards

Hemoglobin's Structure

Hemoglobin is a protein with four polypeptide chains (2 alpha-like and 2 beta-like) that form a quaternary structure. Each chain has a heme group, allowing it to bind four oxygen molecules.

Signup and view all the flashcards

Myoglobin Function

Myoglobin is a single polypeptide chain with a heme group. It stores oxygen in muscles and can bind oxygen even at low concentrations.

Signup and view all the flashcards

Heme Group Function

The heme group contains an iron atom bound to a porphyrin ring; it's responsible for oxygen binding in both myoglobin and hemoglobin.

Signup and view all the flashcards

Hemoglobin Heme Pocket

The heme pocket is a hydrophobic region within the hemoglobin protein that keeps the heme group away from water, allowing for reversible oxygen binding and preventing iron oxidation.

Signup and view all the flashcards

Human Serum Albumin Function

Human Serum Albumin is the most abundant plasma protein, transporting ions, xenobiotics, hormones, and fatty acids.

Signup and view all the flashcards

Hb Gower 1

The first embryonic hemoglobin, made up of two zeta (ζ) and two epsilon (ε) subunits, found in the yolk sac.

Signup and view all the flashcards

HbF

Fetal hemoglobin, composed of two alpha (α) and two gamma (γ) subunits, has a higher affinity for oxygen than adult hemoglobin, aiding oxygen transport to the fetus.

Signup and view all the flashcards

HbA

The main adult hemoglobin, composed of two alpha (α) and two beta (β) subunits, responsible for carrying oxygen throughout the body.

Signup and view all the flashcards

HbA2

A minor adult hemoglobin, made up of two alpha (α) and two delta (δ) subunits, plays a lesser role in oxygen transport compared to HbA.

Signup and view all the flashcards

What factors influence Hb glycosylation?

The glycosylation (sugar attachment) of hemoglobin is directly affected by the concentration of glucose in the blood. Higher glucose levels lead to increased glycosylation.

Signup and view all the flashcards

What is the Bohr effect?

The Bohr effect is the decrease in oxygen affinity of hemoglobin in response to a lower blood pH caused by an increase in carbon dioxide concentration.

Signup and view all the flashcards

How does carbon dioxide affect hemoglobin-oxygen binding?

Carbon dioxide reacts with water in blood to form carbonic acid. This acid releases H+ ions which bind to hemoglobin, reducing its affinity for oxygen. This allows more oxygen to be delivered to tissues where it's needed.

Signup and view all the flashcards

What is Cl- shift?

Chloride shift is the movement of chloride ions into red blood cells to compensate for the bicarbonate ions moving out. This maintains the electrical balance of the blood.

Signup and view all the flashcards

What is 2,3-BPG?

2,3-Bisphosphoglycerate (2,3-BPG) is a molecule produced during glycolysis that binds to hemoglobin, reducing its oxygen affinity. This helps release oxygen into tissues.

Signup and view all the flashcards

Why is 2,3-BPG important in transfused blood?

Transfused blood often has reduced 2,3-BPG levels, which can prevent oxygen from being released to tissues. Therefore, a 2,3-BPG solution is added to transfused blood to ensure proper oxygen delivery.

Signup and view all the flashcards

What happens to the HbO2 dissociation curve at lower pH?

At lower pH (more acidic), the HbO2 dissociation curve shifts to the right. This means hemoglobin releases more oxygen at a given partial pressure of oxygen.

Signup and view all the flashcards

How does carbon monoxide affect oxygen carrying capacity?

Carbon monoxide binds to hemoglobin with much higher affinity than oxygen, blocking oxygen from binding. This reduces the blood's oxygen-carrying capacity, causing oxygen deprivation.

Signup and view all the flashcards

What is the relationship between oxygen affinity and carbon dioxide levels?

There is an inverse relationship between oxygen affinity and carbon dioxide levels. As carbon dioxide levels increase, hemoglobin's affinity for oxygen decreases, leading to more oxygen release in tissues.

Signup and view all the flashcards

Study Notes

Protein Classification and Function

  • Proteins are classified based on shape (structural) and composition.
  • Structural proteins have various shapes, including fibrous and globular.
  • Fibrous proteins are typically insoluble in water, strong, and provide structural support. Examples include keratin, collagen, and elastin.
  • Globular proteins have a complex, roughly spherical shape, and are usually soluble in water. They have diverse functions. Examples include hormones, enzymes, antibodies, and transport proteins (like hemoglobin and myoglobin).
  • Protein composition can be simple or conjugated. Simple proteins consist only of amino acids. Conjugated proteins contain additional components such as metals, lipids, or carbohydrates.

Learning Objectives

  • Students will be able to classify proteins.
  • Students will understand the structural properties of fibrous proteins.
  • Students will compare and contrast the structures of keratin, collagen, and elastin.
  • Students will know the definition and structural properties of globular proteins.
  • Students will understand the structures and functions of myoglobin and its oxygen-binding properties.
  • Students will understand the structures and functions of hemoglobin and its oxygen-binding properties.

Classification of Proteins

  • Structural (Shape): Determined by amino acid sequence. Fibrous proteins are elongated and provide strength (e.g., keratin in hair). Globular proteins are compact and often have diverse functions.
  • Composition: Simple proteins consist only of amino acids. Conjugated proteins contain other molecules (e.g., heme in hemoglobin).

Fibrous Proteins

  • Scleroproteins: Insoluble in water, resistant to digestion, provide strength and structure. Examples include keratin (hair, nails), collagen (connective tissue), elastin (elastic fibers).

Collagen

  • Accounts for ~30% of total body protein and is essential for connective tissues.
  • Has various types, with different structures and functions.
  • Physical properties (e.g., elasticity, strength) differ depending on the tissue location.
  • Crucial for skin, bones, tendons, and ligaments.
  • Essential for wound healing.

Elastin

  • Provides elasticity and flexibility in tissues such as skin, blood vessels, and lungs.
  • Predominantly hydrophobic.
  • Rich in glycine, alanine, and lysine; contains small amounts of hydroxyproline but no hydroxylysine.

Silk Fibroin

  • A fibrous protein found in silk.
  • A β-sheet structure composed of repeating amino acid sequences (mostly glycine and alanine).
  • Provides strength and flexibility to the silk fiber.

Globular Proteins

  • Mostly conjugated, meaning they have additional components besides amino acids.
  • Examples include albumins and globulins.
  • Diverse functions including catalysis, transport, storage, gene regulation, immunity, etc.
  • They are usually soluble in water

Albumins

  • Part of the larger protein family.
  • Abundant in blood, approximately 50% of plasma proteins.
  • Involved in transporting hormones, fatty acids.
  • Important for maintaining osmotic pressure (keeping blood in the blood vessels).

Globulins

  • Larger than albumins.
  • Less soluble in water.
  • Important in various bodily functions, including blood clotting, immune responses, and transporting various molecules.

Hemoglobin and Myoglobin

  • Function: Carry or store oxygen.
  • Structure: Contain heme groups. These groups have iron, which binds to oxygen.
  • Myoglobin: Single polypeptide chain, stores oxygen in muscle tissue.
  • Hemoglobin: Four polypeptide chains, transports oxygen in the blood.

2,3-BPG and Hemoglobin

  • 2,3-BPG is a molecule that binds to hemoglobin, reducing its affinity for oxygen, and aids the release of oxygen in tissues.

Carbon Monoxide and Hemoglobin

  • Carbon monoxide binds tightly to heme, preventing oxygen binding.
  • It displaces the oxygen, effectively blocking oxygen transport.

Bohr Effect

  • The effect of pH on hemoglobin's oxygen binding capacity.
  • As pH decreases, hemoglobin's affinity for oxygen decreases, facilitating oxygen release in tissues.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Protein Classification and Function PDF

Description

Test your knowledge about fibrous proteins, including collagen and keratin, as well as muscle protein functions. This quiz covers key properties, types, and common diseases associated with protein deficiencies. Challenge yourself with questions on the roles of different proteins in the human body.

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser