Protein Structure and Function Quiz

HCl denatures proteins, making them more accessible to proteolytic enzymes, and activates pepsinogen into pepsin for protein breakdown.

Proteins serve in catalysis (enzymes), transport (hemoglobin), and mechanical support (collagen).

Proteolytic enzymes, such as pepsin and trypsin, break down proteins into smaller peptides and amino acids, facilitating nutrient absorption.

<p>Metabolism encompasses all biochemical reactions; anabolism builds complex molecules from simpler ones, while catabolism breaks down molecules for energy.</p> Signup and view all the answers

<p>Phenylketonuria (PKU) is a disorder resulting from a deficiency in the enzyme phenylalanine hydroxylase, leading to the accumulation of phenylalanine.</p> Signup and view all the answers

<p>Globular proteins have a coiled shape with hydrophobic amino acids inside, while fibrous proteins consist of long, parallel chains linked by disulphide bridges.</p> Signup and view all the answers

<p>Enzymes catalyze metabolic reactions, facilitating the breakdown and transformation of substances in the body.</p> Signup and view all the answers

<p>Collagen provides structural support and tensile strength in bones, cartilage, tendons, and ligaments.</p> Signup and view all the answers

<p>Protein digestion starts when dietary protein stimulates the secretion of gastrin, increasing hydrochloric acid (HCl) production in the stomach.</p> Signup and view all the answers

<p>Zymogens are inactive precursors of peptidases that prevent autodigestion and are activated in the intestinal lumen.</p> Signup and view all the answers

<p>The three phases of protein digestion are gastric (in the stomach), pancreatic (in the small intestine), and intestinal (also in the small intestine).</p> Signup and view all the answers

<p>Nitrogen, obtained from dietary proteins, is metabolized and excreted from the body as urea and ammonia.</p> Signup and view all the answers

<p>The exposure of hydrophilic amino acids allows globular proteins to be soluble in aqueous environments, facilitating their biological functions.</p> Signup and view all the answers

<p>HCl reduces the pH of the stomach to 1-2, acting as both an antiseptic agent and a denaturating agent for proteins.</p> Signup and view all the answers

<p>Pepsin is activated from pepsinogen in the acidic gastric environment and functions as an endopeptidase, hydrolyzing peptide bonds involving Phe, Tyr, Trp, and Met.</p> Signup and view all the answers

<p>The key endopeptidases include Trypsin, Chymotrypsin, and Elastase, crucial for the digestion of proteins in the small intestine.</p> Signup and view all the answers

<p>Bicarbonate raises the intestinal pH to optimum levels for pancreatic enzyme activity, which is around pH 8.</p> Signup and view all the answers

<p>Endopeptidases cleave internal peptide bonds within a protein, while exopeptidases cleave terminal peptide bonds, releasing free amino acids or dipeptides.</p> Signup and view all the answers

<p>Trypsin preferentially cleaves at arginine and lysine residues, while chymotrypsin targets aromatic amino acids.</p> Signup and view all the answers

<p>Di- and tri-peptides are hydrolyzed into free amino acids within the enterocyte after absorption.</p> Signup and view all the answers

<p>The secretion of pancreatic juice is stimulated by the peptide hormone cholecystokinin.</p> Signup and view all the answers

<p>They are immediately hydrolyzed into single amino acids.</p> Signup and view all the answers

<p>Amino acids are absorbed via sodium-dependent secondary active transport.</p> Signup and view all the answers

<p>It can lead to immune responses and food allergies due to immunogenic reactions.</p> Signup and view all the answers

<p>Celiac disease results in immune-mediated damage to the small intestine.</p> Signup and view all the answers

<p>Premature activation of trypsinogen within the pancreas initiates autodigestion.</p> Signup and view all the answers

<p>It leads to incomplete digestion and absorption of fats and proteins.</p> Signup and view all the answers

<p>Free amino acids are released through sodium-independent transporters on the basolateral membrane.</p> Signup and view all the answers

<p>The absorption process is energy-requiring, utilizing ATP for carrier-mediated transport.</p> Signup and view all the answers