Biology: Enzymes and Their Functions

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Questions and Answers

Which enzyme is primarily responsible for breaking down proteins in the stomach?

Chymotrypsin

Trypsin

Lipase

Pepsin (correct)

What is the primary function of lipases in the digestive system?

To facilitate the absorption of vitamins

To convert proteins into amino acids

To break down fats into fatty acids and glycerol (correct)

To break down carbohydrates into sugars

During inhalation, which muscles contract to allow the lungs to inflate?

Internal intercostal and diaphragm muscles

Diaphragm and external intercostal muscles (correct)

Intercostal and abdominal muscles

Pectoral and diaphragm muscles

Which part of the respiratory system is primarily responsible for filtering out dust and particles?

Nasal cavity Signup and view all the answers

What structure prevents the trachea from collapsing?

Cartilage rings within the trachea Signup and view all the answers

Which part of the respiratory system is involved in the actual gas exchange?

Alveoli Signup and view all the answers

Which part of the nephron is primarily involved in reabsorbing water and electrolytes based on hormonal signals?

Distal Convoluted Tubule (DCT) Signup and view all the answers

What is the primary function of the glomerulus in the nephron?

Filtering blood to allow small molecules to pass into the renal tubule Signup and view all the answers

What does the collecting duct regulate in relation to urine?

The concentration of urine in response to antidiuretic hormone (ADH) Signup and view all the answers

How do the kidneys contribute to maintaining homeostasis?

They maintain a stable internal environment by regulating water balance Signup and view all the answers

Which segment of the nephron reabsorbs the majority of filtered nutrients?

Proximal Convoluted Tubule (PCT) Signup and view all the answers

What occurs in the loop of Henle that is crucial for kidney function?

A concentration gradient is created in the medulla Signup and view all the answers

When the body is dehydrated, what action do the kidneys take?

Conserve water by producing concentrated urine Signup and view all the answers

What role does the distal convoluted tubule (DCT) have in blood pH regulation?

It secretes hydrogen ions and potassium ions into the tubular fluid Signup and view all the answers

What occurs when the body becomes overhydrated?

The kidneys excrete excess water, leading to dilute urine. Signup and view all the answers

What is one of the primary roles of electrolytes in the body?

They maintain cellular function and muscle contraction. Signup and view all the answers

Which ion do the kidneys excrete to help regulate blood pH?

Hydrogen ions Signup and view all the answers

How do the kidneys respond when blood pressure drops?

They release renin to promote vasoconstriction. Signup and view all the answers

What are the metabolic wastes filtered by the kidneys?

Urea, creatinine, and uric acid Signup and view all the answers

What is the primary function of the skin?

To regulate temperature and provide a protective barrier Signup and view all the answers

What is the role of the dermis in the skin?

It contains blood vessels and nerve endings. Signup and view all the answers

Which system do the kidneys interact with to restore blood volume?

Renin-angiotensin-aldosterone system (RAAS) Signup and view all the answers

How do kidneys maintain electrolyte balance?

By selectively reabsorbing or excreting ions in urine. Signup and view all the answers

What is the function of bicarbonate ions in the kidneys?

To regulate acid-base balance by reabsorption. Signup and view all the answers

What role do binding proteins play in the circulation of lipid-soluble hormones?

They assist in hormone transport and protect them from degradation. Signup and view all the answers

Study Notes

Proteases and Lipases

Proteases, such as pepsin, trypsin, and chymotrypsin, are enzymes responsible for the breakdown of proteins into amino acids.
Lipases function in fat breakdown, converting lipids into fatty acids and glycerol, aiding nutrient absorption for energy, growth, and repair.

Respiratory System

Organs of Respiration

The respiratory system is key for gas exchange, mainly oxygen and carbon dioxide, through upper and lower airways.
Upper Airways: Include the nose, nasal cavity, pharynx, and larynx. The nose filters air; the nasal cavity warms and humidifies it; the pharynx serves both air and food; the larynx contains vocal cords for speech.
Lower Airways: Comprise the trachea, bronchi, bronchioles, and alveoli. The trachea supports air passage, bronchi split into bronchioles, and alveoli are sites for gas exchange.

Physiology of Breathing

Breathing involves inhalation, where diaphragm and external intercostal muscles contract, expanding the chest cavity and inflating the lungs.
Exhalation occurs when these muscles relax, decreasing chest cavity size and expelling air.

Regulation of Respiratory Functions

The respiratory rate and depth are controlled by the respiratory center in the brainstem, adjusting to the body's needs.

Nephron Structure and Function

Renal Corpuscle: Contains glomerulus for blood filtration and Bowman's capsule to collect filtrate.
Renal Tubule: Consists of:
- Proximal Convoluted Tubule (PCT): Reabsorbs water, electrolytes, and nutrients; secretes waste.
- Loop of Henle: Establishes a concentration gradient for water reabsorption.
- Distal Convoluted Tubule (DCT): Further reabsorbs water and electrolytes; regulates blood pH.
- Collecting Duct: Receives urine, fine-tunes concentration under hormone influence (ADH, aldosterone).

Kidneys and Homeostasis

The kidneys maintain homeostasis by regulating water, electrolytes, acid-base balance, blood pressure, and waste removal.
Water Balance: Control volume and concentration of body fluids based on hydration status.
Electrolyte Balance: Regulate electrolytes to maintain cellular function and fluid balance.
Acid-Base Balance: Adjust pH by excreting hydrogen and reabsorbing bicarbonate.
Blood Pressure Regulation: Release renin for the renin-angiotensin-aldosterone system (RAAS) to maintain blood pressure through volume and vessel constriction.
Waste Removal: Filter and excretes metabolic wastes, toxins, and excess substances in urine.

Skin and Temperature Control

The skin, composed of the epidermis, dermis, and hypodermis, aids in temperature regulation and osmoregulation.
Epidermis: Protective barrier against pathogens and dehydration.
Dermis: Contains blood vessels, nerves, and accessory structures.

Hormone Transport and Regulation

Lipid-soluble hormones circulate bound to carrier proteins, which extend half-life, increase solubility, and regulate hormone availability.
Hormones bind specifically to receptors on target cells, initiating physiological responses.

Hormone-Receptor Interaction

Specificity in binding ensures hormone effects are targeted; high binding affinity strengthens interaction; saturation occurs at high hormone concentrations.

Types of Receptors

Cell-Surface Receptors (Membrane Receptors):
- G Protein-Coupled Receptors (GPCRs): Activate intracellular pathways via G proteins.
- Ion Channel Receptors: Open/close in response to hormones, altering membrane potential.
- Enzyme-Linked Receptors: Activate intrinsic enzymatic activity leading to cellular process modulation through phosphorylation cascades.

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Description

This quiz covers the role of proteases and lipases in the digestive system. Learn how these enzymes break down proteins and fats into absorbable nutrients essential for the body's energy and growth. Test your understanding of the functions and importance of these enzymes.