Class32-Overview-501-F2024

Unit Overview

  • Unit Title: Energy Storage: Anabolism (biosynthesis) and Bio-signaling

  • Instructor: Dr. Mario Pennella

  • Contact Information: mpennella@wisc.edu

  • Office Hours:

    • Tuesdays: 11:00 AM - 12:30 PM

    • Thursdays: 2:00 PM - 3:30 PM

Overview of Learning Objectives

  • Main Goal: Understand body's regulation of reactions under various metabolic conditions, focusing on

    • Effects of feeding on different tissues

    • Intercellular communication

    • Metabolic disorders resulting from hormonal regulation disruption

  • Resources: Lehninger, 8e, Fig. 23-9, p. 848

Key Concepts Covered

  1. Biosynthesis Requirements:

    • General understanding of anabolic pathways.

  2. Signal Transduction Principles:

    • Relationship with hormonal signaling.

  3. Hormonal Regulation in Metabolic States:

    • Major hormones during fasting and fed states.

  4. Pathway Activation:

    • Pathways active during fasting vs. fed states.

  5. Carbohydrates Classification:

    • Distinction between monosaccharides, disaccharides, polysaccharides.

  6. Glycosidic Bonds:

    • Differentiate alpha and beta anomers, naming glycosidic bonds.

  7. Bond Identification:

    • Types of bonds linking monosaccharides in polysaccharides.

  8. Glycogen Structure:

    • Description of glycogen's structure.

  9. Glycosidic Bond Types:

    • Contrast between glycogen and cellulose.

  10. Sugar Classification:

    • Understanding reducing vs. non-reducing sugars.

Energy-Rich Molecules

  • Categories:

    • Energy-Rich Molecules: Fats, Carbohydrates, Proteins

    • Catabolic Products: CO2, H2O, NH3

  • Hormonal Modulation:

    • Hormones regulate cellular pathways via energy carriers (ADP, NAD+, FAD+, NADP+, ATP, NADH, FADH2, NADPH).

Hormonal Signaling Overview

  • Definition: Hormones as biological signals connecting organs by relaying information between the central nervous system and tissues.

Principles of Signal Transduction

  • Reception of Information: Cells process environmental information through signaling pathways.

  • Signaling Mechanism:

    • Odorant molecules bind receptor proteins on olfactory neurons, modifying enzyme activity and turning pathways on or off.

Hormones Discussed

  1. Glucagon:

    • Released when blood glucose is low (fasting). Primarily affects liver and fat cells.

  2. Epinephrine:

    • Released during stress and activity. Affects liver, fat, and muscle cells.

  3. Insulin:

    • Released when blood glucose is high (fed). Affects fat, liver, and muscle cells.

  4. Leptin:

    • Secreted post-meal. Signals the brain to suppress appetite.

Metabolic State Pathways

Fed State Activities:

  • General Function: Reduce blood glucose through cellular uptake and various biochemical transformations.

  • Key Pathways:

    • Glycogenesis (storage in liver/muscle)

    • Glycolysis (ATP production in multiple tissues)

    • Fatty Acid Synthesis (fat production/storage)

    • Cholesterol Synthesis

    • Pentose Phosphate Pathway (NADPH production).

Fasting State Activities:

  • Function: Release stored fuel for energy.

  • Key Pathways:

    • Glycogenolysis (increase blood glucose levels in the liver)

    • Gluconeogenesis (create glucose)

    • Lipolysis (release fatty acids)

    • Ketogenesis (produce ketone bodies).

Carbohydrate Basics

  • Definition: Molecules that yield aldehydes or ketones with hydroxyl groups or that yield these upon hydrolysis.

  • Empirical Formula: Many carbohydrates follow (CH2O)n.

Classes of Carbohydrates

  • Monosaccharides: Simple sugars (e.g., D-glucose).

  • Disaccharides: Two monosaccharides linked by glycosidic bonds (e.g., sucrose).

  • Oligosaccharides: Short chains of monosaccharides.

  • Polysaccharides: Long chains (e.g., starch, glycogen).

Glycosidic Bonds and Structures

  • O-Glycosidic Bonds: Formed via reaction between hydroxyl and anomeric carbon.

  • N-Glycosidic Bonds: Linkage of sugar and amines.

  • Glycogen vs. Cellulose:

    • Glycogen is a branched polymer; cellulose is unbranched (β-1,4 linkage vs. α-1,4 linkage).

Reducing and Non-reducing Sugars

  • Reducing Sugars: React with oxidizing agents; involve anomeric carbon present.

  • Common Disaccharides:

    • Sucrose, Lactose, Maltose – each characterized by their linkages.

Learning Strategies for Success

  1. Focus studies on learning objectives and practice material.

  2. Organize study materials:

    • Use tables, concept maps, drawings.

  3. Engage in active problem solving through practice exams and discussions.

Additional Learning Objectives for Future Classes

  1. Identify hormones in response to fasting and fed states, and their pathways.

  2. Explain glucose metabolism and insulin signaling, including gluconeogenesis and glycolysis.

  3. Understand ketone bodies' role and glucose needs in human metabolism.