sci biomolecules notes

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Objectives for Understanding Biomolecules

• Recognize major categories of biomolecules such as carbohydrates, lipids, proteins, and nucleic acids.

• Reference Image: Biomolecules. (n.d.). Giphy.

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Key Questions

• What are the major categories of biomolecules?

• What are the functions of carbohydrates, lipids, proteins, and nucleic acids in the body?

Definition of Biomolecules

• Also known as biopolymers.

• Large organic molecules produced by living organisms.

• Main components consist of:

  • Carbon (C)

  • Hydrogen (H)

  • Oxygen (O)

  • Nitrogen (N)

Functions of Biomolecules

• Provide energy.

• Serve as building blocks for tissue formation.

• Regulate metabolism.

  • Reference Image: Biomolecules

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Major Categories of Biomolecules

• What are the four major categories?

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The Four Major Categories

• Carbohydrates

• Proteins

• Lipids

• Nucleic Acids

• Reference Image: Biomolecules

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Carbohydrates

• Most abundant organic constituents in plants, often found as cellulose.

• Important source of chemical energy in organisms.

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Carbohydrates Classification

• Also referred to as polyhydroxy aldehydes or polyhydroxy ketones.

• Polyhydroxy indicates the presence of -OH (hydroxyl) groups.

• Aldehydes and ketones contain a carbonyl group.

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Classifications of Carbohydrates

• What are the three classifications?

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Types of Carbohydrates

• Carbohydrates are classified as:

  • Monosaccharides

  • Disaccharides

  • Polysaccharides

Monosaccharides

• Simplest carbohydrates; cannot be hydrolyzed further.

• Named according to the number of carbon atoms and type of group (aldose/ketose).

• Common examples:

  • Glucose (dextrose)

  • Fructose (fruit sugar)

  • Galactose (milk sugar)

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Monosaccharides: Examples

• Glucose and Fructose

  • Essential for bodily functions; provide energy for digestion and cellular respiration.

  • High sources include corn syrup.

  • Glucose is known as 'blood sugar' and also present in plant sap.

  • Fructose is found in fruits.

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Disaccharides

• Formed from two linked monosaccharides through dehydration (removal of one molecule of water for each linkage).

• Common examples:

  • Sucrose (table sugar)

  • Lactose (milk sugar)

  • Maltose (malt sugar)

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Disaccharides: Detailed Examples

• Sucrose: Found in sugarcane; formed from glucose and fructose.

• Lactose: Present in cow's and human milk; formed from galactose and glucose.

• Maltose: Found in beer; formed from glucose.

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Polysaccharides

• Comprised of many monosaccharide units.

• Consist of hundreds/thousands of linked monosaccharides.

• Common examples include:

  • Starch

  • Glycogen

  • Cellulose

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Polysaccharides: Common Examples

• Starch: Main food reserve of plants, found in tubers, roots; sources include potatoes, rice, and corn.

• Glycogen: Energy storage in animals, mainly in the liver and muscles.

• Cellulose: Provides structural support in plants; aids in digestion via movement through the intestines.

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Importance of Biomolecules: Carbohydrates

• Key Functions:

  • Assists in energy production and storage.

  • Acts as building blocks for macromolecules.

  • Helps spare proteins and participate in lipid metabolism.

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Lipids Overview

• Made of hydrocarbons, soluble in alcohol but usually not in water.

• Common examples include:

  • Fats

  • Oils

  • Some vitamins

  • Hormones

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Function of Lipids

• Serve as energy storage.

• Part of cell membrane structure.

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Classification of Lipids

• Saponifiable Lipids: Can break down into simple and compound lipids.

• Nonsaponifiable Lipids: Do not break down in the presence of a base.

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Types of Lipids and Examples

• Saponifiable Lipids:

  • Simple Lipids: Waxes (e.g., beeswax).

  • Compound Lipids: Phospholipids, Glycolipids.

• Nonsaponifiable Lipids:

  • Steroids (e.g., cholesterol).

Uses of Lipids

• Natural fats are used in production of soaps, varnishes, and cosmetics.

• Waxes provide protective coatings on various materials.

• Lecithin acts as an emulsifying agent in food products.

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Fatty Acids

• Essential components of some lipids; long-chain carboxylic acids with even-numbered carbon atoms.

• Types:

  • Saturated fats: Contain only single bonds.

  • Unsaturated fats: Contain one or more double bonds.

Lipid Classification

• Difference between saturated and unsaturated fats.

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Importance of Lipids

• Serve as structural components of cell membranes.

• Function as energy reserves and signaling molecules.

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Proteins Overview

• Account for 50% of the body's weight and are structurally complex polymers.

• Polymers are large molecules made from repeating units known as monomers (amino acids).

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Protein Functions

• Major components in skin, nails, cartilage, and muscles.

• Functions include:

  • Participation in biochemical reactions.

  • Defense against diseases.

  • Aiding in food digestion.

  • Oxygen transport in blood.

  • Regulating cell activities.

• Collagen: Most abundant protein in humans, essential for connective tissues.

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Components of an Amino Acid

• Building blocks of proteins; consist of:

  • Amino Group

  • Carboxyl Group

  • R-Chain

• Peptide Bonds: Bonds between amino acids.

• Peptides: Short chains of amino acids.

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Classifications of Proteins: Properties

1. Simple Proteins: Composed only of amino acids.

   • Examples: Albumins, Globulins, Glutenin, Casein.

2. Conjugated Proteins: Contain non-protein molecules along with amino acids.

   • Examples: Hemoglobin, Glycoproteins, Lipoproteins.

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Classifications of Proteins: Physical Characteristics

1. Globular Proteins: Stable in water; e.g., enzymes, hemoglobin.

2. Fibrous Proteins: Insoluble in water; e.g., keratin, collagen.

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Classifications of Proteins: Biological Functions

1. Blood Proteins

2. Catalytic Proteins (e.g., enzymes)

3. Contractile Proteins

4. Digestive Proteins

5. Hormonal Proteins

6. Immune Defense Proteins (e.g., antibodies)

7. Repressor Proteins

8. Respiratory Proteins

9. Structural Proteins (e.g., collagen)

10. Transport Proteins (e.g., hemoglobin)

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Structures of Proteins

• Determined by amino acid sequences leading to functional forms:

  1. Primary Structure: Sequence of amino acids.

  2. Secondary Structure: Local folding (alpha-helix, beta-sheet).

  3. Tertiary Structure: 3D folding of a single chain.

  4. Quaternary Structure: Multiple polypeptides forming a functional unit.

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Nucleic Acids Overview

• Biopolymers found in the nucleus of cells, carriers of genetic information.

• Composed of monomers called nucleotides.

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Components of a Nucleotide

• Nucleotide structure and types.

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Two Types of Nucleic Acids

1. DNA (Deoxyribonucleic Acid): Genetic material determining characteristics of living things.

2. RNA (Ribonucleic Acid): Involved in protein synthesis.

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Key Differences: DNA vs. RNA

Feature

DNA

RNA

Structure

Double-stranded

Single-stranded

Sugar

Deoxyribose

Ribose

Base Pair

Thymine

Uracil

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Nitrogen-Containing Bases

1. Pyrimidines: Simple, six-member rings; include

   • DNA: Cytosine (C), Thymine (T)

   • RNA: Cytosine (C), Uracil (U)

2. Purines: Include carbon and nitrogen atoms; adenine (A), guanine (G) for both DNA and RNA.

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Nitrogenous Bases Summary

• Nitrogenous bases specific to DNA and RNA.

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Closing

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