TEAS 7 Biology Notes

TEAS 7 Biology Study Notes

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Macromolecules

What are Macromolecules?

  • Large, complex organic molecules essential for life.

  • Contain carbon atoms that form covalent bonds with various elements.

  • Mostly polymers made of smaller building blocks called monomers.

  • Dehydration Synthesis: Process of building macromolecules by removing water.

  • Hydrolysis: Process of breaking down macromolecules by adding water.

Key Concepts:

  • Dehydration: Builds polymers by losing water.

  • Hydrolysis: Breaks polymers by adding water.

  • Covalent Bonds: Atoms share one or more electron pairs.

Main Classes of Macromolecules:

  1. Carbohydrates
       - Monomers: Monosaccharides (e.g., glucose)
       - Functions: Source of energy, structure (e.g., cellulose).
       - Examples: Sugars, starches, grains.

  2. Lipids
       - Monomers: Fatty Acids + Glycerol
       - Functions: Long-term energy storage, cell membranes.
       - Examples: Fats, oils (butter, lard), phospholipids, steroids.

  3. Proteins
       - Monomers: Amino Acids
       - Functions: Enzymes, structure, transport, muscle movement, hormone regulation.
       - Examples: Pepsin, hemoglobin, myosin.

  4. Nucleic Acids
       - Monomers: Nucleotides
       - Functions: Stores genetic information.
       - Examples: DNA (deoxyribonucleic acid), RNA (ribonucleic acid).

Detailed Components of Macronutrients:

  • Carbohydrates Composition:
       - Made up of carbon, hydrogen, and oxygen in a 1:2:1 ratio (C:H:O).
       - Types:
         - Monosaccharides (one sugar unit: simple sugars like glucose, fructose).
         - Disaccharides (two sugars: sucrose, lactose).
         - Polysaccharides (long chains of monosaccharides: starch, cellulose, glycogen).
       - Energy Processes: Both fermentation and respiration start with glycolysis that breaks down glucose.

  • Lipids Types:
       - Triglycerides: Composed of three fatty acids + glycerol.
         - Saturated: Single bonds (solid at room temp).
         - Unsaturated: Double bonds (liquid at room temp).
       - Phospholipids: Form cell membranes.
       - Steroids: Include cholesterol, estrogen, testosterone.

  • Protein Structure:
       - Amino acids consist of: central carbon, amine group (-NH₂), carboxylic acid group (-COOH), hydrogen (H), R-group.
       - Functions: Enzymes catalyze reactions, muscle tissues, hormones, antibodies, structural components.

  • Nucleotide Structure:
       - 5-carbon sugar (ribose or deoxyribose), phosphate group, nitrogenous base (A, T, G, C for DNA; A, U, G, C for RNA).
       - Types:
         - DNA: Double helix, stores genetic info.
         - RNA: Single stranded, helps in protein synthesis.
         - ATP (adenosine triphosphate): Energy-carrying nucleotide.

Macromolecules - Exam Notes

Key Points for Each Class (Usage in Questions):

  • Carbohydrates:
      - Energy, digestion of sugars, blood sugar levels (glucose, insulin, glycogen).

  • Lipids:
      - Long-term energy storage, fat digestion/metabolism, phospholipids in cell membranes, insulation/hormonal roles, hydrophobic properties.

  • Proteins:
      - Enzymatic activity, muscle tissue repair, signaling hormones (e.g., insulin), immune function (antibodies), structural components.

  • Nucleic Acids:
      - Questions mentioning DNA/RNA, genetic code, heredity, protein synthesis, nucleotide structures, ATP, or phosphate bonds correlate with nucleic acids.

Reactions Related to Metabolism:

  • Anabolic Reactions:
      - Build larger molecules from smaller ones (require energy). Example: Amino acids forming proteins.

  • Catabolic Reactions:
      - Break larger molecules into smaller ones (release energy). Example: Glycogen breakdown to glucose.

Introduction to the Cell

Cell Theory:

  • Basic unit of life; all living organisms are made of cells.

  • Common features shared by cells: cell membrane, cytoplasm, genetic material.

  • Hierarchy of life begins from cells to tissues, to organs, to organ systems, finally leading to organisms.

Cell Types:

  1. Eukaryotic Cells:
       - True nucleus, membrane-bound organelles.
       - Found in plants, animals, fungi, protists.

  2. Prokaryotic Cells:
       - Lack a true nucleus, no membrane-bound organelles.
       - Found in bacteria and archaea.

The Plasma Membrane

Structure:

  • Phospholipid bilayer with embedded proteins.

  • Hydrophilic heads (water-loving) and hydrophobic tails (water-fearing).

  • Selectively permeable, controlling entry/exit of substances based on:
      - Size, charge, polarity.

  • Small nonpolar molecules (O₂, CO₂) diffuse easily, while large molecules (glucose) require protein channels.

Cytoplasm and Cytosol

Definitions:

  • Cytoplasm: Everything within plasma membrane excluding nucleus; contains cytosol, organelles, and molecules.

  • Cytosol: Jelly-like substance, mostly water with dissolved ions, nutrients, and waste.

Organelles:

  • Nucleus: Control center, double membrane-bound, stores DNA in chromosomes, directs cellular activity, contains nucleolus (ribosome production).

  • Ribosomes: Sites of protein synthesis; free-floating or bound to Rough ER.

Endoplasmic Reticulum (ER)

  • Rough ER: Membrane-bound organelle covered in ribosomes; synthesizes proteins, helps in folding and quality control.