Biology Flashback Review Notes

Unit 1: Interdependence

Living Things and Their Needs

  • Essentials for Survival:

    • Living things require:

    • Water

    • Food

    • Oxygen

    • Shelter

    • Light

    • Reasons for Needs:

    • To survive, grow, get energy, reproduce, and carry out life processes.

    • Sources of Essentials:

    • Water from rivers and lakes

    • Food from plants or animals

    • Air provides oxygen

    • Sunlight for energy

    • Shelter from the environment

Organic Nutrient Molecules

  1. Four Key Organic Nutrients:

    • Carbohydrates:

    • Provide energy

    • Proteins:

    • Build and repair body structures

    • Lipids (Fats):

    • Store energy and create cell membranes

    • Nucleic Acids (DNA & RNA):

    • Store and transmit genetic information

  2. Elements Making Up Each:

    • Carbohydrates: Carbon (C), Hydrogen (H), Oxygen (O)

    • Proteins: C, H, O, Nitrogen (N) (sometimes Sulfur (S))

    • Lipids: C, H, O (sometimes Phosphorus (P))

    • Nucleic Acids: C, H, O, N, P

  3. Body Utilization:

    • Carbohydrates: Main energy source

    • Proteins: Build/repair tissues and make enzymes

    • Lipids: Store energy, make cell membranes, provide insulation

    • Nucleic Acids: Store and transmit genetic information

  4. Polymers and Monomers:

    • Carbohydrates:

    • Polymer: Starch/Glycogen

    • Monomer: Glucose

    • Proteins:

    • Polymer: Protein/Polypeptide

    • Monomer: Amino acids

    • Lipids:

    • Polymer: Triglycerides/Fats

    • Monomer: Glycerol + Fatty acids

    • Nucleic Acids:

    • Polymer: DNA/RNA

    • Monomer: Nucleotides

  5. Origins of Nutrients:

    • Each organic nutrient is provided by specific kingdoms of organisms (e.g., plants for carbohydrates).

Enzymes

  1. Definition:

    • Enzymes are proteins made of amino acids structured for catalyzing chemical reactions.

  2. Classification:

    • Enzymes are organic molecules because they contain carbon and support life.

  3. Function:

    • Provide energy, build structures, store information, and support life processes.

  4. Factors Affecting Activity:

    • Temperature, pH, and substrate concentration.

Biogeochemical Cycles

  1. Four Key Cycles:

    • Water Cycle

    • Carbon Cycle

    • Nitrogen Cycle

    • Phosphorus Cycle

  2. Role in Organic Molecule Formation:

    • Water Cycle: Provides H₂O for hydrolysis and dehydration synthesis.

    • Carbon Cycle: Supplies carbon for building biomolecules.

    • Nitrogen Cycle: Provides nitrogen to make amino acids/nucleotides.

    • Phosphorus Cycle: Supplies phosphorus for nucleotides and ATP.

  3. Climate Change Indicators:

    • Rising temperatures

    • Melting ice

    • Extreme weather patterns

    • Increased greenhouse gases.

  4. Impact of Limiting Factors:

    • Addition of fertilizers can cause algal blooms, depleting oxygen and harming aquatic life.

Food Webs

  1. Definition:

    • A food web is a diagram illustrating energy and nutrient flow between organisms through various feeding relationships in an ecosystem.

  2. Components of Food Webs:

    • Producers: Convert sunlight into energy (e.g., plants, algae).

    • Primary Consumers: Herbivores that eat producers.

    • Secondary/Tertiary Consumers: Carnivores/omnivores that eat other consumers.

    • Decomposers: Break down dead organisms, returning nutrients to soil.

  3. Consequences of Removing Organisms:

    • Disruption of food webs can lead to population changes and ecosystem instability.

  4. Energy Pyramids:

    • Diagrams showing energy flow through trophic levels, indicating declining energy availability at higher levels and explaining fewer top predators.

Labs/Activities

  • Review:

    • Food Log

    • Organic Compounds in Food

    • Pine Barrens Food Web

    • Chemical Cycle diagrams

    • Test review worksheet.

Unit 2: Transport and Homeostasis

Movement of Substances

  • Methods of Movement:

  1. Diffusion:

    • Movement of substances from high to low concentration.

  2. Osmosis:

    • Movement of water across the membrane.

  3. Active Transport:

    • Energy-dependent movement of substances from low to high concentration.

  4. Exocytosis/Endocytosis:

    • Mechanisms for expelling (exocytosis) or taking in (endocytosis) large particles.

Factors Affecting Transport

  • Concentration differences (greater differences yield faster movements)

  • Temperature (higher temperatures increase rate of movement)

  • Size of molecules (smaller molecules are easier to move)

  • Type of transport (active transport requires energy, passive does not).

Chemistry of Bonding

  1. Covalent Bonding:

    • Definition: Electrons are shared between atoms forming stable bonds.

    • Application: In lipids, covalent bonds form between glycerol and fatty acids via ester bonds during dehydration synthesis.

  2. Hydrolysis and Dehydration Synthesis:

    • Hydrolysis: Uses water to break large molecules into smaller ones.

    • Dehydration Synthesis: Removes water to join small molecules into larger ones.

    • Water (H₂O) is involved as a reactant in hydrolysis and a product in dehydration synthesis.

  3. Saturated vs. Unsaturated Fats:

    • Saturated Fats:

    • No double bonds, raises LDL cholesterol levels if consumed excessively.

    • Typically derived from animal sources (e.g., butter, meat, cheese).

    • Unsaturated Fats:

    • Contains one or more double bonds, generally healthier for the heart.

    • Mostly from plant sources (e.g., oils, nuts, seeds, fish).

  4. Ionic Bonding:

    • Definition: One atom transfers electrons to another, forming charged ions that attract each other.

    • pH: A measure of a solution's acidity/basicity based on hydrogen ion concentration (H⁺).

  5. Acids and Bases:

    • Acids: Release H⁺ ions, pH below 7.

    • Bases: Release OH⁻ ions or accept H⁺ ions, pH above 7.

Water as a Polar Molecule

  • Significance of Polarity:

    • Water has an uneven charge distribution (partial positive and negative sides).

    • Explained Properties:

    • Cohesion: Causes water molecules to bond with each other.

    • Surface Tension: A strong surface created due to cohesive forces.

    • Transpiration: Cohesion aids in water transport in plants.

Cellular Transport Processes

  1. Types of Cellular Transport:

    • Passive Transport:

    • No energy used; substances move from high to low concentration (oxygen, carbon dioxide).

    • Active Transport:

    • Requires energy; moves substances from low to high concentration (ions, larger molecules).

    • Bulk Transport:

    • Uses vesicles to transport large particles (endocytosis and exocytosis).

  2. Differences in Transport Types:

    • Passive vs. Active Transport:

    • Passive: No energy, high to low concentration

    • Active: Requires energy, low to high concentration

    • Transport Proteins:

    • Help substances cross cell membranes via channels/carriers (passive) or pumps (active).

Types of Passive Transport:

  1. Diffusion:

    • Movement of molecules down their concentration gradient.

  2. Osmosis:

    • Specific type of diffusion for water through membranes.

  3. Facilitated Diffusion:

    • Utilizes transport proteins for moving substances down their concentration gradient.

  4. Types of Bulk Movement:

    • Exocytosis: Used to expel large molecules (e.g., waste, hormones).

    • Endocytosis: Used to intake large molecules.

    • Pinocytosis: Ingestion of liquid ("cell drinking").

    • Phagocytosis: Ingestion of large solids ("cell eating").

Osmosis and Solution Types

  • Solution Types:

  1. Hypotonic:

    • Lower solute concentration than the cell; water moves into the cell (cell swells).

  2. Hypertonic:

    • Higher solute concentration than the cell; water moves out of the cell (cell shrinks).

  3. Isotonic:

    • Equal solute concentration; water moves in and out evenly (cell remains unchanged).

  • Related Conditions:

  1. Plasmolysis:

    • Occurs when a cell loses water in a hypertonic solution (membrane pulls away).

  2. Cytolysis:

    • Occurs when a cell takes in excess water in a hypotonic solution (cell may burst).

  3. Turgor Pressure:

    • Pressure maintained by water in plant cells in a hypotonic environment (keeps cells firm).

  4. Dynamic Equilibrium:

    • Continuous molecular movement with no net concentration change across the membrane.

Organelles Involved in Transport

  1. Cell Membrane:

    • Controls entry and exit of substances.

  2. Endoplasmic Reticulum (ER):

    • Transports proteins and lipids within the cell.

    • Rough ER: Moves proteins.

    • Smooth ER: Moves lipids.

  3. Golgi Apparatus:

    • Modifies, packages, and ships molecules.

  4. Vesicles:

    • Transport substances in bulk to/from the cell.

  5. Cytoskeleton:

    • Aiding movement of vesicles and organelles.

Cell Membrane Structure and Function

  • Structure:

    • Composed of a phospholipid bilayer with embedded proteins.

    • Phospholipids: Form a selectively permeable barrier.

    • Proteins: Serve as channels, pumps, or receptors aiding transport/communication.

    • Cholesterol: Provides membrane stability and flexibility.

  • Why Bilayer?

    • Due to hydrophilic heads facing out and hydrophobic tails within, providing a durable barrier in aqueous environments.

  • Selectively Permeable Nature:

    • The hydrophobic interior restricts some molecules, while proteins facilitate specific substance passage.

Cell Walls

  • Function:

    • Provide structure and support for certain cells, aiding in transport by maintaining shape and preventing bursting.

    • Important for processes like osmosis and turgor pressure.

  • Organisms with Cell Walls:

    • Present in plants, fungi, bacteria, and some protists.

  • Composition:

    • Plants: Cellulose

    • Fungi: Chitin

    • Bacteria: Peptidoglycan

    • Some protists: Varies (e.g., cellulose or other polysaccharides)

Central Vacuoles

  • Function:

    • Store water, nutrients, and waste, assisting in transport and maintaining turgor pressure in plant cells.

  • Organisms:

    • Present in plant cells and some protists.

  • Role in Photosynthesis:

    • Maintain turgidity for optimal chloroplast positioning for sunlight capture.

Contractile Vacuoles

  • Function:

    • Found in some freshwater protists; pump out excess water for osmoregulation.

  • Importance for Life:

    • Prevent bursting in hypotonic conditions; vital for survival.

  • Example Organisms:

    • Freshwater protists (e.g., Paramecium) and unicellular algae.

Labs/Activities

  • Review:

    • The Effect of Acids and Bases on the Enzymatic Browning of Apples

    • Building Organic Molecules – Lipids

    • Mystery Lab (sugar cubes and tea bags)

    • Comparative Cell Diagrams

    • Osmosis in Red Onion Cells

    • Transport Lab Part II – Protista

    • Test review worksheet.