Unit 2: Basic Chemistry

Unit 2: Basic Chemistry

• Only one element can be broken down into one substance (e.g., H, C, O)
• More than one element can be broken down into multiple substances (e.g., H₂O, O₂, H₂).
• Atoms of different elements combine to form chemical combinations (e.g., H₂O, C₆H₁₂O₆, CO₂).
• Dehydration synthesis is used to create larger molecules.
• Electronegativity of an atom is a measure of its tendency to attract electrons from another atom. Closer to being full means it's more electronegative, and this trend increases as you move to the right on the periodic table.
• Attraction between molecules is called hydrogen bonding, a weak bond due to the uneven distribution of charge within the molecule, causing polarity.
• Polar covalent bonds are stronger than nonpolar covalent bonds.
• Different types of chemical reactions include exothermic (releases heat) and endothermic (absorbs heat).
• Acids increase the concentration of H+ ions in a solution, while bases reduce it.
• Chemical reactions can change the shape and function of molecules and the energy levels of the system; high levels indicate kinetic energy.
• Stabilizing pH is accomplished by removing or replacing H+ ions. Protons act as sensors.

Different Types of Chemical Reactions

• Exothermic reactions release heat, while endothermic reactions absorb heat.
• Acids increase the concentration of H+ ions in a solution.
• Bases reduce the concentration of H+ ions in a solution.
• Chemical reactions change shape, function, and energy levels.
• High levels of energy indicate kinetic energy.
• Maintaining a stable pH is crucial, achieved through the addition or removal of H+ ions.

Unit 3: Cellular Level of Organization

• Cells are the basic units of life.
• Prokaryotic cells lack a nucleus; eukaryotic cells have a nucleus.
• A nucleus contains genetic material (DNA).
• Cytoplasm is a gel-like substance inside cells that holds organelles.
• The plasma membrane controls the passage of substances in and out of a cell.
• A cell wall is a rigid outer layer found in plant, fungi, and some bacterial cells.
• Ribosomes produce proteins in both prokaryotic and eukaryotic cells.
• Endoplasmic Reticulum (ER) transports materials; smooth ER synthesizes lipids, and rough ER synthesizes proteins.
• Golgi apparatus modifies, sorts, and packages proteins for transport.
• Mitochondria are the "powerhouses" of cells, performing cellular respiration.
• Chloroplasts are the sites of photosynthesis in plant cells.
• Lysosomes contain digestive enzymes to break down waste and cell debris.
• Vacuoles are storage sacs for nutrients, water, and waste.
• Cytoskeleton provides structure and helps with cell movement.

Cellular Level of Organization (continued)

• Microtubules and microfilaments are part of the cytoskeleton.
• Centrioles aid in cell division in animal cells.
• DNA (Deoxyribonucleic Acid) is genetic material, and RNA (Ribonucleic Acid) plays a role in protein synthesis.
• Chromosomes are condensed structures of DNA during cell division; mitosis and meiosis are types of cell division.
• Diffusion is the movement of particles from high to low concentration.
• Osmosis is the diffusion of water across a membrane.
• Active transport moves molecules against a concentration gradient (requiring energy).
• Endocytosis is taking substances into a cell, and exocytosis is expelling substances from it.
• Cell signaling involves communication between cells via chemical signals.
• Tissues are groups of cells working together, maintaining homeostasis, a stable internal environment.

Types of Tissues

• Tissues support, connect, and separate tissues and organs.
• Extracellular matrix functions as a support network.
• Fibroblasts produce the fibrous components of connective tissue.
• Collagen fibers provide strength, and elastic fibers allow for flexibility.
• Tissues include loose connective tissue, dense connective tissue, adipose tissue, cartilage, bone, and blood.

Unit 3: Integumentary System

• Epidermis (thin) + Dermis (thick) + Hypodermis (anchors skin to deeper tissues)
• Sweat glands (regulate body temperature)
• Arrector pili muscles control hair follicles (goosebumps)
• Skin is an organ.

Skin Composition & Structure

• Skin is composed of several layers, including stratum corneum(dead cells), stratum lucidum (clear layer), stratum granulosum (granular layer), stratum spinosum (spiny layer), and stratum basale (base layer).
• Keratinocytes produce keratin, a protein that waterproofs skin.
• Melanocytes produce melanin, a pigment that gives skin its color and filters UV light.
• Dendritic cells fight against foreign materials (antigens)
• Intercellular junctions (tight junctions, desmosomes, gap junctions) help cells bind together and form barriers in the skin

Skin Layers and Functions

• Papillary layer contains capillaries, lymphatic vessels, and nerves.
• Reticular layer provides strength and flexibility to skin.
• Melanin helps determine skin color

Burns & Age Changes

• First degree burns affect the epidermis; second degree burns affect the epidermis and dermis; third degree burns affect all layers.
• Skin's response to injury, sensitivity to heat and cold, changes due to age

Cancer

• Benign tumors do not spread.
• Malignant tumors spread, including basal and squamous cell carcinomas.

Immune System

• Innate immunity is present at birth, providing a quick response to pathogens (inflammation, skin barrier, natural killer cells).
• Acquired immunity develops after exposure to pathogens and involves an antibody-mediated response (humor) and cellular response (cell-mediated).
• Key cells of the immune system include neutrophils, macrophages, dendritic cells, natural killer cells, antigen-presenting cells, B lymphocytes (antibody production), and T lymphocytes (cell-mediated response).
• Immunity protects the body through barriers (skin, mucous membranes) and inflammatory responses.

Body Systems

• Tonsils (immune response) + Thymus + Spleen (blood filtering and immune function).