Biology: pH Scale, Biomolecules, and Lipids

pH Scale

• Ranges from 0 to 14
• Most acidic at 0, least acidic at 14
• Logarithmic scale (10x difference between each unit)
• pH > 7 is basic
• pH < 7 is acidic

Biological Elements

• Four most prevalent: Hydrogen, Oxygen, Carbon, Nitrogen
• Percentages: Hydrogen (62%), Oxygen (25%), Carbon (9%), Nitrogen (1%)

Carbohydrates

• Composed of carbon, hydrogen, and oxygen (1:2:1 ratio)
• Types:
  • Monosaccharides: single ring of carbon atoms (e.g., glucose, fructose)
  • Disaccharides: two rings of carbon atoms (e.g., sucrose)
  • Polysaccharides: many rings of carbon atoms (e.g., glycogen, starch, cellulose)

Lipids

• Structures:
  • Fatty acids: chains of carbon and hydrogen with a carboxyl group at one end
  • Triglycerides: 3 fatty acids attached to glycerol
  • Phospholipids: 2 fatty acids attached to glycerol
  • Steroids: 4 fused rings (e.g., cholesterol)
• Saturated fatty acids: no double bonds, solid at room temperature
• Unsaturated fatty acids: at least one double bond, liquid at room temperature (cis or trans)

Nucleic Acids

• DNA and RNA structures:
  • Composed of nucleotides (sugar, nitrogenous base, phosphate group)
  • Double helix structure (DNA)
  • Single-stranded (RNA)
  • Different bases (DNA: A, T, C, G; RNA: A, U, C, G)
  • Phosphodiester bonds link the nucleotides in the chains

Proteins

• Composed of amino acids linked by peptide bonds
• Types of structures:
  • Primary: amino acid sequence
  • Secondary: alpha-helices or beta-sheets
  • Tertiary: 3D folded structure
  • Quaternary: multiple polypeptide chains

Central Dogma

• DNA replication, transcription, and translation
• DNA polymerase replicates DNA
• RNA polymerase transcribes DNA into RNA
• Ribosomes translate mRNA into proteins

Cell Organelles (and their function)

• ER: protein folding, glycosylation, lipid synthesis,
• Golgi apparatus: protein and lipid packaging and transport
• Mitochondria: ATP production
• Lysosomes: digestion of cellular waste
• Peroxisomes: oxidative reactions, detoxification
• Nucleus: DNA storage
• Nuclear envelope: separates nucleus from cytosol
• Ribosomes: protein synthesis
• Nucleolus: rRNA synthesis

Mitosis

• Cell division process involved in growth and repair
• Stages: Interphase, Prophase, Prometaphase, Metaphase, Anaphase, Telophase, and Cytokinesis

Meiosis

• Cell division process creating gametes (sex cells)
• Stages: Meiosis I, including Prophase I, Metaphase I, Anaphase I, Telophase I, and Meiosis II, including Prophase II, Metaphase II, Anaphase II, and Telophase II

Cancer

• Hallmarks of cancer: evading growth suppressors, deregulating cellular energetics, sustaining proliferative signaling, enabling replicative immortality, genome instability and mutation, activating invasion and metastasis, inducing angiogenesis, resisting cell death, avoiding immune destruction
• Vocabulary: tumor, malignant, benign, proto-oncogenes, tumor-suppressor genes

Genetics

• Independent assortment: alleles separate independently
• Nondisjunction: failure of chromosomes to separate correctly
• Codominance: both alleles are expressed
• Incomplete dominance: phenotype is intermediate
• Incomplete penetrance: genotype does not always result in phenotype
• Epistasis: one gene affects the phenotypic expression of another
• Mosaic: having more than one genotype in a single organism
• Chimera: result of combining two zygotes

Digestive System

• Mouth: intake & chewing
• Pharynx: throat, food passageway
• Esophagus: food transport tube
• Stomach: food mixing, digestion
• Small intestines: absorption of nutrients
• Large intestines: water absorption, waste elimination

Nutrition

• Macronutrients: carbohydrates, fats, proteins
• Micronutrients: vitamins, minerals

Cardiovascular System

• Veins: carry deoxygenated blood towards the heart
• Arteries: carry oxygenated blood away from the heart
• Capillaries: connect arteries and veins for exchange
• Heart chambers: right and left atria, right and left ventricles
• Blood flow through the heart: superior vena cava, right atrium, right ventricle, pulmonary artery, lungs, pulmonary vein, left atrium, left ventricle, aorta

Urinary System

• Kidneys: filter blood and produce urine
• Nephrons: functional units of the kidneys
• Glomerular filtration: non-selective filtration of blood
• Tubular reabsorption: selective reabsorption of needed substances from filtrate
• Tubular secretion: active transport of substances from blood into filtrate
• Urine production and elimination

Immune System

• Innate immunity: immediate response
• Adaptive immunity: slower, specific response (using T and B cells)
• Somatic recombination: shuffling of gene segments creating diverse antibodies
• B cells: antibody production
• T cells: cell-mediated immunity

Lymphatic System

• Organs: Peyer's patches, tonsils, thymus, spleen, appendix, lymph nodes

Test your understanding of key biological concepts including the pH scale, the four most prevalent biological elements, and the structures of carbohydrates and lipids. This quiz covers the composition and classification of essential biomolecules in living organisms. Challenge yourself with questions on acids, bases, and the building blocks of life.