Biology 11 & 12 Cheatsheet

Cheatsheet Content

### Cell Structure & Function - **Prokaryotic Cells:** No nucleus or membrane-bound organelles (e.g., bacteria). DNA in nucleoid region. - **Eukaryotic Cells:** Nucleus and membrane-bound organelles (e.g., plants, animals, fungi, protists). - **Key Organelles:** - **Nucleus:** Contains genetic material (DNA), controls cell activities. - **Mitochondria:** Site of cellular respiration, produces ATP (powerhouse of cell). - **Chloroplasts (Plants/Algae):** Site of photosynthesis, converts light energy into chemical energy. - **Endoplasmic Reticulum (ER):** Network of membranes. - **Rough ER:** Has ribosomes, involved in protein synthesis and modification. - **Smooth ER:** No ribosomes, involved in lipid synthesis, detoxification. - **Ribosomes:** Site of protein synthesis (translation). - **Golgi Apparatus:** Modifies, sorts, and packages proteins and lipids. - **Lysosomes (Animal Cells):** Contain digestive enzymes, break down waste. - **Vacuoles (Plant Cells):** Large central vacuole stores water, nutrients, maintains turgor pressure. - **Cell Membrane:** Phospholipid bilayer, selectively permeable, regulates passage of substances. - **Cell Wall (Plants/Fungi/Bacteria):** Provides structural support and protection. ### Cell Transport - **Passive Transport:** No energy required, movement down concentration gradient. - **Diffusion:** Movement of molecules from high to low concentration. - **Osmosis:** Diffusion of water across a selectively permeable membrane. - **Facilitated Diffusion:** Movement with help of transport proteins (e.g., channels, carriers). - **Active Transport:** Requires energy (ATP), movement against concentration gradient. - **Pumps:** e.g., Sodium-Potassium pump. - **Bulk Transport:** - **Endocytosis:** Cell takes in substances (Phagocytosis - solids, Pinocytosis - liquids). - **Exocytosis:** Cell expels substances. ### Biological Molecules - **Carbohydrates:** - **Monomer:** Monosaccharides (e.g., glucose, fructose). - **Polymer:** Polysaccharides (e.g., starch, glycogen, cellulose, chitin). - **Function:** Energy source, structural support. - **Lipids:** - **Types:** Fats, oils, phospholipids, steroids. - **Structure:** Hydrophobic. Fats/oils: glycerol + fatty acids. Phospholipids: glycerol + 2 fatty acids + phosphate group. - **Function:** Energy storage, cell membrane component, hormones. - **Proteins:** - **Monomer:** Amino acids (20 different types). - **Polymer:** Polypeptides. - **Structure:** Primary (amino acid sequence), Secondary (alpha-helix, beta-pleated sheet), Tertiary (3D folding), Quaternary (multiple polypeptide chains). - **Function:** Enzymes, structural components, transport, immunity, hormones. - **Nucleic Acids:** - **Monomer:** Nucleotides (sugar, phosphate, nitrogenous base). - **Polymer:** DNA (deoxyribonucleic acid), RNA (ribonucleic acid). - **Function:** Store and transmit genetic information. ### Enzymes - **Definition:** Biological catalysts, mostly proteins, speed up biochemical reactions without being consumed. - **Mechanism:** Bind to specific substrates at the active site, lowering activation energy. - **Factors Affecting Activity:** Temperature, pH, substrate concentration, enzyme concentration, inhibitors. - **Denaturation:** Loss of enzyme's 3D structure and function due to extreme conditions. ### Photosynthesis - **Equation:** $6CO_2 + 6H_2O + \text{Light Energy} \rightarrow C_6H_{12}O_6 + 6O_2$ - **Location:** Chloroplasts (in plant cells). - **Stages:** - **Light-Dependent Reactions:** Occur in thylakoid membranes. Light energy converted to ATP and NADPH. Water is split, releasing $O_2$. - **Light-Independent Reactions (Calvin Cycle):** Occur in stroma. Uses ATP and NADPH to convert $CO_2$ into glucose. ### Cellular Respiration - **Equation:** $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{ATP (Energy)}$ - **Location:** Cytoplasm (glycolysis) and Mitochondria (Krebs cycle, ETC). - **Stages:** - **Glycolysis:** Glucose split into 2 pyruvate molecules. Occurs in cytoplasm. Produces small amount of ATP and NADH. - **Krebs Cycle (Citric Acid Cycle):** Pyruvate converted to Acetyl-CoA, enters cycle. Produces ATP, NADH, FADH2, $CO_2$. Occurs in mitochondrial matrix. - **Electron Transport Chain (ETC):** Electrons from NADH and FADH2 passed along protein complexes. Creates proton gradient, used by ATP synthase to produce large amounts of ATP. Occurs in inner mitochondrial membrane. - **Anaerobic Respiration (Fermentation):** Occurs without $O_2$. Produces less ATP. - **Lactic Acid Fermentation:** In animals (e.g., muscle cells). - **Alcoholic Fermentation:** In yeast. ### Genetics & Heredity - **DNA Structure:** Double helix, sugar-phosphate backbone, nitrogenous bases (A-T, C-G). - **DNA Replication:** Semiconservative process, produces two identical DNA molecules. - **Central Dogma:** DNA $\rightarrow$ RNA $\rightarrow$ Protein. - **Transcription:** DNA to mRNA. Occurs in nucleus. - **Translation:** mRNA to protein. Occurs in ribosomes. - **Codon:** Three-nucleotide sequence on mRNA that codes for an amino acid. - **Mendelian Genetics:** - **Allele:** Different forms of a gene. - **Genotype:** Genetic makeup (e.g., AA, Aa, aa). - **Phenotype:** Observable traits. - **Dominant/Recessive:** Dominant allele expressed over recessive. - **Homozygous/Heterozygous:** Homozygous (AA, aa), Heterozygous (Aa). - **Punnett Squares:** Predict offspring genotypes/phenotypes. - **Monohybrid Cross:** Cross involving one trait (e.g., Tt x Tt). - **Dihybrid Cross:** Cross involving two traits (e.g., TtYy x TtYy). - **Non-Mendelian Inheritance:** - **Incomplete Dominance:** Blending of traits (e.g., red + white = pink). - **Codominance:** Both alleles expressed fully (e.g., AB blood type). - **Multiple Alleles:** More than two alleles for a trait (e.g., ABO blood type). - **Sex-Linked Traits:** Genes on sex chromosomes (e.g., color blindness, hemophilia). ### Cell Division - **Mitosis (Somatic Cells):** - Purpose: Growth, repair, asexual reproduction. - Stages: Prophase, Metaphase, Anaphase, Telophase (PMAT). - Result: Two identical diploid (2n) daughter cells. - **Meiosis (Germ Cells):** - Purpose: Sexual reproduction, produces gametes. - Stages: Meiosis I (Prophase I, Metaphase I, Anaphase I, Telophase I) and Meiosis II (PMAT II). - Key Events: - **Crossing Over (Prophase I):** Exchange of genetic material between homologous chromosomes, increases genetic variation. - **Independent Assortment (Metaphase I):** Random alignment of homologous chromosomes. - Result: Four genetically different haploid (n) daughter cells. ### Evolution - **Natural Selection:** "Survival of the fittest." - Variation in population. - Heritability of traits. - Differential survival/reproduction. - Adaptation to environment. - **Evidence of Evolution:** - Fossil record. - Comparative anatomy (homologous, analogous structures). - Embryology. - Molecular biology (DNA, protein similarities). - Biogeography. - **Speciation:** Formation of new species. - **Allopatric Speciation:** Geographic isolation. - **Sympatric Speciation:** Occurs in same geographic area. ### Ecology & Ecosystems - **Levels of Organization:** Organism ### Human Body Systems - **Digestive System:** Breaks down food, absorbs nutrients. - Organs: Mouth, esophagus, stomach, small intestine, large intestine, liver, pancreas. - **Circulatory System:** Transports oxygen, nutrients, hormones; removes waste. - Components: Heart, blood vessels (arteries, veins, capillaries), blood. - **Respiratory System:** Gas exchange ($O_2$ in, $CO_2$ out). - Organs: Lungs, trachea, bronchi, diaphragm. - **Nervous System:** Controls and coordinates body functions. - Components: Brain, spinal cord, nerves. - **Neurons:** Basic unit (dendrite, cell body, axon). - **Synapse:** Junction between neurons. - **Endocrine System:** Produces hormones, regulates growth, metabolism, reproduction. - Glands: Pituitary, thyroid, adrenal, pancreas, gonads. - **Immune System:** Defends against pathogens. - **Non-specific (Innate) Immunity:** First line of defense (skin, fever, phagocytes). - **Specific (Adaptive) Immunity:** Targets specific pathogens (B cells, T cells, antibodies).