CSEC Biology cheat sheet

CSEC Biology: Core Concepts and Exam Facts

• Cell theory: all living things are made of cells; the cell is the basic unit of structure and function; new cells arise from pre-existing cells by division.

• Prokaryotic cells (bacteria) lack a membrane-bound nucleus and membrane-bound organelles; eukaryotic cells (plants, animals, fungi, protists) have a true nucleus and organelles such as mitochondria and chloroplasts.

• Plant cells uniquely possess a cellulose cell wall, a large permanent central vacuole, and chloroplasts; animal cells have centrioles and small temporary vacuoles and no cell wall.

• Organelle functions: nucleus controls activities and holds DNA; mitochondrion is the site of aerobic respiration (ATP release); chloroplast carries out photosynthesis; ribosome synthesises protein; rough endoplasmic reticulum transports protein; lysosome contains digestive enzymes.

• Diffusion is net movement of particles from high to low concentration (passive); osmosis is diffusion of water across a partially permeable membrane from dilute to concentrated solution; active transport moves substances against a concentration gradient using energy (ATP).

• Enzyme facts: biological catalysts that are proteins, are specific to their substrate, and are denatured by high temperature or extremes of pH; reaction rate peaks at the optimum temperature and pH.

• Photosynthesis equation: 6CO2 + 6H2O -> C6H12O6 + 6O2, requiring light and chlorophyll; light intensity, CO2 concentration and temperature are limiting factors.

• Aerobic respiration equation: C6H12O6 + 6O2 -> 6CO2 + 6H2O + energy; anaerobic respiration in muscle gives lactic acid, and in yeast gives ethanol and CO2 (fermentation).

• Classification hierarchy: Kingdom, Phylum, Class, Order, Family, Genus, Species; binomial nomenclature uses Genus (capitalised) plus species (lowercase), e.g. Homo sapiens.