Biology Fundamentals

Cell Biology

• Cell Structure:
  • Plasma membrane: semi-permeable membrane that surrounds the cell
  • Cytoplasm: jelly-like substance inside the cell membrane
  • Nucleus: control center of the cell where DNA is stored
  • Mitochondria: generate energy for the cell through cellular respiration
• Cellular Processes:
  • Photosynthesis: process by which plants convert light energy into chemical energy
  • Cellular Respiration: process by which cells generate energy from glucose
  • Mitosis: process of cell division that results in two identical daughter cells
  • Meiosis: process of cell division that results in four non-identical daughter cells (gametes)

Genetics

• Mendel's Laws:
  • Law of Segregation: each pair of alleles separates during gamete formation
  • Law of Independent Assortment: alleles of different genes are sorted independently
  • Law of Dominance: dominant allele is expressed over recessive allele
• DNA Structure:
  • Double helix model: two complementary strands of nucleotides twisted together
  • Nucleotides: building blocks of DNA, composed of sugar, phosphate, and nitrogenous base
• Genetic Variation:
  • Mutations: changes in DNA sequence that can result in genetic variation
  • Genetic Drift: random changes in allele frequency over time
  • Gene Flow: movement of genes from one population to another

Evolution

• Mechanisms of Evolution:
  • Natural Selection: process by which organisms with favorable traits are more likely to survive and reproduce
  • Genetic Drift: random changes in allele frequency over time
  • Gene Flow: movement of genes from one population to another
  • Mutation: changes in DNA sequence that can result in genetic variation
• Evidence for Evolution:
  • Fossil Record: chronological record of ancient life forms
  • Comparative Anatomy: similarities and differences in body structures across species
  • Molecular Biology: similarities and differences in DNA and protein sequences across species

Ecosystems and Ecology

• Ecosystem Components:
  • Producers: organisms that produce their own food through photosynthesis
  • Consumers: organisms that obtain energy by consuming other organisms
  • Decomposers: organisms that break down dead organic matter
• Energy Flow:
  • Energy Pyramid: graphical representation of energy flow through an ecosystem
  • Food Chain: sequence of organisms that eat other organisms
• Ecological Interactions:
  • Symbiosis: close and often long-term relationship between different species
  • Competition: struggle for limited resources between organisms
  • Predation: predator-prey relationships