Introduction to Genetics

• Biology is the scientific study of life and living organisms.
• It encompasses a broad range of topics, from the molecular mechanisms within cells to the interactions of entire ecosystems.
• Key themes in biology include evolution, genetics, ecology, physiology, and cell biology.

Genetics

• Genetics is the study of heredity and variation in living organisms.
• It explores how traits are passed from parents to offspring through genes.
• Genes are segments of DNA that contain instructions for building proteins, which determine traits.
• DNA (deoxyribonucleic acid) is the molecule that carries genetic information in most organisms.
• Chromosomes are structures within cells that contain DNA.
• Genes reside on chromosomes.
• Alleles are different versions of a gene.
• Genotype refers to the genetic makeup of an organism.
• Phenotype refers to the observable characteristics of an organism, resulting from the interaction of its genotype with the environment.
• Mutation is a change in the DNA sequence and can lead to altered traits.
• Genetic engineering involves manipulating the genes of organisms for various purposes.
• Mendelian genetics describes the principles of inheritance based on the work of Gregor Mendel, including segregation and independent assortment.
• Population genetics studies the genetic variation within and among populations.
• Genomics involves the study of entire genomes, including gene sequencing and analysis.

Evolution

• Evolution is the process of change in the heritable characteristics of biological populations over successive generations.
• Natural selection is a mechanism of evolution where organisms with advantageous traits are more likely to survive and reproduce.
• Adaptation is the process by which populations become better suited to their environment through natural selection.
• Speciation is the process by which new species arise from existing ones.
• Evidence for evolution comes from various sources, including the fossil record, comparative anatomy, embryology, and molecular biology.
• The fossil record provides a history of life on Earth and shows how organisms have changed over time.
• Comparative anatomy reveals similarities and differences in the structures of different organisms, indicating common ancestry.
• Homologous structures are structures that have a common origin but may have different functions.
• Analogous structures are structures that have similar functions but different origins, indicating convergent evolution.
• Molecular biology provides evidence for evolution through the comparison of DNA and protein sequences.
• Phylogeny is the study of the evolutionary relationships among organisms.
• Genetic drift is a random process that can cause changes in the genetic makeup of populations.
• Gene flow is the movement of genes between populations.

Ecology

• Ecology is the study of the interactions between organisms and their environment.
• It examines how organisms interact with each other and with the physical world.
• Ecosystems are communities of organisms interacting with their physical environment.
• Populations are groups of individuals of the same species living in the same area.
• Communities are groups of different species living in the same area.
• Habitats are the places where organisms live.
• Niches are the roles that organisms play in their environment.
• Food chains and food webs describe the flow of energy and nutrients through ecosystems.
• Trophic levels represent the different feeding levels in an ecosystem.
• Producers are organisms that make their own food through photosynthesis or chemosynthesis.
• Consumers are organisms that obtain energy by eating other organisms.
• Decomposers are organisms that break down dead organic matter.
• Biogeochemical cycles describe the movement of elements, such as carbon, nitrogen, and phosphorus, through ecosystems.
• Population ecology studies the factors that affect population size and growth.
• Community ecology studies the interactions between different species in a community.
• Ecosystem ecology studies the flow of energy and nutrients through ecosystems.
• Conservation biology is the study of how to protect and manage biodiversity.

Physiology

• Physiology is the study of the functions and mechanisms in a living system.
• It explores how organisms perform their vital functions, from the molecular level to the whole-organism level.
• Homeostasis is the maintenance of a stable internal environment in the body.
• Organ systems are groups of organs that work together to perform specific functions.
• The nervous system controls and coordinates bodily functions through electrical and chemical signals.
• The endocrine system regulates bodily functions through the release of hormones.
• The cardiovascular system transports blood, oxygen, and nutrients throughout the body.
• The respiratory system is responsible for gas exchange, taking in oxygen and releasing carbon dioxide.
• The digestive system breaks down food and absorbs nutrients.
• The excretory system removes waste products from the body.
• The immune system protects the body from pathogens and disease.
• Muscle physiology studies the structure and function of muscles.
• Neurophysiology studies the function of the nervous system.
• Endocrinology studies the endocrine system and its hormones.
• Cardiovascular physiology studies the function of the heart and blood vessels.
• Respiratory physiology studies the function of the lungs and respiratory system.

Cell Biology

• Cell biology is the study of cells, their structure, function, and behavior.
• The cell is the basic unit of life.
• Cell theory states that all living organisms are composed of cells, cells are the basic units of structure and function in living organisms, and all cells arise from pre-existing cells.
• Eukaryotic cells have a nucleus and other membrane-bound organelles.
• Prokaryotic cells lack a nucleus and other membrane-bound organelles.
• The plasma membrane is the outer boundary of the cell and controls the movement of substances into and out of the cell.
• The nucleus contains the cell's DNA and controls gene expression.
• Ribosomes are responsible for protein synthesis.
• The endoplasmic reticulum (ER) is involved in protein and lipid synthesis.
• The Golgi apparatus processes and packages proteins.
• Mitochondria are the powerhouses of the cell and produce energy through cellular respiration.
• Lysosomes contain enzymes that break down cellular waste and debris.
• Cytoskeleton is a network of protein filaments that provides structural support and facilitates cell movement.
• Cell division is the process by which cells reproduce, including mitosis and meiosis.
• Mitosis is the process of cell division that produces two identical daughter cells.
• Meiosis is the process of cell division that produces four haploid gametes (sex cells).
• Cell signaling is the process by which cells communicate with each other.
• Cancer is a disease characterized by uncontrolled cell growth and division.