Cell Structure and Function

Cell Structure and Function

• Cells are the basic units of life, exhibiting diverse structures and functions
• Prokaryotic cells (bacteria and archaea) lack a membrane-bound nucleus and other organelles, while eukaryotic cells (plants and animals) possess a nucleus and organelles
• Common cellular components include:
  • Cell membrane: A selectively permeable barrier regulating the passage of substances
  • Nucleus: Contains the genetic material (DNA)
  • Cytoplasm: The fluid-filled region within the cell membrane, housing organelles
  • Mitochondria: Sites of cellular respiration, generating ATP (energy)
  • Ribosomes: Sites of protein synthesis
  • Endoplasmic reticulum (ER): Involved in protein and lipid synthesis
  • Golgi apparatus: Modifies, sorts, and packages proteins
  • Vacuoles: Storage structures, especially prominent in plant cells
  • Chloroplasts: Found in plant cells, perform photosynthesis, converting light energy into chemical energy
  • Lysosomes: Contain digestive enzymes, breaking down materials
  • Cytoskeleton: Network of protein fibers providing structural support and facilitating movement within the cell

Cellular Processes

• Cellular respiration: A process that breaks down glucose to release energy in the form of ATP
• Photosynthesis: A process used by plants and some other organisms to convert light energy into chemical energy in the form of glucose
• Mitosis: The process of cell division resulting in two genetically identical daughter cells, critical for growth and repair
• Meiosis: A specialized form of cell division resulting in four genetically unique daughter cells, essential for sexual reproduction

Genetics

• DNA (deoxyribonucleic acid) is the primary hereditary material
• DNA is organized into structures called chromosomes
• The structure of DNA is a double helix
• Genes, segments of DNA, code for specific proteins
• The process of protein synthesis involves transcription (DNA to RNA) and translation (RNA to protein)
• Mutations are changes in DNA sequence, potentially causing alterations in protein function
• Genetic variation is crucial for adaptation and evolution

Biological Systems

• Organisms are made up of organ systems, working together to maintain homeostasis
• The cardiovascular system transports oxygen and nutrients throughout the body
• The respiratory system facilitates gas exchange (oxygen and carbon dioxide)
• The digestive system breaks down food for absorption
• The nervous system coordinates bodily functions
• The endocrine system regulates the body using hormones
• The excretory system eliminates waste products
• The musculoskeletal system provides support and movement

Ecology

• Ecosystems consist of interacting biotic (living) and abiotic (non-living) components
• Food chains and webs depict energy flow within ecosystems
• Population dynamics describe changes in population size over time
• Biodiversity encompasses the variety of life on Earth, essential for ecosystem stability
• Ecological succession describes the process of ecosystem development over time
• Relationships between organisms, including competition, predation, and symbiosis, are fundamental to ecosystem dynamics

Evolution

• Evolution is the process of change in heritable characteristics of biological populations over successive generations
• Natural selection is a key mechanism of evolution, favoring traits that enhance survival and reproduction
• Common ancestry explains the shared characteristics between different species
• Phylogenetic trees depict evolutionary relationships among organisms based on shared characteristics
• Speciation is the process by which new species arise
• The fossil record provides evidence for evolutionary change over time