Science 3

• Biology is the area of science dealing with living things
• It includes biological concepts and process skills, technology, and attitudes and values for addressing the needs and problems of society
• Genetic engineering techniques and increased understanding of the molecular basis of cellular processes have led to the emergence of biotechnology
• Organic compounds are characterized by the presence of carbon
• Carbohydrates:

  • Made up of carbon, hydrogen, and oxygen atoms
  • Sizes range from simple sugars to complex forms like starch and glycogen
  • Serve as energy molecules or reserves in living organisms
  • Cellulose gives strength and protection to plant cells
• Lipids:

  • Macromolecules such as fats, oils, and waxes
  • Made up of carbon, hydrogen, and oxygen
  • Fats are formed by fatty acids and glycerol
  • Some excess food is stored as fats
  • Waxes serve as protective body coverings
• Proteins:

  • Made up of repeating units of amino acids
  • Component of muscles and all other tissues
  • Enzymes control the rate of chemical reactions inside the cell
• Enzymes:

  • Proteins that act as catalysts
  • Specific in their actions
  • Not used up in the reaction
• Nucleic Acids:

  • Carriers of hereditary information in living organisms
  • Control the organism's appearance and abilities
• Vitamins:

  • Necessary in very small amounts for body growth and activity
  • Needed to prevent certain diseases
  • Essential organic substances not required as energy sources
• Inorganic compounds are characterized by the absence of carbon
• Carbon dioxide:

  • Supplies carbon found in substances made by living things
• Water:

  • Most abundant inorganic compound
  • Medium of transport for food, minerals, and other substances in living systems
• Life functions:

  • All living things carry out activities to maintain life
• Minerals:

  • Chemical elements or compounds occurring naturally
  • Absorbed by plant roots in the form of ions
• Nutrition:

  • Process of ingesting and absorbing food for energy, growth, and repair
  • Transport:
  • Involves movement of nutrients, water, ions, and other materials into and out of cells and tissues
  • Metabolism:
  • Process of forming complex molecules for growth and breaking down molecules to release energy
  • Homeostasis:
  • Internal balance in all aspects of metabolism and biological function
  • Digestion:
  • Breaks down food into smaller molecules and releases energy
  • Absorption:
  • Allows small molecules to pass through cell membranes
  • Behavior:
  • Response to stimuli in the environment
• • Excretion:
  • Elimination of waste products
  • Reproduction:
  • Process by which organisms produce offspring
• Cell structure:

  • Cells are the smallest structures capable of basic life processes
• Prokaryotic cell:

  • Found in bacteria and archaebacteria
  • Components, including DNA, mingle freely in the cell's interior
  • Can be rod-like, spherical, or spiral in shape
  • Surrounded by a protective cell wall
  • Live in a watery environment
• Eukaryotic animal cells:

  • Typically ten times larger than prokaryotic cells
  • Plasma membrane forms the cell's outer boundary
  • Contains membrane-bound organelles like the nucleus, mitochondria, ribosomes, Golgi apparatus, and lysosomes
• Organelles enable specialized functions to be carried out efficiently
• Building of proteins and lipids takes place in separate organelles with specialized enzymes
• Plasma membrane surrounds eukaryotic cells and is composed of two layers of phospholipid molecules interspersed with cholesterol and proteins
• Nucleus of a cell is the largest organelle in an animal cell and contains numerous strands of DNA
• Endoplasmic reticulum is an elongated membranous sac attached to the nuclear membrane and takes two forms: rough and smooth
• Ribosomes in eukaryotic cells help assemble proteins that are typically exported from the cell
• Smooth endoplasmic reticulum lacks ribosomes and functions in lipid synthesis, carbohydrate metabolism, detoxification, and calcium ion storage
• Golgi apparatus is an organelle packed with enzymes that complete the processing of proteins
• Lysosomes function as the cell's recycling center and garbage disposal
• Cytoskeleton is a dynamic network of protein tubes, filaments, and fibers that provide shape and structure to the cell
• Mitochondria are the powerhouses of the cell, converting nutrients into energy in the form of ATP
• Plant cells have additional features compared to animal cells, including chloroplasts, a central vacuole, and a cell wall
• Central vacuole stores water, nutrients, pigments, and plant wastes in a plant cell
• Chloroplasts convert light energy into glucose through photosynthesis
• Cell wall surrounds and protects the plasma membrane in plant cells, providing rigidity and support
• Biologists use binomial nomenclature to give scientific names to organisms, using genus and species names
• Levels of classification include kingdom, phylum, class, order, family, genus, and species
• Family is a group of genera with related characteristics, genus is a group of closely related species, and species are able to interbreed and produce fertile offspring
• The five kingdoms are Prokarya, Animalia, and Eukarya, with differences in the presence of a nucleus and other major characteristics
• Kingdom Animalia is comprised of multi-celled organisms that develop from an embryo resulting from fertilization