Midterm-BIOMOLECULES(Cell,Buffer,Proteins)

• Biochemistry


  Scientific discipline that seeks to explain life at the molecular level
• Molecules studied in biochemistry

  • Nucleic acids
  • Carbohydrates
  • Proteins
  • Lipids

  
• Biochemistry


  Studies the physical structure and chemical reactivity of biomolecules
• Biochemistry


  Is a chemical science and a study in thermodynamics
• Cells


  • Are the building blocks of all organisms
  • In single-celled organisms, the cell is everything - no hierarchy of organization
• Cell theory


  • Cells are basic units of life
  • All living organisms are made up of cells
  • All cells come from preexisting cells
• Common components in cells

  • Enclosing plasma membrane
  • Cytoplasm
  • DNA
  • Ribosomes

  
• Prokaryotes


  • Are smaller than eukaryotes because of efficiency
  • Unicellular; may stick together to form associations & biofilms
  • Less than 1 mm in diameter
  • No membrane-enclosed internal compartments
  • Have a nucleoid
  • Have plasmids
  • Reproduce asexually through binary fission
  • Genetic recombination occurs through horizontal gene transfer
  • Flagella are simpler in nature
  • Metabolic processes include oxygenic & anoxygenic photosynthesis
  • Cell wall contains peptidoglycan
  • Are believed to be much like the first cells
• Eukaryotic cell


  • Organelles unique to animal cells: Centrosome, Lysosome
  • Organelles unique to plant cells: Cell wall, Chloroplast, Plastids, Central vacuole, Plasmodesmata
• Types of junctions


  • Tight junction
  • Gap junction
  • Desmosomes
• Properties of life


  • Order
  • Sensitivity or Response to Stimuli
  • Reproduction
  • Adaptation
  • Regulation/Homeostasis
  • Energy Processing
  • Evolution
• Levels of organization of living things

  • Atom
  • Molecule
  • Organelles
  • Cells
  • Tissues
  • Organs
  • Organ System
  • Organism
  • Population
  • Community
  • Ecosystem
  • Biosphere
• Evolution


  Source of diversity
• Phylogenetic tree


  Shows the evolutionary relationships among biological species based on similarities and differences in genetic or physical traits or both

  
• Carl Woese


  • Microbiologist that constructed a phylogenetic tree using data obtained from sequenced ribosomal RNA genes
  • Bacteria, Archaea: prokaryotic cells with microbes that lack membrane-enclosed nuclei and organelles
  • Archaea: extremophiles
  • Eukarya: includes unicellular organisms (protists), together with three remaining kingdoms (fungi, plants, and animals)

  
• Branches of biological study

  • Molecular biology and biochemistry
  • Forensic science
  • Neurobiology
  • Paleontology
  • Zoology and botany
• Cell types


  • Epithelial cells
  • Bone cells
  • Immune system cells
  • Blood and blood cells
• Cell membrane


  Extremely pliable structure composed of a phospholipid bilayer

  
• Hydrophilic phosphate head


  Phosphate + glycerol; negatively-charged; attracted to water in the intracellular fluid

  
• Hydrophobic lipid tail


  Saturated and unsaturated fatty acids; uncharged; meet at inner region of the membrane

  
• Phospholipids


  Amphipathic; contains both a hydrophilic and hydrophobic region
• Intracellular fluid (ICF)


  Fluid interior of the cell

  
• Extracellular fluid (ECF)


  Fluid environment outside the enclosure of the cell membrane

  
• Interstitial fluid (IF)


  Extracellular fluid not contained within blood vessels
• Membrane proteins


  • Integral protein: channel protein, cell recognition proteins (receptor, ligand)
  • Glycoprotein: glycocalyx
  • Peripheral protein

  
• Transport across the cell membrane

  Regulation of the concentration of substances inside the cell; includes ions and waste products

  
• Passive transport


  Requires no energy
• Active transport


  Uses ATP
• Concentration gradient


  Difference in concentration of a substance across a space
• Diffusion


  Movement of particles from an area of higher concentration to an area of lower concentration
• Facilitated diffusion


  Used for large, charged, polar substances; passive so does not require ATP
• Osmosis


  Diffusion of water through a semipermeable membrane; occurs when there is an imbalance of solutes outside vs. inside the cell
• Hypertonic


  Solute is highly concentrated outside the cell, water will come out from the cell into the solution resulting in crenation; in plant cells: plasmolyzed
• Hypotonic


  Solution outside the cell has solute in lower concentration, water from the solution will go inside the cell resulting in lysis; in plant cells: turgid
• Isotonic


  Solute inside and outside the cell is equal; achieved through homeostasis; in plant cells: flaccid
• Active transport


  Requires ATP, often with the help of carrier proteins, usually against its concentration gradient
• Facilitated diffusion


  • Movement of glucose into the cell using a carrier protein called the glucose transporter
  • Movement of sodium ions into the cell through membrane proteins that form sodium channels or pores
• Sodium-potassium pump (Na+/K+ ATPase)


  Abundant in nerve cells (neurons), maintaining electrochemical gradients across cell membranes
• Mnemonic: PISO


  Potassium in, sodium out
• Electrical gradient


  Difference in electrical charge across a space