Human Physiology Chapter 2

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Human Physiology Chapter 2
2012-01-25 19:27:31
Human Physiology From Cells systems

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  1. What are the levels of organization of the body?
    • Chemical level: a molecule in the membranes that encloses a cell
    • Cellular level: epithelial cell, cell=basic unit of life
    • Tissue level: layers of tissue in the stomach wall
    • Organ level: the stomach
    • System level: the digestive system
    • Organism level: the whole body
  2. What are the basic charactersitic of cells?
    • Smallest living subdivision of the human body
    • Diverse in structure and function
    • Divided into organelles
  3. What are organelles?
    • Structures and compartments in the cell
    • Isolation of chemical reactions
    • Each organelle performs a specific function
  4. What are the basic cell functions?
    • Obtain nutrients and oxygen from surrounding environment
    • Perform chemical reactions that provide energy
    • Eliminate carbon dioxide and other wastes
    • Synthesize needed cellular components
    • Control exchange of materials between cell and its surrounidng environment
    • Sensing and responding to changes in surrounding environment
    • Reproduction
  5. What are the three primary regions of the cells?
    • Plasma membrane
    • Cytoplasm
    • Nucleus
  6. What does the plasma membrane do?
    • Outer boundary of cell
    • Separates intracellular environment from the extracellular environment
    • Regulates movement of materials in and out of cell
  7. Describe the structure of the plasma membrane.
    • Composed of Lipids, Proteins and Carbohydrates
    • -Arranged in bylayer of phospholipids with proteins suspended and attached
    • -"Fluid mosaic model"
  8. What projects from the plasma membrane?
    • Microvilli
    • Cillia
    • Flagella
  9. Describe microvilli.
    • Found on the apical surface of some cells
    • Fingerlike projections
    • Greatly increase surface area
    • Facilate movement of materials between intracellular and extracellular fluids
  10. Describe Cillia
    • Hair-like structures projecting into the extracellular fluid
    • Contain microtubules
    • Generate flow in extracellular fluid
  11. Describe Flagella
    • Long whip-like structures found on mature sperm
    • Contain microtubule
    • Allows sperm to swim
  12. Cytoplasm?
    Portion of cell interior not occupied by the nucleus
  13. What does the cytoplasm consists of?
    • Organelles (little organs") - Distinct, highly organized, membrane-enclosed structures
    • Cytoskeleton - Framework of cell
    • Gel-like material inside cells outside organelles
  14. What are the function of the cytoplasm?
    • Enzymatic regulation of intermediate metabolism
    • Place where proteins are made
    • Storage of fat, glycogen and secretory vesicles
  15. What is the cytoskeleton?
    • Network of protein fibers throughout cytosol
    • Ex: Microtubules, Microfilaments
  16. What are the functions of the Cytoskeleton?
    • Structural support and shape of cell
    • Movement of materials inside the cell
    • External movement - Cilia and flagella
  17. What are some examples of Organelles?
    • Nucleus
    • Endoplasmic reticulum
    • Golgi complex
    • Lysosome
    • Perxisome
    • Mitochondrion
  18. What are Lysosomes and what do they do?
    • Sac-like organelles which contain enzymes
    • Break down large molecules
    • -cell's "digestive system"
    • Destroy: Bacteria, Old organelles, Food Molecules
  19. Give examples of Lysosome Disorders.
    • Lysosomal Storage Diseases
    • -Accumulation of macromolecules (proteins, polysaccharides, lipids) in the lysosomes
    • -Genetic failure to manufacture an enzyme needed for their breakdown
    • -Tay-Sach's Disease
  20. What does perxisomes do?
    • Membranous sacs
    • -Detoxify H2O2
    • -Breakdown of fatty acids
    • -Bud off from ER
    • -Choleserol synthesis
  21. What is a mitochondria and what does it do?
    • Structure - double membrane
    • Possess own DNA
    • Power generators of the cell - synthesize cellular fuel (ATP) using energy released from the breakdown of food
  22. What are Ribosomes?
    • Large protein-RNA complexes
    • Found free floating in cytosol or attached to endoplasmic reticulum
    • Synthesize proteins
  23. Rough Endoplasmic Reticulum
    • Coated with ribosomes
    • Synthesizes proteins for :
    • -Cell membranes
    • -Interior (lumen) of membrane-bound organelles
    • -Export out of the cell
  24. Smooth Endoplasmic Reticulum
    • No ribosomes
    • Functions
    • -Lipid synthesis
    • -Ca2+ storage
    • Metabolize various molecules
  25. Describe the Nucleus.
    • Cell's "control center"
    • Largest organelle
    • Surrounded by double lipid bilayer (nuclear envelope) linked to the cytosol by nuclear pores
    • Contain DNA in the form of chromosome
  26. What are chromatin?
    • DNA and associated proteins
    • One single DNA double-helix + associated proteins forms a chromosome
  27. Golgi Complex
    Stacks of flattened sacs
  28. What do the Golgi do?
    • Processes ER products into final form
    • Sort and direct finished products to final destinations (intracelluar or extracellular)
  29. Vesicles
    • Small membrane-enclosed chambers used to transport materials within the cell
    • -Delivery within and outside cells
  30. Describe the steps of protein synthesizes.
    • 1. The rough ER synthesizes proteins
    • 2. The smooth ER packages the products into transport vesicles, which bud off and move to the Golgi complex.
    • 3. The transport vesicles fuse with the Golgi complex, open up, and emty their contents into the closest Golgi sac.
    • 4. The golgi complex, modifies the proteins into final form; sorts and directs the finshed products
    • 5. Secretory vesicles bud off the Golgi complex and remain in the cytosol, storing the products until signaled to empty.
    • 6. On stimulation, secretory vesicles fuse with the plasma membrane, open, and empty.
    • 7. Lysosomes also bud from the Golgi.
  31. Genes
    • Sequences of DNA containing information needed to make proteins with the proper amino acid sequence
    • Genes can encode for more than one protein
    • Different types of cells express different sets of genes
  32. Genome
    The total of all the genes in the human body (~25,000)
  33. Proteome
    All the different proteins produced in the human body (~100,000)
  34. Structure of DNA
    • Double Helix
    • Nucleotide : Base, Phosphate, Sugar
  35. DNA as a Blueprint
  36. Transcription
    • complimentary base pairing of DNA
    • DNA read in groups of three nucleotides
    • Codon=mRNA
  37. In transcription, what determines the sequence of amino acids?
    The sequence of triplets
  38. Translation
    • RNA sequence read by ribosomes
    • -Ribosome binds to mRNA
    • -Reads codons
    • -Binds tRNA with complementary sequences (anticodons) carrying specific amino acids
    • -Catalyzes reaction that transfer the aminio acid from tRNA to a growing polypeptide chain
    • -Ribosome shifts, then reads the next codon and repeats the process
  39. Explain DNA Replication
    • DNA must be copied prior to cell division
    • Strands of a double helix are separated
    • Each strand used as a template to synthesize a new copy of the complementary strand
  40. Explain mitosis
    • Formation of two identical daughter cells
    • 4 Stages
    • Strands of a double helix are separated
    • Each strand used as a template to synthesize a new copy of the complementary strand
  41. What are the four stages of mitosis?
    • 1. Prophase - condensation of DNA
    • 2. Metaphase - chromosomes line up
    • 3. Anaphase - chromosomes are pull apart
    • 4. Telophase - plasma membranes and nucleus reform
  42. What are the 2 types of cell death?
    • Necrosis
    • Apoptosis
  43. Necrosis
    • Pathological cell death
    • -Death of cells damages adjacent cells
  44. Apoptosis
    • Homeostatic cell death
    • -Process where specific cells die off in a controlled fashion that does not damage adjacent cells.
  45. Metabolism
    • Energetic sum of all chemical reactions occuring in a living organism
    • -break down of some substances=catabolism
    • -build up of other substances=anabolism
  46. What is the first law First Law of Thermodynamics?
    Matter and energy cannot be created or destroyed, but can be converted from one form to another
  47. What is ATP
    • Adenosine Triphosphate
    • Energy carrier molecule
    • -ATP--> ADP + P, (energetically very favorable)
    • -Energy released is used to drive unfavorable reactions
    • ATP must be continually resynthesized by the cell from ADP and inorganic phosphate (Pi)
  48. Metabolism Pathways
    • long series of enzyme-catalyzed reactions
    • allow high degree of control + regulation
  49. How is the Metabolic Pathways regulated?
    By the end product inhibition enzymes
  50. What are the two methods for breaking down food?
    • 1. Aerobic Respiration: oxygen utilizing
    • 2. Anaerobic Respiration: no oxygen used
  51. Why does cellular respiration release energy in small steps?
    It would explode if all the energy were release at once.
  52. Explain Aerobic Respiration
    • Uses oxygen in breakdown of materials and release of energy
    • Energy is released in small increments via long metabolic pathways
    • -Allows cells to efficiently release and use energy contained in food molecules
  53. What are the three phases in Aerobic Respiration? What happens in each?
    • Glycolysis - Glucose --> pyruvic acid
    • Krebs Cycle - formation of electron carriers and CO2
    • Oxidative Phosphorylation - electron carriers used to generate ATP
  54. Glycolysis
    • Occurs in the cytoplasm
    • Breakdown of one glucose molecule into two pyruvate molecules
    • Anaerobic
  55. What is the net ATP gain from glycolysis?
  56. Anaerobic Respiration
    • Process of producing ATP without consuming oxygen
    • Used regularly by skeletal muscle fibers and red blood cells
    • Lactic Acid Frementation
    • -Pyruvic acid reacts with NADH to produce lactic acid and NAD+
    • -Regenerates NAD+ needed for glycolysis