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Chapter 3: The Chemical Basis of Life II, Chapter 4: General Features of…

- - - - identical bonding relationships but different spatial positioning of atoms
      - cis-trans isomers
        
        positioning around double bond
      - enantiomers
        
        mirror image molecules
    - - contain same atoms but in different bonding relationships
- - - - 5 or 6 carbons. pentoses & hexose
      - ring or linear structure
    - - consist 2 monosaccharides
      - dehydration/condensation reaction
      - glycosidic bond
      - sucrose, maltose, lactose
    - - monosaccharides join to form long polymer
      - starch or glycogen for storage
      - Starch- moderately branched
      - Glycogen- highly branched
      - Cellulose- unbranched
  - - - 1 glycerol bonded to 3 fatty acids
      - forms ester bond
      - fatty acids can be saturated or unsaturated
        
        saturated- all carbons linked by single bonds
        
        unsaturated- contain 1 or more double bonds
    - - 1 glycerol, 2 fatty acids, 1 phosphate group
      - polar, hydrophilic phosphate head
      - non polar, hydrophobic fatty acid tail
  - - - built by amino acids
      - carboxy + amino forms peptide bond
      - polymers of amino acids are known as polypeptides
      - Proteins have 4 main structures
        
        Secondary: certain sequences form hydrogen bonds causing the region to fold into an alpha helix or a beta pleated sheet
        
        Tertiary: Secondary structures and random coiled regions fold into a 3D shape
        
        Quaternary: two or more polypeptides may bind to each other to for a functional protein
        
        Primary: linear sequence of amino acids
  - - - stores genetic information encoded in the sequence of nucleotide monomers
      - Adenine, Guanine, Cytosine common in both
      - Thymine
      - 2 strands, double helix, deoxyribose
    - - decodes DNA into instructions for linking together a specific sequence of amino acids
      - Uracil
      - single strand, ribose
    - - made from phosphate group, 5C sugar and a nitrogen base
- - - - Nucleus
        
        chromosomes
        
        nuclear matrix
        
        ribosome assembly
      - Endoplasmic Reticulum
        
        network of membranes that form flattened, fluid-filled tubules or cisternae
        
        ER membrance encloses the ER lumen
        
        Rough ER
        
        studded with ribosomes, involved in protein sorting and synthesis
        
        Smooth ER
        
        detoxification, carbohydrate metabolism, calcium balance, modification of lipids
      - Golgi apparatus
        
        vesicles transport materials between stacks
        
        secretion, processing and protein sorting
        
        flattened membrane bound compartments
      - Lysosymes
        
        contain acid hydrolases that perform hydrolysis
        
        autophagy
        
        breakdown proteins, carbs, nucleic acids and lipids
      - Vacuoles
        
        contractile vacuole in protists for expelling excess water
        
        phagocytic vacuoles in protists for degradation
        
        central vacuoles in plants for storage
      - Plasma Membrane
        
        boundary between the cell and extracellular environement
        
        cell signalling using receptors, cell adhesion
        
        membrane transport in and out of the cell
- - - - complex cells, DNA enclosed within nucleus
        
        ANIMAL CELLS
        
        Nucleolus
        
        Lysosome
        
        Nuclear Envelope
        
        Ribosome
        
        Nucleus
        
        Nuclear Pore
        
        PLANT CELLS
        
        Chromatin
        
        Plasma membrane
        
        Cytosol
        
        Golgi Apparatus
        
        Peroxisome
        
        Cytoskeleton
        
        Mitochondria
        
        Smooth ER
        
        Rough ER
        
        Centrosome
        
        Chloroplast
        
        Central Vacuole
        
        Cell Wall
    - - simple structure, no nucleus
        
        Bacteria
        
        most are not harmful although some species cause diseases
        
        abundant in our bodies
        
        small 1 - 10 micrometers
        
        cytoplasm, nucleoid region and ribosomes inside the plasma membrane
        
        cell wall, glycocalyx and appendages outside the plasma membrane
        
        Archaea
        
        1 - 10 micrometers
        
        found in extreme environments
- - - - long, hollow cylindrical structures.
    - - intermediate in size, twisted rope like structure
    - - known as microfilaments, long thin fibers
- - - - transmembrane proteins
        
        region(s) are physically embedded in the hydrophobic portion of the phospholipid bilayer
      - lipid-anchored proteins
        
        an amino aicd of the protein is covalently attached to a lipid
    - - noncovalently bound either to integral membrane proteins that project out from the membrane. or to polar head groups of phospholipids
- - - - double bond creates kink making bilayer more fluid
    - - effects vary depending on temperature
      - cholesterol tend to stabilize membranes
    - - shorter acyl tails make membrane more fluid
- - - - enzymes cleave off nucleotides from end
      - 5' to 3'
    - - multiprotein complex uses exonucleases
      - 3' to 5'
- - - - positioning reactants together
      - changing local environment
      - straining bonds in reactants
  - - - inhibits ability of substrate to bind
      - Apparent Km increases- more substrate needed
      - molecules bind to active site
    - - lowers Vmax without affecting Km
      - binds to allosetric site, not active site
- - - - enzyme directly transfers phosphate from one molecule to another molecule
    - - energy stored in an electrochemical gradient is used to make ATP from ADP snd Pi
- - - - diploid or 2n
        
        humans have 23 pairs of chromosomes
      - haploid or n
        
        gametes have 1 member of each pair of chromosome or total 23 chromosomes
    - - in diploid species, members of a pair of chromosomes are called homologues
- - - - prometaphase I- spindle apparatus complete, chromatids attach to kinetochore microtubules
      - metaphase I- bivalents organized along metaphase plate as double row
      - prophase I- chromosomes condense, bivalents form and nuclear membrane breaks down
      - Anaphase I- connections between bivalents break, but sister chromatids stay connected together. Each joined pair moves to one pole
      - Telophase I- sister chromatids have reached their respective poles and decondense and nuclear membranes reform
      - Cytokinesis
      - end of Meiosis I- two haploid cells with no pair of homologous chromosomes
      - Meiosis II
        
        no S phase between meiossi I and meiosis II
        
        sorting evemts similar to mitosis
        
        sister chromatids separated in anaphase II unlike anaphase I
  - - - nuclear membrane dissocaites into small vesicles
      - chromatids condense into highly copacted structres
      - chromosomes have replicated already and are joined as pairs of sister chromatids
    - - pairs of sister chromatids are aligned along a plane between the poles called as the metaphase plate
      - organized into a single row
      - after alignment is complete, cell is in metaphase
    - - each individual chromatid is linked to only one pole by kinetochore microtubules
      - kinetochore microtubules shorten, pulling chromosome toward the poles
      - connections broken between sister chromatids
      - the two poles move away from each other
    - - chromosomes have reached their respective poles and decondense
      - nuclear membranes now re-forms to produce two separate nuclei
    - - two nuclei are segregated into separated daughter cells
      - process is different in animals and plants
        
        animals- cleavage furrow constricts like a drawstring to separate cells
        
        plants- cell plate forms a cell wall between the two daughter cells
      - mitosis is quickly followed by cytokinesis