Bio 1107 - EXAM 1

• Electronegativity: Attractive force of electrons and ability to take electrons from other atoms.

  Ionic Bond: One atom has a higher electronegativity

  Covalent Bond: Electronegativity is almost equal
• S-Orbitals are a sphere shape, and hold up to 2 electrons per energy level

  P-Orbitals are a dumbell shape, and hold up to 6 electrons per energy level

  D-Orbitals are a clover shape, and hold up to 10 electrons per energy level
• Aufbau Principle: electrons fill lower energy levels before higher ones
• Van der Waals: Weak, transient force most seen in nonpolar bonds due to electron charge asymmetry
• Properties of Water: Polar, good solvent due to W-bonds, high heat capacity and heat of vaporization due to H-bonds, Cohesive and Adhesive due to H-bonds
• Proteins:

  Monomer = Amino Acids

  Polymer = 2, 3, 4 structure

  Type of covalent bond = peptide bond
• Nucleic Acids:

  Monomer = Nucleotides

  Polymer = DNA and RNA

  Type of Covalent Bond = Phosphodiester Bond
• Carbohydrates:

  Monomer = Monosaccharides (glucose)

  Polymer = Disaccharides and Polysaccharides (glycogen)

  Type of Covalent Bond = Glycosidic Bond
• Lipids:

  Monomer = All lipids are monomers

  Polymer = None

  Type of Covalent Bond = Ester Linkage
• Typical protein structural plan: central carbon atom attached to amino group next to carboxyl group, hydrogen atom, and variable “R” group
• 4 levels of protein structure:

  Primary structure = unique sequence of amino acids forming a polypeptide

  Secondary structure = amino acid chain forms alpha coils twisted into right hand spiral and beta sheets zigzagging on a flat plane

  Tertiary structure = 3D folding turns into protein. conformational changes are alterations in shape in reaction to chemical modification, R groups interact and form chemical bonds

  Quaternary structure: Multiple polypeptide chains
• Denaturing = Loss of protein function from extreme pH or temperature

  Peptide bond = covalent bonds between amino and carboxyl groups, that link amino acids into polypeptide chains, subunits of proteins

  Directionality = N to C
• Nucleotide = Consists of 3 parts linked together via covalent bonds, 5C sugar, Nitrogenous base, and PO4 groups

  Directionality = 5 to 3

  Nitrogenous base pairs = Purines (2 rings): Adenine, Guanine; link w/ pyrimidines (1 ring): Cytosine, Thymine, Uracil. link covalently to 5-carbon sugar in DNA and RNA.

  Nucleoside = structure with only nitrogenous base and 5-carbon sugar
• Carb structure = consists of ratio 1C:2H:1O

  Glucose = monosaccharide, makes starch (alpha) and cellulose (beta)

  Glycosidic Bonds = joins sugar to another group, used by energy storing carbs (alpha), and structural carbs (beta)

  Monosaccharides = Glucose, fructose, galactose

  Disaccharides = Sucrose, Lactose, Maltose

  Polysaccharides = Starch, glycogen, cellulose
• Neutral Lipids = used as energy source, easily storable

  -Saturated Fatty Acid = straight chain of single bonds, solid at room temp

  -Unsaturated Fatty Acid = bends at double bond, fluid at room temp

  Phospholipids = form cell membranes, have polar hydrophilic heads and nonpolar hydrophobic tails

  Steroids = regulate cell activities, structures based on nonpolar 4-carbon rings, cholesterol keeps membrane fluid, sex hormones are nonpolar

  -good source of chemical energy because electrons are shared equally across covalent bonds. breaking bonds yields high amounts of energy.
• Process of Digestion: Ingestion, Digestion, Absorption, Excretion
• Mouth

  Process: Mechanical processing (chewing)

  Macromolecules: Carbs via salivary amylase
• Stomach

  Process: HCl and Pepsin breaks down food into smaller peptides and amino acids

  Macromolecules: Proteins
• Small Intestine

  Process: Absorbs monomers of macromolecules by pancreas enzymes

  Macromolecules: Carbs, proteins, nucleic acids, lipids
• Large Intestine

  Process: H2O and mineral absorption

  Macromolecules: None, just H2O and minerals left
• Salivary amylase breaks down carbs in the mouth and food via chewing. Food becomes a bolus and goes down esophagus via peristalsis
• Sphincters let bolus travel through stomach regions.

  Gastrin = hormone that stimulates parietal cells to release HCl

  Parietal Cells = secrete HCl when stimulated by gastrin

  Chief Cells = release pepsinogen

  Pepsin = becomes pepsin from pepsinogen when exposed to low pH via HCl

  Goblet Cells = secretes mucus to protect stomach wall

  Chyme = pushes food out of stomach via peristalsis
• In the small intestine...

  Secretin releases bicarbonate to help neutralize chyme

  CCK triggers release of pancreatic enzymes when lipids in chyme enter duodenum

  GIP stimulates insulin release in pancreas and makes glucose to be taken up into cells
• Pancreatic Proteases break proteins into amino acids (trypsin, chymotrypsin, carboxypeptidase, aminopeptidase)

  Pancreatic Amylase breaks carbs into poly/disaccharides, then monosaccharides

  Pancreatic nucleases breaks nucleotides into nitrogenous bases, phosphates, and 5C sugars

  Pancreatic lipase breaks lipids into monoglycerides and fatty acids (not monomers), aided by bile which is stimulated by liver and stored in gallbladder
• 3 parts of large intestine: cecum, colon, rectum

  large intestine secretes mucus and HCO3 to absorb H2O and ions which cause digested contents to condense into feces
• • Cell membranes are amphipathic (polar and nonpolar)
  • Allows for semipermeability of molecules
  • Permeable when membrane is unsaturated fatty acids, liquidy
  • Impermeable when membrane is saturated fatty acids, dense
• • Transmembrane protein: interacts with interior and exterior of plasma membrane
  • Integral membrane protein: Spans entirety of membrane
  • Peripheral protein: Anchored to one side of membrane
  • Favorable concentration gradient: More of one molecule on one side than other side, can create ionic current until reaching equilibrium
• • Membrane proteins: help molecules enter or leave cell
  • Transport proteins: form channels to allow selected polar molecules and ions pass through membrane
  • Cell-cell recognition proteins: ID cells as self or foreign, lets in self and IDs foreign cells to not let in
  • Receptor proteins: Recognize and bind molecules to begin cell signal transduction
  • Cell adhesion proteins: bind cells together by recognizing and binding receptors or chemical groups
  • Enzymatic proteins: specific to particular membranes
• • Passive Transport: Ions or molecules pass through membrane from high to low concentrations
  • Simple diffusion: nonpolar/small molecules pass through membrane w/ no help
  • Usually requires thinner concentration gradient
  • Facilitated diffusion: polar and charged molecules need transport proteins to get across membrane, requires favorable concentration gradient
• • Active transport: Ions or molecules move from low to high concentrations, uses energy and requires favorable concentration gradient
  • Primary active: transports substance directly using ATP
  • Secondary active: indirectly uses ATP to transport substance, uses concentration gradients from transporters
  • Symport: both molecules move same direction
  • Antiport: molecules move in opposite directions
• • Transport proteins
  • Channel proteins form channels for molecules to go through
  • Aquaporins facilitate transport of water between cells
  • Ion channels allow passage of ions
  • Gated channels are closed, but open when a specific ion binds to the protein
  • Carrier proteins change shape to bring certain molecules through membrane
• • Isotonic: concentrations of solutes inside and outside cell are balanced
  • Hypertonic: high solute concentration and low water concentration,  outside environment is hypertonic with respect to dissolved solutes
  • Hypotonic: low solute concentration and high water concentration, inside of cell environment is hypotonic with respect to dissolved solutes, water is gonna head outside because it goes from higher concentration to lower concentrated
  • Less solutes in red blood cell plasma than inside of cells, cause water to concentrate in them which can lead to bursting
• • Exocytosis: movement of molecules out of cell with vesicles (molecular shopping bags)
  • Endocytosis: movement of molecules into cell with vesicles
• • Classes of vitamins include water soluble (hydrophilic), fat soluble (hydrophobic)
  • Fat soluble vitamins can be stored for later use
  • Excess of water soluble vitamins are excreted in urine
• Essential fatty acids: Linoleic acid, linolenic acid
• Animals primarily dispose of solid waste at end of digestive process, instead of cellular or metabolic waste
• Food is broken down into molecules by enzymatic hydrolysis, chemical bonds are broken by adding H and OH
• Sterols: most common steroids have single polar OH group linked to one end and nonpolar hydrocarbon chain at other
• Waxes form from fatty acids combining w long chain alcohols or hydrocarbon structures
• Atherosclerosis occurs from build up of plaques in coronary arteries, plaques form from buildup of cholesterol (saturated fats)