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NWHSU Bioch I Exam 3
NWHSU Biochem I Exam #3
Question | Answer |
---|---|
What is a Glycoconjugate? | Composite of a carbohydrate and a protein(peptide) |
What is a Glycoprotein? | - ≥Oligosaccharide attached to a protein - Common in membrane proteins - For communication. Huge variety of oligosaccharides - eg. Blood Type, hormones, antibodies, secreted proteins(milk proteins) |
What are some examples of glycosidic bonds? | - Acetal - Ketal - Bonds between carb & AA r-group - Bonds between carb & lipid |
What are Proteoglycans? | - Polysaccharide(s) connected to proteins - Structure in extracellular matrix - In connective tissue |
What are Glycolipids? | - In cytoplasm membranes - eg. Blood Types |
Glycoconjugates: If you have a smaller carbohydrate then what do you have? | Oligosaccharide: -Protein = Glycoprotein -Lipid = Glycolipid They are in membranes communication |
Glycoconjugates: If you have a larger carbohydrate then what do you have? | Polysaccharide: -Protein = Proteoglycan-extracellular matrix, storage of H2O,joint lubercation -Lipid = Lipopolysaccharide-outer membrane of gram negative bacteria |
What is a Lipopolysaccharide? | - Outer membrane of gram negative bacteria - Recognized by humman immune system - Variations of building blocks in polysaccharides ---> different serotypes - Lipid acts a toxin ---> reaction from immune system |
Describe the Sugar Code? | -Spec. interactions between distinct oligosaccharides and receptors -Large number of possible oligosaccharides -Large # of building blocks -Few restrictions w/ respect to size -Branching (unristricted) -∂&ß connections combined w/ OH in various posit |
What are Lectins? | Proteins with a specific ligand binding site for a specific oligosaccharide(receivers of information) -Cell-Cell recognition -Transfer of hormone signals -Adhesion between cells |
What is the basic structure of Nucleotides? | Building blocks |
What are the 3 distinct components of nucleotides? | 1. Pentose 2. 1-3 phosphate 3. Base |
What are the 2 base components of nucleotides? | 1. Purine (Adenine & Guanine)-All Good 2. Pyrimidine (Cytosine, Uricile & Thymine)CUT |
There is a(n)______ bond between monophosphate and _______. | ester, pentose |
Bases: _____:Cytosine, Thymine, Uracil How many rings are present? | Pyrimidines, 1 |
Bases: _____:Adenine, Guanine How many rings are present? | Purines, 2 |
What is the function of nucleotides? | 1. Building blocks for DNA & RNA synthesis 2. Energy currency of biological systems(ATP) 3. Chemical links in homonal signals ("2nd messengers") 4. Structural components of several coenzymes(NAD÷, FAD, coenzyme A) |
______bonds link successive nucleotides in nucleic acids. | Phosphodiester |
Backbone begins at___end/site and terminates at___end/site. | 5^1, 3^1 |
There are phosphodiester linkages in the covalent backbone of _______and________. | DNA, RNA |
What are the 3 ways to express nucleic acids in a simplified manner? | 1. pA-C-G-T-Aoh 2. pApCpGpTpA 3. pACGTA |
Hydrogen bonding is the______ _______of the double helix(as well as base stacking) | stabilizing force |
Base stacking is the ______ ______of adjacent bases. | hydrophobic interaction |
James_____& Francis_____(Publication in Nature) was in the year_____ | Watson, Crick, 1953 |
Maurice______received the Nobel Prize in the year______ | Wilkins, 1962 |
______Franklin also credited with the discovery of the structure of DNA in the year of ______ | Rosalind, 1953 |
______are alterations in DNA that permanently alter genetic information | Mutations |
What are the two types of mutations? | 1. Spontaneous 2. External Factors |
Describe spontaneous mutations? | Two types: a. deamination=loss of amino group(-NH2), happens 1/10^7 every 24hrs b. depurination=purine-pentose bond breaks, happens 1/10^8 every 24hrs |
[choose one]_________(deamination, depurination) occurs when the glycosidic bond between pentose and_______(DNA, RNA, base, ATP) is broken. | depurination, base |
Describe external factor mutation? | Physical forces UV radiation-makes covalent bonds with bases Ionizing radiation-x-ray+gamma ray -braking of covalent bonds -opens rings of bases -breaks bonds in backbone -formation of ROS(Reactive Oxygen Species) |
Describe Chemical forces? | Deaminating agents: nitrous acid HNO2 -Nitrosamine - found in cured meats Oxidative agents: -H2O2, oxygen radicals,<---quenched by antioxidants -Origin: -Ionizing radiation -Aerobic cellular respiration •exercise •infections •growing kids |
Lipids: -Diverse with regard to______ -->have little to no ______ ______ -Diverse with regard to ________ | Structure Water solubility Function |
What are 5 functions of Lipids? | •Structure: (cell) membranes •energy storage •energy source •coenzymes or prosthetic groups •signal transduction •hormones(regulation, communication) •pigments(retinal from ß-carotene) |
Storage lipids consists of _____and______ fatty acids, covalently connected by a(n)______bond. | Glycerol (also known as triglycerol or triacylglycerol) 3 ester |
Structure of Fatty Acids: Two Types 1.______-carboxyl group combined with ______or aliphatic tail 4-36 carbons in length with no double bonds. 2.______-has 1 or more double bonds and could be cis or trans configuration. | Saturated FA, hydrocarbon Unsaturated FA |
In Unsaturated FA's, which configuration is found in plants & fatty fish? | cis |
In Unsaturated FA's _____is the "unhealthy" fat structure. | trans |
Which FA is needed for proper function of membranes & cant be replaced by TFA. a. Saturated FA b. Unsaturated FA | b. Unsaturated FA |
What are 2 sources of trans-fatty acids? | 1. In meat: bacterial activity in ruminating animals like cows 2. Human-developed process: Partial Hydrogenation -->use oils for margarine - solid at room temp due to less double bonds & trans-config of remaining double bonds |
Trans FA behave a lot like______? | Saturated FA's |
Saturated FA's have_____hydrophobic interactions. Unsaturated FA's have______hydrophobic interactions. | Many Less |
Double bonds in cis-config. _____=pro-inflamitory _____=anti-inflamitory | Ω6 Ω3 |
Name this FA: 18:3^Δ9,12,15 / CH3CH2C=CCH2C=CCH2C=C(CH2)7COOH / Omega-3, essential | Alpha-linolenic acid |
Name this FA: 16:0 / CH3(CH2)14COOH / End product of fatty acid synthesis | Palmitic acid |
Name this FA: 20:5^Δ5,8,11,14,15 / CH3(CH2C=C)5(CH2)3COOH / Omega-3, precursor, conditionally essential | Eicosapentaenoic acid (EPA) |
Name this FA: 18:2^Δ9,12 / CH3(CH2)4C=CCH2C=C(CH2)7COOH / Omega-6, essential | Linoleic acid |
Name this FA: 20:4^Δ5,8,11,14 / CH3(CH2)3(CH2C=C)4(CH2)3COOH /Omega-6, precursor for regulatory compounds in inflammation, conditionally essential | Arachidonic acid |
Name this FA: 22:6^Δ4,7,10,13,16,19 / CH3(CH2C=C)6(CH2)2COOH / Omega-3, conditionally essential | Docosahexaenoic acid (DHA) |
Describe Triacylglycerols | -In liver and adipose tissue -Glycerol = backbone -Condensation reaction -Ester formation -Hydrolysis – in small intestine -Completely hydrophobic |
Energy storage: List differences of carbs vs. fats | -Fats have higher energy content per weight -Fats: longer-term energy storage, slow mobilization process -Fats have insulating properties -Glycogen: short term energy storage, quickly accessible -Each gram of glycogen has ~2g of water associated with |
What are the 2 basic types of membrane lipids? | 1. (glycero)phospholipids – majority of membrane lipids 2. Sphingolipids – glycolipids |
_______lipids = amphipathic | Membrane |
What are Glycerophospholipids? | -Glycerol backbone -3 ester bonds -Phosphate group -2 fatty acids – which form the lipid bilayer •Hydrophilic head •Hydrophobic tail |
Describe Choline? | –CH2-CH2-N(CH3)3+ -Typically associated with lipids |
Phosphatidylcholine =_______ | lecithin |
Describe Sphingolipids? | - Sphingosine backbone - Amide bond -Hydrophobic tail -Hydrophilic head -1 fatty acid -Glucosylcerebroside, lactosylceramide, ganglioside GM2 = oligosaccharides (water soluble) |
Sphingomyelin =_______ | choline component |
Storage lipids(neutral): What are the components of Triacylglycerols? | Glycerol backbone with 3 fatty acid chains |
Membrane lipids(Polar): - Phospholipids •What are the components of Glycerophospholipids? | Glycerol backbone with 2 fatty acid chains and 1 PO4-alcohol chain |
Membrane lipids(Polar): - Phospholipids •What are the components of Sphingophospholipids? | - Sphingosine backbone with 1 FA chain and 1 PO4-choline chain - Sphingomyeline |
Membrane lipids(Polar): -Glycolipids •What are the components of Sphingolipids? | Sphingosine backbone with 1 FA and 1 mono or oligosaccharide chain |
Membrane lipids(Polar): -Glycolipids •What are the components of Galactolipids(sulfolipids)? | - Glycerol backbone with 2 FAs and 1 mono or disaccharide-SO4 chain - Only in plants |
Membrane lipids(Polar): -Archaebaterial ether lipids have________linkage | Ether linkage -See chart on page 9 of lipids chapter |
Ether-lipids: -Describe Membrane Lipids | - In cytoplasmic membrane of heart and muscle cells (plasmalogen) - Ether bond - Hydrophobic tail - Hydrophilic head – choline and phosphate components |
Ether-lipids: -Describe Platelet activating factor | -(regulatory compound) -In blood -Promotes blood clotting -Released by WBCs -Functions related to immunity: •Release of serotonin (vasoconstriction) •Upregulation of inflammation •Impacts allergic reactions -Pregnancy: |
Isoprenoids: -Isoprene=______ Building Block -Used to make________ | -C5 -Cholesterol |
Isoprenoids: -Cholesterol •Hydrophobic •Hydrophilic hydroxy group – makes cholesterol________ •Recognize typical structure for steroids | amphipathic |
Describe Steroid hormones: | Endocrine: -Produced in special glands and carried in blood to target tissues |
Describe Eicosanoids: (“Eicosa” = 20) | Paracrine: - Produced and acts locally - Derived from C20 omega-3/omega-6 fatty acids |
What are some biologically active isoprenoid compounds? | - Vitamin E - Vitamin K - Warfarin - Ubiquinone |
Name 3 Eicosanoid derivatives: (“Eicosa” = 20) | 1. Prostaglandin (PGE1) 2. Thromboxane A2 3. Leukotriene A4 • All listed are pro-inflammatory regulators • Enzyme used = cyclooxygenase (COX) blocked NSAIDS |
Describe Retinol and Retinal: | - vision pigment in eyes - Vitamin A with cis double bond - Retinol - no double bond - AL-->OL enzymatic conversion |
Biological membranes and transport: -Composition and architecture •Diameter = ______nm •3 Main components = 1. Phospholipids 2. Protein 3._______ | 5-8nm Glcocalyx |
List characteristics of the composition and architecture of Biological membranes and transport: | - Flexible (cells can change shape – ex: RBCs and capillaries) - Separation of compartments (creating order) - Selectively permeable (proteins) - Membrane bilayer - Hydrophobic core of membrane (in between bilayer) |
According to the Fluid Mosaic Model, what structures are located on the outside of the membrane structure? | 1. Glycolipid 2. Glycoprotein |
According to the Fluid Mosaic Model, what structures are located on the inside(cytoplasm) of the membrane structure? | 1. Phospholipids 2. Peripheral protein (non-covalently linked) 3. Integral proteins (single trans-membrane helix) 4. Cholesterol 5. Peripheral protein (covalently linked) 6. Integral protein (multiple trans-membrane helix) |
List the 3 types of diffusion for phospholipids in a bilayer? | 1. Uncatalyzed transverse diffusion: •“flip-flop” •Very slow 2. Transverse diffusion catalyzed by flippase: •Flippase •Fast 3. Uncatalyzed lateral diffusion: •Within layer •Very fast |
What are the 2 types of Membrane Proteins? | 1. Alpha-Helix 2. Beta-Barrel |
Describe Alpha-Helix member proteins | - Amino-terminus (N-terminus) on outside - Carboxyl-terminus (C-terminus) on inside - Majority of amino acid R groups are hydrophobic in membrane-spanning alpha-helices |
Describe Beta-Barrel membrane proteins - “_______” lining pores in membranes - _______ amino acids to span membrane once - ~20 sections of beta-helical __________ for 1 pore | -Ribbons - ~7-9 - polypeptide |
Describe additional characteristics Beta-Barrel membrane proteins: - Produced by________ - Gram-negative is in_______ membrane | - Bacteria - outer - Creates pores - Staph aureus releases alpha-hemolysin subunits assemble into pores (multi-subunit complexes) - → monocytes and platelets - Alpha-hemolysin toxin = human cytoplasmic membrane – pore is deadly for cell |