Flashcards
Biochem Module 5-2
Cards in this deck (90)
- 1carbohydrates contain with elements?carbon, oxygen, and hydrogen atoms
(CH2O)n - 2what is the minimum number of carbons needed to be considered a carbohydrate?3
- 3Energy is stored in carbohydrates in the form of _____chemical bonds
- 4what are monosaccharides?small carbohydrates that cannot be decomposed by hydrolysis
- 5monosaccharides are characterized by ______a carbonyl and 1 or more hydroxyl groups
they are polyhydroxyalcohols containing at least three carbons - 6monosaccharides are classified according to ____-the chemical nature of their carbonyl group (aldehyde/ketone)
-the number of carbon atoms - 7What type of monosaccharide is D-glucose?aldohexose
- 8how many chiral centers does d-glucose have?4
- 9how many stereoisomers of d-glucose exist?2^4=16
- 10define an epimersugars that differ only in the configuration of one carbon atom
-type of configurational isomer - 11define enantiomernon superimposable mirror image (D and L forms of monosaccharides)
-type of configurational isomer - 12what is a conformational isomer?differ in bond angles
- 13what type of monosaccharide is d-fructose?ketohexose
- 14how many chiral centers does d-fructose have?3
- 15how many stereoisomers of d-fructose exist?2^3=8
- 16are D or L sugars more abundant?D sugars
- 17name the 5 most important aldosesglyceraldehyde, ribose (pentose), glucose (hexose), mannose (C-2 epimer of glucose), galactose (c-4 epimer of glucose)
- 18name the 3 most important ketosesdihydroxyacetone, ribulose (pentose), fructose (hexose)
- 19what is the anomeric carbon?when a sugar cyclizes, the carbonyl carbon becomes a chiral center (carbon 1)
- 20what's the difference between an alpha and beta D glucose?the OH points down in alpha and the OH points up in beta
- 21what are anomers?isomers differing only at the carbonyl carbon
- 22Lactose is a disaccharide of which two monosaccharides?beta-galactose and beta-glucose
- 23what type of glycosidic bond is formed in lactose?1-4 beta
- 24sucrose if formed by which two monosaccharides?alpha-glucose and beta-fructose
- 25what type of glycosidic bond is formed in sucrose?1-2 alpha
- 26of lactose and sucrose, which one is a reducing sugar?lactose - reducing sugar
sucrose - nonreducing sugar - 27what is a reducing sugar?potential free aldehyde group would be oxidized, has a free anomeric carbon
- 28define polysaccharidemonosaccharides joined by glycosidic bonds
- 29starch is a mixture of _____ and _____amylose and amylopectin
- 30what type of polysaccharide is amylose and amylopectin?storage polysaccharides
- 31what is the usage of starch?plants synthesize starch as their food reserve (nighttime/wintertime, plants put away glucose for further use)
- 32what do humans use as their food reserve?humans synthesize fat as food reserve (long-term)
- 33describe the shape of amylose-it is linear, adopts helical conformation
- 34describe the stability of amyloseamylose is energetically most stable, as the hydrogen bonds stabilize the helix
- 35describe the glycosidic bond that forms in amylosealpha 1-4 links
- 36describe the role of the reducing end in the role of the amyloseonly has one nonreducing end, so only releases 1 glucose at a time. This leads to more long-term storage
- 37describe the conformation of amylopectincontains branching points
- 38what type of glycosidic bond is in amylopectin?alpha 1-6 forms branch point
alpha 1-4 links adjacent glucose - 39what's the difference between linear and branched?branched gives immediate energy (fight or flight)
in branched, many enzymes can simultaneously go to branch to release glucose - 40what is the storage of polysaccharides in animals?glycogen
- 41in which cells are glycogen present?in all cells, most prevalent in skeletal muscle and in liver
- 42why do we need to store glucose as glycogen?-glucose is small, rapidly diffusing molecule
-if present in large quantities, would cause high osmotic pressure, but polymers won't diffuse - 43amylose, amylopectin, and glycogen are all polymers of ______alpha-D-glucopyranose
- 44what is cellulose?the primary structural component of plant cell walls
- 45what type of polysaccharide is cellulose?linear homopolysaccharide of D-glucose
- 46what type of glycosidic linkage is in cellulose?beta 1-4
- 47what is the difference between cellulose and starch?animal enzymes are able to cleave alpha 1-4 bonds, but not the beta 1-4 bond in cellulose
- 48what are the two types of linkages in glycoproteins?O-linked and N-linked oligosaccharides
- 49what is O linked oligosaccharide?glycosidic bond between N-acetylgalactosamine and hydroxyl group of threonine or serine residue
- 50what is N-linked oligosaccharides?attached through nitrogen atom of a side chain amide group in asparagine residue
- 51what are lectins?ubiquitous proteins that bind to carbohydrates, often appear at the cell surface
- 52what are leucocytes?they bind to damaged tissue due to interactions of oligosaccharides with selectins
- 53what is the difference between the cell wall of gram positive and negative bacteria?-the peptidoglycan of gram positive bacteria is cross-linked multilayered polysaccharide peptide complex
-the peptidoglycan of gram negative is single-layered
-gram negative contains LPS in the outer membrane - 54what is the role of peptidoglycan?-strong surface to help bacteria survive harsh environmental conditions. Protects against lysis in blood of host animals
- 55the peptidoglycan consists of alternating copolymers of ____ and ____NAG and NAM
- 56copolymers of NAM are attached to ______tetrapeptides
- 57how many bacterial cells in a gram of soil?~40,000,000 (40 million)
- 58how many bacterial cells in a milliliter of fresh water?~1,000,000 (1 million)
- 59there are ______ bacteria on Earth5X10^30
- 60what's the main difference between lipids and proteins, nucleic acid and carbs?a lipid is not a polymer - they have great structural variety
- 61what are the 3 major biological functions of lipids?1) essential components of biomembranes
2) energy reserves
3) signaling molecules - 62what are the 5 classifications of lipids?fatty acids, triacylglycerols, glycerophospholipids, sphingolipids and steroids
- 63what are fatty acids?carboxylic acids with long-chain hydrocarbon groups
- 64In most naturally occurring unsaturated fats, orientation about double bonds is _____cis
- 65Of saturated and unsaturated, which is more flexible?unsaturated, rotation of bonds adjacent to double bond are free, less tightly packed
- 66what are triacylglycerols?triesters of fatty acids and glycerol
- 67traicylglycerols are synthesized and stored in _____adipocytes
- 68what is the difference between fat and oil?fat is a lipid, oil is not a lipid
- 69what are glycerophospholipids?-amphiphilic molecules with nonpolar aliphatic tails and polar heads
-they are the major lipid component of biological membranes - 70glycerophospholipids have a _____ chargenegative from the phosphate group
- 71what are sphingolipids?-components of biomembranes
-built on sphingosine, the head group contains saccharides - 72what is the difference between cerebrosides and gangliosides?Cerebroside: R1 is a monosaccharide
Ganglioside: R1 is an oligosaccharide - 73what is the most common sphingolipid?sphingomyelins, components of myelin (the insulator of nerves)
- 74what is cholesterol?-most abundant steroid in animals
-important lipid constituent of many membranes
-biosynthetic precursuor for steroids - 75why do micelles form?-energetically favourable
-hydrophobic groups avoid unfavourable contacts with water - 76describe a lipid bilayer-a tail of two fatty acids yields a roughly cylindrical molecule, packed in parallel array
- 77what is a liposome?solvent filled vesicles bound by a phospholipid bilayer, very stable
- 78what are the two types of lipid movement?transverse diffusion and lateral shift
- 79of the two types of movement which is more likely?lateral shift, transverse is less likely because hydrophilic doesn't like hydrophobic
- 80what is the transition temperature (Tm)?the temperature of the "melting" of the membrane
- 81If temperature is below Tm, what state are lipids?Gel state: hydrocarbon tails are packed together in a highly ordered gel state
- 82If temperature is above Tm, what state is the lipid?liquid crystal state: movement of the chains becomes more dynamic, and the interior of the membrane resembles a liquid hydrocarbon
- 83which state do you want your lipid membranes to be?liquid state! You want to allow protein movement, so your body temperature must be above Tm
- 84Biological membranes contain _____ and ______lipids and proteins
- 85what is the fluid mosaic model?assymmetric lipid bilayer is fluid and carries a host of proteins
- 86what are the 2 types of membrane proteins?Integral membrane proteins and peripheral membrane proteins
- 87what are integral membrane proteins?TIGHTLY bound to membranes by HYDROPHOBIC interactions and expose hydrophilic surfaces to aqueous environment at BOTH sides of membrane
- 88What are peripheral membrane proteins?HYDROPHILIC, bind the hydrophilic surface of membrane or hydrophilic surface of integral membrane protein. Only exposed at ONE membrane face
- 89what is the glucose transport protein?-integral membrane protein with hydrophobic exterior and hydrophilic interior
-responsible for transport of glucose - 90what are the conformations of glucose?inside open conformation: allows glucose to enter
outside open conformation
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- Flashcards on Biochem Module 5-2, created by A D on 17/04/2016.
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- A D · Apr 2016
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- Jul 14, 2016
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