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102 Cards in this Set
- Front
- Back
what are the 4 main biomolecules
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Carbohydrates
Nucleic Acids Amino Acids Lipids |
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define carbohydrate
general formulae for carbohydrates? |
Carbohydrate – literally hydrated carbon
(C.H2O)n n=3 or more |
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essential for?
most abdundant...? formed primarliy by? basic units of monosacharides are known as> |
Essential for all living organisms
The most abundant class of biological molecules Formed primarily by photosynthesis The basic units of carbohydrates are known as monosaccharides |
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The predominant carbohydrates encountered in the body are structurally related to?
Carbohydrates contain at least ... and are therefore? |
related to the aldotriose glyceraldehyde or to the ketotriose dihydroxyacetone.
asymmetrical (chiral) carbon and are, therefore, optically active. |
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In addition, carbohydrates can exist in either of two conformations, as determined by
what carbohydrates exist in the D conformation mirror image conformations are called? |
the orientation of the hydroxyl group about the asymmetric carbon farthest from the carbonyl.
those of physiological significance exist in the d conformation enantiomers, and exist in the l conformation |
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how are the monosacharides commonly found in humans classified?
the major monosacharides contain? |
classified according to the number of carbon atoms they contain in their backbone structures
the major monosacharides contain 4-6 carbon atoms |
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catergory name given to carbohydrates with
3,4,5,6,7,"",9 carbon atoms |
triose, tetrose, pentose, hexose, heptose, Nonose
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examples of triose, tetrose, pentose, hexose, heptose, Nonose carbohyddrates
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triose- glyceraldehyde
tetrose - ethyrose pentose- ribose, ribulose hexose- glucose, galactose, fructose heptose- sedoheptulose nonose - neruaminic acid/ sialic acid |
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which carbon atom is labelled one
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The carbon atoms in a carbohydrate are numbered, with carbon 1 containing the reactive carbonyl group (H-C=O) e.g
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The aldehyde and ketone groups of carbohydrates with 5 and 6 carbons will spontaneously react with .........
to produce? |
alcohol groups in neighbouring carbons to produce intramolecular hemiacetals and hemiketals respectively
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draw the structure of alpha glucose
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6 carbons
c6h1206 oh is below |
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This results in the formation of 5- or 6-membered
As the 5-membered ring structure resembles the ... and sooo. Those with 6-membered rings resemble ,"",,"",, and soo.... |
rings
This results in the formation of 5- or 6-membered rings. As the 5-membered ring structure resembles the organic molecule furan, derivatives with this structure are termed furanoses. Those with 6-membered rings resemble the organic molecule pyran and are termed pyranoses. |
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how can such structures be depicted?
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can be depicted using either fischer or Haworth style diagrams.
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The rings can open and re-close, allowing .....
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allowing rotation to occur about the carbon bearing the reactive carbonyl yielding two distinct configurations (a and b)
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The carbon about which this rotation occurs is the ...
and the 2 forms are termed |
anomeric carbon
anomers |
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what is mutarotation
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the process by which Carbohydrates can change spontaneously between the a and b configurations-- a process known as mutarotation
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what happens when drawn in the fischer projection
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When drawn in the Fischer projection, the a configuration places the hydroxyl attached to the anomeric carbon to the right, towards the ring.
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what happens when drawn in the Haworth projection
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When drawn in the Haworth projection, the a configuration places the hydroxyl downward.
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what are glycosidic bonds
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Covalent bonds between the anomeric hydroxyl of a cyclic sugar and the hydroxyl of a second sugar (or another alcohol containing compound) are termed glycosidic bonds.
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state several important disaccharides
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Several physiogically important disaccharides: sucrose, lactose and maltose.
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what is lactose made of?
where is it found? glycosidic bonds found where? |
Lactose: is found exclusively in the milk of mammals and consists of galactose and glucose in a b-(1,4) glycosidic bond.
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sucrose, found where, made of? bonds between?
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Sucrose: prevalent in sugar cane and sugar beets, is composed of glucose
and fructose through an a-(1,2)b-glycosidic bond. |
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Most of the carbohydrates found in nature occur in the form of
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the form of high molecular weight polymers called polysaccharides.
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the predominant monosaccharide found in polysaccharides is
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D glucose
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define homopolysacharides
define heteropolysacharides |
When polysaccharides are composed of a single monosaccharide building block, they are termed homopolysaccharides
Polysaccharides composed of more than one type of monosaccharide are termed heteropolysaccharides |
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what is the function of glucagon
homo or hetero polymer specific branching comment on its structure benefit of its structure |
Glycogen is the major form of stored carbohydrate in animals.
This crucial molecule is a homopolymer of glucose in a-(1,4) linkage; it is also highly branched, with a-(1,6) branch linkages occurring every 8-10 residues. Glycogen is a very compact structure that results from the coiling of the polymer chains. This compactness allows large amounts of carbon energy to be stored in a small volume, with little effect on cellular osmolarity. |
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what is starch
structure similar to? describe the different types |
Starch is the major form of stored carbohydrate in plant cells.
Its structure is identical to glycogen, except for a much lower degree of branching (about every 20-30 residues). Unbranched starch is called amylose; branched starch is called amylopectin. |
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what can derivatives of carbohydrates also contain
what else can carbohydrates form |
Derivatives of the carbohydrates can contain nitrogens, phosphates and sulphur compounds.
Carbohydrates also can combine with lipid to form glycolipids or with protein to form glycoprotein. |
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The most abundant heteropolysaccharides in the body are
describe its structure |
The most abundant heteropolysaccharides in the body are the glycosaminoglycans (GAGs). These molecules are long unbranched polysaccharides containing a repeating disaccharide unit.
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The disaccharide units contain either of two.......
what else does it contain , give e.g.'s |
N-acetylgalactosamine (GalNAc) or N-acetylglucosamine
(GlcNAc) and a uronic acid such as glucuronate or iduronate |
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GAGs are highly .... with extended.....
what does this impart on the solution |
GAGs are highly negatively charged molecules, with extended conformation that imparts high viscosity to the solution
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where are gags located
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GAGs are located primarily on the surface of cells or in the extracellular matrix (ECM).
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what are GAGs ideal for and why
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Along with the high viscosity of GAGs comes low compressibility, which makes these molecules ideal for a lubricating fluid in the joints.
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name atleast 3 gags of physiological significance
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The specific GAGs of physiological significance are hyaluronic acid,
dermatan sulfate, chondroitin sulfate, heparin, heparan sulfate, and keratan sulfate. |
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althought each of these gags has a predominant................
where does heterogeneity exist in the gags |
Although each of these GAGs has a predominant disaccharide component, heterogeneity does exist in the sugars present in the make-up of any given class of GAG.
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where can the gag - HYALURONATE BE FOUND
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synovial fluid, vitreous humor, ECM of loose
connective tissue |
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where can Chondroitin sulfate be found
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cartilage, bone, heart valves
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Where can heparan sulfate be found
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basement membranes,components of cell surfaces
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where can the gag Dermatan sulfate be found
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skin, blood vessels, heart valves
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The majority of GAGs in the body are linked to .... forming
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core proteins, forming proteoglycans.
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The GAGs extend ....... forming what type of structure
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perpendicularly from the core in a brush-like structure.
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The linkage of GAGs to the protein core involves....
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a specific trisaccharide composed of two galactose residues and a xylulose residue.
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The trisaccharide linker is coupled to..........
how |
the protein core through an O-glycosidic bond to a Serine residue in the protein
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The protein cores of proteoglycans are rich in
why |
Serine and Threonine residues, which allows multiple GAG attachments
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where can Glycoproteins be found
3 examples |
Cell-surface antigens e.g. ABO blood groups
Virus coat proteins (can be used for vaccines/immunisation) Cell receptors (allow communication between cells) |
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Membrane associated carbohydrate is usually in the form of.....
attached to? how? |
the form of oligosaccharides covalently attached to proteins forming glycoproteins.
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Nucleotides are found primarily as
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the monomeric units comprising the major nucleic acids of the cell, RNA and DNA.
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The major functions of nucleic acids include
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1. Energy stores for use in phosphate transfer reactions. These reactions are predominantly carried out by ATP.
2. Important in coenzymes such as NAD+, NADP+, FAD and coenzyme A. 3. Mediators of cellular processes as second messengers in signal transduction events. The predominant second messenger is cyclic-AMP (cAMP). 4. Activated intermediates in biosynthetic reactions e.g. S-adenosylmethionine in methyl transfer reactions |
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The nucleotides found in cells are derivatives of what type pf compounds
which 2 compounds |
the heterocyclic highly basic, compounds, purine and pyrimidine.
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The derivatives of purine are called
derivatives of pyrimidine are called |
derivatives of purine are called adenine and guanine
derivatives of pyrimidine are called thymine, cytosine and uracil. |
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The purine and pyrimidine bases in cells are linked to...........
and in this form are termed |
The purine and pyrimidine bases in cells are linked to carbohydrate and in this form are termed, nucleosides
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The bases are coupled to
through a |
The bases are coupled to D-ribose or 2'-deoxy-D-ribose
through a b-N-glycosidic bond between the anomeric carbon of the ribose and the N9 of a purine or N1 of a pyrimidine. |
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draw the structues of adenosine
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what 3 nucelosides are found in rna
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Nucleosides are found in the cell primarily in what form
termed |
Nucleosides are found in the cell primarily in their phosphorylated form. These are termed nucleotides.
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The most common site of phosphorylation of nucleotides found in cells is
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is the hydroxyl group attached to the 5'-carbon of the ribose.
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The carbon atoms of the ribose present in nucleotides are designated with a prime (') mark why?
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to distinguish them from the backbone numbering in the bases
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Nucleotides can exist in ... what phosphorylated form
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Nucleotides can exist in the mono-, di-, or tri-phosphorylated forms.
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Nucleotides are given distinct abbreviations to allow
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Nucleotides are given distinct abbreviations to allow easy identification of their structure and state of phosphorylation.
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The nucleotides found in DNA are unique from those of RNA in that
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in that the ribose exists in the 2'-deoxy form and the abbreviations of the nucleotides contain a d designation.
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Deoxynucleotides need to be synthesised from
using the enzyme what hypothesis does this support |
Ribonucleotides
Ribonucleotide reductase This supports the hypothesis that an RNA world preceded the current DNA one. |
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This supports the hypothesis that an RNA world preceded the current DNA one.
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d
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The nucleotide uridine is not usually found in
and thymine is almost exclusively found in |
DNA
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Thymine is found in ..... but not
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but not rRNAs nor mRNAs.
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The most common adenosine derivative is the cyclic form
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, 3'-5'-cyclic adenosine monophosphate, cAMP.
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This compound is a very powerful ......
involved in.... |
This compound is a very powerful second messenger
involved in passing signal transduction events from the cell surface to internal proteins, e.g. cAMP-dependent protein kinase (PKA). |
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PKA phosphorylates a number of proteins, thereby affecting
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, thereby, affecting their activity either positively or negatively
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Formation of cAMP occurs in response to
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activation of receptor coupled adenylate cyclase. These receptors can be of any type, e.g. hormone receptors.
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S-adenosylmethionine is a form of
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S-adenosylmethionine is a form of activated methionine which serves as a methyl donor in methylation reactions.
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A cyclic form of what? is also found in cells involved as a second messenger moelcule
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A cyclic form of GMP (cGMP) also is found in cells involved as a second messenger molecule.
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In many cases its' role is to
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antagonize the effects of cAMP
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Formation of cGMP occurs
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occurs in response to receptor mediated signals similar to those for activation of adenylate cyclase.
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Polynucleotides are formed
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Polynucleotides are formed by the condensation of two or more nucleotides.
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The condensation most commonly occurs between
forming what bond |
the alcohol of a 5'-phosphate of one nucleotide and the 3'-hydroxyl of a second, with the elimination of H2O, forming a phosphodiester bond.
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The formation of phosphodiester bonds in DNA and RNA exhibits......?
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directionality
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The primary structure of DNA and RNA (the linear arrangement of the nucleotides) proceeds in what direction
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in the 5' ----> 3' direction.
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The common representation of the primary structure of DNA or RNA molecules is to write the nucleotide sequences from
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left to right synonymous with the 5' -----> 3' direction as shown:
5'-pGpApTpC-3' |
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Amino Acids are the building blocks from which
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protiens are synthesised
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They all have the same general chemical formula, differing only
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the side chain
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The side chains are important in providing each amino acid with its
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characteristic properties
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draw the general shape of an amino acid
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draw the peptine bond formation between 2 amino acids
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Definition of a lipid
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Biological molecules that are insoluble in aqueous solutions and soluble in organic solvents are classified as lipids.
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The lipids of physiological importance for humans have what four major functions:
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They serve as structural components of biological membranes.
They provide energy reserves, predominantly in the form of triacylglycerols. Both lipids and lipid derivatives serve as vitamins and hormones. Lipophilic bile acids aid in lipid solubilization |
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Fatty acids fill two major roles in the body
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1. as the components of more complex membrane lipids.
2. as the major components of stored fat in the form of triacylglycerols. |
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Fatty acids are long-chain......molecules containing......
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Fatty acids are long-chain hydrocarbon molecules containing a carboxylic acid moiety at one end.
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The numbering of carbons in fatty acids begins with
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The numbering of carbons in fatty acids begins with the carbon of the carboxylate group.
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At physiological pH, the carboxyl group is readily
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At physiological pH, the carboxyl group is readily ionized, rendering a negative charge onto fatty acids in bodily fluids.
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Fatty acids that contain no carbon-carbon double bonds are termed .... and the ones containing double carbon carbon bonds are called
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Fatty acids that contain no carbon-carbon double bonds are termed saturated fatty acids; those that contain double bonds are unsaturated fatty acids.
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Triacylglycerides are composed
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of a glycerol backbone to which 3 fatty acids are esterified
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draw the structure of a triacylglyceride
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The basic structure of phospolipids is very similar to that of ... except...
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the triacylglycerides except that C-3 of the glycerol backbone is esterified to phosphoric acid.
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The building block of the phospholipids is
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phsophatic acid
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name atleast 3 different phospholipid structures
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Phosphatidylcholine (PC)
Phosphatidylethanolamine (PE) Phosphatidylserine (PS Phosphatidylinositol (PI) |
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Cholesterol an important biological molecule with roles in
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with roles in membrane structure and as a precursor for the synthesis of the steroid hormones and bile acids.
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Both dietary cholesterol and that synthesized de novo are transported through the circulation in
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are transported through the circulation in lipoprotein particles.
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The synthesis and utilization of cholesterol must be tightly regulated in order to prevent
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over-accumulation and abnormal deposition within the body.
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Of particular importance clinically is the abnormal deposition of cholesterol and cholesterol-rich lipoproteins in
why |
in coronary arteries which can lead to atherosclerosis.
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Vitamin D is what type of hormone and what does it regulate
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Vitamin D a steroid hormone that regulates gene expression.
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what is The biologically active form of the hormone
what is its function |
The biologically active form of the hormone is 1,25-dihydroxy vitamin D3 which functions primarily to regulate calcium and phosphorous homeostasis.
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name 4 steroid hormones
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pregnenolone
estradiol. progesterone testosterone |
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how is each one produced and what is its function
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Pregnenolone: produced directly from cholesterol, the precusor molecule for all C18, C19 and C21 steroids
Estradiol: an estrogen, principal female sex hormone, produced in the ovary, responsible for secondary female sex characteristics Progesterone: produced directly from pregnenolone and secreted from the corpus luteum, responsible for changes associated with luteral phase of the menstral cycle Testosterone: an androgen, synthesized in the testes, responsible for secondary male sex characteristics |