ch 7 Flashcards
what is the anomeric carbon
the carbonyl carbon (of aldehyde or ketone) in the open chain form of the sugar or the carbon bonded to the ring oxygen and a hydroxyl group in the cyclic form.
what is mutarotation
the observed change in the optical rotation of the alpha or beta anomers of glucose upon dissolution in solvent
is the anomeric carbon considered a chiral carbon
no because its constantly changing between the open and closed form of glucose.
how is the anomeric carbon generated in carbohydrates
when the open chain monosaccaride cyclizes OH in C-5 attacks the carbonyl causes equilibrium between open and closed forms
what is the furanose form?
five membered ring
what is the pyranose form
six membered ring
alpha carbohydrates have OH on anomeric carbon up or down
down
beta carbohydrates have OH on anomeric carbon up or down
up
what are aldoses
sugars with aldehydes attached to them
what are ketoses
sugars with ketones attached to them
how to find stereoisomers of a sugar
2 to the number of chiral carbons ex 2^4=16 stereoisomers
what is characteristic of an alpha glyosidic bond
down
what is characteristic of an beta glyosidic bond
up
what is a reducing sugar
any sugar with a free anomeric carbon
lactose is made up of what
glucose with galactose
sucrose is made up of what
glucose with fructose
what are two sugars used for energy storage
glycogen (animals) and starch
what are two examples of starch
amylopectin and amylose
glycogen and starch are what kind of polysaccharides
homopolysaccharides
energy storage sugars have what linkage
alpha 1 to 4
what are two sugars used for structural
cellulose and chitin
cellulose and chitin are what kind of polysaccharides
homopolysaccharides
cellulose has what kind of linkage
beta 1 to 4
chitin has what kind of linkage
beta 1 to 4
what sugar is used for signaling
glyconjugates (sugar with protein/sugar with lipids)
lactose has what linkage
beta 1-4
sucrose has what linkage
beta 1 to alpha 2
cellulose is made up of what monosaccharides? what linkage does it have and what is its function?
its monosacc is glucose, linkage beta 1to 4 and function is structural
glycogen is made up of what monosaccharides? what linkage does it have and what is its function?
its monosacc is glucose, linkage alpha 1 to 4 and function is energy
peptidoglycan is made up of what monosaccharides? what linkage does it have and what is its function?
its monosacc is NAM+ NAG, linkage beta 1 to 4 and structure is structural
peptidoglycan is what kind of polysaccaride
it is a heteropolysaccaride
which structural homopolysaccaride combines with protein or CaCO3 to harden the exoskeleton
chitin, in between the acetyl groups you put something strong in between
what is bacterial cell walls made of
peptidoglycan (NAG and NAM)
what is the difference between gram positive and gram negative bacteria
gram positive has pentaglycine bridges/crosslinks that connect the amino acids while gram negative have a direct amide bond joining the tetra peptides together
explain how lyzosyme and penicillin can affect gram + but not gram - bacteria (4 things) forth is most important for lysozyme
- penicillin is an irreversible inhibitor of the bacterial enzyme that produces the pentaglycine crosslink.
- lyzozyme cant reach the peptidoglycan because they have another membrane making it harder to reach by lysozyme
3.lysozyme is thin so between two membrane in gram - making it difficult to reach - lysozyme isnt able to reach the outer membrane because peptidoglycan protects the membrane from lysozyme
sugar with lipid is called what
lipopolysaccharides/glycolipid
sugar with a lot of protein is called
glycoprotein
sugar with a little protein is called
proteoglycans
what do we call glycolipids on the surface of gram - bacteria and why do we call them that
we call them endotoxins and we call them that because they elicit a strong immune response due to weird sugars
preteoglycans have what kind of characteristic
they are very feather like
glycoproteins have what type of sugar chains? what is the percent of protein content? what charge do they have?
type of sugar chains: varied, protein content: 50-60%, charge: (-) or neutral
glycoproteins are located where? and what is function?
located in blood or cell bound and function is signaling
proteoglycans have what type of sugar chains? what is the percent of protein content? what charge do they have?
sugar chains: repeated disaccharide units
protein content: 10-15%, charge: (-)
proteoglycans are located where? and what is function?
location: extracellular matric in connective tissue and function is structural
what are glycosaminoglycans
glucosamine or galactosamine paired with an acid to bind to the protein part of the preteoglycan
what amino acids are part of o linked glycoproteins
Ser or Thr
what amino acids are part of n linked glycoproteins
Asn
antifreeze glycoprotein are O linked glycoproteins that allow fish to survive the cold waters near the poles. explain how the Thr bound disaccharides can achieve that
sugars hydrogen bond to incipient to disrupt the freezing process.
what does sialic acid do
they tend to be at the end of a sugar chain like a cap and an enzyme determines its half life by how many molecules of sialic acids its cut off to reach the sugar.
explain the following statement: the half life of a protein can be regulated by the number of added sialic acid units on the end of the oligosaccharide N linked to the protein
as these are hydrolyzed galatose is exposed and the liver has receptors for galactose and we internalized this and digest to break apart
what is A1c and what is a normal level? this is used as a diagnostic tool for disease
A1c is hemoglobin A1c is the amount of sugar attached to the hemoglobin. the normal level is <5.6% diabetes is 6-5% and anything in between in prediabetes
proteoglycans in the ECM interact with what proteins and what glycoproteins
with integrin and collagen and the glycoprotein is fibronectin
what makes a good anticoagulant
it has a negative charge strengthen the interaction with antithrombin
Heparin is a proteoglycan (core protein + glycosaminoglycan) that acts as an anticoagulant. Describe what structural feature makes the glycosaminoglycan portion a good anticoagulant. What would make a good antidote to heparin?
heparin binds to antithrombin III and it accelerates its activity 1000 fold. antithrombin is a serine protease inhibitor that inhibits the conversion of prothrombin to thrombin thus preventing coagulation
what is the sugar code
glycoconjugates are recognized and bound by a class of proteins called glycan-
binding proteins (GBPs or lectins), produced by all types of cells.
Lectins are ??? that recognize and bind to specific ??? . Selectins are a type of
lectin that are embedded in the inner wall of blood vessels. They bind to the ??? ligands on the surface of circulating ???, slowing down their movement until they reach a site of inflammation.
lectins are PROTEINS, and bind to specific SUGARS in glyconjugates. selectins binds to SUGAR ligands on the surface of circulating LYMPHOCYTES
????, released by macrophages at the site of inflammation, cause the
glycoprotein ????? to bind and immobilize these cells, until they can move out of the
circulatory system towards the site of tissue damage or infection in a process called ????
CHEMOKINES, released by macrophages at the site of inflammation, cause the
glycoprotein INTEGRIN to bind and immobilize these cells, until they can move out of the circulatory system towards the site of tissue damage or infection in a process called EXTRAVASATION
What are lectins
proteins that can read the suagr code and has a high affinity for certain sugar coating cells (glycoconjugates)
MBP and CRP are what
lectins that coat foreign antigens
what does MBP bind to
to mannose rich glycans in microbes with mannose as the terminal sugar
what CRP bind to
binds to the microbe promoting phagocytosis as part of the immune response
what is the most dominant surface feature of the outer membrane of gram negative bacteria.
lipopolysaccaride
