Chapter 10: Carbohydrates Flashcards
Carbohydrates are rich in ______ groups.
Hydroxyl (-OH)
Monosaccharides are ______ and ______ that contain two or more ______ groups.
Aldehydes and ketones that contain two or more alcohol groups.
D-Ribose
D-Deoxyribose
D-Glucose
D-Mannose
D-Galactose
D-Fructose
Name the 6 key monosaccharides for biological processes.
- ) D-Ribose
- ) D-Deoxyribose
- ) D-Glucose
- ) D-Mannose
- ) D-Galactose
- ) D-Fructose
An aldehyde can react with an alcohol to form a _____.
Hemiacetal
A ketone can react with an alcohol to form a ______.
Hemiketal
The (chair/boat) form is more stable due to less steric hindrance.
Chair
a-D-Glucopyranose is an anomer that is _____ present in our blood.
1/3
The open chain of Glucopyranose is found in about ___ of our blood.
1%
B-D-Glucopyranose is an anomer that is present in about ___ of our blood.
2/3
Because of it’s open chain form, glucose can react with _____.
Hemoglobin
What is an A1c test?
- Tests for glucose added to hemoglobin.
- Allows us to take an average of someone’s blood glucose over a span of time.
- Allows monitoring of the long-term control of blood glucose levels in diabetics (effectiveness of treatments).
A1c is also known as?
Glycosylated Hemoglobin
If you have high levels of glucose, you have …
High levels of the open chain reaction.
In non-diabetics, ____ of hemoglobin is glycosylated.
<6%
In diabetics, glycosylated hemoglobin is ____.
Almost 10%
Monosaccharides can react with ______, _____ and ______.
Alcohols, amines and phosphates
Bond formed between the anomeric carbon and an amine is called?
N-glycosidic bond
Bond formed between the anomeric carbon and a hydroxyl group is called?
O-glycosidic bond
Carbohydrates also form ____ linkages to phosphates.
Ester
Maltose, a disaccharide, has what type of bond?
a-1,4-Glycosidic bond
3 monosaccharides can link in over ____ ways.
12,000
What class of enzymes catalyze the formation of glycosidic bonds?
Glycosyltransferases
-Transfering glycosyl unit (like a glucose), moving 2 things together that are carbohydrates
What % of glycosyltransferases are present in organisms?
1-2% (considered large)
What are the most common disaccharides?
Sucrose, lactose and maltose
Lack of lactase (cleaves lactose) in the small intestine causes…
Lactose intolerance/deficiency
Name the three storage forms of glucose.
Glycogen (animals)
Starch (plants)
Cellulose (plants’ structure)
Glycogen is very large polysaccharide that is the storage form of glucose in animals. Formed with what type of linkage?
a-1,4-glycosidic linkage with branches formed by a-1,6-glycosidic bonds
-Has a compact structure that takes little space to store
Starch when unbranched is called?
Amylose
Starch that is branched is called?
Amylopectin
Cellulose has what type of linkage?
B-1,4-glycosidic bonds (forms strong fibrils that form the plant’s structure)
The protein (AA) is the largest component by weight in this carbohydrate attached to a protein?
Glycoprotein
By weight, _____ are mainly carbohydrate. These play structural roles or act as lubricants.
Proteoglycans
_____ are predominantly carbohydrate. Also functions as a lubricant.
Mucins or mucoproteins
Carbohydrates can only react with _____
Side chains of AAs (must contain amines, hydroxyls or phosphate)
Erythropoietin is an example of a _____.
Glycoprotein
Erythropoietin is secreted by the kidney into the blood that stimulates the production of ____.
Red blood cells
Erythropoietin enhances the stability of the protein and contains both O-linked and N-linked. Without the carbs for glycosylation present,
The protein degrades faster
Proteoglycans can have as much ____ of its weight coming from carbohydrates.
95%
Proteoglycans have repeating units of just two different sugars. One of two will have a strong ______.
Negative charge which allows interacton with water.
Proteoglycans need to be able to be recycled. Enzymes missing to degrade proteoglycan can result in…
Skeletal deformation and lower life expectancy (if there is an inability to break down. Ex: Hurler’s disease
Proteoglycans are also important components of ______.
Cartilage (need a molecule that can compress and be reshaped.
- Proteoglycans have water that releases on impact and acts as a “shock absorber” and water rebinds.
- All because of the charge of these proteoglycans
Mucins have a massive series of ______.
O-linked glycans
In mucin, there is a region of the protein backbone rich in serines and threonines and it is the site of ______.
Glycosylation.
Human ABO glood groups reflect the specificity of __________.
Glycosyltransferases (presence or absence)
-O antigen does not have the transferases present
Lectins (glycan-binding proteins) facilitate ________. What are selectins and what can they do?
Cell-to-cell interaction (can bring two cells together)
- Interacting with the extracellular matrix
- Selectins (class of lectins) bind to immune cells to sites of injury and allow attachment of an embryo to the mother’s uterus. Carb-driven process
Influenza virus binds to oligosaccharides composed of ______ and ______ to allow attachment to target cells.
Sialic acid and Galactose
Neuraminidase cleaves glycosidic bonds, otherwise the virus is stuck to the host. How do you fix this?
Tamiflu and Relenza target the neuraminidase (a neuraminidase inhibitor) to prevent the release of newly made viruses and cause an accumulation.
Lactose, from milk, is made up of which monosaccharides?
Galactose and Glucose
Which one of the following monosaccharides is used to synthesize nucleotides?
D-Ribose
The major carbohydrate stored in humans is?
Glycogen
Which amino acids in proteins can have O-linked sugars attached to them?
Serine, tyrosine and threonine
Sucrose, also known as table sugar, is made up of which monosaccharides?
Glucose and Fructose
Starch, obtained from grains, corn, flour, rice and potatoes, is a polymer of…
Glucose
Which carbon is used to define the D- or L- configuration of glucose?
The farthest chiral carbon from the carbonyl group
Which one of the following is NOT correct for glycoproteins?
- Carbohydrates are attached to serine/threonine residues through O-glycosidic linkages
- Carbohydrates are attached to asparagine residues through N-glycosidic linkages
- Protein glycosylation enhances the correct targeting of membrane proteins
- Protein glycosylation decreases the solubility of proteins
- Protein glycosylation increases the stability of proteins
- Protein glycosylation decreases the solubility of proteins
