Flashcards in March 2, 2015 --> Cards 1-15 Deck (79):
What are the six distinct classes of GAGs
1. Chondroitin Sulfate
2. Dermatan Sulfate
3. Keratan sulfate
4. Heparan sulfate
Which of the six classes of GAGs is not sulfated?
- Is also not covalently attached to protein
What is the charge of GAGs? What causes this?
-Highly negatively charged molecules
-The uronic acid and sulfate residues cause GAGs to be negatively charged
Describe the general make-up and characteristics of a GAG
Long, linear carbohydrate chains that contain REPEATING DISACCHARIDE units
- Usually contain a hexosamine and a uronic acid
Are GAGs branched or unbranched? What acid do they not contain?
They are unbranched and do not contain N-acetylneuraminic acid
Where are GAGs located primarily?
on the surface of cells or in the ECM
Hyaluronic acid is unique among the GAGs why?
It does not contain any sulfate and is not found covalently attached to proteins as are proteoglycans
The majority of GAGs in the body are linked to core proteins forming what?
Proteoglycans (also called mucoppolysaccharides)
What structure in microbiology contains a hetropolysaccharide made up of alternating N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) units?
Bacterial cell wall.
Describe where Hyaluronate can be found in the body
ECM of loose CT
Describe where Chondroitin sulfate can be found in the body
Where can Heparan sulfate be found
Components of cell surfaces
Heparin can be found in the body where?
Component of intracellular granules of mast cells lining the arteries of the lungs, liver, and skin
Where can Dermatan sulfate be found in body?
Where can Keratan sulfate be found in body
Cartilage aggregated with chondroitin sulfates
What is the most abundant GAG in body
What is the most heterogenous GAG
What GAG serves as an anticoagulant, more sulfated than heparan sulfate
Which GAG can be described as large polymers and shock absorbing
Which GAG contains higher acetylated glucosamine than heparin
Proteins with covalently linked oligosaccharide (glycan) chains
Function of glycoproteins
Complex carbohydrates that have a central protein molecule to which many GAGs are attached in a radial (brush-like) pattern
What is the composition of a proteoglycan?
What is the linkage of a GAG to the central protein
Involve a trisaccharide: 2 galactose + 1 xylose
GAGs are attached to central protein how? This also means that proteoglycans are rich at the central protein in what molecules?
Proteoglycans are located mostly where?
Proteoglycans are most often repeating dissacharides of what molecules?
amino sugar (N-acetyl) and Uronic acid (sugar with COO-)
Maltose consists of what two sugars?
2 Glucose molecules
Lactose consists of what two sugars?
glucose and galactose
Sucrose consists of what two sugars?
Glucose and fructose
Describe the formation of a glycosidic bond
Bonds form when the hydroxyl group on the anomeric carbon of a monosaccharide reactis with an OH or NH group of another compound
If oxygen is involved, the glycosidic bond is classified as what?
If nitrogen is involved, the glycosidic bond is classified as what?
O-glycosidic (found in polysaccharides)
N-glycosidic (found in glycoproteins and nucleotides)
What monosaccharide is the most important of the aldohexoses?
Two most important storage polysachharides
Starch and glycogen
What two main components make up Starch
Amylopectin (highly branched chains w/ a-1,6 linkages)
Glycogen has what linkages
a-1,4 linkages and a,1-6 linkages
Where is glycogen especially abundant
In the liver
Cleavage of glycogen beyond a branching point requires what enzymes?
What is the most common organic compound on earth
Is cellulose digestible by humans?
Not digestible and is often referred to as "dietary fiber" or "roughage" acting as bulking agent for feces
Linkage of cellulose
Term glycan refers to what?
A polysaccharide or an oligosaccharide
How does the carbohydrate portion of most glycoproteins differ from that of proteoglycans?
It is shorter and branched
Glycolipids are derived from what molecule?
the lipid Ceramide
Components of Proteoglycan
Characteristic of Proteoglycan
Protein + GAGs
Long & Straight
Lubrication, ECM, molecular "sieve"
Components of Glycoprotein
Protein + Carbohydrate
Short & Branched
Enzymes, Hormones, antibodies, structural proteins
Components of Glycolipids
Lipid + Carbohydrate
Cell membrane receptors
What is an important property of Chondroitin Sulfate
Holding water and nutrients, and allowing other molecules to move through cartilage, important because there is no blood supply to cartilage
What enzyme will promote depolymerization of the ECM
It splits hyaluronic acid and so lowers its viscosity and increases the permeability of CT and the absorption of fluids
What GAG contains the largest proportion of sulfate
What is a Dextran
A homopolymer of glucose formed by the hydrolysis of sucrose via glycosyl transferase (dextran sucrase)
What bacteria can produce dextran?
What is a side product of dextran productions
Fructose which is formed into levans (fructans) and stored intracellularly as reserve nutrients
T or F, Fructans also increase the adhesion of bacteria to surfaces of the teeth and promote the formation of dental plaque
Rods contain a photopigment called what?
Rods are numerous in what part of the retina
Cones are primarily responsible for what?
The four different photopigments consits of what?
A protein called an opsin to which a chromophore molecule called retinal is attached.
The majority of the bending of light rays is accomplished by what?
T or F, The shape of the cornea changes with age
False, it does not change
majority of the focusing is done by what part of the eye
The cornea, not the lens
What part of the eye is analogous to the film in a camera?
Cones are especially densely packed in what area?
Which part of the eye is filled with vitreous humor?
Which part of the eye is filled with aqueous humor?
Anterior segment (anterior and posterior chambers)
Parts of the External ear
Auricle (directs sound waves)
External auditory canal (contains hair and cerumen)
Parts of Middle ear
Auditory tube (equalizes pressure)
Ossicles (Malleus, incus, stapes)
Parts of Inner ear
Vestibule (saccule and utricle) - balance
Semicircular canals (concerned with equilibrium)
Cochlea ( two membranes, vestibular and basilar)
What portion of the inner ear is responsible for hearing
Cochlea, it is the basic functional unit of hearing because this portion transforms fluid vibrations from sound waves into a nerve impulse
What is Miosis:
Constriction of the pupil of the eye. Can be caused by a normal response to an increase in light, certain drugs or pathological conditions
what is Mydriasis:
Prolonged abnormal dilation of pupil of the eye induced by a drug or caused by a disease and causes the eyes to become extra sensitive to light
How to treat mypoia
Myopia is nearsightedness, eye is too long for refractive power of the lens
- Concave lenses are used
How to treat hyperopia
Hyperopia is farsightedness, occurs when light entering the eye focuses behind the retina instead of directly on it. Cause by a cornea that is flatter, or an eye that is shorter.
- Convex lenses are used
Astigmatism is what?
occurs when the curvature of the lens is not uniform and is corrected with cylindric lenses
Presbyopia is what?
The inability of the eye to focus sharply on nearby objects, resulting from the loss of elasticity of the lens with advancing age.
- Corrected with bifocals
Hgb value depends on what?
Number of RBCs and amount of Hgb in each RBC
Blood leaving the lungs is what % saturated with oxygen? Blood returning to the lungs (venous blood) is what % saturated with oxygen?