Carbohydrates Part 1 Flashcards
What is a carbohydrate? What is it composed of?
Biomolecules consisting of C, H, and O atoms
Primary energy source for metabolic processes
What are saccharides? What are the 4 types and examples of each?
A group that includes sugars, starch and cellulose
Monosaccharides- sugars, glucose
Disaccharides- lactose, sucrose
Oligosaccharides
Polysaccharides- starch, glycogen
Describe Monossacharides. How many carbons? What are they defined by?
Simple sugars
3-9 C atoms
Defined by location of carbonyl group
Describe Aldose. Where is the location of the carbonyl group? What kind of group is it?
Monosaccharide
Carbonyl group is on endmost C atom
Aldehyde group
Describe Ketose. Where is the location of the carbonyl group? What kind of group is it?
Monosaccharide
Carbonyl group within sugar backbone
Ketone group
What is a functional group?
Characteristic groups in organic molecules that give them their reactivity
What is a chiral carbon on a monosaccharide?
4 different atoms or groups of atoms attached
C atom farthest from the carbonyl group
What is the orientation of the OH group within D-sugar? What sugar exists naturally in this form?
On the chiral center on the right
Glucose
What is the orientation of the OH group within L-sugar?
On the chiral center on the left
Which glucose (D or L) is the natural form? What is their relationship to each other?
D glucose is the natural form
Enantiomers
Are monosaccharides soluble in water? By what process do they form rings? What is the significance of this phenomenon?
Soluble in water
Form rings via internal cyclization
Thermodynamically more stable form
What is a pyranose ring?
Ring with 5C and 1O atom forms
The hydroxyl group on carbon 5 reacts with aldehyde at carbon 1
What is a furanose ring?
Ring with 4 C and 1 O atom forms
The hydroxyl on carbon 4 reacts with the aldehyde at carbon 1
How is a hemiacetal formed? What do they contain?
Formed when an alcohol reacts with an aldehyde
Contain alcohol (OH) and an ether (OR) group attached to the same carbon
What are anomers?
Geometric variation of cyclic sugars
What is the most common form of glucose at equilibrium in aqueous?
Pyranose
Define glycosides/glycosidic bonds/linkage. What portions of the carbohydrate are involved?
Covalent bond that joins carbohydrate (sugar) to another carbohydrate (sugar) to form disaccharide
Hydroxyl group of carbohydrate and hydrogen of another sugar or organic molecule
Ex: glucose and galactose can form Lactose structure
What is a glycosidic bond? What is a glycoside? What atoms may be involved with this bond?
Sugar (OH group) may form a glycosidic bond with another biomolecule that is not a carbohydrate (can be between sugar and sugar or sugar and non carbohydrate
Substance containing a glycosidic bond
O, N, S, or C
What is a nucleotide? What is a nucleoside, what bond is involved? What are the 5 nitrogenous bases?
Phosphate, ribose sugar and nitrogenous base
Ribose sugar and nitrogenous base (linked by glycosidic bond)
Adenine, guanine, cytosine, thymine, uracil
Is the dominating form of D-glucose the open chain form or the furanose form?
Furanose ring
What is formed when monosaccharides (alcohols) react with acids?
Esters
What are the three components of a nucleoside triphosphate? (ATP) What does it function as?
Nitrogenous base adenosine
Sugar ribose
Triphosphate
Energy source
What are the contents of the enzyme Nicotinamide Adenine Dinucleotide? (NAD)
Adenine (nitrogenous base)
2x the sugar ribose
2x phosphate
Nicotinamide (form of vitamin B3)
What is NAD involved in?
Coenzyme involved in oxidation reduction reaction
Glycolysis, fatty acid oxidation, TCA cycle, mitochondrial respiratory chain
What is NADP+? How is it formed? How is NADPH formed?
Universal electron carrier
Additional phosphate added to NAD+
NADPH formed form NADP+ through pentose pathway to glucose-6-phosphate dehydrogenase
What occurs during reduction of D-Ribose? What is produced?
Carbonyl group of aldehyde is reduced to an alcohol
Results in reduced sugar (D-ribitol)
What are the components of flavin adenine dinucleotide (FAD)? What reactions is it involved in?
Adenine
Sugar ribose
2x phosphate (diphosphate)
Riboflavin (vitamin B2)
Redox active metabolic reaction
Is FAD an oxidizing or reducing agent? What occurs when it goes through the opposite process?
FAD is oxidizing agent and is reduced to FADH 2
FADH2 is reducing agent and is oxidized to FAD
What is hyperglycemia?
High blood sugar
Diabetes
How do glucose, sucrose and fructose compare to each other when considering sweetness? (Least to most)
Glucose
Sucrose
Fructose (sweetest common sugar, less calories b/c less is needed)
How do artificial sweeteners compared to real sugars? What kind of effects do they have on the body?
More sweet
Can cause changes in stomach bacteria leading to inflammation, obesity, heart disease and diabetes
What are disaccharides? What are they joined together by? What are 3 examples?
2 monosaccharides joined but a glycosidic bond
Ex: sucrose, maltose, lactose (milk sugar?
What enzyme to deficient in lactose intolerance?
When does lactose intolerance form?
Lactase
Almost everyone is born with ability to digest it (breast milk), can develop at any age
How many monosaccharides are joined in oligosaccharides?
3-10
How many monosaccharides are joined in polysaccharides? What are some examples?
More than 10
Glycogen, starch, cellulose (polymers of D/glycose)
What is starch? What is it produced by? What does it consist of?
Polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds (white, tasteless, odorless)
Produced by most green plants for energy storage
Consists of amylose and amylopectin
What can a starch be processed into?
Sugars used in processed food
Sugars and then fermented to produce ethanol for alcohol
What is glycogen? Where can it be found/ made? What are the 2 forms?
Polysaccharide of glucose, serves as energy storage
In animals, fungi and bacteria
Produced and stored in cells of the liver and skeletal muscle
Two forms: glycogen for short term, triglyceride in adipose tissue for long term
What controls glycogen breakdown? What is made from this breakdown?
Glucagon
Peptide hormone is produced
How does liver glycogen function?
Short term energy
Responds to blood glucose level
Liver does not use glycogen for its own energy needs
How does muscle glycogen function?
Provides readily avaible source of glucose during exercise
Supports anaerobic and aerobic
Muscle cannot release glucose into blood due to lack of glucose-6-phosphatase
Besides the liver and skeletal muscle, where else can small amounts of glycogen be found?
Kidneys, RBC, WBC, glial cells in the brain, uterus during pregnancy to nourish embryo
Where within the cell is glycogen stored?
Stored in the cytoplasm of animal cells for food energy
Forms energy reserve
What are glycosaminoglycans (GAGs)? What roles do they have in the cell/body?
Structural carbohydrates
Role in cell signaling, regulation of cell growth, proliferation, promotion of adhesion, anticoagulation, wound repair, lubricant
What else are GAGs called? Where are these found? What are two examples?
Mucopolysaccharides because of viscous, lubricating properties
Found in mucous secretions (ex: bladder lining protection from urine)
Ex: hyaluronic acid, heparin sulfate
What is the charge and structure of GAGs (mucopolysaccharides)? What are they a part of?
Negatively charged
Long linear polysaccharides consisting of repeating disaccharide units
Part of proteoglycans (ex: cornea)
Describe the structure of a glycosaminoglycan.
Repeating two-sugar unit consists of an uronic sugar and an amino sugar => amine group replaced hydroxyl group (OH)
What is hylauronic acid? Where is it found? What is its function?
Anionic, non-sulfated glycosaminoglycan distributed throughout tissues
Part of ECM for cell proliferation and migration, progression of malignant tumors, wound repair
What is the function of the hylauronic acid in the eye? What can it be used to treat?
Lubricant
Present in corneal endothelium and tears
Dry eye treatment
Lowers inflammation speeds up healing
Which proteoglycan is important in neural development and also contributes to glia scar formation – hence preventing axonal growth (regeneration)?
Chondroitin sulfate proteoglycan (CSPGs)
What is heparin sulfate composed of? What is its function? where can it be found in the eye?
Glucuronic acid (GlcA) linked to N-acetylglucosamine (GlcNAc)
Regulation, development, angiogenesis, blood coagulation, tumor metastasis
All retinal layers, choroid
What is heparin?
A medication and naturally occurring glycosaminoglycan
Treats heart attacks
What is chondroitin sulfate? Where can it be found?
Sulfated glycosaminoglycan
Attached to proteins part of proteoglycan
Structural component of cartilage
What are proteoglycans? What does it consist of? Where can it be found?
Heavily glycosylated proteins
Consists of core protein with covalently attached GAG chain
Found in connective tissue
Which proteoglycan is the major PG in the cornea?
Keratan sulfate
What is Chondroitin sulfate proteoglycan (CSPGs) a structural component of?
Cartilage
What are glycoproteins?
oligosaccharide chains (glycans) covalently
bound to the polypeptide chain
increase of hydrophilic nature of the protein
What is a form of glycosylation resulting in creating a membrane anchor?
Glypiation
