40 Questions
What is the percentage of pyranose in the equilibrium mixture?
99%
What is the result of the reaction between a hydroxyl group of C-5 and the carbonyl oxygen on C-1?
Formation of a pyranose ring
What is the significance of the ring closing reaction in terms of carbon C-1?
It makes carbon C-1 chiral
What is the byproduct of fermentation in yeast?
Carbon dioxide and ethyl alcohol
What is the arrangement of -CH2OH and -OH on carbon C-1 in the cis arrangement?
They are on opposite sides of the plane of the ring
What is the molecule that bends over in solution to form a ring structure?
D-Glucose
Where does the aerobic breakdown of glucose take place?
Mitochondrion
What is the general term for the form of glucose shown in the figure?
Hexose
What is the purpose of insulin in the body?
To decrease blood sugar levels
What is the percentage of the open chain form in the equilibrium mixture?
1%
What happens to excess glucose in the liver and muscles?
It is stored as glycogen
What is the function of glucagon?
To increase blood sugar levels
What is the result of the reaction between the hydroxyl group of C-5 and the carbonyl oxygen on C-1 in terms of the structure of glucose?
Formation of a cyclic structure
What is the energy source for brain cells?
Glucose
What is the result of glycosylation on enzymes?
It destroys their function
What is the significance of the low rate of glycosylation in the presence of glucose?
It reduces the occurrence of long-term health complications
What type of bond is formed between two monosaccharide sugars in a disaccharide?
Glycosidic bond
What is the byproduct of the synthesis process in the formation of disaccharides?
Water (H2O)
What is the type of reaction that forms a disaccharide?
Condensation reaction
What is formed when a hydroxyl group on C-1 of a glucose molecule reacts with a hydroxyl group on C-2 of fructose?
Water (H2O)
What is the term for the bond formed between carbon 1 (C1) of one hexose sugar and carbon 4 (C4) of the second sugar unit?
Glycosidic bond
What is the type of disaccharide formed by joining two α-glucose molecules?
Maltose
What is the term for the removal of a water molecule in the formation of a disaccharide?
Dehydration
What is the bond referred to in the formation of a disaccharide?
Oxygen bridge
What is the first step in the conversion of glucose to energy?
Hexokinase
What is the main function of cellulose in plants?
Structural support
What is the difference between glucose and glycogen as energy sources?
Glucose requires more energy to convert to energy, while glycogen requires less energy
What is the composition of cellulose?
A polymer of a chain of cellobiose molecules
What is the approximate range of glucose units in natural cellulose chains?
2000 to 14000
What is the main component of wood?
Cellulose
What is the main component of cotton?
Cellulose
What is the structure of cellulose?
Linear
What is the main difference between the structure of cellulose and chitin?
The replacement of -OH on carbon C-2 with -NH.CO.CH3 in chitin
What type of linkage is present in the polymer of chitin?
1,4- linkage
What is the functional group attached to carbon C-2 in chitin?
-NH.CO.CH3
What is the repeating unit in the polymer of chitin?
Modified glucose unit
What is the side chain attached to the nitrogen atom in chitin?
-NH.CO.CH3
How many -OH groups are present in each repeating unit of chitin?
4
What is the molecular structure of chitin similar to?
Cellulose
What is the main function of chitin in nature?
Not specified in the text
Study Notes
Glucose
- Glucose is a hexose sugar that can exist in both open chain and cyclic forms.
- In solution, glucose is in equilibrium with several cyclic isomers, but primarily exists as a pyranose ring (99%).
- The pyranose ring is formed through a reaction between a hydroxyl group on C-5 and the carbonyl oxygen on C-1.
Structural Forms of Glucose
- The open chain form of glucose is in equilibrium with its cyclic isomers.
- The cyclic forms of glucose can exist as either pyranose (more common) or furanose rings.
- The pyranose ring can have a cis or trans arrangement of the -CH2OH and -OH groups on carbon C-1.
Breakdown of Glucose
- Glucose can be broken down through fermentation (in the absence of oxygen) or aerobic respiration (in the presence of oxygen).
- Fermentation produces carbon dioxide and ethyl alcohol, while aerobic respiration produces carbon dioxide and water.
Biological Relevance of Glucose
- Glucose is an important energy source for cells, particularly brain cells.
- The digestive system breaks down carbohydrates into glucose, which is then absorbed into the bloodstream.
- Insulin and glucagon hormones regulate blood sugar levels by facilitating glucose uptake and storage in cells.
Disaccharides
- Disaccharides are formed through condensation reactions between two monosaccharide sugars.
- The synthesis process involves the formation of a glycosidic bond between carbon 1 of one sugar and carbon 4 of the second sugar.
- Common disaccharides include sucrose, lactose, and maltose.
Maltose
- Maltose is a disaccharide formed by joining two α-glucose molecules through a condensation reaction.
- The reaction removes water and forms an α 1-4 glycosidic bond between the two glucose units.
Cellulose
- Cellulose is a polymer of cellobiose molecules, used for structural support in plant cell walls.
- It is an important polysaccharide found in wood, cotton, and paper.
- Cellulose is a linear polymer composed of glucose units, with a molecular weight ranging from 2,000 to 14,000 glucose units.
Chitin
- Chitin is a polymer of modified glucose units, similar in structure to cellulose.
- It is found in the exoskeletons of insects and crustaceans, and is a major component of fungal cell walls.
- Chitin is composed of repeating units of modified glucose molecules linked through β 1-4 glycosidic bonds.
This quiz is about the structure of D-Glucose and its reaction with a hydroxyl group in a solution. It involves understanding the molecular composition of glucose and its properties.
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