Monosaccharides PP - DONE Flashcards
What does the carbohydrate consist of?
- Carbon
- Hydrogen
- Oxygen
What is more accuratly to view them asm structurally?
Polyhydroxy aldehydes and ketones
What is the atom ratio for hydrogen and oxygen in carbohydrates?
2:1
Carbohydrates are divided into 4 chemical groups:
- Monosaccharides
- Disaccharides
- Oligosaccharides
- Polysaccharides
Monosaccharides and disaccharides:
- lower molecular weight
- referred to as sugars
Polysaccharides
Serve for the storage of energy (starch and glycogen) and as structural components (cellulose in plants)
Ribose
The monosaccharide ribose is an imprtent component of coenzymes (ATP, FAD, and NAD) and the backbone of genetic molecule known as RNA.
Carbohydrates = ?
Saccharides
What is monosaccharides general formula?
(CH2O)n, where “n” is three or more
What can be hydrolyzed to simple sugar?
- oligosaccharides
- polysaccharides
Classification of monosaccharides based on three different characteristics:
- the placement of its carbonyl group
- the number of carbon atoms it contains
- its chiral handedness
If the carbonyl group is an aldehyde, ……….
the monosaccharide is an aldose
If the carbonyl group is a ketone, …….
the monosaccharide is a ketose
Monosaccharides with X carbon atoms are called:
- 3 carbon atoms are called trioses.
- 4 carbon atoms are called terroses
- 5 carbon atoms are called pentoses
- 6 carbon atoms are called hexoses
- and so on….
What is the major source of energy for metabolism (glucose) and in biosynthesis?
Monosaccharides
Examples of polysaccharides:
- glycogen
- starch
Trioses
Intermediate metabolites of biosynthesis and degradation of other sugars
Tetroses
E.g. erythrose, the intermediary in the conversion of glucose
Pentoses
Such as ribose (component of RNA), deoxyboza (component of DNA), xylose, xylulose
Hexoses
Such as glucose, galactose, mannose, fructose (energy sources)
Heptoses
Only sedoheptulosa occurs in living organisms
Examples of pentoses:
- D-ribose
- D-ribulose
- D-deoxyribose
- D-xyloze
- D-xylulose
Examples of hexoses:
- D-glucosa
- D-mannose
- D-galaktose
- D-fucose
- D-fructose
Examples of trioses:
- D-glyceraldehyde
- D-dihydroxyacetone
Examples of tetroses:
- D- erythrose
- D-erythrulose
Epimerism
Epimerism is when two monosaccharides differ in the position of substituents (-H and -OH) at the same carbon atom, WITH THE EXEPTION OF THE CARBONYL GROUP
What is the general formula for carbohydrates?
Cm(H2O)n
Entantiomers
It is the presence of sugar in the two lirror forms. Entantiomers differ in the position of substituents at the chiral carbon atom. In the body the D-sugars are dominated forms, L-entantiomers occur sporadically.
Anomeric carbon
Most of the sugars are present in ring forms. The transition of sugars from a chain on a ring results in the formation of additional chiral C-atom, called anomeric carbon.
How can the anomers be distinguished?
They can be distinguished by enzymes
What is the difference between “alfa” and “beta” anomers?
The optical rotation
Which is the stable and which is the unstable form of glucose;
A. The chair form
B. The boat form
The chair form is the stable one, ehile the boat form is the unstable one.
What is the most simplest polysaccharide?
Disaccharide
Monosaccharide + monosaccharide = ?
Disaccharide
What is the covalent bond between two monosaccharides known as?
Glycosidic linkage
What reaction forms the glycosidic linkage?
It is formed by a dehydration reaction
Whatis the fromula for unmodified disaccharides?
C12H22O11
Give examples of disaccharides:
- Sacharose
- Maltose
- Lactose
- Isomaltose
Classification of polysaccharides:
- Hemopolysaccharides (homoliganes)
- Heteropolysaccharides (heteroglikanes)
Hemopolysaccharides (homoliganes)
Are composed of identical units of sugar (starch, glycogen, cellulose)
Heteropolysaccharides (heteroglikanes)
Are made up of various units and non-sugar components
What is the most important energy sources im humans?
Starch and glycogen
What two substances is starch composed of?
- Amylose
- Amylopectin
Which polysaccharide is important for intestinal function?
Cellulose
Which enzyme is in saliva?
Amylase
What does amylase do?
It breaks down starchy carbohydrates
What type of saccharide is isomaltose?
Disaccharide
What happens with isomaltose and maltose when it gets inside the body?
The maltose and isomaltose are then absorbed into the lining cells of the intestine and are further simplified, being converted into glucose molecules that can be absorbed into the blood. Glucose is carried through the bloodstream to the liver, where it is stored or used to provide energy for the work of the body.
