3.1.2 carbohydrates Flashcards
What is the structure of amylose?
- Formed from alpha glucose
- Straight chain
- Only 1-4 glycosidic bonds
- Often forms a spiral held together by hydrogen bonds
What bonds join monosaccharides?
Glycosidic
Are disaccharides soluble? Are disaccharides reducing sugars?
Are soluble- dissolve to form sweet tasting solutions
Some are reducing sugars like maltose and lactose
What are maltose, sucrose and lactose? How is each formed?
Disaccharides formed in condensation reactions of…
* Glucose and glucose = maltose
* Glucose and galactose = lactose
* Glucose and fructose = sucrose
Forming a glycosidic bond
What are the polymers present in starch?
Amylose and amylopectin
Monosaccharides with 6 carbon atoms are called…
Hexoses
What are 3 examples of hexoses? What are they used for?
Glucose, fructose and galactose. Used as a source of energy in respiration and to form larger molecules.
Monosaccharides are s______ , w_____ c_________ solids.
Monosaccharides are soluble, white crystalline solids.
What is the general formula of carbohydrates?
Cx(H20)y
What are 3 common groups of monomers? MOVE
Monosaccharides
Amino acids
Nucleotides
Describe the structure and function of cellulose
- Long straight beta glucose chains joined by 1-4 glycosidic bonds in condensation reactions
- Become linked together by many hydrogen bonds to form (micro)fibrils
- Provide strength to cell wall
What are the 2 main roles of carbohydrates?
- Structural
- Energy sources
What specific glycosidic bonds can form in the condensation of monosaccharides?
- 1 - 4 glycosidic bond or 1-6 glycosidic bond
- Hydrogen from carbon 1 reacts with hydroxyl group from carbon 4/6
What are the 3 main groups of carbohydrates?
Monosaccharides
Disaccharides
Polysaccharides
Monosaccharides are __________ sugars
Reducing (donate electrons)
How do beta glucose molecules form cellulose?
Due to different position of C1 OH group, molecules rotate 180* when they condense to form a chain.
Hydrogen bonds between chains.
What are the isomers of glucose? What’s the difference between them?
ABBA
Alpha (OH on C1 is) Below ring
Beta (OH on C1 is) Above ring
What is the structure and function of glycogen
- lots of branching (bc 1-6 glycosidic bonds) –> large SA for quick and easy hydrolysis into a glucose by enzymes for respiration
- Large but compact –> maximises amount of energy stored
- Insoluble–> WP not affected, can’t leave cells, easy storage
- polysaccharide of alpha glucose joined by 1-4 and 1-6 glycosidic bonds
- Main storage compound in animals
- Stored in liver (released into blood for widespread use) and muscle cells (for muscles)
What isomers of glucose form a. Starch b. Glycogen c. Cellulose
A. a glucose
B. a glucose
C. B glucose
What is the structure and function of starch?
- Coiled/helical - so it’s compact, can store a lot in a small space
- Insoluble - so there is no osmotic effect/ doesn’t affect water potential, doesn’t diffuse out of cells
- (Amylopectin) is branched - so it’s easy and faster to hydrolyse into alpha glucose for use in respiration
- Large molecule - so can’t leave cell, large number of glucose molecules provides respiratory substrate for energy release
What’s the general formula of monosaccharides? What is n between?
CnH2nOn
(CH2O)n
3 and 7
Which enzymes hydrolyse a. Maltose, b. Sucrose, c. Lactose? Where are they produced?
A. Maltase
B. Sucrase
C. Lactase
Epithelial cells that line the small intestine (ileum)
How is the structure of glycogen adapted for its function?
- coiled so compact
- polymer of glucose so easily hydrolysed
- branched so many ends for faster hydrolysis
- polymer of glucose so provides respiratory substrate for energy release
- Insoluble so doesn’t affect water potential or osmosis/ not easily lost from cell
Describe the role of enzymes in the digestion of starch
- Amylase
- starch to maltose
- maltase
- maltose to glucose
- hydrolysis
- of glycosidic bond
