Topic 1: Carbohydrates Flashcards
Name the four main dietary risk factors for CVD
- High CARBOHYDRATES (especially sugars) may cause obesity - depending on the ENERGY BALANCE
- High saturated fat (lipid)
- High cholesterol (lipid)
- High salt
Name the THREE elements that all carbohydrates are made from.
- Carbon
- Hydrogen
- Oxygen
NOTE: The word ‘carbohydrate’ means hydrated carbon (carbon with water added)
Define condensation reaction (3 points)
- Joining of monomers or smaller molecules to make a larger molecule
- Water is removed, so produced
- A bond is formed
Define hydrolysis reaction (3 points)
- {Splitting/ breaking down} of polymers or large molecule into smaller {molecules / monomers }
- Water is added
- A bond is broken
Define Hexose sugar (1 point)
- Six carbon sugar
Define Monosaccharide (1 point)
Give its formula (1 point)
- Single sugar unit - no glycosidic bond
1. Formula CnH2nOn (n is a number)
Define disaccharide (1 point)
- {Two/double} sugar units joined together by a glycosidic bond in a condensation reaction
Key Summary: Differences between a monosaccharide and a disaccharide (or named ones)
(3 points)
- A monosaccharide is a single sugar unit, a disaccharide is a double sugar unit
- A disaccharide contains {A / ONE} glycosidic BOND, a monosaccharide has NO glycosidic bond
- A monosaccharide has the formula CnH2nOn (n is a number)
Note: The question could give names – so you need to learn the 3 monosaccharides and 3 disaccharides e.g. explain the difference between glucose and maltose
List the monosaccharides (3 monosaccharides)
- Glucose
- Fructose
- Galactose
List the Disaccharides (3 disaccharides)
- Maltose
- Sucrose
- Lactose
List the Polysaccharides (5 polysaccharides)
- Starch
- Amylose
- Amylopectin
- Glycogen
- Cellulose
Glucose: List properties (3 points), biological function (3 points)
Properties: Sweet, soluble, Crystalline
Biological function:
(1) IMMEDIATE ENERGY SOURCE FOR RESPIRATION.
(2) Can be joined to form starch or glycogen for energy storage
(3) cellulose for cell walls
Fructose: List properties (3 points), biological function (2 points)
Properties: Sweet, soluble, crystalline
Biological function:
(1) IN FRUIT - ATTRACTS ANIMALS FOR SEED DISPERSAL
(2) Component of sucrose (plant transport sugar)
Galactose: List properties (3), biological function (1)
Properties: Sweet, soluble, crystalline
Biological function:
1. Component of lactose (found in milk)
Key Summary: Explain how the structure of a monosaccharide (eg. glucose) makes it suitable for its role
(1 point to state role) + (3 points for how it is suitable for its role)
- ROLE IS IMMEDIATE ENERGY SOURCE FOR RESPIRATION
- SMALL – DOES NOT NEED TO BE HYDROLYSED, so can be quickly and easily absorbed into blood and diffuse into cells
- SOLUBLE – IS A POLAR MOLECULE WITH HYDROPHILIC OH GROUPS ON THE OUTSIDE – these can form hydrogen bonds with water making it SOLUBLE so quickly absorbed into the blood + transported dissolved in blood
- Carried to tissues eg. muscle - quickly absorbed into cells (to be immediately used for respiration to release energy)