Carbohydrates Flashcards
What is the general formula for carbohydrates?
(CH20)n
How are carbohydrates formed
Primarily by photosynthesis
1) light dependent reaction
2) light independent reaction
Name the basic unit of carbohydrates?
Monosaccharides
*Give examples of some food in which carbohydrates are found (7)
- Bread
- Beans
- Milk
- Popcorn
- Potatoes
- spaghettis
- soft drinks
*Give some common forms of carbohydrates
- Sugars
- Fibres
- Starches
What are disaccharides?
Two simple sugars linked by a covalent bond
What are polysaccharides?
They are hundred or thousands of monosaccharides
Give some examples of polysaccharides
- Starch
- Glycogen
- Cellulose
How are monosaccharides commonly found in humans classified?
According to the number of carbons they contain in their backbone structure
How many carbon atoms do the major monosaccharides contain?
4-6
How are carbohydrates formed in plants?
By photosynthesis from carbon dioxide and water in the precise of sunlight
Other than photosynthesis how else can glucose be synthesised?
glucose can be synthesized from other organic molecules in processes of gluconeogenesis
In animals what is glucose synthesis called?
gluconeogenesis
What does gluconeogenesis usually start with in animals?
Can start with lactate, amino acids or glycerol
How is lactate produced in animals?
produced by anaerobicglycolysis
Where are amino acids derived from in animals?
From the breakdown of protein
How is glycerol produced in animals?
Produced by the breakdown of lipids
What is a glycogenic amino acid?
It is an amino acid that can be converted into glucose through glycogenesis
Give examples of glycogenic amino acid
Alanine Arginine Asparagine Asparticacid Cysteine Glutamicacid Glutamine Glycine.
Name the most commonly occurring monosaccharides
- Fructose
- Glucose
- Galactose
What is fructose found in?
Fruits
Honey
Vegetables
What can fructose be derived from?
Can be derived from the digestion of sucrose
What is glucose found in?
Small amounts are found in some fruits, vegetables and honey
Commonly found in manufactured foods
What can glucose be derived from?
The digestion and conversion of other carbohydrates
What can galactose be derived from?
The digestion of lactose
Are disaccharides taken up by cells?
Disaccharides are not taken up by cells
How are disaccharide formed?
A covalent bond between the anomeric hydroxy of a cyclic sugar and the hydroxyl of a second sugar forms a glycoside
What is the covalent bond between the anomeric hydroxy of a cyclic sugar and the hydroxyl of a second sugar called?
Called a glycosidic bond
Name some nutritionally important disaccharides
- Sucrose
- Lactose
- Maltose
*Where is lactose found?
Found exclusively in the milk of mammals
*What is lactose made up of?
Consists of a galactose and glucose in a beta-(1-4) glycosidic bond
What is an amino acid that can be converted into glucose called?
A glycogenic amino acid
What is sucrose derived from?
Derived from sugar cane and sugar beet
*Where is sucrose found?
produced naturally in plants
- Sweet root vegetables like BEETROOT and CARROTS
- Sugar canes and sugar beets
- Table sugar
- Manufactured food
*which type of plant stores the most sucrose?
sugar canes + sugar beets
table sugar + sucrose in processed foods are extracted from ^
*what is maltose produced from??
from fermented germinated grain like:
barley
rice
malted barley (maltose)= source of sugars which are fermented into beer by yeast
*What is maltose?
alpha-(1-4) glycosidic bond
intermediate in intestinal digestion of starch + glycogen
natural sweetener
*where do we find oligosaccharides?
- partial breakdown of polysaccharides
- naturally occurring: found in plants
*Name the predominant monosaccharide found in polysaccharides
D glucose
*Name the main polysaccharides
- Glycogen (can digest alpa 1-4/1-6 bonds= digestable)
- Starch
- Cellulose (can’t digest BETA 1-4 glycosidic bonds)
composed of D glucose
Name the major form of stored carbohydrates in animals
Glycogen