Structure Of Carbohydrates - What Are Carbohydrates Made Of -Structure Of Glucose Fructose Galactose
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7 سال پیش
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In this video we look
In this video we look at the structure of carbohydrates, and what elements and bonding of elements form carbohydrates. We cover the structure of monosaccharides, including glucose, fructose and galactose, disaccharides, including sucrose (table sugar), lactose and galactose, and polysaccharides, including starch, glycogen and cellulose.
Transcript/notes
Structure of carbohydrates
All carbohydrates contain carbon, oxygen and hydrogen, usually in a ratio of 1 to 2 to 1, as you can see in this linear model of a glucose molecule. Which has 6 carbon atoms, 12 hydrogen atoms and 6 oxygen atoms.
There are 3 types of carbohydrates, monosaccharides, which are also called simple sugars, disaccharides, which are also called double sugars, and polysaccharides, or complex sugars. Monosaccharides and disaccharides are also known as simple carbohydrates.
Let’s start by looking at monosaccharides. Monosaccharides are smaller molecules, of which the most important being glucose. Glucose is a 6 carbon carbohydrate as you can see in this linear model of the molecule. When glucose is dissolved in water it will form a ring, as represented in this ring model. A 3 dimentional model of glucose looks like this.
I have shown you 3 different models here, but keep in mind that these models all represent the same molecule. 2 other important 6 carbon monosaccharides are fructose and galactcose. Like glucose both of these molecules have 6 carbon atoms, 12 hydrogen atoms and 6 oxygen atoms, but their structures are all slightly different.
Not all monosaccharides are 6 carbon molecules, as ribose and deoxyribose have only 5 carbon atoms in their structure, and we will cover them in depth in the nucleic acids video.
Disaccharides, or double sugars, are composed of 2 monosaccharide molecules bonded together through a dehydration synthesis reaction which results in the loss of a water molecule. Sucrose, maltose and lactose are important disaccharide molecules.
Sucrose, or table sugar, is formed when a glucose and fructose molecule bond together as you see here. As this bond takes place, a water molecule is removed. Maltose, which is found in sweet potatoes and many cereals, is the result of 2 glucose molecules bonding together, again a water molecule is removed during the bonding.
Lactose, which is mainly found in milk, is formed when a galactose and glucose molecule bond together, and again, a water molecule is removed.
Polysaccharides are formed when many monosaccharide molecules bond together. There are 3 important polysaccharides that are important to the body, starch, glycogen and cellulose.
Starch consists of many glucose molecules bonded together forming long chains called amylose or branched chains called amylopectin.
Water molecules are also removed as these bonds are formed. Starchy foods include potatoes, rice, wheat, and corn. Glycogen is not a dietary carbohydrate, as it is a storage form of glucose found in the muscles and liver.
And cellulose is a component of plant food referred to as fiber. The human body cannot break the bonds of these molecules, so they are not digestible, but it has many benefits to overall health, which we will cover in another video.
Polysaccharides are often called polymers of monosaccharides, as polymers are made up of many identical small molecules.
Timestamps
0:00 The elements of carbohydrates
0:18 The 3 main types of carbohydrates
0:35 Monosaccharides
1:26 Disaccharides
2:11 Polysaccharides
Transcript/notes
Structure of carbohydrates
All carbohydrates contain carbon, oxygen and hydrogen, usually in a ratio of 1 to 2 to 1, as you can see in this linear model of a glucose molecule. Which has 6 carbon atoms, 12 hydrogen atoms and 6 oxygen atoms.
There are 3 types of carbohydrates, monosaccharides, which are also called simple sugars, disaccharides, which are also called double sugars, and polysaccharides, or complex sugars. Monosaccharides and disaccharides are also known as simple carbohydrates.
Let’s start by looking at monosaccharides. Monosaccharides are smaller molecules, of which the most important being glucose. Glucose is a 6 carbon carbohydrate as you can see in this linear model of the molecule. When glucose is dissolved in water it will form a ring, as represented in this ring model. A 3 dimentional model of glucose looks like this.
I have shown you 3 different models here, but keep in mind that these models all represent the same molecule. 2 other important 6 carbon monosaccharides are fructose and galactcose. Like glucose both of these molecules have 6 carbon atoms, 12 hydrogen atoms and 6 oxygen atoms, but their structures are all slightly different.
Not all monosaccharides are 6 carbon molecules, as ribose and deoxyribose have only 5 carbon atoms in their structure, and we will cover them in depth in the nucleic acids video.
Disaccharides, or double sugars, are composed of 2 monosaccharide molecules bonded together through a dehydration synthesis reaction which results in the loss of a water molecule. Sucrose, maltose and lactose are important disaccharide molecules.
Sucrose, or table sugar, is formed when a glucose and fructose molecule bond together as you see here. As this bond takes place, a water molecule is removed. Maltose, which is found in sweet potatoes and many cereals, is the result of 2 glucose molecules bonding together, again a water molecule is removed during the bonding.
Lactose, which is mainly found in milk, is formed when a galactose and glucose molecule bond together, and again, a water molecule is removed.
Polysaccharides are formed when many monosaccharide molecules bond together. There are 3 important polysaccharides that are important to the body, starch, glycogen and cellulose.
Starch consists of many glucose molecules bonded together forming long chains called amylose or branched chains called amylopectin.
Water molecules are also removed as these bonds are formed. Starchy foods include potatoes, rice, wheat, and corn. Glycogen is not a dietary carbohydrate, as it is a storage form of glucose found in the muscles and liver.
And cellulose is a component of plant food referred to as fiber. The human body cannot break the bonds of these molecules, so they are not digestible, but it has many benefits to overall health, which we will cover in another video.
Polysaccharides are often called polymers of monosaccharides, as polymers are made up of many identical small molecules.
Timestamps
0:00 The elements of carbohydrates
0:18 The 3 main types of carbohydrates
0:35 Monosaccharides
1:26 Disaccharides
2:11 Polysaccharides
7 سال پیش
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