Exercise 5 Flashcards
What is the main purpose of carbohydrates?
The main purpose of carbohydrates is to function as immediate and short-term energy storage.
What are the two basic categories of carbohydrates?
The two basic categories of carbohydrates are simple carbohydrates and complex carbohydrates.
Briefly explain the difference between monosaccharides, disaccharides and polysaccharides.
Monosaccharides (single sugars) and disaccharides (double sugars) are considered to be simple carbohydrates. Monosaccharides have anywhere from three to seven carbon atoms. A disaccharide is composed of two monosaccharides joined together. A polysaccharide (many sugars) is a complex carbohydrate because it contains many monosaccharides (glucose) joined together.
List three types of monosaccharides, two types of disaccharides, and three types of polysaccharides
Three types of monosaccharides of the hexose designation are glucose, fructose and galactose. Two types of disaccharides are maltose and sucrose (table sugar) and three types of polysaccharides are starch glycogen and cellulose.
What do cells use glucose for?
Cells use glucose as an immediate source of energy.
What are the storage forms of glucose?
The polysaccharide starch is the storage form of glucose in plants and the polysaccharide glycogen is the storage form of glucose in animals.
What two atoms does a carbohydrate molecule always contain and what kind of molecule is it because of this?
Carbohydrates always contain carbon and hydrogen atoms and because of this they are called organic molecules.
- Where is cellulose found and how does it function in our diet?
8.Cellulose is found in plant cell walls. Because of the types of bonds that appear in cellulose, the body is unable to digest it and hence cellulose passes through our body as fibre or roughage.
- What are carbohydrates digested to?
9.Carbohydrates are digested or broken down by the digestive system into simple sugars. Glucose, a simple sugar referred to as a monosaccharide, will be used in cellular respiration to produce energy for the cell.
- In order to maintain blood glucose levels what three molecules can be converted to glucose?
10.Blood glucose levels can be maintained by breaking down glycogen into glucose or by converting glycerol from fats or amino acids from proteins into glucose.
- Brain cells unlike body cells will only use what for an energy source?
Brain cells will only use glucose as an energy source as they are unable to use glycogen, glycerol or amino acids. Therefore it is essential to include carbohydrates in our diet.
- What is the best type of carbohydrate and what are some common food sources of this type of carbohydrate?
The best source of carbohydrate is a complex carbohydrate because they are digested to sugars gradually, are more likely to be accompanied by other nutrients and fibre. Examples of complex carbohydrates are bread, cereal, rice and pasta.
13.What is the difference in function between soluble fibre and insoluble fibre? Give examples of food containing these two types of fibre.
- Insoluble fibre has a laxative effect, increasing the peristaltic action of the large intestine. Wheat bran is a source of insoluble fibre. Soluble fibre combines with bile acids and cholesterol in the intestine and prevents them from being absorbed. Oat bran contains soluble fibre.
Give examples of foods that have a high glycemic index. What does this term mean?
- Simple sugars such as candy and ice cream and simple sugars that result from the digestion of white bread and potatoes enter the bloodstream immediately. Because of this they are said to have a high glycemic index. These foods cause insulin levels to be high in the blood stream as it attempts to bring the high glucose levels under control.
