BM: Carbohydrates

Question 1

Describe the structure of a monosaccharide and give one example.

Answer 1

Monosaccharides are the simplest form of carbohydrates, with the general formula CnH2nOn. They consist of a single sugar unit and are soluble in water. An example is glucose, which serves as a primary energy source.

Question 2

Explain how a glycosidic bond forms between two monosaccharides

Answer 2

A glycosidic bond forms during a condensation reaction, where two monosaccharides join, releasing a molecule of water. This covalent bond links the sugar units to form a disaccharide or polysaccharide.

Question 3

State the difference between alpha-glucose and beta-glucose

Answer 3

In alpha-glucose, the hydroxyl group (-OH) on carbon 1 is positioned downward. In beta-glucose, the hydroxyl group is positioned upward. Humans can digest alpha-glucose but not beta-glucose.

Question 4

Outline the role of glycogen in energy storage

Answer 4

Glycogen is a branched polysaccharide stored in the liver and muscles. It provides a quick energy source by breaking down into glucose when blood sugar levels are low.

Question 5

Describe the roles of insulin and glucagon in regulating blood glucose levels

Answer 5

• Insulin lowers blood glucose by promoting glucose uptake into cells and stimulating glycogenesis.
• Glucagon raises blood glucose by stimulating glycogen breakdown in the liver.

Question 6

Explain why cellulose cannot be digested by humans

Answer 6

Cellulose is made of beta-glucose units linked by beta-glycosidic bonds. Humans lack the enzyme needed to break these bonds, making cellulose indigestible.

Question 7

Identify the carbohydrate found in plant cell walls and describe its function

Answer 7

Cellulose is found in plant cell walls. It provides structural support and rigidity due to its strong beta-glycosidic bonds.

Question 8

Explain the difference between a monosaccharide and a disaccharide

Answer 8

A monosaccharide consists of a single sugar unit (e.g., glucose), while a disaccharide is formed by two monosaccharides joined by a glycosidic bond (e.g., sucrose).

Question 9

State one biological role of pentose sugar

Answer 9

Pentose sugars, such as ribose, are components of nucleotides, forming part of RNA and DNA.

Question 10

Describe the process of glycogensis and its significance

Answer 10

Glycogenesis is the process of converting excess glucose into glycogen for storage, mainly in the liver and muscles. It helps regulate blood glucose levels and provides an energy reserve.

Question 11

Explain the role of fiber in digestion

Answer 11

Fiber, such as cellulose, aids digestion by promoting gut motility, preventing constipation, and supporting healthy gut bacteria.

Question 12

Identify two examples of disaccharides and their constituent monosaccharides

Answer 12

• Sucrose: Glucose + Fructose
• Lactose: Glucose + Galactose

Question 13

Describe how hydrolysis of a polysaccharide occurs

Answer 13

Hydrolysis involves breaking down a polysaccharide into monosaccharides by adding water, breaking the glycosidic bonds.

Question 14

Explain why glucose is considered a primary energy source

Answer 14

Glucose is rapidly absorbed and metabolized during cellular respiration to produce ATP, the energy currency of cells.

Question 15

Define a glycosidic bond

Answer 15

A glycosidic bond is a covalent bond that links monosaccharide units together in carbohydrates. It forms during a condensation reaction and can be broken by hydrolysis.

Question 16

Explain how a glycosidic bond is formed between two monosaccharides

Answer 16

A glycosidic bond forms during a condensation reaction. The hydroxyl group (-OH) of one monosaccharide reacts with the hydrogen (H) of another, releasing a molecule of water and creating the bond between the sugars.

Question 17

Describe the process of hydrolyzing a glycosidic bond

Answer 17

Hydrolysis of a glycosidic bond involves adding a water molecule, which breaks the bond and releases the individual monosaccharides.

Question 18

Explain why hydrolysis is important in carbohydrate digestion

Answer 18

Hydrolysis is essential in digestion because it breaks down complex carbohydrates into monosaccharides, which can be absorbed and used by the body for energy.

Question 19

Describe the difference between condensation and hydrolysis reactions in carbohydrates

Answer 19

Condensation reactions form glycosidic bonds by joining monosaccharides and releasing water.

Hydrolysis reactions break glycosidic bonds by adding water, releasing individual monosaccharides.

Question 20

Explain the role of water in breaking glycosidic bonds

Answer 20

Water provides the hydrogen and hydroxyl groups needed to break the glycosidic bond during hydrolysis, separating the monosaccharides.

Question 21

identify the type of bond formed between monosaccharides and state how it can be broken

Answer 21

Water provides the hydrogen and hydroxyl groups needed to break the glycosidic bond during hydrolysis, separating the monosaccharides.

Question 22

Define carbohydrates and explain their main function in the body

Answer 22

Carbohydrates are organic molecules made of carbon, hydrogen, and oxygen (CnH2nOn) Their main function is to provide energy, as glucose is used in cellular respiration to produce ATP.

Question 23

Explain how glycogen functions in the body

Answer 23

Glycogen, a branched polysaccharide, stores glucose in the liver and muscles. When energy is needed, glycogen is broken down into glucose (glycogenolysis) to maintain blood glucose levels and provide energy.

Question 24

state the role of insulin and its effect on glycogen

Answer 24

Insulin, secreted by the pancreas, lowers blood glucose by promoting glucose uptake into cells and stimulating glycogenesis, converting glucose into glycogen for storage.

Question 25

Explain how glucagon affects blood glucose levels

Answer 25

Glucagon, secreted by the pancreas, raises blood glucose by stimulating glycogenolysis, breaking down glycogen into glucose, and releasing it into the bloodstream.

Question 26

Identify the carbohydrate found in DINA and RNA and explain its significance

Answer 26

The carbohydrate in DNA is deoxyribose, and in RNA, it is ribose. These sugars form the backbone of nucleotides, which are essential for genetic material and protein synthesis.

Question 27

Explain why glucose is the preferred energy source in the body

Answer 27

Glucose is rapidly absorbed and metabolized through cellular respiration, providing a quick and efficient source of ATP, the body’s primary energy currency.

Question 28

describe how the body uses polysaccharides for sustained energy

Answer 28

Polysaccharides like glycogen and starch are broken down gradually, providing a steady release of glucose for energy over time, ensuring long-term energy availability.

Question 29

explain the health implications of hight and low blood glucose levels

Answer 29

High blood glucose (hyperglycemia) can lead to diabetes complications, affecting organs like the heart and kidneys.

Low blood glucose (hypoglycemia) can cause dizziness, confusion, and, in severe cases, unconsciousness.