30 Questions
What is the primary function of carbohydrates?
To provide energy for tissues
Which of the following is not a characteristic of carbohydrates?
Containing only one carbon atom
Which type of carbohydrate is responsible for the rapid heartbeats and sweating experienced by the patient in the case scenario?
Monosaccharides
What is the name of the condition experienced by the patient in the case scenario?
Hypoglycemia
Which of the following is not a function of carbohydrates?
Regulation of blood pressure
What is the primary reason for studying carbohydrate chemistry?
To understand the structure and function of carbohydrates
What is the primary classification of carbohydrates based on?
The number of sugar units they contain
Which of the following is an example of a disaccharide?
Sucrose
Monosaccharides are further classified based on which two criteria?
The number of carbon atoms and the presence of an aldehyde or ketone group
Which of the following monosaccharides is the principal sugar found in the blood?
Glucose
Which type of carbohydrate contains more than 10 sugar units?
Polysaccharides
Which of the following monosaccharides is the primary energy source for sperms?
Fructose
What is the main function of dextrin as mentioned in the text?
Being used as mucilage
Why is cellulose not digested in humans?
Due to the presence of B glucosidase enzyme
Which type of heteropolysaccharide serves as an anticoagulant?
Heparin
What is the structure of glycosaminoglycans (GAGs) according to the text?
Composed of a repeating disaccharide unit
Which heteropolysaccharide is a component of cell surface lubricant and shock absorbent according to the text?
Hyaluronic acid
What enzyme is absent in humans leading to the non-digestibility of cellulose?
B glucosidase
What is the biological importance of the monosaccharide galactose?
It enters in the formation of lactose (milk sugar) and galactolipids & glycoproteins
What are the biological roles of pentoses like ribose?
They are components of nucleic acids, energy compounds, coenzymes, second messengers, and vitamins
What is the biological importance of mannose?
It enters in the formation of glycoproteins
What are sugar acids?
They are monosaccharides derived from the oxidation of other monosaccharides
What is the principle behind the glucose test strips used to measure glucose levels in urine and blood?
The oxidation of glucose by the enzyme glucose oxidase to produce gluconic acid
What is the importance of glucuronic acid in biological systems?
It is involved in the formation of mucopolysaccharides and detoxification processes
Which sugar alcohol is a constituent of DNA?
Mannitol
Which fluid contains the highest concentration of fructose?
Seminal fluid
Galactose is a main constituent of which type of sugar?
Honey
Which statement about polysaccharides is true?
Polysaccharides are large carbohydrate molecules made up of more than 3 units of monosaccharides
Is the statement 'Pentose is a disaccharide important in RNA' true or false?
False
Is Maltose a polysaccharide formed of glucose and fructose? True or false?
False
Study Notes
Classification of Carbohydrates
- Classified into two main categories: simple carbohydrates and complex carbohydrates
- Simple carbohydrates: monosaccharides, disaccharides, and oligosaccharides
- Complex carbohydrates: polysaccharides
Monosaccharides
- Definition: simplest sugar molecules formed of one sugar unit, cannot be hydrolyzed into smaller units
- Classified according to:
- Number of C atoms: trioses (3 C), tetroses (4 C), pentoses (5 C), hexoses (6 C)
- Active sugar group: aldehyde (aldoses) and ketone (ketoses)
- Biologically important monosaccharides:
- Glucose: principal sugar in blood, primary source of energy for tissues, and can be converted to other sugars
- Fructose: sugar of seminal plasma, used for energy production by sperm
- Monosaccharides derivatives:
- Sugar acids: derived from monosaccharides through oxidation, includes aldonic acids and uronic acids
- Sugar alcohols: derived from monosaccharides through reduction, includes sorbitol, mannitol, and galactitol
- Aminosugars: derived from monosaccharides through replacement of OH group with amino group, includes D-glucosamine and D-galactosamine
- Deoxysugars: derived from monosaccharides through replacement of OH group with H, includes 2-deoxy-D-ribose, a constituent of DNA
Disaccharides
- Definition: carbohydrates formed of two monosaccharide units joined by an O-glycosidic bond
- Examples: maltose, sucrose, and lactose
Polysaccharides
- Definition: carbohydrates formed of more than 10 monosaccharide units
- Types:
- Homopolysaccharides: composed of a single type of monosaccharide, includes starch, glycogen, and cellulose
- Heteropolysaccharides: composed of different types of monosaccharides, includes glycosaminoglycans (GAGs) and mucopolysaccharides
- Examples:
- Starch: composed of α-glucose units, used as mucilage and in infant feeding
- Glycogen: composed of α-glucose units, used to maintain blood glucose level during fasting
- Cellulose: composed of β-D-glucose units, structural component of plant cell walls, and used to increase bulk and prevent constipation
- Glycosaminoglycans (GAGs): includes heparin, heparan sulfate, hyaluronic acid, keratan sulfate, chondroitin sulfate, and dermatan sulfate, used in various biological functions such as anticoagulation, lubrication, and shock absorption
This quiz focuses on the learning outcomes for carbohydrate chemistry, including defining carbohydrates, classifying them, identifying types and functions of mono, di, and polysaccharides, and summarizing their biological importance. A case scenario about a patient named Hossam is also presented.
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