Biochemistry: Carbohydrates and Biomolecules

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Questions and Answers

What are the principal types of biological molecules studied in biochemistry?

Carbohydrates, Vitamins, Hormones, Enzymes

Lipids, Hormones, Vitamins, Water

Carbohydrates, Lipids, Proteins, Nucleic Acids (correct)

Proteins, Nucleic Acids, Steroids, Minerals

Which of the following biomolecules is primarily produced as an energy reservoir in plants?

Starch (correct)

Cellulose

Glycogen

Chlorophyll

Which of the following statements accurately describes carbohydrates?

They contain only carbon and hydrogen in their molecular structure.

They are exclusively used for structural purposes in living organisms.

They can produce energy through oxidation during respiration. (correct)

They provide long-term energy storage in plants.

What is the molecular formula believed to represent carbohydrates?

(CH2O)n Signup and view all the answers

Which process leads to the formation of carbohydrates in plants?

Photosynthesis Signup and view all the answers

Which sugar class typically ends with the suffix '-ose'?

Sugars Signup and view all the answers

What is the primary source of carbon atoms for the synthesis of other biochemical substances?

Carbohydrates Signup and view all the answers

Which of the following disciplines has considerable overlap with biochemistry?

Molecular genetics Signup and view all the answers

Which of the following sugars is known as 'brain sugar'?

Galactose Signup and view all the answers

What is the primary structural characteristic of fructose?

Five membered cyclic form Signup and view all the answers

What type of isomers are enantiomers?

Non-superimposable mirror images Signup and view all the answers

In the context of glucose levels in blood, what is the range typically considered normal?

70 - 100 MG/100 ML Signup and view all the answers

Which type of monosaccharide contains an asymmetric carbon atom?

Both aldose and ketose Signup and view all the answers

Which monosaccharide is an intermediary in metabolism and found in many fruits?

Fructose Signup and view all the answers

What defines diastereomers in terms of molecular structure?

Molecules with multiple chiral centers that are not mirror images Signup and view all the answers

Which sugar type is classified as a derivative of monosaccharides with an amine group?

Amino sugar Signup and view all the answers

What role does NADH play in the body?

It generates energy by participating in metabolic reactions. Signup and view all the answers

Which compound is utilized during the last part of cellular respiration?

FADH2 Signup and view all the answers

What is the primary function of ATP in living cells?

To serve as an energy carrier and transfer energy. Signup and view all the answers

Which of the following statements about ADP is true?

It is a byproduct of ATP breakdown. Signup and view all the answers

What is NADPH required for?

CYP-mediated biotransformation. Signup and view all the answers

Which type of isomerism involves molecules that differ by the position of the OH group on one carbon atom?

Epimerism Signup and view all the answers

What is the correct term for carbohydrates that can rotate plane-polarized light clockwise?

Dextrorotatory Signup and view all the answers

Which of the following reactions involves the conversion of a monosaccharide to an alcohol?

Reduction Signup and view all the answers

Which of the following describes oligosaccharides?

Short polymers containing 2-10 monosaccharide residues Signup and view all the answers

Which type of acid can be formed by selectively oxidizing C1 of aldoses?

Aldonic acids Signup and view all the answers

What is produced when a monosaccharide reacts with an alcohol in the presence of an acid catalyst?

Glycoside Signup and view all the answers

Which of the following correctly describes anomeric carbon?

The carbon that was originally a carbonyl carbon Signup and view all the answers

What distinguishes D and L isomers of carbohydrates?

The specific arrangement of the hydroxyl groups on the penultimate carbon Signup and view all the answers

What type of sugar is maltose classified as?

Reducing sugar Signup and view all the answers

Which polysaccharide functions primarily to store energy in plants?

Starch Signup and view all the answers

Which enzyme is responsible for hydrolyzing β-(1-4) bonds in cellulose?

Cellulase Signup and view all the answers

What percentage of cellulose does cotton fiber contain?

90% Signup and view all the answers

Which of the following is a characteristic of glycogen?

It contains approximately 8-12 glucose units Signup and view all the answers

What is the primary role of ATP in biological systems?

Energy transfer Signup and view all the answers

Which sugar combination forms sucrose?

Fructose and glucose Signup and view all the answers

Which polysaccharide provides structural support in plants?

Cellulose Signup and view all the answers

What is the general formula for carbohydrates?

CNH2NON Signup and view all the answers

Which monosaccharide is classified as an aldohexose?

Glucose Signup and view all the answers

How many carbon atoms do pentoses contain?

5 Signup and view all the answers

Which of the following sugars is an example of a ketose?

Fructose Signup and view all the answers

What differentiates aldoses from ketoses?

Aldoses have an aldehyde group, ketoses have a ketone group. Signup and view all the answers

What type of structure do monosaccharides often form?

Crystalline solids Signup and view all the answers

What is the characteristic taste of some monosaccharides?

Sweet Signup and view all the answers

Which of the following is a feature of ketoses?

They have a ketone group in the middle. Signup and view all the answers

Which of the following represents a structure of an aldotetrose?

C4H8O4 Signup and view all the answers

Which vision of monosaccharide classification includes both the number of carbon atoms and type of carbonyl group?

Carbon and Carbonyl Classification Signup and view all the answers

Study Notes

Introduction to Medical Chemistry and Biochemistry

The presentation is about Medical Chemistry and Biochemistry, specifically focusing on the Faculty of Dental Medicine.
The presenter is Dr. Aksu Samet.

Introduction to Biochemistry

Biochemistry is the study of the chemistry of living things.
It includes organic molecules and their chemical reactions.
Biochemistry is often considered synonymous with molecular biology.

Principal Types of Biological Molecules

The principal types of biological molecules (biomolecules) are:
- Carbohydrates
- Lipids
- Proteins
- Nucleic acids
- Vitamins
- Hormones

Biochemistry is closely related to other biological sciences dealing with molecules:
- Molecular genetics
- Pharmacology
- Molecular biology
- Chemical biology

Carbohydrates

Carbohydrates literally mean "hydrates of carbon."
They consist of carbon, hydrogen, and oxygen.
The ratio of hydrogen to oxygen is the same as in water (H₂O).
About 75% of dry plant material is carbohydrate.
Carbohydrates are critical for energy production and storage, structural components, etc.

Carbohydrate Functions

Carbohydrates' usefulness stems from their ability to produce energy through oxidation during respiration.
They store energy in the form of glycogen, providing short-term energy reserves for bodily functions.
Carbohydrates also supply carbon atoms for the synthesis of other biochemical substances, like proteins, lipids, and nucleic acids.
They are also part of the structural framework of DNA and RNA.

Classification of Carbohydrates

Carbohydrates are categorized based on the number of subunits:
- Monosaccharides
- Oligosaccharides
- Polysaccharides
- Disaccharides
- Trisaccharides
- Tetrasaccharides

Monosaccharides

Monosaccharides are single sugar units.
They typically contain 3-7 carbon atoms and have aldehyde or ketone functional groups.
They are usually colorless, water-soluble, and crystalline solids.
Some are sweet.
Examples include glucose, fructose, galactose, xylose, and ribose.
Monosaccharides are classified by the number of carbon atoms (e.g., triose, pentose, hexose).

Important Monosaccharides

Aldoses have an aldehyde group, while ketoses have a ketone group.
Glucose is a crucial monosaccharide.
Fructose is notable for its sweetness.
Galactose is associated with lactose (milk sugar).
Ribose is vital in RNA and ATP.

Important Members of Monosaccharides

Aldoses: Monosaccharides with one aldehyde group
Ketoses: Monosaccharides with one ketone group
D-Glucose: an aldohexose
Fructose: a ketohexose

Glucose, Fructose, and Galactose

Glucose is the primary circulating sugar in the bloodstream.
Fructose is a ketohexose notable for its sweetness.
Galactose, a component of lactose, also participates in cellular processes and serves as a structural component of certain tissues.

Ribose and Deoxyribose

Ribose and deoxyribose are aldopentoses found in RNA, DNA, and ATP.
They are crucial components of vital biological molecules.

Derivatives of Monosaccharides

Amino sugars: sugar molecules where a hydroxyl group is substituted with an amine group.
Example: D-glucosamine.
Uronic acids: oxidized sugar acids containing a carboxyl group.
Example: glucuronic acid

Glycosides

Glycosides are acetal derivatives formed when a monosaccharide reacts with an alcohol in the presence of an acid catalyst.
They contain glycosidic bonds.

Stereoisomerism

Stereoisomers have the same molecular formula but differ in the spatial arrangement of their atoms.
Enantiomers: non-superimposable mirror images.
Diastereomers: non-mirror image isomers.
Forms of isomerism in monosaccharides include:
- D and L enantiomers
- Pyranose and furanose ring structures
- Alpha and beta anomers
- Epimers
- Aldose and ketose isomerism
- Optical activity

Cyclic Forms of Carbohydrates

The structures of carbohydrates, such as glucose, can be represented in three ways:
- Straight chain form
- Haworth projection
- Chair form

Chemical Reactions of Carbohydrates

Oxidation reactions can turn aldoses into aldonic acids, e.g. glucose into gluconic acid.
Reduction reactions convert aldoses into alditols, e.g. glucose into sorbitol.
Glycosides are formed from the reaction of the hemiacetal group of a carbohydrate with an alcohol.

Oligosaccharides

Oligosaccharides are short polymers (2-10 monosaccharide units) linked by glycosidic bonds.
Maltose, lactose, and sucrose are examples.

Polysaccharides

Polysaccharides contain 10 or more monosaccharide units.
Starch acts as an energy storage molecule in plants.
Cellulose provides structural support to plant cell walls.
Glycogen, a branched polymer, is an energy storage molecule in animals.

Metabolism of Glucose

Glucose is vital for energy production in the human body.
Glucose is transported into cells through facilitated diffusion or active transport.
Various metabolic pathways utilize glucose, including glycolysis, the pentose phosphate pathway, glycogenolysis, gluconeogenesis, and glycogen synthesis.

Glucose Transport in Cells

Glucose transport across cell membranes is facilitated by specific glucose transporters (GLUTs).
The different GLUTs vary in their tissue distribution, regulation by hormones like insulin, and transport mechanisms.

Importance of Glucose in the Body

Glucose is a crucial fuel source for the brain and other tissues.
Maintaining proper blood glucose levels is essential for overall health.

Regulation of Blood Glucose

Hormones like insulin and glucagon regulate blood glucose levels.
Insulin promotes glucose uptake, while glucagon stimulates glucose release.

Metabolic Pathways of Glucose

Glycolysis, the pentose phosphate pathway, and the Krebs cycle utilize glucose for energy.
Glycogen synthesis and glycogenolysis allow for glucose storage and release.

Blood Glucose Levels After Meals

A meal's impact on blood glucose, insulin, and glucagon is charted over time.
These graphs show how these levels fluctuate throughout digestion.

Glycemic Index

A concept for how rapidly a particular food raises blood glucose (GI).
The GI graph visually represents how blood glucose changes following the consumption of a food categorized by type, (normal or disease state).

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Description

Test your knowledge on the principal types of biological molecules in biochemistry, with a focus on carbohydrates. This quiz covers various aspects such as their classification, energy storage in plants, and their structural characteristics. Challenge yourself and discover how well you understand these essential biomolecules!