Biology Chapter 3: Organic Compounds

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What distinguishes α-Glucose from β-Glucose?

The type of glycosidic linkage

Their molecular weight

The position of the hydroxyl group (correct)

The number of carbon atoms

Which structure is formed when two monosaccharides join together?

Polysaccharide

Disaccharide (correct)

Oligosaccharide

Dimer

Which of the following is a common disaccharide made up of glucose and fructose?

Maltose

Raffinose

Lactose

Sucrose (correct)

What type of linkage connects the monosaccharide units in a disaccharide?

Glycosidic linkage Signup and view all the answers

Which polysaccharide is most commonly associated with energy storage in animals?

Glycogen Signup and view all the answers

What are the two forms of starch found in plants?

Amylose and Amylopectin Signup and view all the answers

Which of the following best describes cellulose?

A structural polysaccharide in plants Signup and view all the answers

What is the primary structural feature of disaccharides?

A covalent bond between two sugar units and an oxygen Signup and view all the answers

What best describes lipids?

Compounds composed mainly of carbon and hydrogen Signup and view all the answers

Which of the following is NOT a biologically important group of lipids?

Carbohydrates Signup and view all the answers

Which organelle is specifically involved in storing starch in buttercup root cells?

Amyloplasts Signup and view all the answers

What type of linkage forms triacylglycerols?

Ester linkage Signup and view all the answers

How does the structure of glycogen differ from that of plant starch?

Glycogen is more extensively branched and more water soluble. Signup and view all the answers

Which of the following characterizes fatty acids?

They include a long hydrocarbon chain and a carboxyl group Signup and view all the answers

What type of linkages do humans have enzymes to break down?

α 1—4 glycosidic linkages Signup and view all the answers

What is the primary role of triacylglycerols in living organisms?

Energy storage Signup and view all the answers

During digestion, triacylglycerols are hydrolyzed into which products?

Fatty acids and glycerol Signup and view all the answers

What is the main role of cellulose in plants?

Structural component of plant fibers Signup and view all the answers

Which of the following statements about chitin is correct?

Chitin forms the exoskeletons of arthropods. Signup and view all the answers

How many hydroxyl groups does glycerol contain?

Three Signup and view all the answers

What is the correct order of formation for triglycerides from glycerol and fatty acids?

Monoglyceride, Diglyceride, Triglyceride Signup and view all the answers

What type of molecule is a glycoprotein?

A combination of carbohydrate and protein Signup and view all the answers

Which type of carbohydrate is considered the most abundant?

Cellulose Signup and view all the answers

What is the structural composition of a phospholipid head?

A phosphate group, glycerol, and an organic group Signup and view all the answers

What characterizes the linkages in cellulose that humans cannot break down?

β 1—4 glycosidic linkages Signup and view all the answers

What characteristic makes phospholipids amphipathic?

They contain both hydrophobic and hydrophilic regions. Signup and view all the answers

What happens to phospholipids when they interact with water?

They form a lipid bilayer. Signup and view all the answers

Which of the following best describes carotenoids?

5-carbon hydrocarbon monomers that function in photosynthesis. Signup and view all the answers

Which of the following substances is produced from carotenoids in animals?

Retinal Signup and view all the answers

What is a defining feature of steroids?

They contain four attached carbon rings. Signup and view all the answers

Which steroid is essential for maintaining cell membrane integrity?

Cholesterol Signup and view all the answers

What is the role of cortisol in the body?

To function as a stress hormone secreted by the adrenal gland. Signup and view all the answers

What is the primary reason that carbon-containing compounds can form a wide variety of molecular shapes?

Freedom of rotation around carbon-to-carbon single bonds. Signup and view all the answers

Which type of isomer has different covalent arrangements of atoms?

Structural isomers Signup and view all the answers

How do enantiomers differ from each other?

They are mirror images of one another. Signup and view all the answers

Which statement about isomers is true?

Isomers may have different common names and properties. Signup and view all the answers

What effect do functional groups have on organic molecules?

They change the properties of organic molecules. Signup and view all the answers

Which type of isomer is characterized by spatial arrangement due to double bonds?

Geometric isomers Signup and view all the answers

What is a defining characteristic of structural isomers?

They have the same molecular formula but differ in molecular shape. Signup and view all the answers

Why is it significant that one isomer is often biologically active while another is not?

It allows cells to differentiate between reactive and non-reactive forms. Signup and view all the answers

What characteristic distinguishes saturated fatty acids from unsaturated fatty acids?

Saturated fatty acids have maximum hydrogen atoms. Signup and view all the answers

What is typically a physical state of unsaturated fatty acids at room temperature?

Liquid Signup and view all the answers

Which fatty acid is an example of a monounsaturated fatty acid?

Oleic acid Signup and view all the answers

What effect does hydrogenation have on unsaturated fatty acids?

It converts them to saturated fatty acids. Signup and view all the answers

What is a major health concern associated with trans fats?

They increase the risk of cardiovascular disease. Signup and view all the answers

What structural feature prevents unsaturated fatty acids from aligning closely with one another?

The double bond creates a bend in the chain. Signup and view all the answers

Which of the following statements regarding saturated fatty acids is true?

They are found in animal fats and solid vegetable shortening. Signup and view all the answers

What type of fatty acids contain two or more adjacent double bonds?

Polyunsaturated fatty acids Signup and view all the answers

Study Notes

Chapter 3: The Chemistry of Life: Organic Compounds

Organic compounds are molecules where carbon atoms are covalently bonded to form the molecule's structure.
Organic compounds are extremely varied.
More than five million organic compounds have been identified, including modular subunits like carbohydrates, lipids, proteins, and nucleic acids.
Carbon atoms form bonds with more elements than any other atom type.

3.1 Carbon Atoms and Organic Molecules

Carbon atoms complete their valence shell by forming four covalent bonds.
Carbon-carbon bonds are strong but not so strong that cells cannot break them.
Carbon-carbon bonds can have single, double, or triple bonds.
Hydrocarbons are organic compounds containing only carbon and hydrogen.
Hydrocarbons can exist as unbranched or branched chains, or rings.

3.1 Carbon Atoms and Organic Molecules (continued)

The shape of a molecule determines its biological function and properties.
Carbon atoms link to produce various 3-D shapes and not just a single plane.
Single carbon bonds allow rotational freedom, leading to a variety of molecular shapes.
Double and triple bonds do not allow rotation.

Isomers

Isomers are compounds with the same molecular formula but different structures and, therefore, different properties.
They may have different common names.
One isomer may be biologically active while another is not.
Cells can distinguish between isomers because they have different properties.
There are three main isomers: structural isomers, geometric isomers, and enantiomers.

3.2 Carbohydrates

Carbohydrates contain carbon, hydrogen, and oxygen atoms; the ratio is roughly 1:2:1.
Carbohydrates include sugars and starches.
Monosaccharides are simple sugars containing 3-7 carbon atoms.
In a monosaccharide, a hydroxyl group is bonded to each carbon except one, which forms a carbonyl group.
Examples include trioses, pentoses, and hexoses (like glucose, fructose, and galactose).
Glucose is a crucial monosaccharide for energy and synthesis.
Glucose can exist as α- or β- glucose, depending on the structure.
Disaccharides consist of two monosaccharides joined by a glycosidic linkage.
Common examples are maltose, sucrose, and lactose.

Monosaccharides

Monosaccharides have 3-7 carbon atoms.
In monosaccharides, a hydroxyl group is attached to each carbon except one, and that carbon has a carbonyl group.
Aldehyde: carbonyl group at the end of the chain.
Ketone: carbonyl group at any other position.
Examples: Triose-glyceraldehyde; Dihydroxyacetone, Pentose- ribose, deoxyribose; Hexose-glucose, fructose, galactose

Polysaccharides

Polysaccharides are complex carbohydrates made up of repeating units of simple sugars, often glucose.
Examples include starch, glycogen, and cellulose.
Starch is a plant energy storage polysaccharide.
Glycogen is an animal energy storage polysaccharide.
Cellulose is a structural polysaccharide found in plants.
Modified complex carbohydrates like amino sugars play special roles in the body (e.g., cartilage and exoskeletons).

3.3 Lipids

Lipids are compounds soluble in non-polar solvents and relatively insoluble in water.
Lipids consist mostly of carbon and hydrogen atoms with few oxygen-containing functional groups.
Lipids are hydrophobic (water-repelling).
Important lipids include fats, phospholipids, carotenoids, steroids, and waxes.
Lipids serve as energy storage, structural constituents of cell membranes, and are involved in key hormones.

Triacylglycerols (Triglycerides)

Triacylglycerols (triglycerides or fats) are made from glycerol and three fatty acids.
They are the most abundant lipids in living organisms.
Triacylglycerols are an economical way to store energy.
Triglycerides consist of glycerol joined to three fatty acids.
Ester linkages connect glycerol and fatty acids.

Fatty Acids

Fatty acids are long, unbranched hydrocarbon chains with a carboxyl group at one end.
Saturated fatty acids have the maximum number of hydrogen atoms.
Unsaturated fatty acids have one or more double bonds.
The presence of double bonds causes a bend in the hydrocarbon chain, influencing the physical properties of fatty acids.
Saturated fats are usually solid at room temperature due to efficient van der Waals interactions.
Unsaturated Fats are typically liquid at room temperature, due to space created by bends in their structure.

Hydrogenated Oils and Trans Fats

Hydrogenated or partially hydrogenated cooking oils convert unsaturated fats to saturated fats to solidify them.
This process creates trans fats, which mimic saturated fats but do not have the same benefits/risks.

Phospholipids

Phospholipids are amphipathic lipids.
They have a hydrophilic (water-loving) head and a hydrophobic (water-fearing) tail.
Phospholipids consist of a glycerol molecule, a phosphate group, and an organic group (e.g., choline) in the head region; the tail region consists of two fatty acids.
Phospholipids are crucial components of cell membranes, forming a phospholipid bilayer.

Carotenoids

Carotenoids are orange and yellow pigments in plants.
They are classified as oils.
They function in photosynthesis.
They consist of 5-carbon hydrocarbon monomers (isoprene units).
Animals convert carotenoids to vitamin A; one form of vitamin A is retinal, which functions in light reception in eyes.

Steroids

Steroids are lipids with four rings of carbon atoms.
Side chains differentiate one steroid from another.
Examples include cholesterol, bile salts, reproductive hormones, cortisol, and other hormones.
Plant cell membranes contain molecules similar to cholesterol.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Explore the chemistry of life in this quiz focusing on organic compounds. Learn about the vital roles carbon atoms play in forming diverse molecules like carbohydrates, lipids, proteins, and nucleic acids. Test your understanding of carbon bonding and the structural variations of organic molecules.