Biology Chapter 3: Organic Compounds & Macromolecules

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Questions and Answers

What property of carbon allows it to form diverse organic compounds?

Carbon can form isomers.

Carbon can bond with four other atoms. (correct)

Carbon primarily forms hydrocarbons.

Carbon can exist in multiple structural forms.

Which statement correctly describes isomers?

Isomers cannot exist in the same environment.

Isomers always display the same physical properties.

Isomers differ in the arrangement of their atoms. (correct)

Isomers have different molecular formulas.

What role do hydrophilic functional groups play in organic molecules?

They solely determine the size of organic molecules.

They make organic molecules hydrophobic.

They provide specific chemical properties to organic molecules. (correct)

They enhance the sweetness of organic compounds.

How do testosterone and estradiol differ from each other?

They contain different functional groups. Signup and view all the answers

What constitutes macromolecules in biological systems?

Large complex molecules made from a limited set of small molecules. Signup and view all the answers

Which phrase best describes hydrocarbons?

They are exclusively made up of carbon and hydrogen. Signup and view all the answers

What is primarily responsible for the diverse properties of organic compounds?

The arrangement of carbon and its functional groups. Signup and view all the answers

Which statement about the four classes of biological molecules is true?

They are typically referred to as macromolecules due to their large size. Signup and view all the answers

What process is involved in linking amino acids to form a polypeptide?

Dehydration reaction Signup and view all the answers

Which level of protein structure is characterized by the sequence of amino acids?

Primary structure Signup and view all the answers

What stabilizes the secondary structure of proteins?

Hydrogen bonds Signup and view all the answers

What term describes proteins formed from more than one polypeptide chain?

Quaternary structure Signup and view all the answers

Which component is NOT part of a nucleotide?

Amino acid Signup and view all the answers

What structural form does DNA take?

Double helix Signup and view all the answers

Which molecule serves as the blueprint for proteins?

Nucleic acids Signup and view all the answers

What distinguishes the 20 different amino acids?

The R groups Signup and view all the answers

What type of polysaccharide is cellulose classified as?

A structural polysaccharide Signup and view all the answers

Which statement best describes saturated fatty acids?

They contain the maximum number of hydrogens. Signup and view all the answers

What are trans fats primarily formed from?

Unsaturated fats being hydrogenated. Signup and view all the answers

What health risks are associated with trans fats according to the scientific studies mentioned?

They pose a greater health risk than saturated fats. Signup and view all the answers

What is the primary composition of lipids?

Mostly carbon and hydrogen. Signup and view all the answers

What is the typical state of unsaturated fatty acids at room temperature?

Liquid Signup and view all the answers

What distinguishes hydrogenated oils from other oils?

They undergo a process of hydrogenation. Signup and view all the answers

Which type of fats typically contains one or more double bonds?

Unsaturated fats Signup and view all the answers

What is the main consequence of disseminating or selling parts of this work?

It will diminish the integrity of the work. Signup and view all the answers

Who is primarily allowed to distribute the materials from this work?

Instructors using the accompanying text. Signup and view all the answers

What do all recipients of this work need to adhere to?

The intended pedagogical purposes. Signup and view all the answers

Which of the following statements best reflects the copyright policy for this work?

The work must remain limited to teaching and assessment by instructors. Signup and view all the answers

What is implied about the integrity of the work if it is improperly shared?

The work will lose its intended educational purpose. Signup and view all the answers

What role do mutations in DNA play in the evolution of lactose tolerance among human populations?

They permanently activate the lactase gene in specific groups. Signup and view all the answers

Which of the following groups is highlighted in research regarding lactose tolerance evolution?

East African ethnic groups Signup and view all the answers

What is a significant factor in the development of lactose tolerance in certain human populations?

The domestication of dairy cattle Signup and view all the answers

How is lactose tolerance linked to human evolution?

It reflects adaptation to agricultural lifestyle changes. Signup and view all the answers

What is the significance of the lactase gene in populations that have developed lactose tolerance?

It allows for continuous lactose digestion into adulthood. Signup and view all the answers

Which of the following best describes lactose in dietary terms?

A disaccharide composed of glucose and galactose. Signup and view all the answers

What kind of evidence suggests that trans fats are more unhealthy than saturated fats?

Research indicates greater risk of heart disease with trans fats. Signup and view all the answers

Which chemical group is crucial for understanding biological molecules involved in lactose digestion?

Simple sugars in carbohydrates Signup and view all the answers

What process is used to link monomers together to form polymers?

Dehydration synthesis Signup and view all the answers

Which statement about monosaccharides is true?

They generally have a formula that is a multiple of C${n}$H${2n}$O. Signup and view all the answers

What is the primary role of enzymes in the context of polymer formation?

To speed up reactions Signup and view all the answers

Which combination of monosaccharides forms the disaccharide lactose?

Glucose and galactose Signup and view all the answers

What distinguishes a polysaccharide from a monosaccharide?

Polysaccharides are larger and consist of many monomers. Signup and view all the answers

Which reaction primarily leads to the breakdown of polymers into monomers?

Hydrolysis Signup and view all the answers

Why are sugars often referred to as 'empty calories' in nutrition?

They lack essential nutrients. Signup and view all the answers

What is the significance of hydroxyl and carbonyl groups in monosaccharides?

They determine solubility in water. Signup and view all the answers

Study Notes

Chapter 3: The Molecules of Cells

Most adults cannot properly digest dairy products due to lactose intolerance, a deficiency in the enzyme lactase.
Biological molecules like lactase are crucial for daily bodily functions.
Carbon's ability to bond with four other atoms is the foundation for the complexity of organic compounds.
Carbon chains form the backbone of most organic molecules.
Isomers have the same molecular formula but different structures.
Hydrocarbons are composed solely of carbon and hydrogen.
Examples of different carbon skeletons include:
- Ethane, Propane
- Butane, Isobutane
- 1-Butene, 2-Butene
- Cyclohexane, Benzene

Isomers

Structural isomers: Differ in the arrangement of their atoms.
Geometric isomers: Differ in the spatial arrangement of atoms around a double bond.
Enantiomers: Mirror images of each other, and they differ in their three-dimensional shape which gives them unique biological activities.

Important Chemical Groups

An organic compound's properties are determined by the size and shape of its carbon skeleton and the atoms attached to it.
Hydrophilic functional groups give organic molecules specific chemical properties.
Table 3.2 illustrates six important chemical groups:
- Hydroxyl
- Carbonyl
- Carboxyl
- Amino
- Phosphate
- Methyl

Sex Hormones

The sex hormones testosterone and estradiol (a form of estrogen) differ only in the atoms highlighted in Figure 3.2.

Macromolecules

The four classes of biological molecules contain very large molecules.
These molecules are called macromolecules because of their large size.
These molecules are also called polymers because they are made of identical or similar building blocks linked together.
The building blocks of polymers are called monomers.

Dehydration Synthesis and Hydrolysis

Monomers are linked together to form polymers through dehydration synthesis (condensation) reactions.
Polymers are broken apart by hydrolysis.
Enzymes speed up these reactions.

Carbohydrates

Carbohydrates range from simple sugar molecules (monomers) to complex polysaccharides.
Monosaccharides are the simplest sugar monomers.
A monosaccharide generally has a formula that is a multiple of CH₂O, and contains hydroxyl groups and a carbonyl group.
Examples of monosaccharides: Glucose and Fructose
Examples of Disaccharides: Lactose

Polysaccharides

Starch and glycogen are storage polysaccharides.
Cellulose is structural and found in plant cell walls.
Chitin is a structural component of insect and crustacean and fungal cell walls.

Lipids

Lipids are diverse hydrophobic (water-fearing) compounds composed largely of carbon and hydrogen.
Fats (triglycerides) consist of glycerol linked to three fatty acids.
Some fatty acids contain one or more double bonds, forming unsaturated fatty acids which are typical of plant oils.
Fats with the maximum number of hydrogens are called saturated fatty acids, found in animal fats like butter or lard.
Hydrogenation converts unsaturated fats into saturated fats, creating trans fats.

Phospholipids and Steroids

Phospholipids are components of cell membranes.
Steroids, including cholesterol and some hormones, have a carbon skeleton consisting of four fused rings.
Cholesterol is a common component in animal cell membranes, and a precursor for other steroids.

Proteins

Proteins are involved in nearly every dynamic function in the body.
Proteins function as enzymes, transport, defensive, signal, receptor, contractile and storage proteins.
Proteins are composed of differing arrangements of 20 amino acid monomers.
Denaturation is the process where a protein unravels and loses its function.
Amino acid monomers are linked together in a dehydration reaction, creating a peptide bond.
R groups distinguish 20 amino acids with specific properties.
Proteins have four levels of structure: primary, secondary, tertiary, and quaternary.

Nucleic Acids (DNA and RNA)

The monomers that make up nucleic acids (the blueprint for proteins) are nucleotides.
Nucleotides consist of a sugar, a phosphate group, and a nitrogenous base.
DNA is a double helix, while RNA is a single-stranded polynucleotide chain.
DNA is the molecule of inheritance.

Lactose Tolerance

Mutations in DNA have led to lactose tolerance in human populations who raised dairy cattle.
Researchers have identified mutations in East Africa that keep the lactase gene permanently turned on.

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Description

This quiz covers key concepts in biology related to organic compounds and macromolecules. You will explore properties of carbon, the nature of isomers, and the roles of functional groups in organic molecules. Additionally, it delves into proteins, nucleotides, and the distinctive features of various biological molecules.