Biology Chapter on Macromolecules

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Questions and Answers

What is chitin primarily used for in medical applications?

To enhance tissue regeneration

To bond synthetic materials together

To produce a strong and flexible surgical thread (correct)

To create a waterproof seal

Which of the following describes lipids?

Lipids are comprised mostly of hydrocarbons and are hydrophobic (correct)

Lipids have high affinity for water

Lipids form polymers to create complex structures

Lipids are soluble in water due to polar bonds

What two types of molecules are fats constructed from?

Glycerol and cholesterol

Glycerol and amino acids

Glycerol and fatty acids (correct)

Fatty acids and steroids

How do fats behave in the presence of water?

They separate from water because water forms hydrogen bonds Signup and view all the answers

What are the characteristics of saturated fatty acids?

They have the maximum number of hydrogen atoms possible Signup and view all the answers

What structural feature leads to the bending of unsaturated fatty acids?

Presence of cis double bonds Signup and view all the answers

What type of linkage connects fatty acids to glycerol in fats?

Ester linkage Signup and view all the answers

Which of the following statements is true regarding lipids?

Lipids serve as a means of energy storage and structural components Signup and view all the answers

What are the four classes of large biological molecules that make up all living things?

Carbohydrates, lipids, proteins, and nucleic acids Signup and view all the answers

Which of the following statements accurately describes a polymer?

A polymer is made up of many similar or identical monomers Signup and view all the answers

What occurs during a dehydration reaction?

A water molecule is removed to form a new bond Signup and view all the answers

What is the reverse process of dehydration that disassembles polymers into monomers?

Hydrolysis Signup and view all the answers

Which of the following statements is true regarding macromolecules?

Molecular structure and function are inseparable Signup and view all the answers

What type of fats are solid at room temperature?

Saturated fats Signup and view all the answers

Which of the following is NOT a major function of fats?

Hormone production Signup and view all the answers

What is the primary characteristic of phospholipids?

They have a hydrophilic head and hydrophobic tails. Signup and view all the answers

Which fatty acids must be supplied in the diet?

Omega-3 fatty acids Signup and view all the answers

What is the basic structure of a steroid?

Four fused rings Signup and view all the answers

Where are phospholipids primarily found?

In cell membranes Signup and view all the answers

Which function is NOT attributed to proteins?

Energy storage Signup and view all the answers

What is the primary role of omega-3 fatty acids in the diet?

For normal growth and cardiovascular protection Signup and view all the answers

What is cholesterol's role within animal cells?

It is a component of cell membranes. Signup and view all the answers

Which statement about unsaturated fats is true?

They are liquid at room temperature. Signup and view all the answers

What is the primary function of storage proteins?

Storing amino acids for later use Signup and view all the answers

Which of the following is an example of a hormonal protein?

Insulin Signup and view all the answers

What function do receptor proteins perform?

Detecting signaling molecules Signup and view all the answers

Which type of protein is primarily responsible for muscle contraction?

Motor proteins Signup and view all the answers

Which protein type provides structural support in animal connective tissues?

Structural proteins Signup and view all the answers

What is the role of transport proteins in the body?

Transporting substances across cell membranes Signup and view all the answers

How do transport proteins contribute to blood function?

They transport oxygen throughout the body. Signup and view all the answers

What is the primary function of contractile proteins?

Facilitating movement Signup and view all the answers

What is the simplest form of carbohydrates?

Monosaccharides Signup and view all the answers

Which type of sugar is glucose classified as?

Aldose Signup and view all the answers

What type of reaction forms a disaccharide from two monosaccharides?

Dehydration Signup and view all the answers

What is the main storage polysaccharide in plants?

Starch Signup and view all the answers

Glycogen is primarily stored in which types of cells in animals?

Liver and muscle cells Signup and view all the answers

The structural polysaccharide cellulose differs from starch in which way?

Cellulose has 1-4 linkages of beta glucose monomers. Signup and view all the answers

Which polysaccharide serves structural roles in fungi and the exoskeleton of arthropods?

Chitin Signup and view all the answers

How are monosaccharides usually represented in terms of their molecular formula?

As multiples of CH2O Signup and view all the answers

Which bond forms between two monosaccharides during a dehydration reaction?

Glycosidic linkage Signup and view all the answers

Which of the following statements is true about cellulose?

Its structure includes beta glucose linkages. Signup and view all the answers

What characteristic distinguishes alpha glucose from beta glucose?

The geometry of the ring structure. Signup and view all the answers

How do herbivores digest cellulose?

Through the action of symbiotic microbes. Signup and view all the answers

Which of the following carbohydrates is made solely from glucose monomers?

Glycogen Signup and view all the answers

Which type of carbohydrate is a polymer composed of many sugar building blocks?

Polysaccharides Signup and view all the answers

Study Notes

The Molecules of Life

All living organisms are composed of four main types of large biological molecules: carbohydrates, lipids, proteins, and nucleic acids.
Macromolecules are large molecules constructed from thousands of covalently linked atoms.
Molecular structure and function are interconnected.

Macromolecules are polymers, built from monomers

Polymers are long molecules comprised of repeating smaller subunits called monomers.
Carbohydrates, proteins, and nucleic acids are all polymers.

Synthesis and Breakdown of Polymers

Dehydration reactions create bonds between monomers by removing a water molecule.
Hydrolysis breaks down polymers by adding a water molecule, breaking the bonds.

Carbohydrates serve as fuel and building material

Carbohydrates include sugars and polymers of sugars.
Monosaccharides are simple sugars, while polysaccharides are polymers of many sugar units.

Sugars

Monosaccharides have molecular formulas that are multiples of CH2O.
The most common monosaccharide is glucose (C6H12O6).
Monosaccharides are classified as either aldoses (containing an aldehyde group) or ketoses (containing a ketone group), and by the number of carbon atoms.

Polysaccharides

Polysaccharides serve as storage or structural molecules.
Their structure and function are determined by the arrangement of their sugar monomers and glycosidic linkages.

Storage Polysaccharides

Starch is a storage polysaccharide in plants, composed of glucose monomers.
Plants store starch as granules within chloroplasts and other plastids.
Amylose is the simplest form of starch.
Glycogen is a storage polysaccharide in animals, primarily stored in liver and muscle cells.

Structural Polysaccharides

Cellulose is a major component of plant cell walls, also composed of glucose monomers.
Cellulose and starch differ in the configuration of their glycosidic linkages, which affects their structure.
Cellulose has a straight, fibrous structure due to its  glucose monomers.
These fibers create strong building materials for plants.
Humans lack the enzymes to break down cellulose, which is why it’s considered dietary fiber.
Chitin is a structural polysaccharide found in the exoskeletons of arthropods, and the cell walls of fungi.

Lipids are a diverse group of hydrophobic molecules

Lipids are a class of non-polymer large biological molecules.
They are hydrophobic because they consist mostly of hydrocarbons.
The main types of lipids are fats, phospholipids, and steroids.

Fats

Fats are constructed from glycerol and fatty acids.
Glycerol is a three-carbon alcohol with a hydroxyl group on each carbon.
Fatty acids have a carboxyl group attached to a long carbon chain.
Three fatty acids join to glycerol via ester linkages to form a triacylglycerol, or triglyceride.

Fatty Acids

Fatty acids vary in length and the number and position of their double bonds.
Saturated fatty acids have no double bonds and are solid at room temperature.
Unsaturated fatty acids contain one or more double bonds and are liquid at room temperature.
Essential fatty acids, like omega-3 fatty acids, are not synthesized in the body and must be consumed.

Functions of Fats

Fats serve primarily for energy storage.
Mammals store fat in adipose cells, which also cushions vital organs and provides insulation.

Phospholipids

Phospholipids contain two fatty acids and a phosphate group attached to glycerol.
The fatty acid tails are hydrophobic, while the phosphate group and its attachments form a hydrophilic head.
In water, phospholipids form a bilayer with hydrophobic tails facing inward and hydrophilic heads facing outward.
They are the major component of all cell membranes.

Steroids

Steroids have a distinct structure with four fused rings.
Cholesterol is an important steroid found in animal cell membranes.
High cholesterol levels in the blood can contribute to cardiovascular disease.

Proteins include a diversity of structures with a wide range of functions

Proteins make up over 50% of the dry mass of most cells.
They perform various functions including structural support, storage, transport, cellular communication, movement, and defense.

Protein Functions

Enzymatic proteins catalyze chemical reactions.
Defensive proteins protect against disease.
Storage proteins store amino acids.
Transport proteins transport substances.
Hormonal proteins coordinate cellular activities.
Receptor proteins bind to signaling molecules.
Contractile and motor proteins facilitate movement
Structural proteins provide support.

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Description

Explore the essential biological molecules that make up living organisms. This quiz covers macromolecules like carbohydrates, lipids, proteins, and nucleic acids, focusing on their structures, functions, and synthesis processes. Test your understanding of how these molecules are formed and broken down.