Biology Chapter 5: Biological Molecules

Questions and Answers

What are the classes of the large molecules that all living things fall into?

Lipids (correct)

Proteins (correct)

Nucleic acids (correct)

Carbohydrates (correct)

What is a macromolecule?

A giant molecule formed by the joining of smaller molecules, usually by a dehydration reaction.

Define polymer.

A long molecule consisting of many similar or identical monomers linked by covalent bonds.

Define monomer.

Subunits that serve as the building blocks of proteins and nucleic acids of a polymer. Signup and view all the answers

What type of reaction connects monomers?

Dehydration reaction. Signup and view all the answers

Polymers are converted to monomers in what type of reaction?

Hydrolysis. Signup and view all the answers

What does the root word 'hydro' mean?

Water. Signup and view all the answers

What does the root word 'lysis' mean?

Break. Signup and view all the answers

Is glucose a monomer or a polymer?

Monomer. Signup and view all the answers

When two monomers are joined, what molecule is always removed?

Water. Signup and view all the answers

What are the monomers of all carbohydrates?

Monosaccharides. Signup and view all the answers

What is the formula of a hexose sugar?

C6H12O6. Signup and view all the answers

What is the difference between aldehyde sugar and ketone sugar?

Location of the carbonyl group. Signup and view all the answers

Which two monosaccharides form maltose?

Two molecules of glucose. Signup and view all the answers

Which two monosaccharides are involved in the formation of carbohydrates in plants?

Carbohydrates and sucrose. Signup and view all the answers

Which two monosaccharides form sucrose?

Glucose and fructose. Signup and view all the answers

Which two monosaccharides form lactose?

Glucose and galactose. Signup and view all the answers

What is glycosidic linkage?

Covalent bond formed between two monosaccharides by a dehydration reaction. Signup and view all the answers

What are the two types of polysaccharide?

Starch and glycogen. Signup and view all the answers

Provide examples of starch.

Glucose, amylose, amylopectin. Signup and view all the answers

Provide examples of glycogen.

Similar to amylopectin but more extensively branched. Signup and view all the answers

Why can't humans digest cellulose? What organisms can?

Enzymes cannot digest beta sheets because of shape. Cows and termites can. Signup and view all the answers

What is cellulose?

Has 1-4 beta glucose linkages and composes plant cells. Signup and view all the answers

What is glycogen?

A storage polysaccharide produced by vertebrates that is stored in the liver. Signup and view all the answers

What forms maltose?

Two monomers of glucose. Signup and view all the answers

What is 'milk sugar'?

Lactose. Signup and view all the answers

What is the structural polysaccharide that gives cockroaches their crunch?

Chitin. Signup and view all the answers

What characteristic do all lipids share?

Mix poorly with water - hydrophobic. Signup and view all the answers

What is included in the term lipid?

Fats, waxes, oils, phospholipids, and steroids. Signup and view all the answers

If a fat is composed of three fatty acids and one glycerol molecule, how many water molecules will be removed to form it?

One molecule of water. Signup and view all the answers

Name two saturated fats.

Lard, butter, animal fats. Signup and view all the answers

What are the building blocks of fat and how do you draw an unsaturated fat?

Unsaturated fat has a double bond between the carbons; saturated fat does not. Signup and view all the answers

Name two unsaturated fats.

Olive oil, cod liver. Signup and view all the answers

Why are many unsaturated fats liquid at room temperature?

Kinks where the cis double bonds are located prevent the molecules from packing tightly. Signup and view all the answers

What is a trans fat?

An unsaturated fat, formed artificially during hydrogenation of oils, containing one or more trans double bonds. Signup and view all the answers

List four functions of fats.

<ol> <li>Omega 3 - normal growth in children and protect against heart disease in adults. 2. Energy storage. 3. Cushioning organs. 4. Insulate the body.</li> </ol> Signup and view all the answers

Why are the tails hydrophobic on a phospholipid?

Excluded from water; phospholipids self-assemble into bilayers shielding their hydrophobic portions from water. Signup and view all the answers

Which of the two fatty acid chains in a phospholipid is unsaturated?

The chain with phosphorus at the head. Signup and view all the answers

What is a phospholipid?

Glycerol attached to a phosphate group and two fatty acid chains. Signup and view all the answers

What are examples of steroids?

Vertebrate sex hormones. Signup and view all the answers

Summarize five types of proteins.

<ol> <li>Enzymatic - selective acceleration of chemical reactions. 2. Storage - storage of amino acids. 3. Hormonal - coordination of activities. 4. Structural - support. 5. Defensive - protection against disease.</li> </ol> Signup and view all the answers

What is represented by R in amino acids?

R may be a hydrogen atom or a carbon skeleton. Signup and view all the answers

What is a peptide bond?

Covalent bond between the carboxyl group on one amino acid and the amino group on another, formed by a dehydration reaction. Signup and view all the answers

What is a dipeptide?

Peptide composed of two amino acid residues. Signup and view all the answers

Define polypeptide.

Polymer of many amino acids linked together by peptide bonds. Signup and view all the answers

What is primary protein structure?

Linked series of amino acids. Signup and view all the answers

What is secondary protein structure?

Regions of repetitive coiling or folding of the polypeptide backbone due to hydrogen bonding. Signup and view all the answers

What is an alpha helix?

A coil held together by hydrogen bonding between every fourth amino acid. Signup and view all the answers

What is a beta pleated sheet?

Polypeptide chain folds back and forth, C=chain parallel to each other and held together by hydrogen bonds. Signup and view all the answers

What is tertiary protein structure?

Overall shape of a polypeptide resulting from interaction between the side chains of various amino acids. Signup and view all the answers

Define quaternary protein structure.

Overall protein structure that results from the aggregation of these polypeptide subunits. Signup and view all the answers

Explain sickle cell anemia.

Substitution of one amino acid (valine) for normal one (glutamic acid) at a particular position in hemoglobin. Signup and view all the answers

Besides mutation, what else changes the primary structure of a protein?

Denaturation. Signup and view all the answers

What are the three components of a nucleotide?

<ol> <li>Nitrogen-containing base. 2. 5 carbon sugar (pentose). 3. One or more phosphate groups.</li> </ol> Signup and view all the answers

What is the shape of DNA called?

Double Helix. Signup and view all the answers

Why are the strands of DNA called antiparallel?

The two sugar phosphate backbones run in opposite directions. Signup and view all the answers

What two molecules make up the 'uprights' of the DNA structure?

Sugar phosphate backbone. Signup and view all the answers

What molecules make up the rungs of DNA?

Hydrogen bonds between nitrogen bases. Signup and view all the answers

Study Notes

Classes of Large Biological Molecules

Four main classes: carbohydrates, proteins, nucleic acids, and lipids.

Macromolecules

Giant molecules made by joining smaller units through dehydration reactions.

Monomers and Polymers

Monomer: building blocks of polymers.
Polymer: long chains of repeating monomers linked by covalent bonds.

Dehydration and Hydrolysis Reactions

Dehydration reaction connects monomers by removing water.
Hydrolysis breaks polymers into monomers by adding water.

Carbohydrates

Monosaccharides are the monomers of carbohydrates (e.g., glucose).
Hexose sugar formula is C6H12O6, indicating a 1:2:1 ratio.
Aldehyde sugars have carbonyl groups at the end (e.g., glucose), while ketone sugars have them in the middle (e.g., fructose).

Disaccharides

Maltose is composed of two glucose molecules.
Sucrose is formed from glucose and fructose.
Lactose is made from glucose and galactose.

Polysaccharides

Types include starch and glycogen, which serve as energy storage.
Cellulose has 1-4 β-glucose linkages and is a structural component of plant cells.

Lipids

Lipids are hydrophobic and include fats, oils, phospholipids, waxes, and steroids.
Fats consist of three fatty acids and one glycerol; dehydration removes one water molecule to form them.

Saturated and Unsaturated Fats

Saturated fats are solid at room temperature (e.g., lard, butter).
Unsaturated fats are liquid at room temperature due to cis double bonds causing kinks (e.g., olive oil).

Phospholipids

Structure includes glycerol, phosphate group, and two fatty acid chains; hydrophobic tails and hydrophilic heads.
Phospholipids form bilayers in aqueous environments.

Proteins

Functions: enzymatic, storage, hormonal, structural, and defensive.
Amino acids are linked by peptide bonds through dehydration reactions.
Protein structure levels: primary (amino acid sequence), secondary (coiling or folding), tertiary (overall shape due to side chain interactions), quaternary (assembly of multiple polypeptides).

Sickle Cell Anemia

Caused by a mutation replacing glutamic acid with valine in hemoglobin, affecting oxygen transport efficiency.

Nucleic Acids

Two types: DNA and RNA.
DNA nitrogenous bases: cytosine, thymine, adenine, guanine; RNA bases: cytosine, uracil, adenine, guanine.
Nucleotide components: nitrogen-containing base, 5-carbon sugar (ribose or deoxyribose), and one or more phosphate groups.
DNA structure: double helix with antiparallel strands formed by sugar-phosphate backbone and hydrogen-bonded bases forming rungs.

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Test your knowledge of large biological molecules with this quiz based on Chapter 5. Explore the structures and functions of carbohydrates, proteins, nucleic acids, and lipids. Perfect for students looking to solidify their understanding of macromolecules.