BIOLOGY

Chapter 3 BIOLOGICAL MACROMOLECULES

Figure 5.1

Large Biological Molecule Terms

• 4 classes of bio. molecules

Carbohydrates (sugars)

Proteins

Nucleic acids

Lipids

• Monomers (subunits): single-part

– Building blocks for macromolecules

• Polymers: many-parts

– Composed of many monomers

– Covalently bonded

Figure 3.1

Figure 2.13

Sugars

Hyd

roly

sis

De

hyd

rati

on

syn

the

sis

Carbohydrate

Energy Energy

Dehydration

Synthesis

• Remove H2O

• Form bonds

• Polymer

formation

• Anabolic

Hydrolysis

• Add H2O

• Break bonds

• Catabolic

• “Digestion”

animation

Figure 5.2(a) Dehydration reaction: synthesizing a polymer

Short polymer Unlinked monomer

Dehydration removesa water molecule,forming a new bond.

Longer polymer

(b) Hydrolysis: breaking down a polymer

Hydrolysis addsa water molecule,breaking a bond.

1

1

1

2 3

2 3 4

2 3 4

1 2 3

Figure 3.2, 3.3

(a) Dehydration reaction: synthesizing a polymer

Short polymer Unlinked monomer

Dehydration removesa water molecule,forming a new bond.

Longer polymer

1 2 3 4

1 2 3

Figure 5.2b

(b) Hydrolysis: breaking down a polymer

Hydrolysis addsa water molecule,breaking a bond.

1 2 3 4

1 2 3

Figure 3.4Aldoses (Aldehyde Sugars) Ketoses (Ketone Sugars)

Glyceraldehyde

Trioses: 3-carbon sugars (C3H6O3)

Dihydroxyacetone

Pentoses: 5-carbon sugars (C5H10O5)

Hexoses: 6-carbon sugars (C6H12O6)

Ribose Ribulose

Glucose Galactose Fructose

Carbohydrates Fuel Building material Monomers = Monosaccharides

Figure 3.4

Aldose (Aldehyde Sugar) Ketose (Ketone Sugar)

Glyceraldehyde

Trioses: 3-carbon sugars (C3H6O3)

Dihydroxyacetone

Functional Groups

Figure 3.6

(a) Linear and ring forms

(b) Abbreviated ring structure

1

2

3

4

5

6

6

5

4

32

1 1

23

4

5

6

1

23

4

5

6

Figure 3.7, 3.8

(a) Dehydration reaction in the synthesis of maltose

(b) Dehydration reaction in the synthesis of sucrose

Glucose Glucose

Glucose

Maltose

Fructose Sucrose

1–4glycosidic

linkage

1–2glycosidic

linkage

1 4

1 2

DisaccharidesCarbohydrates

Figure 3.9

(a) Starch (amylose/amylopectin):a plant polysaccharide

(b) Glycogen:an animal polysaccharide

Chloroplast Starch granules

Mitochondria Glycogen granules

Amylopectin

Amylose

GlycogenWhere stored?Relate this to negative feedback & low blood sugar.

1 m

0.5 m

Polysaccharides 1) Storage Forms

Figure 5.7a

(a) and glucose ring structures

Glucose Glucose

4 1 4 1

Polysaccharidesalpha vs beta glucose

Figure 5.7b

(b) Starch: 1–4 linkage of glucose monomers

(c) Cellulose: 1–4 linkage of glucose monomers

41

41

Polysaccharidesalpha vs beta glucose arrangement

Figure 3.10

Cell wall

Microfibril

Cellulosemicrofibrils in aplant cell wall

Cellulosemolecules

Glucosemonomer

10 m

0.5 m

Polysaccharides

2) Structural Forms

“insoluble fiber”

Which polysaccharide has the

greatest number of branches?

a) cellulose

b) chitin

c) amylose

d) amylopectin

e) glycogen

Fig. 5-9

Why are human enzymes that digest

starch unable to digest cellulose?

a) Cellulose is made of amino-containing sugars that cannot

be metabolized.

b) Cellulose contains L-glucose instead of D-glucose; starch-

digesting enzymes are specific for polymers of D-glucose.

c) Cellulose has beta-glycosidic linkages; starch-digesting

enzymes cleave only alpha-glycosidic linkages.

d) Cellulose has beta-galactoside linkages that only bacterial

beta-galactosidases can cleave.

e) Cellulose fibers are covalently cross-linked; starch-digesting

enzymes cannot cleave these cross-links.

Figure 3.11

Chitin forms the exoskeletonof arthropods.

The structureof the chitinmonomer

Chitin is used to make a strong and flexiblesurgical thread that decomposes after thewound or incision heals.

Polysaccharides

2) Structural Forms

Subunits

a) proteins

b) starch

c) nucleic acids

d) fatty acids

If actively growing cells are fed 14C-labeled glucose,

what macromolecules will become radioactive first?

Figure 3.13

(a) One of three dehydration reactions in the synthesis of a fat

(b) Fat molecule (triacylglycerol)

Fatty acid(in this case, palmitic acid)

Glycerol

Ester linkage

Lipids

Figure 5.10a

(a) One of three dehydration reactions in the synthesis of a fat

Fatty acid(in this case, palmitic acid)

Glycerol

Figure 5.10b

(b) Fat molecule (triacylglycerol)

Ester linkage

Figure 3.14

• Stearic acid is a common saturated fatty acid.

Figure 3.15

• Oleic acid is a common unsaturated fatty acid.

Figure 3.16

• Saturated fatty acids have hydrocarbon

chains connected by single bonds only.

Unsaturated fatty acids have one or more

double bonds. Each double bond may be

in a cis or trans configuration. In the cis

configuration, both hydrogens are on the

same side of the hydrocarbon chain. In

the trans configuration, the hydrogens

are on opposite sides. A cis double bond

causes a kink in the chain.

Figure 3.17

• Alpha-linolenic acid is an example of an omega-3 fatty acid. It has three cis double bonds

and, as a result, a curved shape. For clarity, the carbons are not shown. Each singly bonded

carbon has two hydrogens associated with it, also not shown.

Figure 5.11

(a) Saturated fat(b) Unsaturated fat

Structuralformula of asaturated fatmolecule

Space-fillingmodel of stearicacid, a saturatedfatty acid

Structuralformula of anunsaturated fatmolecule

Space-filling modelof oleic acid, anunsaturated fattyacid

Cis double bondcauses bending.

Saturated vs unsaturated fat comparison

Figure 3.19

Choline

Phosphate

Glycerol

Fatty acids

Hydrophilichead

Hydrophobictails

(c) Phospholipid symbol(b) Space-filling model(a) Structural formula

Hyd

rop

hil

ic h

ea

dH

yd

rop

ho

bic

ta

ils

Lipids

•phospholipid

Figure 3.20

• The phospholipid bilayer is the major component of all cellular membranes.

Compared to tropical fish, arctic

fish oils have

a) more unsaturated fatty acids.

b) more cholesterol.

c) fewer unsaturated fatty acids.

d) more trans-unsaturated fatty acids.

e) more hydrogenated fatty acids.

Lipids

Figure 3.21

Lipids

•Steroids cholesterol

Lipid Functions

• Energy storage

• Insulation

• Cushioning organs

• Prevents water loss

• Chemical messengers

• Membranes

Lipids

a) are made from glycerol and fatty acids.

b) contain nitrogen.

c) have low energy content.

d) are acidic when mixed with water.

e) do not dissolve well in water.

All lipids

Figure 3.22Proteins

•Monomers amino acids

Figure 3.23

Figure 3.24Dehydration Synthesis

Condensation RXN

Figure 5.17

Peptide bond

New peptidebond forming

Sidechains

Back-bone

Amino end(N-terminus)

Peptidebond

Carboxyl end(C-terminus)

Dehydration Synthesis

Condensation RXN

Figure 3.25

Primary structure

Aminoacids

Amino end

Carboxyl end

Primary structure of transthyretin

Protein structure

DNA RNA Protein

Figure 3.28

Secondarystructure

Tertiarystructure

Quaternarystructure

Hydrogen bond

helix

pleated sheet

strand

Hydrogenbond

Transthyretinpolypeptide

Transthyretinprotein

Protein structure

Figure 5.20c

Secondary structure

Hydrogen bond

helix

pleated sheet

strand, shown as a flatarrow pointing towardthe carboxyl end

Hydrogen bond

Figure 5.20d

Secondary Structure pleated sheet

Figure 5.20e

Tertiary structure

Transthyretinpolypeptide

Figure 3.29

1) Hydrogenbond

4) Disulfidebridge

Polypeptidebackbone

5) Ionic bond

2) Hydrophobic

interactions and

3) van der Waals

interactions

Tertiary structure• Possible bonds

Figure 5.20b

Secondarystructure

Tertiarystructure

Quaternarystructure

Hydrogen bond

helix

pleated sheet

strand

Hydrogenbond

Transthyretinpolypeptide

Transthyretinprotein

Protein structure

Figure 5.20g

Quaternary structure

Transthyretinprotein

(four identicalpolypeptides)

Collagen

Figure 5.20h

Figure 5.20i

Hemoglobin

Heme

Iron

subunit

subunit

subunit

subunit

Quaternary structure

Figure 5.19

Primary

Structure

Secondary

and Tertiary

Structures

Quaternary

StructureFunction

Red Blood Cell

Shape

5 µm

Proteins do not associatewith one another; eachcarries oxygen.

Proteins aggregate into afiber; capacity tocarry oxygenis reduced.

5 µm

Normalhemoglobin

Normal 𝛃subunit

𝛃

𝛃 𝛂

𝛂

𝛂

𝛂

𝛃

𝛃

Sickle-cellhemoglobin

Sickle-cell 𝛃subunit

Sic

kle

-cell

No

rma

l

1

2

3

4

5

6

7

1

2

3

4

5

6

7

Protein Structure

a) primary

b) tertiary

c) quarternary

d) all of the above

e) primary and tertiary

structures only

The sickle-cell hemoglobin

mutation alters what level(s)

of protein structure?

Figure 5.22

Normal protein Denatured protein

tu

Denature

• Temperature heat

• pH

• [Ionic]

• Solvents

Macromolecular Structures and Bonds

a) Acidic pH denatures (unfolds and inactivates) proteins by disrupting their hydrogen bonds.

b) Citrus juice denatures proteins by disrupting their ionic bonds.

c) Citrus juice contains enzymes that hydrolyze peptide bonds to break apart proteins.

d) Citrus juice dissolves cell membranes by disrupting hydrophobic interactions.

Ceviche is prepared by marinating fresh raw fish in citrus juice for several hours, until the flesh becomes opaque and firm, as if cooked. How does citrus juice render the seafood safe to eat?

Figure 5.23

The cap attaches, causingthe cylinder to changeshape in such a way thatit creates a hydrophilicenvironment for thefolding of the polypeptide.

Cap

Polypeptide

Correctlyfoldedprotein

Chaperonin(fully assembled)

Steps of ChaperoninAction:

An unfolded poly-peptide enters thecylinder fromone end.

Hollowcylinder

The cap comesoff, and theproperly foldedprotein isreleased.

1

2 3

Chaperonin or chaperone proteins

Misfolded proteins Alzheimer’s, Parkinson’s, and mad cow disease

Figure 5.15a

Enzymatic proteins

Enzyme

Example: Digestive enzymes catalyze the hydrolysis

of bonds in food molecules.

Function: Selective acceleration of chemical reactions

Protein function #1

8 generalized functions of proteins

Figure 5.15b

Storage proteins

Ovalbumin Amino acidsfor embryo

Function: Storage of amino acids

Examples: Casein, the protein of milk, is the major

source of amino acids for baby mammals. Plants have

storage proteins in their seeds. Ovalbumin is the

protein of egg white, used as an amino acid source

for the developing embryo.

Protein function #2

Figure 5.15c

Hormonal proteins

Function: Coordination of an organism’s activities

Example: Insulin, a hormone secreted by the

pancreas, causes other tissues to take up glucose,

thus regulating blood sugar concentration

Highblood sugar

Normalblood sugar

Insulinsecreted

Protein function #3

Figure 5.15d

Muscle tissue

Actin Myosin

100 m

Contractile and motor proteins

Function: Movement

Examples: Motor proteins are responsible for the

undulations of cilia and flagella. Actin and myosin

proteins are responsible for the contraction of

muscles.

Protein function #4

Figure 5.15e

Defensive proteins

Virus

Antibodies

Bacterium

Function: Protection against disease

Example: Antibodies inactivate and help destroy

viruses and bacteria.

Protein function #5

Figure 5.15f

Transport proteins

Transportprotein

Cell membrane

Function: Transport of substances

Examples: Hemoglobin, the iron-containing protein of

vertebrate blood, transports oxygen from the lungs to

other parts of the body. Other proteins transport

molecules across cell membranes.

Protein function #6

Figure 5.15g

Signalingmolecules

Receptorprotein

Receptor proteins

Function: Response of cell to chemical stimuli

Example: Receptors built into the membrane of a

nerve cell detect signaling molecules released by

other nerve cells.

Protein function #7

Figure 5.15h

60 m

Collagen

Connectivetissue

Structural proteins

Function: Support

Examples: Keratin is the protein of hair, horns,

feathers, and other skin appendages. Insects and

spiders use silk fibers to make their cocoons and webs,

respectively. Collagen and elastin proteins provide a

fibrous framework in animal connective tissues.

Protein function #8

8 Protein Functions

1. Structural

2. Storage

3. Transport

4. Hormonal

5. Receptor

6. Contractile

7. Defense

8. Enzymatic

1. Connective tissue (tendons,

ligaments)

2. Albumin, casein

3. Hemoglobin, ion channels, etc

4. Insulin

5. Detects other signals (stimuli)

6. Movement

7. Immune system (antibodies)

8. Increase chemical reactions

(Digestion, cellular respiration)

Figure 3.31

Figure 5.26aSugar-phosphate backbone

5 end

5C

3C

5C

3C

3 end

(a) Polynucleotide, or nucleic acid

(b) Nucleotide

Phosphategroup Sugar

(pentose)

Nucleoside

Nitrogenousbase

5C

3C

1C

Nucleic Acids

• Nucleotide

Figure 5.26b

Nitrogenous bases

Cytosine (C)

Thymine (T, in DNA)

Uracil (U, in RNA)

Adenine (A) Guanine (G)

Sugars

Deoxyribose (in DNA)

Ribose (in RNA)

(c) Nucleoside components

Pyrimidines

Purines

Nitrogenous Bases

Base pair

Phosphate

Sugar

Nucleotide

Nucleic Acids Store Genetic Information

• Structure of DNA (deoxyribonucleic acid)• Double–stranded (dbl helix)

• Nucleotides contain

– Deoxyribose (sugar)

– Nitrogenous bases» Adenine

» Guanine

» Cytosine

» Thymine

• Pairing

» Adenine - Thymine

» Guanine - Cytosine

Figure 5.27

Sugar-phosphatebackbones

Hydrogen bonds

Base pair joinedby hydrogen bonding

Base pair joinedby hydrogen

bonding

(b) Transfer RNA(a) DNA

5 3

53

Base pair rules

Nucleic Acids Store Genetic Information

• Structure of RNA (ribonucleic acid)• Single–stranded

• Nucleotides contain

– Ribose

– Nitrogenous bases

» Adenine

» Guanine

» Cytosine

» Uracil

RNA and DNA

a) DNA encodes hereditary information; RNA does

not.

b) DNA forms duplexes; RNA does not.

c) DNA contains thymine; RNA contains uracil.

d) all of the above

How does RNA differ from DNA?

Figure 5.25-3

Synthesis ofmRNA

mRNA

DNA

NUCLEUS

CYTOPLASM

mRNA

Ribosome

AminoacidsPolypeptide

Movement ofmRNA intocytoplasm

Synthesisof protein

1

2

3

Nucleic Acids

Transcription

• DNA RNA

Translation

• RNA Protein

Nucleic acid functions?

• DNA: instructions for making proteins via

RNA• Information storage

• Information transfer

• RNA: instructions for making proteins • Protein synthesis DNA → RNA → Proteins

• Proteins: direct most of life’s processes

• Transfer of chemical energy

Figure 5.UN02

Figure 5.UN02a

Figure 5.UN02b