c3 biomolecules

8/13/2019 C3 Biomolecules

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Monomers, polymers, and

macromolecules

There are 4 categories of macromolecules:

Carbohydrates

Proteins,

Lipids,and Nucleic acids


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Carbon is the central element

All biomolecules contain a Carbon chain or ring

Carbon has 4 outer shell electrons (valence = 4)

Therefore its bonding capacity is great

It forms covalent bondshence, has strong bonds

Once bound to other elements (or to other

Carbons), it is very stable


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Carbon linkages

Single chains

Rings

Propane

The 4 types of biomolecules often

consist of large carbon chains

= C3H8

CH4 =


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Carbon binds to more than just

hydrogen!!

To OH groups in sugars

To NH2groups in amino

acids To H2PO4groups of

nucleotides of DNA,

RNA, and ATP

Amino acid

OH, NH2, PO4 are called functional groups!


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Fig. 3.1

Functional groups:


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Isomers have the same molecular

formulas but different structures

Structural isomer = difference in the C skeleton structure

Stereoisomer = difference in location of functional groups


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Enantiomers are special types of

stereoisomersEnantiomersare mirror

images of each other

One such enantiomer

contains C bound to 4different molecules and iscalled a chiral molecule

Chiral molecules rotatepolarized light to the right(D form) or to the left (Lform) molecules

Examples: amino acids (Lform)

sugars (D form)


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Monomers and polymers

Monomers are made into polymers via dehydration reactions

Polymers are broken down into monomers via hydrolysis

reactions


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Fig. 3.3


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Carbohydrates (or sugars)

Simple sugars(monosaccharides)

Only one 3-C, 5-C, 6-

C chain or ring

involved


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Fig. 3.5

Examples of sugar monomers*

*Remember how Cs are counted

within the ring structures (startingfrom the right side and counting

clockwise)


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Carbohydrates (sugars)

Double sugars

(disaccharides)

Two 6-C chains orrings bonded together


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Carbohydrates (sugars)

Complex carbos(polysaccharides)

Starch

Cellulose

Glycogen Chitin

Glycogen to glucose

in animals

Fi 3 9


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Fig. 3.9Polysaccharides

Starch structure vs Glycogen structure

Fi 3 10


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Fig. 3.10

Polysaccharides: Cellulose structure


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Proteins

Composed of chainsof amino acids

20 amino acids exist

Amino acids contain

Central Carbon

Amine group

Carboxyl group

R group

Fig 3 20


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Fig. 3.20

The 20 Amino Acids

All differ with respect

to their R group


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Peptide bonds occur between amino acids

The COOH group of 1

amino acid binds tothe NH2 group of

another amino acid

Forms a peptide bond!

Fig 3 21


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Fig. 3.21

The chain (polymer) of amino acids forms a variety of

loops, coils, and folded sheets from an assortment of

bonds and attractions between amino acids within the

chain(s)


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There are at least 7 functions of proteins

Enzyme catalystsspecific for 1 reaction Defenseantibody proteins, other proteins

Transport- Hgb, Mgb, transferrins, etc

Supportkeratin, fibrin, collagen

Motionactin/myosin, cytoskeletal fibers

Regulation- some hormones, regulatory proteins

on DNA, cell receptors

StorageCa and Fe attached to storage proteins

Fig 3 18


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Fig. 3.18


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There are four levels of protein

structure

Primary = sequence ofaas

Secondary = formspleated sheet, helix, orcoil

Tertiary = entirelength of aas foldedinto a shape

Quaternary = severalaa sequences linkedtogether

Fig 3 23


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Fig. 3.23

Motifs and Domains: Important features of 2and 4

structure


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Nucleic acids: DNA and RNA

DNA =

deoxyribonucleic acid

DNA is a double

polymer (chain)

Each chain is made of

nucleotides

The 2 chains bondtogether to form a

helix


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DNA nucleotides

Each nucleotide in

DNA contains:

5-C sugar

(deoxyribose)

PhosphateNitrogen base

-adenine (A)

-guanine (G)

-cytosine (C)

-thymine (T)

Fig. 3.14


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g

One polymer of nucleotides on one backbone of nucleic acid

Fig. 3.15


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g

The DNA double helix


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Lipids: Hydrophobic molecules

Central core of glycerol

Bound to up to 3 fatty acid chains

They exhibit a high number of C-H bondstherefore much energy and non-polar

When placed in water, lipids spontaneously

cluster together

They help organize the interior content of

cells phospholipids


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Saturated and unsaturated fats

The difference resides in the number of Hs attached

to Cs in the fatty acid chains; the amount of

saturation on the Cs


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Saturated vs unsaturated fats and diet Saturated fats raise LDL-cholesterol levels in the

blood (animal fats, dairy, coconut oil, cocoabutter)

Polyunsaturated fats leave LDL-cholesterolunchanged; but lower HDL-cholesterol (safflower

and corn oil) Monounsaturated fats leave LDL and HDL levels

unchanged (olive oil, canola, peanut oil, avocados)

One variety of polyunsaturated fat (Omega-3 fatty

acids) guards against blood clot formation andreduce fat levels in the blood (certain fish,walnuts, almonds, and tofu)


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Phospholipids and cell membranes

P-lipids make up the majority of cell

membranes including:

The plasma membrane

Nuclear envelope

Endoplasmic reticulum (ER)

Golgi apparatus

Membrane-bound vesicles


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Structure of single P-lipid

The 3 Cs of glycerol are bound to:

2 fatty acid chains

phosphate


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Cell environment organizes P-lipid

bilayer to proper orientation

Hydrophilic (polar) heads of P-lipid oriented to the

exterior; hydrophobic (non-polar) tails oriented to

the interior

c3 biomolecules

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