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Biology 105: Biological Molecules

Lecture 3

Reading: Chapter 2, Pages 29-40

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Outline

• Organic Compounds

• Functional Groups

• Biological Molecules

– Carbohydrates

– Lipids

– Amino acids and Proteins

– Nucleotides and Nucleic Acids

• RNA and DNA

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Organic Compounds

• What do you think of when someone says “organic”?

• In biology

– Molecules of one or more elements covalently bonded to one or more carbon atoms

– Organic vs Inorganic

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Carbon Review

• How many electrons in its outer shell?

– How many does it need to be stable?

• How many covalent bonds can it form?

• Can link together to form a

backbone

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Carbon

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Biological Molecules – Functional Groups

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Polar Functional Groups

• Oxygen containing – Carboxyl (-COOH)

– Hydroxyl (alcohol) (-OH)

– Phosphates (-PO4)

– Carbonyl • Ketone (-CO)

• Aldehyde (-CHO)

• Nitrogen containing – Amino (-NH2)

• Sulfur containing (-SH)

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Macromolecules

• Giant molecule of life – Nucleic acid, protein, polysaccharide

– Formed by the joining together of smaller molecules

• Monomers

• Polymer

• Polymer Party

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Organic Compounds • Carbohydrates

– Monosaccharides, Disaccharides, Polysaccharides

• Lipids – Triglycerices, Phopholipids, Steroids

• Proteins – Made of amino acids – Enzymes, Channels, Pores, Transporters, Regulatory,

Structural – Ex. Keratin, Collagen, Actin

• Nucleic Acids – Made of nucleotides – DNA & RNA

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Carbohydrates

• Contain

– Carbon

– Hydrogen

– Oxygen

– Ratio of: C1H2O1

• Example: Glucose C6H12O6

Image From: http://www.diabetes.org/food-and-fitness/food/what-can-i-eat/understanding-carbohydrates/

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Carbohydrates

• Simple Carbohydrates

– Monosaccharide

– Disaccharide

• Complex Carbohydrates

– Polysaccharide

– Polymers

• Made up of Glucose

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Macromolecules – Polymers

• Dehydration Synthesis

– Water is removed

– H from one molecule

– OH from the other molecule

12 Image From: http://www.goldiesroom.org/Note%20Packets/04%20Biochemistry/00%20Biochemistry--WHOLE.htm

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Polymer Formation

• Dehydration Synthesis

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Macromolecules – Polymers

• What do you think occurs when polymers are broken down?

– Hydrolysis

• Hydro = Water

• Lysis = Breaking down

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Polymer Breakdown

• Hydrolysis

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Carbohydrates

• 4 Functions of carbohydrates

1) Rapidly mobilized source of energy

2) Energy storage

3) Structural

4) Coupled with proteins to form glycoproteins

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Simple Carbohydrates

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Glucose – Ring Structure

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CHO

OHH

HHO

OHH

OHH

CH2OH

O

H

HO

H

HO

H

OH

OHHH

OH

CH

CH2OH

HO

OOH

OH

OHCH

CH2OH

OH

O

OH

OH

OHC

CH2OH

OH

O

OH

OH

OH

H

6

6 6 6

6

1

1

1

1 1

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Glucose

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Disaccharides

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Disaccharide - Lactose

• Glucose + Galactose Lactose

• Lactase

• What happens if you do not have this enzyme?

– Lactose intolerance

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Image From: http://youcaneathealthytoo.com/lactose-intolerance-cartoons/

Disaccharide - Lactose

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Image From: http://www.newhealthguide.org/Lactose-Intolerance.html

Complex Carbohydrates

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Complex Carbohydrates

• Functions

2) Energy Storage

– Glycogen (animals)

– Starch (plants)

3) Structural

– Cellulose (cell walls of bacteria and plants )

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Structure of Complex Carbohydrates

• Polysaccharides – Long chains of saccharides (sugars)

– 100s to 1000s

• The difference between the complex carbohydrates is in the structure – Branched

– Unbranched

– Coiled

– Hydrogen Bonded

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Structure of Complex Carbohydrates

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Complex Carbohydrate - Glycogen

• Function

– Stored in animals for energy

• Structure

– Coiled and Branched

• Very easy to digest (break down)

• Stored mainly in liver and muscle

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Complex Carbohydrate - Glycogen

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Complex Carbohydrate - Starch

• Function

– Stored in plants for energy

• Structure

– Coiled, may have some branching

• Stored in amyloplasts

• Used for energy

• Plants that are high in starch

– Potatoes, rice, carrots, corn

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Complex Carbohydrate - Cellulose

• Function

– Carbohydrate used by plants for structure

• Structure

– Hydrogen bonds stabilize chains into tight bundles

• Important fiber in our diet

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Image From: http://lecherialaslapas.com/rios-dairy-breed/

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Complex Carbohydrate - Cellulose

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Complex Carbohydrates - Summary

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Review Questions

• What is the complex carbohydrate stored in animals?

• What monomer is starch composed of?

33 Image From: http://www.sweetpotatobites.com/tag/santa-monica-seafood/

Lipids

• Mainly made of carbon, hydrogen and oxygen

• Usually have many carbons and hydrogens

• Not soluble in water

• 3 types

1) Triglycerides

2) Phospholipids

3) Steroids

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Lipids - Triglycerides

• Function

– Energy storage

– Insulation

– Protection of vital organs

• Structure

– Three fatty acids joined to one glycerol

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Lipids - Triglyceride

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Lipids - Triglyceride

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Lipids - Triglycerides

• Examples

– Butter, lard (animal fat), vegetable oils

• Differences are in the structure of the fatty acids

– Chain length

– Number of double bonds

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Fatty Acids

• Saturated Fatty Acids

– Carbon chain has NO double bonds

– CH3-(CH2-CH2)n-COOH

• Unsaturated fatty acids

– Carbon chain has at least one double bond

– Monounsaturated VS Polyunsaturated

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Fatty Acids

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Fatty Acids

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Triglycerides

• Animal Fats

– Solid at room temperature

• Vegetable Oils

– Liquid at room temperature

• Hydrogenated Oils

– Example – Crisco

– Trans fats

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Trans Fats

• Hydrogenation

– Adding hydrogen to monounsaturated and polyunsaturated oils

• Sources of trans fats

– Cookies, french fries, cakes, popcorn, many other packaged good

• “Partially hydrogenated oil”

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Trans Fats

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Trans Fats

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Fatty Acids and Health

• Heart disease

– Plaque collecting in the blood vessels

– Plaque from oxidized cholesterol

• LDL vs HDL

– LDL and HDL levels vary with the type of fatty acids you eat

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Fatty Acids and Cholesterol

• Trans fats

– Raise LDL and lower HDL

• Saturated fats

– Raise LDL

• Polyunsaturated fats

– Slightly lower HDL

• Monounsaturated fats

– Do not increase either

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Omega-3 Fats

• Type of unsaturated fat

• Has a carbon double bond located 3 carbons from the end

• Healthiest type of fat

• Reduce LDL

• Sources

– Fatty fish (salmon, tuna), walnuts, flax

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Review Questions

• What fat is the least healthy?

• What type of fatty acid does not contain a double bond?

• Triglycerides are so named because they are formed by a reaction between 3 fatty acid molecules and one __________ .

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Lipids - Phospholipids

• Function

– Backbone of cell membranes

• Structure – Glycerol + 2 FAs + charged phosphate group + “R” group

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Lipids - Phospholipids

• Amphipathic

– Phosphate end of molecule is polar

– Lipid (FA) end is nonpolar

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Lipids - Phospholipids

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Lipids - Phospholipids

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Lipids - Phospholipids

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Image from: http://mquay.blogspot.com/

Lipids – Steroids

• Functions – Signaling between cells (hormones), control

metabolic processes and cellular functions

– Part of cell membrane (cholesterol)

• Structure – 4 ring backbone with side chains attached

• Examples – Hormones

– Cholesterol

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Lipids - Steroids

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Lipids – Steroids

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Lipids - Steroids

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Lipids - Steroids

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Lipids - Steroids

• Anabolic steroids

– Testosterone type compounds to enhance athletic performance

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Image From: http://crazygain.com/roid-rage/

Review Question

• What type of lipid is an important component of membranes?

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Proteins • Functions

– Numerous and varied

– Facilitate chemical reactions (enzymes)

– Transport

– Movement of muscles

– Structure

– Cell signaling

– Nutrition

– Defense

– Components of cell membrane

– Immune response

– Hormones (insulin) 64

Proteins

• Polymers made up of amino acids

• There are 20 amino acids

– Each with a different substitution for “R”

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H2N CH C

R

OH

O

Proteins – Amino Acid Structure

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Proteins – Amino Acids

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Proteins

• Amino acids that form proteins are linked by bonds

– Peptide bonds

– Formed through dehydration synthesis

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Proteins

• Peptides

• Polypeptides

• Proteins

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Protein Structre

• 4 different levels of structure that affect their function in the body

– Primary

– Secondary

– Tertiary

– Quaternary

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Protein Structure

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Protein Structure - Primary

• Amino acid sequence

– Determines its function and structure

– AAs have different properties and structures

• AAs bound together by a peptide bond

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Protein Structure - Secondary

• Structural features within a polypeptide chain

• Do the AA form coils or sheets?

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Protein Structure - Tertiary

• Overall folding

– Determined by size and placement of AA in protein

– Chaperone proteins

– Denaturation

• Lose its shape under

some conditions

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Protein Structure - Tertiary

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Protein Structure - Quaternary

• Multiple chains of AAs (polypeptide chains) interacting or binding together to function as one protein

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Protein Structure - Quaternary

• Hemoglobin

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Shape of Protein and Health

• Hemoglobin and Sickle Cell Anemia

– Caused by change of ONE amino acid in the sequence

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Proteins - Enzymes

• Enzymes are proteins that help reactions to happen

• Some require cofactors to function

– Example = iron

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Enzyme Properties

• Usually specific for their substrates

• They are not consumed (destroyed) in the process

• They have optimal conditions

– pH

– Temperature

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Enzyme Example

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Image From: https://www.pinterest.com/pin/568157309215958563/

Enzyme Example

• Pepsin and Trypsin

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pH

Rate

of

reacti

on

Protein Structure

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Enzymes

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Review Question

• Enzymes are a type of __________, which function to __________ .

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Nucleotides

• Function – Energy (ATP)

– Coenzymes that aid enzyme function (NAD+) or are messengers between and within cells (ADP)

• Small compounds – Sugar, attached phosphate groups, nitrogenous base

• 5 different nucleotides – Adenine, Thymine, Uracil, Guanine,

Cytosine

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Nucleotide

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Nucleotide Complex

• Adenosine Triphosphate and Diphosphate – ATP, ADP

– Energy transferring molecules

• Guanosine Triphosphate and Diphosphate – GTP, GDP

– Intracellular signaling molecules and energy transferring molecules

• Nicotinamide Adenine Dinucleotide (NAD) – Energy transfer

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Nucleotide - ATP

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Nucleic Acids

• Polymer

– Chain or chains of nucleotides (monomer)

• Two types

– DNA – Deoxyribonucleic Acid

– RNA – Ribonucleic Acid

• Functions

– Blueprint to make proteins (DNA)

– Protein synthesis (RNA)

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Nucleic Acids – RNA vs DNA

• RNA – Single stranded

– Sugar: Ribose

– Nitrogenous bases • Adenine, Guanine, Cytosine, Uracil

• DNA – Two strands that for double helix

– Sugar: Deoxyribose

– Nitrogenous bases • Adenine, Guanine, Cytosine, Thymine

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Nucleic Acids - RNA

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Nucleic Acids - DNA

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Nucleic Acids - DNA

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Nucleic Acids

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Review: Monomer VS Polymer

• Monomer

– Individual unit that makes up a polymer

– Examples: Starch is a polymer made up of the monomer units of glucose

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Polymer Monomer

Starch Glucose

Cellulose Glucose

Glycogen Glucose

Protein Amino Acids

Nucleic Acids – DNA and RNA Nucleotides

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Important Concepts

• What are the functions of all the biological molecules?

• What are the types of carbohydrates?

• What is the function of each of the carbohydrates?

• Know what types of organisms the complex carbohydrates are found in, the digestibility of the different complex carbohydrates

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Important Concepts

• Know what parts of the body is glycogen mainly stored in

• Know the cause and symptoms of lactose intolerance

• Know what monomers join to form the complex carbohydrates

• Know the structure of the complex carbohydrates (branched, tightly packed and stabilized by hydrogen bonds, coiled, etc)

• Know the types of lipids, their functions and their structures

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Important Concepts

• What is the general structure of triglycerides?

• What are the molecules that make up triglycerides?

• Know the general structure of phospholipids and the molecules that make up the phospholipids and know the properties of phospholipids

• Know the general structure of steroids (ie. that it is a four ring structure) and be able to identify the structure (don’t need to be able to draw it)

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Important Concepts

• What are the monomers that are joined to make proteins and what type of bond joins them

• What is the primary, secondary, tertiary and quaternary structure of proteins

• What monomer units comprise nucleic acids, know the general structure of nucleotides

• Know the molecules that form nucleotides

• Be able to identify from a picture any of the biological molecules

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Important Concepts

• What are the different types of fatty acids • Which fatty acids are healthy and which are not

as healthy – What is the order from healthiest to least healthy

• Know the structure of trans fat and the source of trans fat

• What is the effect of trans fat on the body • What is trans fat called on ingredient labels • Know the functions of the 3 types of lipids • Know the functions of proteins

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Important Concepts

• What are enzymes, what is their function and their properties

• What are the structure differences between RNA and DNA

• What is the function of DNA and RNA

• Which molecules join together to form what molecules (monomer and polymers)

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Definitions • Monosaccharide • Disaccharides • Polysaccharide • Amyloplasts • Saturated fatty

acids • Unsaturated fatty

acids • Monounsaturated

fatty acids • Polyunsaturated

fatty acids • Omega 3s

• Trans fats • Peptide • Polypeptide • Protein • Peptide bond • Enzyme • Active site • Substrate • Product • Cofactors • Lactose • Lactase

• Alpha helix • Beta pleated

sheets • Amphiphathic • Chaperone • Denaturation • Dehydration

synthesis • Hydrolysis • Monomer • Polymer

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The End

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Image From: http://thelibertarianrepublic.com/3-reasons-my-panda-costume-is-terrifying/