Cell Metabolism - Lecture 1 - Bio Molecules

8/14/2019 Cell Metabolism - Lecture 1 - Bio Molecules

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Chemistry of LifeChemistry of Life

You need to know a small amount of

chemistry to understand biology!


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Why do we need to know a small

amount of chemistry? To understand why think of some of the characteristics

of living organisms e.g.

They reproduce.

They grow.

They can move


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Guess what organisms use to generate

energy and as building materials?

Chemicals


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Important Biological

Compounds

1. Carbohydrates

2. Lipids3. Proteins

4. Nucleic Acids5. Vitamins

6. Minerals


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Molecules of LifeMolecules of Life

The chemistry ofcarbon accounts for the

chemistry oforganic compounds.

Organic compounds contain carbon and hydrogen atoms

Macromolecules = polymers that arise when their

specific monomers (unit molecules) are joined

together. Carbohydrates, lipids, proteins, and nucleic

acids are macromolecules with specific

functions in cells.


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CarbohydratesCarbohydrates

Carbohydrates often function as a

ready source ofenergy in most

organisms.

GlucoseGlucose is a simple, six-carbon

sugar (carbohydrate monomer) most

utilized by cells for "quick" energy.

Cn(H2O)n


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CarbohydratesCarbohydrates

Carbohydrates also form major

structural components in plants

and insects.

Cellulose, lignin, chitin etcCellulose, lignin, chitin etc.


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3 Types of Carbohydrates

1. Monosaccharides

2. Disaccharides

3. Polysaccharides


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Hexoses i.e.,

they all contain

6 carbon atoms


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Carbohydrate Synthesis andCarbohydrate Synthesis and

Break DownBreak Down Condensationsynthesis forms carbohydrate

polymers from two or more sugar monomers

Hydrolysis reaction splits bonds to form smaller

molecules.

Plants store glucose as starch, and animals store

glucose as glycogen.

These compounds are polymers of glucose.


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Cellulose is a indigestible plant carbohydrate


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Functions of carbohydrates

As a source of energy

As a building material

Signalling function.


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LipidsLipids

Lipids (triglycerides, phospholipids, &

sterols) are varied in structure and

function

Most lipids are not soluble (dont dissolve) in H2O

Fats and oils (triglycerides) are used

forlong-term energy storage

Triglycerides have glycerol & 3 fatty acids

Fatty acids can be saturated (no double bonds) orunsaturated

(one or more carbon-carbon double bond) .


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Fatty acids

Fatty acids (FAs) are aliphatic molecules with a carboxyl

group at one end.

20 not 18


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Saturated vs. unsaturated FAs

Saturated FAs are solid at room temperature.

Unsaturated FAs are liquid at room temperature


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A Triglyceride


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Lipids: PhospholipidsLipids: Phospholipids

Plasma membranes contain phospholipids

that have a polarized end.

Phospholipids are composed ofglycerol,fattyacids, and a phosphategroup

(charged = polarized).

The phosphate group end of phospholipids is

soluble in water


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Lipids: SterolsLipids: Sterols

Steroids (sterols) are lipids, but with avery different structure.

Cholesterol, a complex ring compound, is

a steroid.

Certain steroidhormones(including

sex hormones) are derived from

cholesterol.

Cholesterol is also an important

component ofcell membranes.


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Functions of lipids

Energy storage molecules

Insulation

Signalling

Cushioning


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Functions of amino acids

The building blocks of proteins.

Neurotransmitters (e.g. dopamine [from tyrosine])

Protection (e.g. histamine [from histidine])


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P t i St tP t i St t


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Protein StructureProtein Structure

Secondary structure: Formed by hydrogen bonds between non-adjacent

amino acids

Often an alpha (a) helix or a beta () pleated sheet.

Tertiary structure: When a polypeptide bends and twists into a 3-D

shape due to covalent bonds between amino acids

in certain regions of the polypeptide.

Quaternary structure: When a protein contains several polypeptides.


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Bonds involved in maintaining the

tertiary structure of a protein


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Functions

Structural (e.g. hair, fingernails, claws etc)

Signalling/information (e.g. hormones)

Transport (e.g. haemoglobin, serum albumin)

Protective (e.g. antibodies, lysozyme [an enzyme])

Movement (e.g. muscle)

Catalysis (e.g. enzymes)


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For more information on proteins

visit:

http://fajerpc.magnet.fsu.edu/Education/2010/Lectures/10_Proteins.htm


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Ribose


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Nucleic Acids - DNANucleic Acids - DNA

Contains the sugar

ribose

Contains the basesadenine, thymine,

guanine and cytosine

Very large molecule

Double stranded


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Nucleic Acids - RNANucleic Acids - RNA

Contains the sugar

deoxyribose

Contains the bases

adenine, uracil, guanineand cytosine

Not as large as DNA

Double stranded

http://165.134.116.28/301/origin/RNA.jpg


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Functions of nucleic acids

DNA stores genetic information.

RNA structural, recognition & transport

NucleotidesNucleotides


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NucleotidesNucleotides

ATPATP (adenosine triphosphate) is theenergy currency of cells.

Its unstable phosphate bonds can beeasily broken, releasing energy

= Hydrolysis ofATP to ADP (adenosine

diphosphate) + Pi (inorganic phosphate)releases energy that is used by cells to do

metabolic work.


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Others

Nicotinamide adenine dinucleotide (NAD)

Flavine adenine dinucleotide (FAD)

NAD and FAD can carry high-energy electrons

Cell Metabolism - Lecture 1 - Bio Molecules

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