What is Life Made of?

Everything is made up of atoms.

Living organisms are made up of cells.

Cells are made up of atoms.

Lecture 2: Bio-moleculesLecture 2: Bio-molecules

Bio-moleculesBio-molecules

1- Structure of Water1- Structure of Water

2- Organic molecules2- Organic molecules الجزيئات العضويةالجزيئات العضوية

a- Carbohydrates a- Carbohydrates الكربوهيدراتالكربوهيدرات

b- Lipidsb- Lipids الدهونالدهون

c- Proteinsc- Proteins البروتيناتالبروتينات

d- Nucleic acidsd- Nucleic acids األحماض النوويةاألحماض النووية

Life exists on Earth because of the abundant Life exists on Earth because of the abundant

liquid waterliquid water..

Water has been referred to as the Water has been referred to as the universal universal

solventsolvent..

Aqueous solutions:Aqueous solutions: are solutions that have are solutions that have

materials dissolved in water.materials dissolved in water.

So, it has slightly So, it has slightly positivepositive and a slightly and a slightly

negativenegative sides sides..

II- Water- Water

Hydrophilic Hydrophilic محب للماءمحب للماء (Glucose)(Glucose):: Is any substance that has an affinity for waterIs any substance that has an affinity for waterتحب الماءتحب الماء ..

Hydrophobic Hydrophobic كاره للماءكاره للماء (Lipid)(Lipid):: Is the substances that have no affinity for water ال تحب الماءال تحب الماء .

Because they have non-ionic and non-polar covalent bonds.– Thus, water molecules cannot form hydrogen bonds with these

molecules.

AmphipathicAmphipathic كاره ومحب للماءكاره ومحب للماء (Phospholipid)(Phospholipid):: Has end with affinity for water and the other end with no affinity Has end with affinity for water and the other end with no affinity

for waterfor water

The Hydrophobic molecules are the major ingredients of cell membranes.

Types of solutions:Types of solutions:

Organisms are sensitive to changes in pHOrganisms are sensitive to changes in pH

The acid:The acid: Is a substance that increasesincreases the hydrogen ion (H+)

concentration in a solution.

When hydrochloric acid is added to water, hydrogen ions

dissociate تنفصل from chloride ions: HCl H+ + Cl-

Addition of an acid makes a solution more acidic.Addition of an acid makes a solution more acidic.

The base:The base: Is any substance that reducesreduces the hydrogen ion

concentration in a solution. Some bases reduce H+ directly by accepting hydrogen

ions. Other bases reduce H+ indirectly by releasing OH-

that combines with H+ to form water.

NaOH → Na+ + OH- OH- + H+ → H2O

Solutions with more OHOH-- than HH++ are basic solutions.

2. Bio-molecules

1. Carbohydrates2. Lipids3. Proteins4. Nucleic Acids

4 main molecules 4 main molecules involved in lifeinvolved in life

(Carbohydrates, Lipids, Proteins and nucleic acids)

Monomer Dimer Polymer

PolymerPolymer is a long molecule consists of a chain of is a long molecule consists of a chain of similar building molecules (similar building molecules (monomersmonomers) ) covalently bounded together.covalently bounded together.

Polymer can be broken down Polymer can be broken down إلى Gسـًـر إلى يُـك Gسـًـر to its to its يُـكmonomers by hydrolysis (adding Hmonomers by hydrolysis (adding H22O).O).

PolymerPolymer can be can be built upbuilt up ىGىيُـبْـنG by linking its by linking its يُـبْـنmonomersmonomers by dehydration (removing H by dehydration (removing H22O).O).

أحادى

ثنائى عديد

Monomers:

PolymerCarbohydrates

Lipids

Proteins

Nucleic acids

MonomerMonosaccharides (single

sugar)

Fatty acid and glycerol

Amino acids

Nucleotides

Carbohydrates

Made of: carbon, hydrogen, and oxygen atoms

Job: provide for living organisms an energy

Examples: sugars and starches (corn, rice, potato, bread)

Consisted of few hundreds to few thousands of monosaccharides.

They are two types:They are two types:

1- Storage:1- Storage: تخزينيةتخزينية

Provide sugarProvide sugar for cell by hydrolysis for cell by hydrolysis ماء ماء إضافة . .إضافة

as Starch ( (in plants) ) النشاالنشا and Glycogen (in animals) ينينججالجليكوالجليكو

2- Structural: 2- Structural: تركيبية

Serve as Serve as building materialsbuilding materials for the organism. for the organism.

as as Cellulose in Cellulose in plants (cell wall) and plants (cell wall) and Chitin Chitin الكيتين in the in the cuticle يدG ـل Sالج of insects

PolysaccharidesPolysaccharides العديد السكر

Lipids

Made of: long chains of carbon and hydrogen atoms (with some oxygen).

Job: store energy.

Examples: fats and oils (butter, olive oil)

• There is no double bonds between the carbons. All There is no double bonds between the carbons. All C C are are linked with linked with HH. .

• Thus, it is saturated with H. Thus, it is saturated with H.

• Most animal fats are saturated. Most animal fats are saturated.

• They are solid at room temperature.They are solid at room temperature.

• Saturated fats-rich diet results in Saturated fats-rich diet results in AtherosclerosisAtherosclerosis تصلبينياالشر . .

• These double bonds are formed by the removal of H atoms.These double bonds are formed by the removal of H atoms.

• Most vegetable fats (oils)Most vegetable fats (oils) and and fish fatsfish fats are unsaturated. are unsaturated.

• They are liquid at room temperature.They are liquid at room temperature.

• They can be synthetically converted to saturated (solid) by They can be synthetically converted to saturated (solid) by adding adding HH ( (Hydrogenation چَـة GرVدGچَـةالَه GرVدGالَه ) () (dehydrogenation الَهيدروجين . .(( نزع

B) Unsaturated FatsB) Unsaturated Fats مشبعة الغير لدهونلدهونا

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Phospholipids have two fatty acids attached to glycerol and a phosphate group at the third position.

The phosphate group carries a negative charge.

Phospholipids

• The fatty acid tails are hydrophobic, but the phosphate group and its attachments form a hydrophilic head.

• Thus, it is amphipathic

ProteinsMade of: Nitrogen, Carbon, Hydrogen, and other

atoms

Job: Many different jobs in our bodies include structural support, storage, transport of other substances, intercellular signaling اإلشـــارات بين.movement, and defense against microbes ,الخلوية

Examples: enzymes, muscles

Nucleic Acids

• Made of: Phosphorous, Carbon, Nitrogen, Oxygen, and Hydrogen atoms

• Job: Store genetic information

• Examples: DNA, RNA