Macromolecules of LifeMacromolecules of Life

Lecture 4Lecture 4

Cell CompositionCell Composition

Water - 70% Inorganic molecules Organic (carbon-containing) molecules

Interaction of water with the other constituents of the cell is paramount

Water - 70% Inorganic molecules Organic (carbon-containing) molecules

Interaction of water with the other constituents of the cell is paramount

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Uniqueness of WaterUniqueness of Water

Water - H2 & 0 Polar molecule - H

side is + Polar molecule - O

side is - Hydrogen bonding Density at 4°C is

key to life

Water - H2 & 0 Polar molecule - H

side is + Polar molecule - O

side is - Hydrogen bonding Density at 4°C is

key to life

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Inorganic MoleculesInorganic Molecules

Sodium Potassium Magnesium Calcium Phosphate Chloride Bicarbonate (HCO3-)

Sodium Potassium Magnesium Calcium Phosphate Chloride Bicarbonate (HCO3-)

Organic MoleculesOrganic Molecules

Most cellular organic molecules belong to the following classes Carbohydrates Lipids Proteins Nucleic Acids

Most cellular organic molecules belong to the following classes Carbohydrates Lipids Proteins Nucleic Acids

MacromoleculesMacromolecules

Proteins Nucleic Acids Carbohydrates

Generally exist as macromolecules and constitute 80 + % of the dry weight of the cell.

Proteins Nucleic Acids Carbohydrates

Generally exist as macromolecules and constitute 80 + % of the dry weight of the cell.

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Naming conventionsNaming conventions

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Animation of condensation reaction

CarbohydratesCarbohydrates

Simple sugars & polysaccarides Simple sugars are the cells preferred

nutrient source Polysaccarides used for storage and some

structure Cellular adhesion & intercellular transport

Simple sugars & polysaccarides Simple sugars are the cells preferred

nutrient source Polysaccarides used for storage and some

structure Cellular adhesion & intercellular transport

Carbohydrates cont…Carbohydrates cont…

Monosaccarides = simple sugar units Glycosidic bonds Oligosaccarides = short polymer Polysaccarides = 100’s to 1000’s Glycogen (animal) & Starch (plant) are storage

forms of carbohydrates, both made of glucose Cellulose (plant) structural role, also made of

glucose

Monosaccarides = simple sugar units Glycosidic bonds Oligosaccarides = short polymer Polysaccarides = 100’s to 1000’s Glycogen (animal) & Starch (plant) are storage

forms of carbohydrates, both made of glucose Cellulose (plant) structural role, also made of

glucose

LipidsLipidsHave 3 major roles in cellsEnergy storage -

as triacylglycerols (fats) which due to the hydrophobic nature of their tails form droplets within the cytoplasm.

Yield upon hydrolysis 2X the energy per unit weight compared to carbohydrates.

Cell membranes - Phospholipid form, which has just 2 fatty acids joined to a polar head

group Phospholipids are AMPHIPATHIC in nature. Key to membrane

formation. Cell signaling

Within cells and between cells as steroid hormones Chemical messenger molecules

Have 3 major roles in cellsEnergy storage -

as triacylglycerols (fats) which due to the hydrophobic nature of their tails form droplets within the cytoplasm.

Yield upon hydrolysis 2X the energy per unit weight compared to carbohydrates.

Cell membranes - Phospholipid form, which has just 2 fatty acids joined to a polar head

group Phospholipids are AMPHIPATHIC in nature. Key to membrane

formation. Cell signaling

Within cells and between cells as steroid hormones Chemical messenger molecules

Nucleic AcidsNucleic Acids

DNA & RNA Principle informational molecules of the

cell. DNA is normally the genetic material RNA can be the genetic material, however

more abundant as mRNA, rRNA, and tRNA. Other functions too.

DNA & RNA Principle informational molecules of the

cell. DNA is normally the genetic material RNA can be the genetic material, however

more abundant as mRNA, rRNA, and tRNA. Other functions too.

ProteinsProteins Most diverse of macromolecules Functional and structural roles Each cell contains several thousand AAs ENZYMES Polymers of 20 different amino acid sub-units. Peptide bonds Polypeptides - Linear molecules, sequence

specific, with 3D configurations

Most diverse of macromolecules Functional and structural roles Each cell contains several thousand AAs ENZYMES Polymers of 20 different amino acid sub-units. Peptide bonds Polypeptides - Linear molecules, sequence

specific, with 3D configurations

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