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Biochemistry

The study of the chemistry of life.

Textbook Chapter 2

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Chemistry Review

• Atom – Basic unit of matter.• Subatomic particles of atoms:

– electrons – negatively charged particle in constant motion around the nucleus.

– protons – positively charged. (Equals atomic #)– neutrons – No charge.

• *Protons & Neutrons form the nucleus ofan atom.

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It’s elemental…

• Element – a pure substance that consists entirely of ONE type of atom and more than 100 known elements. There are only about 2 dozen found in living organisms.

• Compound – Substance formed by the chemical combination of 2 or more elements.

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Bonding

• Ionic Bonds -When electrons are transferred from one atom to another.– Involves a metal and a non-metal

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Bonding, cont.

• Covalent Bonding – between two or more non-metals. Electrons are SHARED. – Most of your compounds in biology are

covalently bonded!

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Covalent Bonding in Water

Oxygen shares its 6 electrons

Each hydrogen shares 1 electron

Oxygen now has 8 electrons around it all times!

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Properties of Water

• Water is the single most abundant compound in living things.

• Water has an unusually high boiling point and freezing point

• Water expands when frozen and is less dense as a solid

• Polarity – molecules in which the charges are unevenly distributed that attract like a magnet. This allows water molecules to easily attract other water molecules.

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States of water

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Adhesion andCohesion• Water is attracted to other water. This is

called cohesion. Water can also be attracted to other materials. This is called adhesion.

• The oxygen end of water has a negative charge and the hydrogen end has a positive charge. – The hydrogens of one water molecule are

attracted to the oxygen from other water molecules. This attractive force is what gives water its cohesive and adhesive properties.

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Surface Tension

• Surface tension is the name we give to the cohesion of water molecules at the surface of a body of water.– All the water molecules on the surface

of the bead are 'holding' each other together or creating surface tension.

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Capillary Action

• Capillary action is related to the adhesive properties of water.

• You can see capillary action 'in action' by placing a straw into a glass of water. The water 'climbs' up the straw.

• Plants use capillary action to pull water into themselves

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Solutions and Suspensions

• Mixture – Materials composed of 2 or more elements or compounds physically mixed together but not chemically. – Ex: salt and pepper: New substance

NOT formed.

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Solutions

• Types of mixtures made with water:1. Solutions – components are evenly distributed.

a. Solute – substance that is dissolved. b. Solvent – substance which does the

dissolving.

Watch this flash movie!

*Water is the universal solvent.

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Acids and Bases

• pH Scale – scale used to determine the concentration of Hydrogen+ ions in a solutions. Scale ranges from 0 – 14. 7 is an equal # of H ions (balance). Below 7= acidic/ Above 7= basic.

• Acid – high concentrations of H ions.• Base – low concentrations of H ions.

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More about pH

• Buffer – weak acid or base that can react with strong acids or bases to prevent sharp, sudden changes in the pH level.

*Maintaining pH is essential to maintaining homeostasis in living

things.

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Suspensions

• Suspension – Mixtures of water and no dissolved materials.– Blood is an example of a

suspension. Can you name these other examples?

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Carbon Compounds

The basis of biochemistry

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Organic Chemistry

– Is the study of compounds that contain carbon atoms.

Carbon can:

1. Bond with many different elements.

2. Forms millions of different, large complex structures.

*No other element comes close to the versatility of carbon which is why it is

found in living things.

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Molecule size

• Macromolecule – Giant molecules.

• Monomer – smaller molecules

• Polymer – many joined monomers.

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Saturated vs. Unsaturated

• Saturated Fats – solid form of fats. These fats do not break down easily. They can cause hardening of the arteries. Only found in animal products.

• Polyunsaturated Fats – liquid at room temperature. Ex: cooking oils, such as corn, sesame, olive oil. Found in plant products.

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Nucleic Acids

• Nucleic Acids – macromolecule - largest in the body. Forms and transmits the genetic code.

• Nucleotides – polymers assembled from individual monomers. – 3 parts:

• Sugars/ Phosphates/ Nitrogen Bases.

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Nucleotides

• 2 types of Nucleotides:– a. DNA – deoxyribonucleic acid. The

master copy of the information code.

– b. RNA – ribonucleic acid. Makes protein molecules.

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4 Groups of Organic Compoundsof Living Things

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Carbohydrates

Carbohydrates – main source of energy in living things. (starches/sugars)

– a. monosaccharides – single sugar molecules. Glucose, galactose (milk), fructose (fruits)

– b. polysaccharides – excess sugar stored in animals & plants.

• 1. glycogen – sugar stored as in animal tissues.

• 2. Cellulose – sugar stored in plant tissues. The tough, flexible fibers found in plants.

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Lipids

• Lipids – not soluble in water. Fats, oils, waxes. – Store energy, – make up membranes– coverings in living things– Steroids are lipids too.

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Proteins

• Proteins – polymer of molecules called amino acids. – Each protein has a specific job such as

cellular components and muscles and bones.

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Amino Acids

• Amino Acids – building blocks of proteins. More than 20 types found in nature.

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Chemical Reactions & Enzymes

*Everything that happens in an organism. Growth, interactions with

the environment, movement, etc. are based on chemical reactions.

• Chemical Reaction – process that changes 1 set of chemicals into another. Always involves change and cannont be undone.

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Chemical Reactions

• Energy exchanges – energy is released anytime chemical bonds form or break.

• Activation energy – energy needed to get a reaction started.

• Enzymes – proteins that speed up chemical reactions.

• Catalyst – substance that speeds up the rate of chemical reactions

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How do Enzymes Work?

1. Substrates – sites where reactions can be brought together. Bonds to the site on the enzyme which fits just right like a lock and key.

2. Regulation – cells that contain proteins that can turn “on” or “off” enzymes when needed.