Unit 2 Study Guide: Biochemistry

Ionic Bond 

Formed when atoms transfer electrons then stick together because they have opposite charges 

Is the ionic bond strong or weak?

Weak

What is the ionic bond broken by?

Water

What types of elements bond together in ionic bond?

Non-metal : metal

Example of molecule with ionic bond

NaCI (sodium chloride)

Covalent Bond

Formed when atom share electrons

Is the covalent bond strong or weak?

Strong

What types of elements can the covalent bond work in?

non-metal : non-metal

All of the major ____ __________ are covalently bonded

Cell molecules

Examples of cell molecules which are covalently bonded

Fats, proteins, lipids, sugars/carbs, nucleic acid

What do structural diagrams do?

Structural diagrams depict a covalent bond with a line and show the number and placement of bonds in a molecule

What do chemical formulas show?

Chemical formulas only show the atoms needed for that molecule 

How many electrons does the “-” represent?

2 electrons

What kind of bond is “H-H”? How many electrons?

It is a single bond and it has 2 electrons

What kind of bond is “O=O”? How many electrons?

It is a double bond with 4 electrons 

What kind of bond is “ N with 3 lines on the top and then an N ”? How many electrons?

It is a triple bond and it has 6 electrons 

What are the two types of covalent bonds?

Non-polar and polar

Non-polar covalent

Equal sharing of electrons and only occurs between 2 of the SAME atoms

Examples of non-polar covalent bonds

O2 = oxygen, H2 = Hydrogen, N2 = Nitrogen

Polar covalent

Unequal sharing of electrons where one atom will hog the electrons

Example of polar covalent

H20 = WATER IS POLAR!!!

Hydrogen Bond

Bond between partial + hydrogen and partial Fluorine, Oxygen, or Nitrogen.

Examples of Hydrogen bond

1. In water the +H’s attract the -O’s 

2. In DNA & proteins the + H’s attract the -N’s 

What is the most electronegative element in the periodic table?

Fluorine

Electronegativity

Reactive and electron hogging in a covalent bond

Are atoms closer to Fluorine have more or less electronegativity?

More

Water has unique properties that make it imperative for life mostly due to what?

Hydrogen bonding between H20 molecules

What are the seven properties of water?

1. Cohesion

2. Adhesion

3. High specific heat

4. High heat of Vaporization

5. Evaporative cooling

6. Water expands when it freezes

7. Universal solvent

Cohesion

• When water sticks to water

• allows surface tension

• allows for transport of water (goes up stems) against gravity 

Adhesion

• When water sticks to surfaces

• Allows for water transportation up a plant (molecules stick to the sides of the xylem)

Cohesion and adhesion allow for what?

Capillary action

High specific heat

• The amount of heat that must be lost or gained for 1 gram of that substance to change the temperature by 1 degree celsius

Water _____ changing its temperature.

Resists

What is the affect of water resisting to change its temperature?

• Stabilizes ocean temperatures for marine life 

• Since organisms are mostly made out of water they resist changes in body temp- homeostasis 

• Coastal regions have milder climate than inland 

What happens when water does change its temperature?

It absorbs or loses a LARGE quantity of heat.

High heat of Vaporization

• Helps moderate Earth temperature

• Aquatic environments don’t evaporate

Evaporative cooling

When water evaporates, the surface it was on cools

Ex. Sweating 

Water expands when it freezes

• Ice floats keeping the aquatic environments insulated for marine life.

Universal solvent 

• Water can dissolve A LOT of things because ti is polar 

Solvent

The substance which is in greater value

Ex. water 

Solute

Whats being dissolved

Ex. salt 

Solution

The mixture of the solute and the solvent

Ex. water + salt = salt water

What is the one group of biomolecules that don’t mix with water?

Lipids (fast and oils)

Hydrophilic

Water loving

• Polar 

• Dissolves in water 

• Ex. salt, amino acids, sugars 

Hydrophobic

Water fearing molecules

• Non polar 

• don not dissolve in water 

• Ex. fats and oil (lipids)

Amphiphilic

Both hydrophobic and hydrophilic 

• Ex. phospholipids 

Carbon skeletons

Way of representing carbon based molecules in shorthand diagram 

Carbon

CO2

• Forms four bonds 

• Lots of possibilities for bonding 

Organic and inorganic molecule 

Organic: Molecules which contain BOTH carbon AND hydrogen (usually also oxygen)

Inorganic: Molecules which do not contain carbon AND hydrogen

Examples of inorganic molecules

Ex.:

• H2O

• NaCI

• CO2

• O2

• NH3

• O3

What are the four biomolecule groups?

• Carbohydrates: AKA polysaccharides

• Proteins: AKA Polypeptides  

• Nucleic Acids 

• Lipids 

What are the monomers for the four biomolecule groups?

• Carbohydrate monomer: Monosaccharides

• Protein monomer: amino acids 

• nucleic acids monomer: Nucleotides

• Lipids monomer: Glycerol and fatty acids 

Polymer

large molecule and up of repeating single molecules

Monomer

Small molecule (building blocks of polymers) different for each type of biomolecule 

Five functional groups 

• Hydroxyl 

• Carboxyl

• Amino 

• Methyl 

• Phosphate 

Hydroxyl group

OH or HO

Carboxyl

COOH

Phosphate

PO3 or PO4

Amino

NH3

Methyl

CH3

What is “R”?

It is a variable like in math that shows that the functional group is attached to another molecule 

Synthesis

building a larger molecule

• reactant + reactant = product 

In cells, synthesis reaction is called ___________ ______________.

Dehydration synthesis

Dehydration synthesis

Monosaccharide + Monosaccaride = Disaccaride + H2O

or

Sugar + sugar = Sugar-sugar + H2O 

Polysaccaride

A polysaccharide is when there is more than three or more sugars 

Degradation

breaking down of a large molecule

Hydrolysis

the cells way of degrading the molecules

• one water molecule is added to a disaccharide to get two monosacchrides 

Carbohydrates function

 

provide short term energy in all organisms

• * some structural support 

Monomers are the same thing as ___________.

polymers are the same things as ____________. Monomers are _______ sugars.

Polymers are ______ carbs. 

All saccrides end in ___.

• Monosaccrides 

• polysaccharides 

• simple 

• complex 

• -ose 

The dehydration of two sugar molecules ( disacchride maltose)

The removal of water is ALWAYS a reaction between two hydroxyl groups when sugars bond together

The covalent bond between 2 sugars is called a __________________ _______. 

Glycosidic bond (there is always an oxygen)

Disaccharides

• maltose

• Sucrose

• Galactose

Maltose ( forms during digestion of carbs )

glucose + glucose = maltose

Sucrose

Glucose+fructose = sucrose

Lactose

Glucose + galactose =lactose

The four polysacchrides

• Cellulose

• Chitin

• Starch

• Glycogen

Cellulose

• Structural material found in plants

• long thin strands of glucoses bonded in parallel = very strong fibers

Chitin

• Found in fungi and in exoskeletons of arthropods

• long thin strands of glucose subunits with a nitrogen containing group

Glycogen

• Energy storage in animals

• highly branched = can be compacted into small places 

Starch (amylum)

• Energy storage in plants

• highly branched = can twist and pack into small bundles 

Carbs in human body

Eat a bagel — broken down by hydrolysis by intestines —- blood sugar rises —- pancreas releases insulin —- cells absorb sugar —— any remaining sugar is bonded through dehydration synthesis and is stored in the liver as a short term energy reserve—- blood sugar lowers

Lipids are overall_______ and ____________

Non polar and hydrophobic

Three sub types of lipids

1. Triglycerides job - stores long term energy 

2. phospholipids job - make up cell membrane 

3. steroid - hormones (ex. cholesterol, estrogen, testosterone)

Lipids vs. Carbs 

Grams per gram lipids contain twice the amount of energy as a carbohydrate!

Ex. 

4 calories per gram form carbs 

4 calories per gram form protein 

9 calories per gram form lipids !

Calories 

The amount of energy the body can get from a food source !!

Glycerol+fatty acids =

Triglycerides

Saturated fats

• All single C—C bonds 

• saturated means full with hydrogen 

• comes from animals

• solid at room temp.

Unsaturated fats

• Double C=C bonds 

• Comes from plants 

• liquid at room temp.

• Less Hydrogen possible 

Phospholipids

• Similar to triglyceride but only 2 fatty acid tails PLUS a phosphate group attached to glycerol

• AMPHIPHILIC

Phospholipd bilayer is

Cell membrane

Steroids

A lipid containing a four fused ring structure

Ex.cholesterol - needed in cell membranes 

Ex. Hormones (communication and signaling the body)

estrogen and testosterone 

Monomer of Nucleic Acids (Polymer)

Nucleotides 

Nucleic acids are _____________ material.

Hereditary

Mutation

Change in genetic material

Mutations change what?

Protein

The sequence of nucleotides is like what?

A sentence to direct proper building of proteins

The bonds between nucleotides

Phosphodiester bond

Purines have a ___ ringed nitrogenous base

two

Pyrimidines have a ____ ringed nitrogenous base.

one

The bonds that link the nitrogenous bases are

hydrogen bonds