Unit 2 – Water’s PropertiesCh2, Sect.3 (2-3) pp39-42

1. Water is POLAR2. Water has SOLUBILTY

3. Water is a great SOLVENT

What is true for MOST substances:

States of Matter

*Solids take up the least amount of space, but have a lot of stored energy*Liquids take up a medium amount of space, and have a little less stored energy because they are moving around*Gases take up the most amount of space, but have the least stored energy because they are moving the most

EXCEPT in water!

Not like this: Like this:

It’s because water is “POLAR”

Gas – no problems – molecules can move

Liquid – no problems – molecules can move

Solid – PROBLEM – can’t moveThe molecules lock into specific arrangement so the

positive end of one water molecule is next to the negative end of the next water molecule – and so on – with HYDROGEN BONDS!

This arrangement takes up more space, causing ICE to be LESS DENSE than liquid water – and why ice floats on liquid water

This is UNIQUE – the solid form of water is less dense than the liquid form. See Fig2-12 p42!

Water’s polarity causes issues - good and bad

Polarity – having oppositely charged “ends”2-3 pp39-40

*Remember, water is covalently bonded – sharing electrons?*BUT, the oxygen “borrows” the 2 hydrogens’ electrons more often, and with more force than each hydrogen atom can borrow an electron from oxygen*Therefore, while the charge of the whole water molecule is neutral, the oxygen end is a little negative – because it is holding the extra electrons from each hydrogen*And the hydrogen end is a little positive because the single electrons of the 2 hydrogen atoms have been held a bit too long by the oxygen atom, and hydrogen atoms are not strong enough to “pull” them back

http://ed.ted.com/lessons/how-polarity-makes-water-behave-strangely-christina-kleinberg

http://www.youtube.com/watch?v=moITG5Q7zzI hydrogen bonding

So, what are these “hydrogen bonds” and why are they so important? They are: *weak, temporary bonds*forming between a negative and positive area*between molecules*not causing changes to molecules*EVERYWHERE!

Molecular arrangements of water as a: SOLID LIQUID GAS

It dissolves all other polar and ionic substances . . . But not oils/lipids because they are covalent and not polar

Water inside and between our cells dissolves minerals, electrolytes and other ionic compounds into individual, charged atoms that we need for VITAL functioning

The good part . . . Water is the universal solvent

http://www.youtube.com/watch?v=ek6CVVJk4OQ

Very important to living organisms:

Properties of water due to polarity and hydrogen bonding

1. Cohesion *Water clings to itself and beads up *It acts as its own best friend *It is drawn up a plant stem from roots to leaveshttp://www.youtube.com/watch?v=tv4Jrc06yLA

Very important to living organisms:

Properties of water due to polarity and hydrogen bonding

2. Adhesion *Liquid water is drawn to solid surfaces *Also helps draw water up tiny tubes in plant stems because the liquid water is attracted to the solid surfaces in the plant’s stem tubes

Very important to living organisms:

Properties of water due to polarity and hydrogen bonding

3. Temperature Moderation*It takes a lot of heat energy to raise the temperature of water – to break hydrogen bonds. *As water absorbs heat energy from the environment, the air in the environment cools*But, it takes time for water to release this heat energy and reform the broken hydrogen bonds*As it slowly cools, water releases its heat energy into the air, warming the air – sea and land breezes in Earth Science ??!!

Very important to living organisms:

Properties of water due to polarity and hydrogen bonding

4. Density of Ice*Go back to slide 43 – solid ice is less dense than liquid water*Ice floats*Bodies of water freeze from the top down in winter – instead of the bottom up!*The covering of ice on top the water forms an insulator against really cold air – protecting the organisms in the water below*This is why regions with winter do not have complete kills in bodies of water

Very important to living organisms:

Properties of water due to polarity and hydrogen bonding

5. Water is an important solvent*Compounds dissolve in it – go back to slide 44*A solute is dissolved in a solvent *Salt is the solute in salt-water*A solvent is the substance in which the solute is dissolved *Water is the solvent in salt-water*Living organisms are “water-based” *Many compounds have to be dissolved in our watery

cell contents to be used in vital reactions!

Unit 2 – Molecules of Life3-2 pp55-60

4 classes of organic compounds essential to, and part of, all living things – YOU, trees, bugs, etc.

Carbon Bonding - pp51-2#6 on periodic table – 6 electrons, p & n

3-1 pp51-54

Monomers & Polymers & WaterMono – “one” so a monomer is one unit of a

molecule

Poly – “many” so a polymer is many monomers joined to form a larger molecule

Carbohydrates, proteins, lipids (fats) and nucleic acids (DNA) are all polymers made of many monomers joined together.

3-1 pp51-54

Monomers & Polymers & WaterCondensation Reactions

Water is formed when monomers combine to form polymers

Usually 1 H from one monomer and 1 OH from the other are released from the monomers and they bond to form a water molecule

3-1 pp51-54

Monomers & Polymers & WaterHydrolysis Reactions

Water is used when bonds in polymers break to form monomers

A water molecule is broken down into 1 H and 1 OH, and each join with a monomer leaving the polymer

This is why we need water to break down our food!

3-1 pp51-54

Monomers, Polymers, Water & ENERGY!ATP – Adenosine Triphosphate

Ribose, a 5-carbon ring sugarAdenine, a nitrogen-containing compound3 Phosphate groups PO4

-

When a phosphate group’s bond is broken, energy is released for cell metabolism – very important

3-1 pp51-54

3.2 pp55-60Molecules of Life

Define: *Organic compound*Composed of C, H, O*Ratio: 1C : 2H : 1Oxygen Functions:*Source of energy – food EX. Bread we eat*Building structures for plants Ex. Bread we eat is made of wheat seeds built as part of a wheat plant – too much and we build fat deposits

Class 1: CARBOHYDRATES 3-2 pp55-60

Construction of Carbohydrates

Simplest form – MonosaccharidesMONO = one Saccharide = sugar

One ring of carbon atoms to form a “simple sugar”This is the “monomer” form – single unit

GlucoseThe “classic” monosaccharideThe preferred food of living cellsOne carbon ringChemical formula: C6H12O6

“Golden ratio” 1 C : 2 H : 1 0xygenCan be written as: (CH20)any # from 2-8

Other monosaccharides . . . .

galactoseCount the C, the H, and the O.What are the ratios, what are the chemical formulas?

YES! They all are C6H12O6

What’s up with that?????Well, take a closer look.The patterns of bonds and atoms are different, so they are different compounds.Molecules with the sameratios and numbers of atoms are called ISOMERS

Carbohydrates with only 2 carbon rings are called DISACCHARIDES “di” means 2

Fructose combines with glucose and one water molecule is released from the 2 monosaccharides

SUCROSE

POLYSACCHARIDES – poly means “many”“Polymer” – means the form with “many”

STARCH*Made or more than 2 glucose monosaccharides

*Plants make it

*Highly branched chains or long, coiled, unbranched chains – like springs

POLYSACCHARIDES can be very complex

CELLULOSE*A very complex polysaccharide*Made by plants*It makes trees hard and very very chewy *Makes plant cells strong and rigid/firm/tough*Humans can’t digest it!*We call it “fiber” - it helps us have regular BM’s!*1,000’s of glucose monomers linked in straight chains

Another important polysaccharide:GLYCOGEN

*Made of 100’s of glucose monosaccharides*Strung together in a highly branched chain*Glucose from your food is assembled into glycogen molecules for short-term storage in your liver*When you’re hungry after school, but don’t have time for a snack before practice, have you noticed you lose the hunger for an hour or so?*The glycogen stored in your liver as “leftovers” from lunch is released and broken down for use as glucose*It is your “liver-snax!” Also called “animal starch.”

You get REALLY HUNGRY – and have to eat to replenish your glucose needs

and glycogen storage depletion

When the glycogen is gone . . . .

KNOW THEM!!!!

3 important forms of polysaccharides

From previous slides:Glycogen – Starch - Cellulose

Know:1.Their source 2.What is their purpose or use3.What is their structure

Define: *Organic compound*Composed of C, H, O & N*Made of many monomers joined in long chains*Made by plants and animals*2 types: *Structural – building things like skin, hair, muscle, etc.

*Functional – reactions important to metabolism

Class 2: PROTEINS

Monomers of Proteins – Single Units Amino Acids

*There are 20 AA’s*Each contains a central C*The central C has 4 single bonds*The 4 bonds are:

(1) A single H (2) Carboxyl group

(3) Amino group(4) R –group

*The R-group is different among the 20 AA’s*SEE p56, figure 3.7!

DIPEPTIDES – 2 bonded amino acids (monomer units)

Just like DISACCHARIDES were 2 bonded simple sugars (monomer units)

*Peptide bonds join AA’s*p57, fig. 3-8*Peptide bonds are Condensation Reactions*A water molecule is produced by the bond

Polymer units – Polypeptides – chains of many AA’sMany polypeptides joined = a protein molecule

Protein shape:*Many are polypeptides that are bent and folded back on themselves*Due to H-bonds along the polypeptide strand*Proteins are sensitive to heat – cooking egg white

Functional Proteins = ENZYMES*Functional proteins acts as catalysts (helpers) in chemical reactions in cells*See p57, figure 3-9*The enzyme acts on the substrate *The substrate is the substance that needs the help of the enzyme*The enzyme and substrate are specifically shaped to “fit” each other*Substrates and enzymes are “specific” for each other*When they link together, chemical bonds in the substrate are weakened*The weakening reduces energy required to start a reaction*When the reaction is over, the enzyme releases the substrate*The enzyme remains unchanged – and can work many times!They are very sensitive to heat and the pH of the environment

Proteins as EnzymesThe enzyme weakens bonds in the substrate

This allows the chemical reactions in the substrate

Class 3: Lipids pp59-601. Large organic compounds2. C-H-O, but far more C & H than O3. Many C-H bonds *More than any other organic compound *This means HIGH STORED ENERGY LEVEL *High calories – used by enzymes in their work as catalysts4. Monomer units are chains of C & H – hydrocarbon chains

5 kinds/types of lipids1. Fatty acids – most common group – in our diet

2. Triglycerides – fats in our blood & storage

3. Phospholipids – found in all cell membranes

4. Waxes – protective coatings in plants & animals

5. Steroids – hormones & cholesterol (good kind)

Fatty AcidsSee Fig3-10 p591. COOH: “carboxyl group” at one end2. Long carbon chain follows: “hydrocarbon”3. Saturated: *All carbon bonds are single – very stable4. Unsaturated: *One or more carbon is double-bonded – not as stable – this is actually good for us!

Fatty Acids continuedSee Fig3-10 p591. COOH – carboxyl group is HYDROPHILIC – likes water *It is Polar (slightly charged) like water

2. Hydrocarbon chain end – HYDROPHOBIC – does NOT like water and is NONpolar 3. This is why fatty acids are not soluble in water – don’t dissolve in water

Triglycerides*3 (TRI-) fatty acids

*Each still has a carboxyl “head”

*Each still has a hydrocarbon tail

*Joined by a molecule of GLYCEROL – which is actually an alcohol

Triglycerides continuedSaturated:*3 saturated fatty acids (all carbons have single bonds)*High melting point, and solid at room temp.

Unsaturated:*3 unsaturated fatty acids (1 or more carbons have double bonds)*Low melting point, liquid at room temp.

PhospholipidsSee Fig3-11 p591. 2 hydrocarbon tails *hydrophobic – oily

2. Glycerol head *hydrophilic – soluble in water

3. Phosphate with head *hydrophilic - soluble in water

Phospholipids continuedSee Fig3-10 p59

1. Phosphate and glycerol heads are green

2. Hydrocarbon tails are gray – positioned toward each other

Phospholipids continuedOily, fatty-acidhydrocarbontails (yellow) aresandwiched between the soluble heads.This forms a barrier betweencell interior andexterior.

Waxes*1 long fatty acid chain bonded to an alcohol head

*Waterproofing*Plants produce them to

reduce water evaporatingfrom leaves during daylight*Animals produce them to

keep skin and hair suppleto protect the skin against

environmental damage and pathogens

Steroids1. This is a “class” of chemicals – not the drugs

taken for athletic performance enhancement2. The do NOT have long hydrocarbon chains, but

all have 4 fused carbon rings bonded to other molecular groups attached

3. Sex hormones: testosterone, androgens, estrogen, and human hormones

4. Cholesterol – used to make bile to break down fats in the intestines, and to coat nerves to insulate them so they work better/faster

Energy is the ability to do work and comes in a variety of forms*While fried chicken has lots of energy stored in the hydrocarbon bonds of its lipids/fats, it can’t run (anymore!)

*But when we digest the lipids, carbohydrates and proteins in it, then start breaking those hydrocarbon bonds with our ENZYMES, WE transfer the chemical energy stored in the food to thermal (heat) and mechanical (moving) energy – AND WE RUN!

So what does all this have to do with YOU?

A CALORIE is a measurement of energy - the energy comes from the bonds between the atoms in the organic compounds we eat1 calorie is the energy needed to raise

the temperature of 1 gram of water 1oC

The more energy in the food – the peanut in the diagram – the longer it will burn, and the more the temperature of the water will raise

Calories on labels? – Actually they are kcals – 1,000 calories is a kilocalorie. So, that big apple that is 220 “calories”, is actually 220,000 “real” calories

Speaking of energy in food, what IS a CALORIE?

MetabolismThe term used to describe all the chemical reactions occurring in an organism while the organism is alive

*Activation energy – the energy required to START a metabolic reaction – usually pretty large!*ENZYMES reduce the activation energy, making

the reaction quicker, easier, more efficient – and profitable!

*ENZYMES speed metabolic reactions, make them require less energy to begin!

*Faster*Easier*Better*Can keep upwith ourneeds

See Figure 2-7 on p37

Class 4: Nucleic Acids1. Very large, complex organic compounds2. They store information

DNA contains information for organism characteristics – Genes/Chromosomes

RNA carries information from DNA for making protein and enzymes

Nucleic AcidsStructure of DNA and RNA is similar:*Monomer units are NUCLEOTIDES*Each contains 3 parts: *Nitrogen-base *Phosphate group *5-carbon sugar**More, much more on these later**

EXTRA SLIDES PULLED FROM 2012 show

Chapter 2-1 pp33 to 34Compounds

Define: Combinations of atoms whose combined characteristics are different from the characteristics of the individual atoms

So, what does THAT mean?A cake contains flour, sugar, eggs, butter, and a few

other thingsTogether, the ingredients taste great, but lose a lot of

their individual tastes – cake is a “compound”

The Rest of the Biochemistry Story!

Salt:Example – NaCl – is a compound we know as salt

*Na (sodium) is a highly reactive metal*Cl (chlorine) is a very toxic gasTogether they are a tasty mineral we need for life!

Another example of a compound

It’s all about the electrons! Atoms are mostcomfortable or“stable” when theoutermost energylevel is “full” of electrons

Compounds are Chemically Bonded

Giving/Taking Sharing/BorrowingIonic – “I OwN it”

Based on having a full outermost energy level

One atom “gives” the electron/s to the other to empty its outermost energy level

The other atom “takes” the electron/s to fill its

outermost energy level*Based on opposite charges

Covalent – let’s COoperateBased on having a full outermost

energy levelOne atom “shares” the electrons

that are “extra” in its outermost energy level

The other atom “borrows” these electrons to fill its outermost energy level

2 basic types of bonds

Ionic bonding of sodium with 11 electrons and chlorine with 17 electrons

Covalent bonding of 2 hydrogen (each with 1 electron) and oxygen with 8 electrons

While many organic and inorganic compounds have O & H, ORGANIC compounds are all bonded

according to the rules of CARBONCondensation Reactions

Form a water moleculeWhen monomers join to form

larger groups/polymers2 hydrogen atoms and 1

oxygen atom are removed from the monomers

They join (condense) to form 1 water molecule

Hydrolysis Reactions Use/require a water molecule When polymers break apart into

individual monomers 1 water molecule is split into 2

hydrogen atoms and 1 oxygen atom which occupy the bond sites on the monomers

This is why we have thirst – we need water to break apart the large organic compounds we eat for energy!

Carbon bonding and organic compounds in 3-1pp51-54

Energy is the ability to do work and comes in a variety of forms*While that fried chicken has lots of energy stored in its hydrocarbon bonds, it can’t run (anymore!)

*But when we digest the lipids, carbohydrates and proteins in it, then start breaking those hydrocarbon bonds with our ENZYMES, WE transfer the chemical energy stored in the food to thermal (heat) and mechanical (moving) energy – AND WE RUN!

2-2 p35 – Review of Energy and States of Matter