Unit 2 – Water’s Properties Ch2, Sect.3 (2-3) pp39-42 1. Water is POLAR 2. Water has SOLUBILTY 3. Water is a great SOLVENT
Dec 16, 2015
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!
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!
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.
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
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
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!
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**
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
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