Presentation on theme: "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."— Presentation transcript:
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
What is true for MOST substances: States of Matter
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 move The 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://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 leaves http://www.youtube.com/wat ch?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 Life 3-2 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 & Water Mono – “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 & Water Condensation 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 & Water Hydrolysis 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 sugar Adenine, a nitrogen-containing compound 3 Phosphate groups PO 4 - 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 – Monosaccharides MONO = one Saccharide = sugar One ring of carbon atoms to form a “simple sugar” This is the “monomer” form – single unit Glucose The “classic” monosaccharide The preferred food of living cells One carbon ring Chemical formula: C 6 H 12 O 6 “Golden ratio” 1 C : 2 H : 1 0xygen Can be written as: (CH 2 0) any # from 2-8
Other monosaccharides.... galactose Count the C, the H, and the O. What are the ratios, what are the chemical formulas?
YES! They all are C 6 H 12 O 6 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 same ratios 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 use 3.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’s Many 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 Enzymes The enzyme weakens bonds in the substrate This allows the chemical reactions in the substrate
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 eat 1 calorie is the energy needed to raise the temperature of 1 gram of water 1 o C 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?
Metabolism The 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 up with our needs See Figure 2-7 on p37
Class 4: Nucleic Acids 1.Very large, complex organic compounds 2.They store information DNA contains information for organism characteristics – Genes/Chromosomes RNA carries information from DNA for making protein and enzymes
Nucleic Acids Structure 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 34 Compounds 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 things Together, 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 gas Together they are a tasty mineral we need for life! Another example of a compound
It’s all about the electrons! Atoms are most comfortable or “stable” when the outermost energy level is “full” of electrons Compounds are Chemically Bonded
Giving/TakingSharing/Borrowing Ionic – “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 COoperate Based on having a full outermost energy level One 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 CARBON Condensation Reactions Form a water molecule When monomers join to form larger groups/polymers 2 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