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Why Study Chemistry in Biology?

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Presentation on theme: "Why Study Chemistry in Biology?"— Presentation transcript:

1 Why Study Chemistry in Biology?

2 I. The Atom A. Definition: smallest particle of an element
BOTH FOR LIVING AND NON LIVING A. Definition: smallest particle of an element

3 B. Composition Proton +1 1 Nucleus Neutron Electron -1
Subatomic Particle Charge Mass Location Proton +1 1 Nucleus Neutron Electron -1 1/1840 the mass of a proton Orbiting nucleus

4 outermost electrons participate in BONDING
Location of Electrons outermost electrons participate in BONDING

5 II. Elements A. Definition: substance that cannot be broken
down into other substances B. Biologically important elements i. Major: C H O N P S (Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, Sulfur)

6 Radioactive Isotopes Thyroid- Uses Iodine- If use an isotope they can trace how much iodine is picked up Reactor Radioisotopes (half-life indicated) Iodine-125 (60 d): Used in cancer brachytherapy (prostate and brain), also diagnostically to evaluate the filtration rate of kidneys and to diagnose deep vein thrombosis in the leg. It is also widely used in radioimmuno-assays to show the presence of hormones in tiny quantities. Iodine-131 (8 d)*: Widely used in treating thyroid cancer and in imaging the thyroid; also in diagnosis of abnormal liver function, renal (kidney) blood flow and urinary tract obstruction. A strong gamma emitter, but used for beta therapy. Radioisotopes can be manufactured in several ways. The most common is by neutron activation in a nuclear reactor- add or remove neutrons nucleus of a radioisotope usually becomes stable by emitting

7 Radioactive bairum- white drink- xrays examine stomach esophagous

8 Bohr Atomic Model

9 Atoms Space

10 Why if atoms have so much space can we be solid?
DO NOW Why if atoms have so much space can we be solid?



13 III. Chemical Compounds
A. Compound definition: a substance containing two or more elements in a fixed ratio Ex: H2O, NaCl, CO2

14 B. Bonds: complete share exchange
Atoms want to fill their outer energy levels to be To do this, they will meet up with other atoms and either or electrons complete share exchange

15 C o v a l e n t B o n d : s h a ri n g I s c a r I n g
Atoms share electrons

16 Examples of covalent molecules

17 ii. Ionic Bonds: gimme’ that electron!
Atoms transfer electrons, becoming (+) or (-) charged The attraction brings them together Ex: Na+ and Cl- = NaCl!

18 JOKE- Don’t Have to write this.
A NEUTRON walks into a diner and sits down to order a meal. When the waitress brings the food over the neutron says “Can you bring the check? I am in a hurry!” The waitress replies, “Don’t worry about it, there is NO CHARGE for you.”

19 JOKE- Don’t have to write this.
Two atoms walk down the street and collide. One atom says to the other, “Are you okay?” The second atom replies, “I think I lost an electron.” The first atom says, “Are you sure?” The second one says, “Yeah, I’m POSITIVE!”


21 iii. Molecules definition: two or more atoms held together by COVALENT bonds



24 Questions to think about
Why do put salt on the roads? Why do we add salt to a pot of pasta water? At a higher altitude why must we cook “boil” something longer?

25 Human Composition: Cells are 70–90% water

26 B. Plant Composition As much as 95% plants can be made of water

27 C. Formula: H2O

28 D. Bonds: i. Hydrogen bonds: Hydrogens from one water molecule are
ATTRACTED to the oxygen of ANOTHER water molecule: they develop a weak bond

29 i. Cohesion 1. Definition: Water “sticks” to each other Ex.: Surface tension 1-inch paperclip over-filled water 3oz Dixie cup Where did we see this is the lab?

30 Jesus Christ Lizard

31 ii. Adhesion 1. Definition: Water molecules attracted to other molecules. 2. Ex. In trees/plants water goes against gravity Called capillary action


33 Water is the a Universal Solvent
Water is able to dissolve other Polar & ionic compounds when mixed by causing the ions to break away and surround them. Water dissolves Salt (Na+Cl-) DOES THIS BC CHARE Know that water is your solvent and salt is your solute

34 iii. Temperature and Water
Boiling Point: 100 oC / 212 oF When you heat molecules move faster When you cool molecules move slower Water takes more energy to heat because energy must break hydrogen bonds

35 Does water boil faster if you add salt to it?
Water Boils when it has enough energy for the molecules to leave

36 Freezing Point 0 oC or 32 oF What would happen if our oceans did not have salt in them? Why do we put salt on our roads? Why at effect does salt have on FREEZING POINT?

37 Why is this important for life?
Water Boiling Point Ethanol Boiling Point

38 Why are higher altitude must we cook “boil” something longer?
Because of the lower atmospheric pressure, water boils at a lower temperature. Boil at 95 degrees not at 100- boil for longer than to get to t

39 Why do we need salt in our ice, when making ice cream? Watch Video

40 LOW DENSITY OF ICE Density- amount of matter in a volume
In most substances the solid state is more dense than the liquid state Water is the opposite ICE IS LESS DENSE THAN WATER and will FLOAT

41 LOW DENSITY OF ICE WHY? Hydrogen bonds in ice (solid) keep molecules spaced out

Ice insulates the liquid water below allowing life to persist

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