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Chemistry in Biology.

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Presentation on theme: "Chemistry in Biology."— Presentation transcript:

1 Chemistry in Biology

2 Elements in the Human Body (CHON 96%)

3 We’ve got chemistry…(which is the study of matter)
The atom is the basic unit of matter. (building block of matter) Atoms consist of subatomic particles Protons (+ charge) Neutrons ( no charge) Electrons (- charge)

4 Protons & neutrons are found in the nucleus.
Electrons orbit the nucleus. Protons & neutrons have about the same mass, and electrons are much less (1/1840 the mass of p & n)

5 Using the Periodic Table to calculate:
Protons = atomic number Electrons = atomic number (neutral atom, not in an ion) Remember Protons are positive and Electrons are negative so they are equal! Neutrons = atomic MASS – atomic number



8 ELEMENT: pure substance, consisting of only 1 type of atom.
COMPOUND: substance formed from the chemical combination of 2 or more elements in definite proportions.

9 Examples of Compounds:
H2O - water contains H and O in a definite proportion (2 to 1) This is the formula for water. What is the formula for table salt?

10 Isotopes atoms of the same element with different numbers of neutrons
Brainpop video: /164155/ html

11 Isotopes of Carbon Carbon Carbon Carbon-14

12 Radioactive Isotopes When a nucleus breaks apart, it gives off radiation that can be detected and used for many applications.

13 Chemical Bonds Involve valence (outermost) electrons.
There are 2 types.

14 1) Ionic Bonds Involves a transfer of electrons.
Produces ions (charged atoms that have gained or lost electrons) Metal + Nonmetal


16 2) Covalent Bonds Electrons are shared between atoms.
Smallest unit of this type of compound is called a molecule. Nonmetal + Nonmetal or diatomic molecules have this type of bond.

17 Chemical Reactions Chemical reaction - process by which atoms or groups of atoms in substances are reorganized into different substances. Clues that a chemical reaction has taken place: 1) heat or light 2) see bubbles 3) something new

18 Chemical Equations Chemical formulas describe the substances in the reaction and arrows indicate the process of change. Reactants are the starting substances, on the left side of the arrow. Products are the substances formed during the reaction, on the right side of the arrow.

19 Glucose and oxygen react to form carbon dioxide and water.

20 Energy of Reactions The activation energy is the minimum amount of energy needed for reactants to form products in a chemical reaction.

21 What is an enzyme? An enzyme is a special type of protein called a catalyst Catalyst: substance that speeds up a reaction because it lowers the activation energy Cells use enzymes to speed up reactions Very specific: usually only catalyzes one item called the SUBSTRATE


23 How do enzymes work? Enzyme comes in contact with substrate at certain spot called ACTIVE SITE Fits together like a “lock & key” Bonding at active site weakens the bonds in the substrate Makes it easier to change substrate



26 What are enzymes used for? What regulates them?
Used for digestion, photosynthesis, & DNA reproduction Regulated by changes in pH, temperature, other proteins, and chemicals

27 Enzyme Lab!

28 Warm up - Make a Venn Diagram for Ionic and Covalent Bonds.
Copy the following: 1) What is this called? Label the reactant(s) and the product(s) H2O2  2H2O + O2

29 Water is soooo special! Most abundant compound in living things.
Liquid at temperatures found over much of earth. Expands when freezes, which causes density less than liquid water. (unusual for a liquid)

30 What is polarity??? Polarity is the uneven distribution of electrons between atoms in a covalent bond. In water, the oxygen is slightly negative because the electrons are attracted more to it than Hydrogen.

31 The hydrogen atoms in water have a slight positive charge because they are missing the electrons attracted more to oxygen.

32 Because of polarity, the water molecules attract each other
Because of polarity, the water molecules attract each other. This is called cohesion. Water is also attracted to molecules of different substances. This is called adhesion.

33 Example of adhesion: water on the sides of a graduated cylinder.
Capillary action is caused by this.

34 Water Lab!!!!

35 Warm up Enzymes p. 159 What is the function of an enzyme?
What type of organic compounds are enzymes? What substance takes part in an enzymatic reaction, but is unchanged by the reaction? Draw Figure 6.18 and label it. (p. 160)

36 Mixtures Two or more elements or compounds that are physically mixed together, but not chemically combined. They can be separated Physically!

37 Solutions vs. Suspensions
Can be made with water…the universal solvent. Solution = solvent + solute solution = homogeneous mixture

38 Universal solvent! Water can dissolve ionic compounds and other polar molecules…it is known as the greatest solvent on earth!

39 Suspension Water and non-dissolved material with small particles that are suspended in the water.

40 Acids & Bases pH scale: indicates the concentration of H+ ions in a solution. Below 7 = acid, the lower the number, the more acidic. Above 7 = Base, the higher the more basic




44 Buffers Weak acid/bases that can react with strong acids or bases to prevent sharp sudden changes in pH.

45 6 C carbon 12.011 Carbon Compounds

46 What is organic chemistry?
The study of all compounds containing the element CARBON Natural elements: make up 96% of the mass of a human: CARBON, HYDROGEN, OXYGEN, NITROGEN (CHON) Trace elements: only needed in small amounts, called “minerals”:

47 What is a macromolecule?
A giant molecule made up of 100’s or 1000’s of smaller units called MONOMERS Monomers link together to form large POLYMERS formed by polymerization

48 The types of macromolecules:

49 Carbohydrates Made of Carbon, Hydrogen & Oxygen atoms
Main source of energy for living things Plants & some animals use for structural purposes Examples: monosaccharide, disaccharide, polysaccharide (sugars & starches)

50 Simple sugars are monosaccharide.
Two monosaccharides join together to form a disaccharide Longer carbohydrate molecules are called polysaccharides (starches).

51 Figure 2-13 A Starch Section 2-3 Starch Glucose Go to Section:

52 Lipids (Fats, Oils & Waxes)
Made mostly from carbon & hydrogen Used to store energy & waterproof coverings Olive oil, peanut oil

53 A triglyceride is a fat if it is solid at room temperature and an oil if it is liquid at room temperature.

54 Nucleic Acids Made of hydrogen, oxygen, nitrogen, carbon, & phosphorus
Made of monomers called nucleotides Nucleotides consist of 1) a 5 carbon sugar 2) a phosphate group 3) a nitrogenous base Store and transmit genetic information.

55 Proteins Made of nitrogen, carbon, hydrogen, & oxygen
Polymers of amino acids Some control the rate of reactions and regulate cell processes Some used to form bones & muscles Others transport substances into or out of cells or help fight disease

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