biology chapter 2 the chemistry of life. 2.1 learning targets list the 3 subatomic particles that...

Biology

Chapter 2

The Chemistry of Life

2.1 Learning Targets

• List the 3 subatomic particles that make up atoms and list their charges

• Describe how isotopes of an element are similar

• Name 4 uses of radioactive isotopes• Distinguish between ionic & covalent

bonds

Section 2-1: Basic Chemistry

What is the basic unit of matter?

The Atom

What are the three subatomic particles?

1. Protons (p+) – (+) charge; weighs 1 amu

2. Neutrons (n0)– neutral charge (0); 1 amu

3. Electrons (e-)– (-) charge; 1/1840 amu

Section 2-1: Basic ChemistryWhat subatomic particles are in the nucleus?

A. Protons & NeutronsB. Overall charge of the nucleus is positive (+)

What subatomic particles are outside of the nucleus?A. ElectronsB. Electrons are constantly moving within orbits known

as energy levels.

What is the charge of an atom?Neutral because the number of protons equals the number of electrons.

Basic Chemistry

What is an element?

Pure substance that is made of only one kind of atom. Cannot be broken down or converted to another substance.

Periodic Table Basics:

1. Atomic Number = # of p+; number of e-

2. Mass Number = number of p+ & n0

# of n0 = (mass #) – (atomic #)


What is an element?

Pure substance that is made of only one kind of atom.

Periodic Table Basics:

1. Atomic Number = # of p+; number of e-

2. Mass Number = number of p+ & n0

# of n0 = (mass #) – (atomic #)


What is an isotope?

A. An atom of an element with an unusual number of neutrons.

B. Isotopes are identified by their mass numbers

C. Isotopes have the same chemical properties because they have the normal number of neutrons


These isotopes of carbon are named or identified by their different MASS numbers. All isotopes of carbon have the same atomic number.


What are radioactive isotopes?

Isotopes that have a nucleus that will decay over time.

What are radioactive isotopes used for?

1. Dating rocks & fossils

2. Treat cancer

3. Kill bacteria in food

4. Used as a label or “tracer” to follow molecules as they move through a cell.

Radioactive Isotope Uses in Medicine

This slide is not in the student note packet.


What is a compound?

1. Substance formed by the chemical combination of two or more elements in a fixed ratio.

2. The physical & chemical properties of a compound are different than the elements that it is made from.


What are valence electrons?

1. e- found in the outer energy level of an atom

2. They are used to form chemical bonds.


What is an ionic bond?

1. Chemical bonds in which electrons are transferred from one atom to another.

2. This makes one atom (+) and the other atom (-).

3. These charged atoms are called ions, and they are attracted to each other.

4. Ionic compounds dissolve in water.

Ionic Bonds A sodium atom easily loses its one valence electron and becomes a sodium ion (Na+).

This slide is not in the student note packet

Ionic Bonds A chlorine atom easily gains an electron (from sodium) and becomes a chloride ion (Cl-).


Ionic Bonds These oppositely charged ions have a strong attraction for each other, forming an ionic bond.


Section 2-1: Basic ChemistryWhat is a covalent bond?

1. Chemical bond in which e- are shared between atoms.

2. e- are shared in pairs.

1 pair = single bond; 2 pair = double bond; 3 pair = triple bond

3. Compounds that have covalent bonds are called molecules.

4. Very strong bond.


What are van der Waals forces?

1. The weak attraction between molecules when they are close together.

2. The feet of geckos use these forces to hang on to smooth surfaces.


• Compare acids & bases in terms of H+ concentration

• Describe differences between a solution & a suspension using blood as an example

• Describe the purpose of buffers in living organisms

Section 2-2: Chemistry of Water

What is cool about H2O?

1. It is the most abundant compound in living things.

2. Most chemical reactions occur in a solution of H2O.

3. It expands when it freezes.

Section 2-2: Chemistry of WaterWhat is polarity?

1. The unequal sharing of e- in a molecule.

2. The oxygen atom of H2O is an e- hog.

3. The oxygen end of the molecule has a partial (-) charge & the hydrogen end has a partial (+) charge.

4. All of the special properties of H2O are related to its polarity.


What is a hydrogen bond?

1. It is the attraction between the partial (+) of one water molecule to the partial (-) of another.

2. H2O can form 4 of these at once.

3. Three dots represent a H+ bond.


What is cohesion?

1. The attraction of H2O molecules to other H2O molecules.

2. H+ bonds form between the molecules.

3. Surface tension is caused by this.


What is adhesion?

1. The attraction of H2O molecules to other substances.

2. Hydrogen bonds are formed between the H2O and the substance.

3. Capillary action is caused by this.


What is a mixture?Two or more substances mixed together without chemically combining.

What is a solution?1. A mixture of substances in which something is dissolved in H2O.

Solvent = does the dissolvingSolute = gets dissolved

2. H2O can dissolve both polar and ionic compounds.


What is a suspension?

1. A mixture in H2O in which the substances do not dissolve.

2. Anything that says “shake well.”

3. Blood is a suspension.


Dissociation of H2O:

H2O can break down to form ions.

What is an acid?

1. Any substance that forms H+ in solution

2. <7 on the pH scale

3. Strong acids have a pH of 1-3.


What is a base?1. Any substance that forms OH- in solution.2. >7 on the pH scale3. Also called alkaline.4. Strong bases have a pH of 11-14.

What is a buffer?5. Substances that resist changes in pH.6. Many are weak acids or bases.7. Many proteins act as buffers.


What is the pH scale?

A measurement of the concentration of H+ in a solution. It is based on powers of 10.

Base: > 7 Neutral = 7 Acid: < 7

Buffers The pH of the fluids within most cells in the human body

must generally be kept between 6.5 & 7.5 in order to maintain homeostasis. If the pH is lower or higher, it will affect the chemical reactions that take place within the cells.

One of the ways that organisms control pH is through dissolved compounds called buffers, which are weak acids or bases that can react with strong acids or bases to prevent sharp, sudden changes in pH.

Buffers Adding acid to an unbuffered solution causes the pH of

the unbuffered solution to drop. If the solution contains a buffer, however, adding the acid will cause only a slight change in pH.

This slide is not in the student notes.


• List the 4 major biomolecules/ organic macromolecules• List the jobs of carbohydrates & identify their structural

monomers• List the jobs of lipids & identify their structural monomers• List the jobs of nucleic acids & identify their structural

monomers• List the jobs of proteins & identify their structural

monomers• Recognize & identify the 6 elements found in the basic

structure of monomers & polymers

Section 2-3: BiomoleculesWhat is organic chemistry?

The study of carbon compounds.

What are carbon’s most important traits?

1. Has 4 valence e-. This allows carbon to make four covalent bonds at once.

2. Carbon can bond with other carbon atoms. This allows it to form chains, rings, chains of rings, or a combination of all.

Section 2-3 Biomolecules

What are the major elements of life? Present in universe, Earth, and human body

Carbon, Hydrogen, Oxygen,

Phosphorous, Nitrogen, & Sulfur

Section 2-3: Biomolecules

What is a hydrocarbon?

The basic carbon compound. It is made of only hydrogen and carbon.

MethaneBenzene


What are functional groups?Compounds attached to carbon chains to give them special properties.

Hydroxyl (-OH) Polar Alcohols

Amino (-NH2 or ) Basic Amino Acids

Carboxyl (-COOH or ) Acidic Amino Acids

Fatty Acids

Section 2-3: BiomoleculesWhat is a macromolecule?

1. “Big” molecule; macro = big2. Biomolecules are macromolecules3. Made of individual subunits

What is the subunit of a macromolecule?1. Monomer. Mono = one; mer = part2. Dimer = two parts; 2 monomers joined together3. Polymer = 3 or more parts; 3 or more monomers

joined together; macromolecules are polymers


What is polymerization?

1. Chemical process in which monomers are joined together to form dimers & polymers.

2. A.K.A. dehydration synthesis because something is produced. Dehydration = take away H2O; synthesis = to make. Take away H2O to make something. Sometimes called condensation.

3. It is an anabolic process because it takes energy & builds new molecules.

4. Functional groups are used for this process.


What is hydrolysis?1. Chemical process in which the bonds

between the monomers in a polymer are broken.

2. A water molecule is used.

3. Hydro = H2O; lysis = to break; using water to break something.

4. It is a catabolic reaction because energy is released and molecules are broken.


What are the four biomolecules?

1. Carbohydrates

2. Lipids

3. Proteins

4. Nucleic Acids


What is a carbohydrate?1. Molecules that contain C, H, and O in a

1:2:1 ratio (glucose = C6H12O6)2. Carbo = carbon; hydrate = H2O

What is the monomer of a carbohydrate?3. Monosaccharide4. Mono = one/single; saccharide = sugar; single

sugar5. All sugars end with –ose (glucose, fructose,

lactose, sucrose, etc.).


What are disaccharides?1. Two monosaccharides joined together.2. This is done by polymerization.3. Sucrose (table sugar) is an example.

Section 2-3: Biomolecules.

What are polysaccharides?1. Three or more monosaccharides joined

together through polymerization.2. Starch & cellulose are examples


What are the functions of carbohydrates?

1. Main source of energy for cells, especially glucose.

2. Energy storage. Plants use starch; animals use glycogen.

3. Structure. Plant cell walls are made of cellulose, the exoskeletons of insects & crabs are made of chitin.


What are lipids?1. Compounds that contain C, H, and O,

but not in a 1:2:1 ratio.2. They are oils, fats, waxes, & steroids.

3. None are soluble in H2O.4. They have no real monomer.5. A triglyceride is the form of a typical fat or

oil. Tri refers to 3 fatty acids; glyceride refers to glycerol.


What is a saturated fatty acid?

1. The hydrocarbon chain only has single bonds between the carbons (C-C).

2. It has the maximum amount of Hydrogens (saturated w/H).

3. Tend to be solid at room temperature (fats).


What is an unsaturated fatty acid?1. The hydrocarbon chain has one double

bond between two carbons (C=C).2. It has less than the maximum hydrogens.

What is a polyunsaturated fat?3. The hydrocarbon chain has lots of C=C.4. They tend to be liquid at room

temperature (oils).


What are the functions of lipids?

1. Energy storage – fats in animals

2. Main component of cell membranes (phospholipids)

3. Chemical messengers (hormones). Many steroids are hormones.

4. H2O proof coverings (waxes).


What are proteins?

1. Arguably the most important biomolecule.

2. Proteins usually end with –in (insulin, hemoglobin, adrenalin, etc.)

Section 2-3: BiomoleculesWhat is the monomer of a protein?

Amino acid

What are the parts of an amino acid?

1. α-carbon (center carbon atom)

2. Carboxyl group (acid group)(-COOH)

3. Amino group (-NH2)

4. Hydrogen atom (H)

5. R group; this is a variable; there are 20 different R groups; 20 different amino acids


How are amino acids joined together?

1. By a peptide bond formed through polymerization.

2. The amino group of one amino acid is connected to the carboxyl group of another.


What is a dipeptide?

Two amino acids joined together.

What is a polypeptide?

Three or more amino acids joined together. Most proteins are polypeptides made of at least 300 amino acids.

What determines a protein’s function?

Its shape/structure.


What are the levels of protein structure?

1. Primary (1o) – amino acid sequence; this determines the next 3 levels

2. Secondary (2o) – the amino acid chains coils and folds

3. Tertiary (3o) – the 2o structure folds on itself

4. Quaternary (4o) – one or more polypeptide chains are added; a.k.a. globular protein; hemoglobin is an example.

Section 2-3: BiomoleculesWhat are the functions of proteins?1. Energy source – after carbs & lipids have been used.2. Structure – microtubules & microfilaments give shape

to cells.3. Movement – actin & myosin are used in muscle

contraction.

4. Transport – hemoglobin transports O2

5. Chemical messengers – many hormones are proteins (insulin)

6. Immunity – antibodies are proteins7. Enzymes – these proteins regulate chemical

reactions; this is the most important function of proteins.


What are nucleic acids?

1. Compounds that contains C, H, O, N, & P.

2. Involved with heredity (DNA)

3. Involved with protein synthesis (DNA & RNA)

4. Involved with energy use (ATP)


What is the monomer of a nucleic acid?

Nucleotide

What are the parts of a nucleotide?

1. 5-carbon sugar (either ribose or deoxyribose)

2. Phosphate group

3. Nitrogenous base (5 different kinds of these)

Section 2-3: BiomoleculesBasic Nucleotide Structure:

ATP Structure:


• Explain what factors influence enzyme activity & the affect of those factors on the enzymes

• Describe the role of energy in chemical reactions & the significance of enzymes in biological reactions

Section 2-4: Chemical Reactions &Enzymes

What is a chemical reaction?

1. Process that changes one set of chemicals into another set of chemicals.

2. Always involves breaking bonds in the reactants & forming new ones in the products.

A + B C + DReactants (left of the arrow) Products (right of the arrow)

The arrow means “yields.”


What is activation energy (EA)?

Energy required to get a chemical reaction started.

What is an anabolic reaction?

1. Absorbs energy; endergonic.

2. The energy is used to make new bonds.

3. Dehydration synthesis is an anabolic reaction.

4. New molecules are built.

Section 2-4: Chemical Reactions & Enzymes

What is a catabolic reaction?

1. Releases energy; exergonic

2. Energy is released because bonds & molecules are broken.

3. Hydrolysis is a catabolic reaction.


What is an enzyme?

1. Proteins that speed up reaction rates by lowering the EA.

2. Enzymes are catalysts; they are not used up during the reaction.

3. They are very specific; one enzyme per reaction.

4. Enzymes end with –ase.

Section 2-4: Chemicla Reacitons & Enzymes

Lock & Key Model of Enzyme Function:

1. Substrate = reactant

2. Active site = place on the enzyme where the work occurs. It is substrate specific.

3. Enzyme-Substrate complex last for a very short time.

Section 2-4: Chemical Reactions & Enzymes

How do you control enzymes?1. Changes in pH2. Changes in temperature; especially

higher temperature3. Chemical regulators – these block the

active sites.

Changes in pH & high temps changes the shape of the enzyme (denature).

biology chapter 2 the chemistry of life. 2.1 learning targets list the 3 subatomic particles that...

Documents

basic chemistry

amu slide

chemistry of life slide

number of electrons

atomic number

number of protons

number of p n

p number of e