Biology 140 Chapter 2 Notes

Biochemistry Matter- substance which occupies space Composes all living and nonliving things Mass- amount of matter in an object Weight-

Elements An element- Based on number of subatomic particles 92 naturally occurring elements organized into the periodic table Based on number of subatomic particles

Common Elements

Atoms Central nucleus Electrons Composed of atoms Atom- smallest functional unit of an element Atomic structure Central nucleus Protons - Neutrons - Electrons

Atom Diagram

Figure 2.1 140 Notes ICC Ms. Jacobson

Figure 2.2 140 Notes ICC Ms. Jacobson

Periodic table of the elements Fig. 2.1 140 Notes ICC Ms. Jacobson

Molecules and compounds Definitions Molecule- Compound- a molecule composed of atoms of 2 or more different elements Ions and ionic bonds An atom which has lost or gained electrons in a chemical reaction Electrostatic interaction between a positive ion (cation) and a negative ion (anion) is called an ionic bond

Figure 2.3 140 Notes ICC Ms. Jacobson

Molecules and compounds, cont’d. Covalent bonds Each atom contributes one electron to the shared pair More than one pair of electrons can be shared Double covalent bond- 2 pairs shared Triple covalent bond-3 pairs shared

Figure 2.4 Covalent Bonding 140 Notes ICC Ms. Jacobson

Hydrogen Bonds Figure 2.5a

Dissociation When Ions dissolve in water, they form electrolytes and the water molecules

Figure 2.7 140 Notes ICC Ms. Jacobson

Chemical Reactions Metabolism-All of the chemical reactions that occur in cells which Reactants are the substances that participate in chemical reactions Products- Types of reactions Synthesis- combining two or more reactants 140 Notes ICC Ms. Jacobson

Types of chemical reactions Ex. ADP + P → ATP Adenosine Diphosphate + phosphate becomes Adenosine Triphosphate Decomposition Reactions- Ex. ATP → ADP + P 140 Notes ICC Ms. Jacobson

Figure 2.8 140 Notes ICC Ms. Jacobson

Types of Reactions Exchange Reactions- Elements from each of the reactants rearrange themselves as follows CO2 + H2O → H+ + HCO3- Energy- the capacity to do work Potential- Kinetic- Mechanical- Chemical-

Rate of Chemical Reactions Properties of the Reactants Concentrations Temperature Catalysts Enzymes

Carbohydrates General structure Functions Ratio of hydrogen atoms to oxygen atoms is 2:1 Characteristic atomic grouping of H-C-OH Functions Principal energy source for cells Structural components 140 Notes ICC Ms. Jacobson

Simple carbohydrates Simple carbohydrates-monosaccharides and dissaccharides Monosaccharides are simple sugars such as glucose (blood sugar), fructose, and lactose Dissaccharides are 2 monosaccharides bonded together- an example is sucrose (glucose+fructose)

Synthesizing a new disaccharide

Complex Carbohydrates Polysaccharides- Carbohydrates made up of long chains of simple sugars Cellulose Structural carbohydrate in plants “fiber” Indigestible by human enzymes Starches and glycogen Quick energy storage Starches are long chains of glucose Glycogen is “animal starch”, composed of long chains of glucose in animal cells

Glycogen

Glycogen structure

Lipids General characteristics Extremely diverse group including fats, oils, steroids, waxes, phospholipids Common characteristic- nonpolar molecules which are insoluble in water Contain more calories of energy per gram so are ideal energy storage molecules Also function as structural components, insulation, cushioning of organs, and hormones

Lipids cont. Fats and oils Oils tend to be liquid at room temperature and are usually of plant origin Fats tend to be solid at room temperature and are usually of animal origin Fats are often called triglycerides, as they are composed of one glycerol and 3 fatty acids Fats are important in energy storage and insulation

Figure 2.12

Lipids cont. Saturated and unsaturated fatty acids Saturated have no double bonds between carbon atoms, and tend to be more solid at room temperature Unsaturated have at least one double bond between carbons Polyunsaturated have multiple double bonds- the more polyunsaturated the fatty acids, the more liquid the fat will be at room temperature

Figure 2.13

Lipids cont. Phospholipids Steroids Attached phosphate gives “polarity” Has a hydrophilic head and two hydrophobic tails Important components of membranes Steroids “Skeleton” of 4 carbon rings Cholesterol is a steroid which functions in membrane structure and hormone synthesis

Figure 2.14

Protein General characteristics An amino acid has a central carbon atom with a carboxyl group (COOH) at one end and an amino group at the other (NH2) Peptides Bonds between amino acids are called peptide bonds

Fig. 2.24 140 Notes ICC Ms. Jacobson

Protein Organization The shape of a protein molecule is critical to its function Primary- shape held together by bonds between r groups chain of amino acids linked by peptide bonds Secondary-coiling or folding of the primary structure to form a helix or a pleated sheet Tertiary-

Figure 2.16 140 Notes ICC Ms. Jacobson

Proteins and Enzymes Proteins Enzymes Denaturation- change the tertiary shape so the proteins do not function anymore Ex. Fried egg pH Enzymes Increase rate of chemical reactions by the energy need to start a chemical reaction

Figure 2.17

Enzymes Lock and Key- The reaction is sped up because the enzyme and reactant are brought so close together 140 Notes ICC Ms. Jacobson

Figure 2.18 140 Notes ICC Ms. Jacobson

Nucleic Acids Two types- DNA and RNA Polymers of nucleotides DNA- codes for the order of amino acids needed to make proteins Ex. Hard drive RNA-functions in synthesis of protein Ex. Flash drive Polymers of nucleotides Nucleotides are composed of a 140 Notes ICC Ms. Jacobson

Figure 2.20 140 Notes ICC Ms. Jacobson

Figure 2.19 140 Notes ICC Ms. Jacobson

Table 2.3