Microbiology Ch 2

The combining capacity of an atom - the number of extra or missing electrons in it outermost shell

attraction between two ions of opposite charge that holds them together to form a stable molecule

cation - + charged Ion

anion - - charged ion

formed when two atoms share one or more pairs of electrons - strong bonds

a hydrogen atom that is covalently bonded to one oxygen or nitrogen is attracted to another oxygen or nitrogen - weak bonds - don't form molecules

involve making or braking of bonds between atoms - involved energy

when chemical bonds are broken - energy released

when chemical bonds make - energy used

Endergonic reactions - absorb more energy than they release (energy in)

Exergonic reactions - release more energy than they absorb (energy out)

Synthesis reactions - to put together - to form new bonds (dehydration synthesis)

anabolism - anabolic reactions - synthesis reactions - building large molecules from smaller ones

catabolism - catabolic reactions - hydrolysis decomposition reactions - tear large molecules down into smaller ones

decomposition reaction - decomposition hydrolysis - to break down into smaller parts

It is polar - oxygen is electronegative and pulls the electrons toward it

• partial (-) charge = oxygen end
• partial (+) charge = hydrogen end

• 1. Solvent - its polarity makes it a good solvent - dissolves charged and polar structures
• - - solute - dissolving substance - things dissociate because they are attracted to the polarity of the water

2. Temperature Buffer - it takes a lot of heat (energy) to break the hydrogen bonds in water to go from liquid to stream (compared to liquids that dont have hydrogen bonds)

always contain carbon and hydrogen

usually lack carbon - simpler structure than organic compounds

power or potential of hydrogen - the amount of H⁺ in a solution -log₁₀[H⁺] each whole number represents a tenfold change from the previous concentration

Pure water has a pH of 7 and is considered neutral because the concentrations of dissociated H⁺ and OH^- are equal

Human pH is 7.35 - 7.45 (slightly basic)

• substance that dissociates into H⁺ and anions (-)
• hydrogen ions negatively charged ions

Proton donor H+

HCL = H⁺ + Cl^-

• substance that dissociates into OH^- and cations (+)
• hydroxide ions and positively charged ions

Proton acceptors

NaOH = OH^- + Na⁺

• substance that dissociates into anions and cations - neither of which are H⁺ and OH^-

compounds that keep the pH from changing drastically

monomer is monosaccharide (glucose, fructose)

Made of C, H. O (NO nitrogen)

Function is to fuel cell activities with ready source of energy (glucose)

• di = 2 sugars (monosaccharides) sucrose (table sugar)
• Poly = many monosaccharides

glycogen = storage unit for glucose in humans and animals

cellulose = polysaccharide that is the main component of plant cell walls - most abundant carbohydrate on earch

chitin - polysaccharide that makes up part of plant cell walls and the exoskeletons of lobsters, crabs, and insects

starch - plant form of glucose storage

dehydration sysnthsis - building - water released

hydrolysis - water consumed

• Fat- - they are non-polar (don't dissolve in water)
• monomers are glycerol and fatty acids
• Made of C, H, O (no nitrogen)

saturated fat - there are no double bonds - all the carbons are "saturated" with hydrogens - solid at room temp

unsaturated fat - double bonds so all carbons are not filled with hydrogen - liquid at room temp

• triglycerides - one glycerol (alcohol) molecule attached to 3 (tri) fatty acid chains
• function as energy storage (adipose tissue) in humans

• phospholipods - complex lipid - one glygerol, two fatty acids, and a phosphate group
• function as an important part of the plasma membrane -phospholipid bilayer - hydrophillic heads out and hydrophobic tails in

• steriods - cholesterol - four interconnected carbon rings
• function as a component of the plasma membrane of animal cells

monomer is amino acids

made of C, H, O, N and S

20 different amino acids - each has an amino group, a carboxyl (acid ) group, and an R group (which contain nitrogen)

dehydration synthesis (water released) between two amino acids - forms a covalent bond (very strong)

primary structure - unique sequence of amino acids held together by peptide bonds

secondary structure - twisting or folding (helix and beta pleated sheets) of the polypeptide chain - shape held by hydrogen bonds between the amino acids

tertiary structure - 3D shape of the protein - fold with hydrophobic portions to the inside - shape held by hydrogen bonds between side groups and ionic bonds between oppositely charged side groups, and disulfide bridges (if the aa cysteine is present) Disulfide bridges are covalent bonds between two cysteine molecules.

quarternary structure - two or more peptide chains that function as a single unit - also held together by hydrogen bonds, ionic bonds, and disulfide bridges.

denaturation - if a protein is in hostile environment (temp, pH, salt concentration) its shape changes and it is no longer functional

• 1. Structural proteins - collagen, keratin, elastin
• 2. Enzymes - speed up chemical reactions
• 3. Transporter proteins - move chemicals through membrane or in blood
• 4. Contractile proteins - actin and myosin
• 5. Hormones
• 6. Antibodies - immune function
• 7. Clotting factors - work w/ platelets to stop bleeding
• 8. Organelles - cytoskeleton, flagella

conjugated proteins are make of amino acids and other organic or inorganic components

• glycoproteins - contain sugar
• nucleoproteins - nucleic acids
• metalloproteins - metal atoms
• lipoproteins - lipids
• phosphoprotiens - phosphate group

monomer is a nucleotide

DNA, RNA, and ATP

made of C, H, O, N, P

• nucleotide
• 1. pentose (5 carbon) sugar -ribose or deoxyribose
• 2. phosphate group
• 3. nitrogenous base (contains nitrogen)
• - purine = Guanine and Adenine
• -pyrymadines = Cytosine, Uracil, Thymine

• Base Pairs
• A-T Held together with 2 hydrogen bonds
• C-G Held together with 3 hydrogen bonds

• DNA - double helix -sides alternate sugar and phosphate groups - rungs of the latter are nitrogen containing bases
• the nucleotide rungs form genes

RNA - single stranded - contains ribose instead of deoxyribose - contains Uracil instead of Thymine

• 1. mRNA - messenger RNA
• 2. rRNA - ribosomal RNA
• 3. tRNA - transfer RNA

ATP - cell energy currency - make of nitrogenous base adenine + ribose + 3 phosphate groups

energy is stored in the phosphate bonds