Bio A Midterm 2 - 10/1 Flashcards

carbohydrates

-a type of macrmolecule essential to our diet

-provide energy to the body (EX: grains, fruits, and vegetables)

-stoichiometric formula: (CH2O)n, where n is the number of carbons

-classified into 3 subtypes: monosaccharides, disaccharides, and poolysaccharides

monosaccharides

-”mono” = one, “sacchard” = sweet

-number of carbons usually ranges from three to seven; names end with “ose”

-aldose: sugar with an aldehyde group (R—CHO)

-ketose: sugar with a ketone group (RC(=O)R’))

-can exist as a linear chai or as ring-shaped molecules

disaccharides

-form when two monosaccharides undergo a dehydration reaction (or a condensation reaction or dehydration synthesis)

-combination of a hydroxyl group and a H release H2O molecule and form a covalent bond → a glycosidic bond (can be alpha or beta type)

-EX: lactose, maltose, sucrose

polysaccharides

-a long chain of monosaccharides linked by glycosidic bonds; chain may be branched or unbranched

-EX: starch, glycogen, cellulose, and chitin

the more even distribution across the membrane is more ______?

random

glycogen

-the storage form of glucose in humans and other vertebrates and is comprised of monomers of glucose; the animal equivalent of starch and a highly branches molecule usually stored in liver and muscle cells

glycogenolysis

process where glycogen breaks down to release glucose when blood glucose levels decrease

cellulose

-the most abundant natural biopolymer

-mostly comprises a plant’s cell wall; provides the cell structural support

-glucose monomers comprise cellulose that beta-14 glycodisic bonds link; every other glucose monomer in cellulose is flipped over and the monomers are packed tightly as extended long chairs → gives cellulose its rigidity and high tensile strength

chitin

a nitrogen-containing polysaccharide that makes up the exoskeleton of arthropods

benefits of carbohydrates

-1g of carbohydrate provides 4.3 kcal (fats provide 9kcal.g)

-contain soluble and insoluble elements

-the insoluble part (fiber) is mostly cellulose; fiber promotes regular bowel movement by adding bulk, and it regulates the blood glucose consumption rate; also helps remove excess cholesterol from the body

ATP

-comprised of three phosphate groups

-adenosine is a nucleotide consisting of the nitrogenous base adenine and a 5-carbon sugar, ribose

-phosphate groups (alpha, beta, and gamma) are linked by 2 equally high-energy bonds (phosphoanhydride bonds) that, when broken, release sufficient energy to power a variety of cellular reactions and processes

-these are high energy because the products of such bond-breaking——adenosine diphosphate (ADP) + 1 inorganic phosphate group—have considerably lower free energy than the reactants: ATP and a water molecule (hydrolysis reaction)

-highly unstable; spontaneously dissociates into ADP and Pi; the free energy released during this is lost as heat

-ATP hydrolysis: ATP + H2O → ADP + Pi + free energy

-ATP formation: ADP + Pi + free energy → ATOp + H2O

phosphorylation

the process of a phosphate group binding to a molecule

substrate

-the chemical recatants to which an enzyme binds

-it can be broken down into multiple products or come together to create one larger molecule

-bound and held in position by non-covalent interactions in the active sit

active site

-the location within the enzyme where the substrate binds; this specific environment is suited to bind to a specific chemical substrate → active sites are subject to local environmental influences

denaturation

-a process that changes the substance’s natural properties

-extreme environmental pH values can cause enszymes to denature

induced fit

-the interaction between an enzyme and substrate causes a mild shift in the enzyme’s structure that confirms an ideal binding arrangement between the enzyme and the substrate’s transition state - this ideal binding maximizes the enzyme’s ability to catalyze its reaction

enzyme use

-the enzyme-substrate complex lowers the reaction’s activation energy

-the enzyme will always return to its original state at the reaction’s completion; after catalysis, an enzyme releases its products

competitive inhibition

an inhibitor molecules competes with the substrate for active site binding

noncompetitive inhibition

an inhibitor molecule binds to the enzyme in a location other than the active site; called an allosteric site, but still manages to prevent substrate binding to the active site

allosteric inhibition

some inhibitor molecules bind to enzymes in a location where their binding induces a conformational change that reduces the enzyme’s affinity for its substrate

helper molecules

-binding promotes optimal conformation and function

1. cofactors: inorganic ions

2. coenzymes: organic + required for enzyme action (EX: dietary vitamins)

feedback inhibition

involves using a reaction product to regulate its own farther production (controls amino acid and nucleotide production)