Biochem Test 3

acetal

organic compound formed from reaction of hemiacetal w/ alcohol

alditol

aldehyde/ketone reduced to alcohol (sorbitol → glucose added to alditols)

aldose

monosaccharides with aldehyde functional group; reducing sugar

amylopectin

branched chains of glucose w/ both α(1,4) linkage and α(1,6) linkage

amylose

straight chains of glucose w/ α(1,4) linkage

anomer

isomer of cyclic sugar that differs from another in its configuration about hemiacetal or acetal carbon (diastereomers formed during cyclization)

cellobiose

intermediate of cellulose breakdown (glucose-glucose) w/ β(1,4) linkage; reducing sugar

cellulose

polysaccharide composed of glucose linked together by β(1,4) linkage

chitin

• exoskeleton of insects and crustaceans

• cell walls of fungi

glycan

polysaccharides connected by glycosidic linkages

glycoconjugate

compound formed by covalent linkage of carbohydrates w/ proteins or lipids

glycogen

• short term glucose storage molecule in vertebrates (animal starch)

• more branched than amylopectin

• found in liver and muscle

glycosidic linkage

link monosaccharides

hemiacetal

aldehyde react w/ alcohol (easily revert to aldehyde)

hemiketal

ketone react w/ alcohol (easily revert to ketone)

heteroglycan

polysaccharides composed of two or more types of monosaccharides

homoglycan

• polysaccharides composed of one type of monosaccharide

• starch (amylose, amylopectin), glycogen, cellulose, chitin

ketal

organic compound formed from reaction of hemiketal w/ alcohol

lactone

cyclic ester formed when carbonyl group and OH group within same molecule react

lactose

milk sugar (glucose-galactose) w/ β(1,4) linkage; reducing sugar

maltose

malt sugar (glucose-glucose) w/ α(1,4) linkage; reducing sugar

oligosaccharide

carbohydrate composed of 2 to 10 monosaccharides

reducing sugar

• sugars that can be oxidized by weak oxidizing agents (Benedict’s reagent)

• contains hemiacetal group (aldehyde)

• can react w/ Cu⁺² (Benedict’s solution)

sucrose

cane sugar or beet sugar (glucose-fructose) w/ α,β(1,2) linkage

epimer

diastereomers that differ in configuration at a single chiral carbon

aerobic respiration

metabolic process in which oxygen is used to generate energy from food molecules

amphibolic pathway

both anabolic and catabolic processes

anaerobic organism

organisms that do not use oxygen to generate energy

antioxidant

• substance that prevents oxidation of other molecules

• vitamin C (ascorbic acid), vitamin E (α-tocopherol), β-carotene

citric acid cycle

• amphibolic pathway that oxidizes two acetyl carbons to form CO₂ and reduced molecules NADH and FADH₂

• Acetyl-CoA + 3NAD⁺ + FAD + ADP → 2CO₂ + 3NADH + FADH₂ + ATP

cori cycle

metabolic process in which lactate (produced in muscle by glycolysis) is transferred to liver, where it is converted to glucose by gluconeogenesis

decarboxylation

removal of carboxylic group from carboxylic acid as carbon dioxide

electron transport system

• series of redox reaction which transfers electrons from NADH and FADH₂ to O₂ to form water

• generates ATP in aerobic respiration

fermentation

• anaerobic process that convert carbohydrates into acids, gases, or alcohol to obtain energy

• NAD⁺ regeneration

gluconeogenesis

• synthesis of glucose from noncarbohydrate molecules

• 2pyruvate + 4ATP + 2GTP + 2NADH → glucose + 4ADP + 2GDP + 2NAD⁺

glycogenesis

anabolic process that adds glucose to growing glycogen polymers when blood glucose levels are high (synthesis of glycogen)

glycogenolysis

catabolic process that removes glucose molecules from glycogen polymers when blood glucose levels are low (use hydrolysis)

glycolysis

• anaerobic pathway that generates energy from glucose in form of two ATP and two NADH

• glucose + 2NAD⁺ + 2ADP → 2pyruvate + 2NADH + 2ATP

pentose phosphate pathway

anabolic shunt from glycolysis to produce NADPH, ribose, and other sugars

aerotolerant anaerobe

organism that depends on fermentation for its energy needs and possesses protection from toxic oxygen metabolites in the form of detoxifying enzymes and antioxidants that detoxify ROS

coenzyme A

• cofactor that carries acetyl and acyl groups required for metabolic reactions

• plays central role in breaking down carbs, fats, and proteins and synthesizing fats, cholesterol, and neurotransmitters

facultative anaerobe

• organism that possesses capacity for detoxifying oxygen metabolites

• energy is generated using oxygen as electron acceptor

• live usually by fermentation

flavin adenine dinucleotide (FAD)

• coenzyme that acts as a prosthetic group that functions in flavoproteins

• acts as electron acceptor and donor

flavin mononucleotide (FMN)

• coenzyme that acts as a prosthetic group that functions in flavoproteins

• acts as electron carrier (strong oxidizing agent)

flavoprotein

conjugated protein in which prosthetic group is either FMN or FAD (electron carriers)

glyoxylate cycle

• modified CAC that occurs in plants, bacteria, and other eukaryotes, which allows growth in these organisms from two-carbon substrates such as ethanol, acetate, and acetyl-CoA

• turn fats into glucose by bypassing decarboxylation steps

nicotinamide adenine dinucleotide (NAD)

• coenzyme form of nicotinic acid involved in electron transfer

• oxidized form NAD⁺’ reduced form NADH

nicotinamide adenine dinucleotide phosphate (NADP)

• coenzyme form of nicotinic acid involved in electron transfer

• oxidized form NADP⁺; reduced form NADPH

obligate aerobe

organism that is dependent on oxygen for energy production

obligate anaerobe

organism that grows only in absence of oxygen and use fermentation to generate energy

β-carotene

plant pigment molecule that acts as absorber of light energy and as antioxidant

chemiosmotic coupling theory

ATP synthesis is coupled to electron transport by electrochemical proton gradient across membrane

ionophore

hydrophobic molecules that acts as a shuttle or creates channels, helping ions pass through membranes

oxidative phosphorylation

• synthesis of ATP coupled to electron transport

• uses energy from electrons (NADH and FADH₂) to power electron transport chain that pumps protons, creating gradient that drives ATP synthase to produce ATP and using oxygen as final acceptor to form water

protonmotive force

electrochemical gradient created by pumping protons out of mitochondrial matrix

radical

atom or molecule w/ unpaired electron

reactive oxygen species (ROS)

• unstable, highly reactive molecules containing oxygen

• oxygen can accepts single electrons to form unstable derivatives

• can cause mutation → cancer

• superoxide, hydroxyl radical ,peroxide, singlet oxygen

α-tocopherol

active form of vitamin E acting as antioxidant

uncoupler

molecule that uncouples ATP synthesis from electron transport by collapsing proton gradient by transporting protons across membrane (flow of H⁺ from ATP synthase)

uncoupling protein

• molecule that dissipates proton gradient in mitochondria by translocating protons

• thermogenin/UCP1 → produces heat by enabling non-shivering thermogenesis