Biochem BM1 PPTs

Monosaccharide

What is a carbohydrate consisting of a single sugar unit?

Aldose

What type of monosaccharide contains an aldehyde group in its open-chain form?

Ketose

What type of monosaccharide contains a ketone group in its open-chain form?

Glucose

What is the major metabolic fuel and most important carbohydrate in humans?

Fructose

Which monosaccharide is a ketose?

D-glucose

Which glucose stereoisomer has the OH group on the right at the chiral carbon farthest from the carbonyl group?

L-glucose

Which glucose stereoisomer has the OH group on the left at the chiral carbon farthest from the carbonyl group?

D/L configuration

What classification of sugar stereoisomers is based on the configuration of the chiral carbon farthest from the carbonyl group?

Enantiomers

What are stereoisomers that are nonsuperimposable mirror images of each other?

Epimers

What are stereoisomers that differ in configuration at only one specific chiral carbon?

Galactose

Which monosaccharide is the C4 epimer of glucose?

Mannose

Which monosaccharide is the C2 epimer of glucose?

Anomers

What are sugars that differ in configuration specifically at the anomeric carbon?

Anomeric carbon

What carbon becomes the anomeric carbon when a monosaccharide forms a ring?

α-anomer

In a D-sugar, what anomer has the anomeric OH group trans to the CH2OH group?

β-anomer

In a D-sugar, what anomer has the anomeric OH group cis to the CH2OH group?

Mutarotation

What process allows α and β anomers to interconvert through the open-chain form?

Pyranose

What is a sugar ring containing six atoms?

Furanose

What is a sugar ring containing five atoms?

Reducing sugar

What type of carbohydrate has a free anomeric carbon capable of forming a carbonyl group?

Benedict's test

What test is used to detect reducing sugars?

Sucrose

Which common disaccharide is nonreducing because both anomeric carbons participate in its glycosidic bond?

Lactose

Which disaccharide consists of glucose and galactose?

Maltose

Which disaccharide consists of two glucose molecules?

Trehalose

Which disaccharide consists of two glucose units joined through their anomeric carbons and is nonreducing?

Glycosidic bond

What bond connects monosaccharides to form disaccharides and larger carbohydrates?

Glycogen

What is the major storage polysaccharide of glucose in animals?

Starch

What is the major glucose storage polysaccharide in plants?

Cellulose

What structural plant polysaccharide contains β(1→4) glycosidic bonds and cannot be digested by humans?

Amylose

Which component of starch is predominantly linear?

Amylopectin

Which component of starch is branched through α(1→6) linkages?

Glycogen branching

What glycosidic linkage creates branches in glycogen?

α(1→4) glycosidic bond

What linkage forms the main chains of glycogen and starch?

β(1→4) glycosidic bond

What linkage characterizes cellulose and makes it resistant to human digestion?

Glycosaminoglycans

What complex carbohydrates contain amino sugars and uronic acids and contribute to extracellular matrix structure?

Hyaluronic acid

Which GAG is an important component of connective tissue and contributes to hydration?

Proteoglycan

What molecule consists of GAG chains attached to a core protein and provides hydration and resistance to compression?

Glycoprotein

What protein-containing molecule has relatively short carbohydrate chains compared with proteoglycans?

Glucosuria

What is the presence of glucose in urine when blood glucose exceeds the renal threshold?

Hemoglobin A1c

What glycated hemoglobin measurement reflects long-term blood glucose control?

Nonenzymatic glycation

What process forms HbA1c by attaching glucose to hemoglobin without enzyme catalysis?

Lactase

What enzyme deficiency causes lactose intolerance?

Lactose intolerance

A patient develops bloating, flatulence, and diarrhea after drinking milk. What condition is most likely?

Galactosemia

A newborn develops cataracts and liver dysfunction due to impaired galactose metabolism. What disorder is most likely?

Inulin

What fructose polymer is freely filtered by the kidney and used to measure GFR?

ABO blood groups

What blood group system is determined partly by specific carbohydrate structures on RBC surfaces?

Simple lipids

What lipid class consists primarily of fatty acids esterified to alcohols?

Fat

What lipid consists of fatty acids esterified to glycerol?

Wax

What lipid consists of fatty acids esterified to long-chain monohydric alcohols?

Complex lipids

What lipid class contains fatty acids, alcohol, and additional groups such as phosphate or carbohydrate?

Phospholipid

What complex lipid contains a phosphate group and is a major component of cell membranes?

Glycerophospholipid

What phospholipid class contains glycerol as its alcohol backbone?

Sphingophospholipid

What phospholipid class contains sphingosine as its backbone?

Glycolipid

What lipid contains sphingosine, a fatty acid, and carbohydrate?

Derived lipids

What lipid category includes fatty acids, glycerol, cholesterol, steroids, and ketone bodies?

Fatty acid

What type of molecule contains a carboxyl group attached to a hydrocarbon chain?

Saturated fatty acid

What fatty acid contains no carbon-carbon double bonds?

Unsaturated fatty acid

What fatty acid contains one or more carbon-carbon double bonds?

Monounsaturated fatty acid

What fatty acid contains exactly one double bond?

Polyunsaturated fatty acid

What fatty acid contains two or more double bonds?

Cis fatty acid

What configuration of an unsaturated fatty acid introduces a kink into the hydrocarbon chain?

Trans fatty acid

What fatty acid configuration keeps the hydrocarbon chain relatively straight?

Oleic acid

What common monounsaturated fatty acid is designated 18:1 Δ9?

Palmitic acid

What saturated fatty acid contains 16 carbon atoms?

Δ nomenclature

In fatty acid nomenclature, what system counts double-bond positions from the carboxyl carbon?

ω nomenclature

In fatty acid nomenclature, what system counts from the terminal methyl carbon?

18:1 Δ9

What fatty acid notation indicates 18 carbons and one double bond beginning at carbon 9 from the carboxyl end?

Linoleic acid

What essential omega-6 fatty acid is abbreviated LA?

α-linolenic acid

What essential omega-3 fatty acid is abbreviated ALA?

Arachidonic acid

What polyunsaturated fatty acid can be synthesized from linoleic acid under normal conditions?

EPA

Which omega-3 fatty acid is a precursor for signaling molecules and is abundant in fish oils?

DHA

Which omega-3 fatty acid is especially important in neural and retinal tissues?

Essential fatty acid

What fatty acid must be obtained from the diet because humans cannot synthesize enough of it?

Cholesterol

What sterol is a membrane component and precursor of steroid hormones, bile acids, and vitamin D?

Steroid hormones

What class of hormones is synthesized from cholesterol?

Bile acids

What cholesterol-derived molecules aid lipid digestion and absorption?

Phospholipid bilayer

What membrane structure forms because phospholipids are amphipathic?

Amphipathic

What term describes a molecule containing both hydrophilic and hydrophobic regions?

Fluid mosaic model

What model describes the plasma membrane as a dynamic lipid bilayer containing embedded proteins?

Membrane fluidity

What property increases when membrane fatty acids contain more cis double bonds?

Cholesterol

What membrane component buffers fluidity by preventing excessive rigidity at low temperatures and excessive fluidity at high temperatures?

Lateral movement

What type of membrane phospholipid movement occurs readily within the same leaflet?

Flip-flop

What membrane phospholipid movement between leaflets is relatively slow and usually requires enzymes?

Nucleoside

What molecule consists of a nitrogenous base attached to a pentose sugar without phosphate?

Nucleotide

What molecule consists of a nitrogenous base, pentose sugar, and one or more phosphate groups?

Purines

Which nitrogenous bases contain two fused rings?

Adenine and guanine

Which nitrogenous bases are purines?

Pyrimidines

Which nitrogenous bases contain a single six-membered ring?

Cytosine, thymine, and uracil

Which nitrogenous bases are pyrimidines?

DNA

Which nucleic acid contains deoxyribose and thymine?

RNA

Which nucleic acid contains ribose and uracil?

2-deoxyribose

What sugar is found in DNA?

Ribose

What sugar is found in RNA?

Adenine-thymine

Which DNA base pair is connected by two hydrogen bonds?

Guanine-cytosine

Which DNA base pair is connected by three hydrogen bonds?

Uracil

Which nitrogenous base replaces thymine in RNA?

Antiparallel

What term describes the opposite 5′→3′ orientations of the two DNA strands?

ATP

What nucleotide functions as the major immediate energy currency of the cell?

5-fluorouracil

Which drug inhibits thymidylate synthase and decreases dTMP synthesis?

Thymidylate synthase

Which enzyme is inhibited by 5-fluorouracil, impairing DNA synthesis?