NU624 2nd Exam Practice Questions and Answers

NU624 2nd Exam Practice Questions and Answers B. Haworth projections -Aldehydes react with alcohols to form hemiacetals, and ketones react with alcohols to form hemiketals—when this intramolecular reaction occurs, the linear monosaccharide forms a cyclic structure -The cyclic structures are called Haworth projections -Lower horizontal bond in the ring is projected toward you, above the plane of the page, and the upper horizontal bond is projected away from you, behind the plane of the page -Cyclization leads to the formation of two possible stereoisomers called anomers -A six-membered cyclic sugar is called a pyranose, and a five-membered sugar ring is called a furanose - Ans:-The cyclic structures of sugars are called A. Chirality B. Haworth projections ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 2/212 C. Fischer projections D. Aromatic structure A. Starch Common disaccharides -Maltose, or malt sugar, is formally named α-D-glucopyranosyl [1↔4] β-D-glucopyranose -Cellobiose contains two glucose molecules joined by a beta glycoside bond and is formally named β-D- glucopyranosyl [1↔4] β-D-glucopyranose -Lactose contains a galactose residue joined by a beta glycoside bond to a glucose residue -Sucrose contains an alpha glucose joined to a beta fructose, and is formally named α-D-glucopyranosyl [1↔2] β-D-fructofuranoside - Ans:-Which of the following is not a disaccharide A. Starch B. Lactose C. Sucrose D. Maltose ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 3/212 C. Cellobiose Polysaccharides -Cellulose is poly [1↔4] β-glucose with beta glycoside bonds -Starch is poly [1↔4] α-glucose with alpha glycoside bonds -Chains of starch molecules can branch by forming [1↔6] glycoside bonds, which leads to more compact forms of starch, such as glycogen and amylopectin - Ans:-Which of the following is not a polysaccharide A. Cellulose B. Starch C. Cellobiose D. None of the above D. None of the above -In an alpha glycoside bond, the linking oxygen atom is pointed up, in the alpha position -In a beta glycoside bond, the linking oxygen atom is pointed down, in the beta position -Acetal and ketal bonds that connect monosaccharides into disaccharides ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 4/212 -All of the above - Ans:-Which of the following statement is false A. In an alpha glycoside bond, the linking oxygen atom is pointed up, in the alpha position B. In a beta glycoside bond, the linking oxygen atom is pointed down, in the beta position C. Acetal and ketal bonds that connect monosaccharides into disaccharides D. None of the above B. Proteins -Proteins—polymers of amino acids, which contain an amine functional group and a carboxylic acid functional group - Ans:-Organic molecule that contains polymers of amino acids, which contain an amine functional group and a carboxylic acid functional group A. Carbohydrates B. Proteins C. Nucleic Acids D. Lipids C. Nucleic Acids ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 5/212 -Nucleic acids—polymers of sugars joined together by phosphate ester linkages, which contain aromatic amines whose shape forms the chemical genetic code through hydrogen bonding - Ans:-Organic molecule that contains polymers of sugars joined together by phosphate ester linkages, which contain aromatic amines whose shape forms the chemical genetic code through hydrogen bonding A. Carbohydrates B. Proteins C. Nucleic Acids D. Lipids D. Lipids -Lipids—biomolecules that are more soluble in organic solvents than in water, and are largely composed of nonpolar hydrocarbon functional groups, in addition to a small proportion of polar functional groups that establish the form and function of the molecule - Ans:-Organic molecule that contains biomolecules that are more soluble in organic solvents than in water, and are largely composed of nonpolar hydrocarbon functional groups, in addition to a small proportion of polar functional groups that establish the form and function of the molecule A. Carbohydrates B. Proteins ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 6/212 C. Nucleic Acids D. Lipids D. None of the above Glycerides -Esters composed of glycerin (1, 2, 3-propantriol) and fatty acids -Triglycerides have three fatty acid residues esterfied to the glycerin backbone and are also known as triacyl glycerols Fatty Acids -Long-chained carboxylic acids -Naturally-occurring fatty acids always have an even number of carbon atoms -Saturated fatty acids have carbon chains that contain only carbon-carbon single bonds, and unsaturated fatty acids have carbon chains that contain at least one carbon-carbon double bond -Monounsaturated fatty acids have one carbon-carbon double bond in the chain, and polyunsaturated fatty acids have two or more double bonds in the carbon chain