VIP Final Bio MCQ-101 Wazery (2) PDF

## DNA Structure and Function - A nucleoside consists of: - Purine or pyrimidine base + sugar + phosphorus - DNA function is: - Carry genetic information - Which of the following components are found in DNA: - A phosphate group, guanine and deoxyribose - The interconnecting bonds that c...

## DNA Structure and Function - A nucleoside consists of: - Purine or pyrimidine base + sugar + phosphorus - DNA function is: - Carry genetic information - Which of the following components are found in DNA: - A phosphate group, guanine and deoxyribose - The interconnecting bonds that connect the nucleotides of DNA & RNA are termed: - 3'-5' phosphodiester linkages - In nucleic acid, nucleotides are linked together by: - phosphodiester bond - The linkage between pentoses and nitrogenous bases in a DNA molecule: - N-glycosidic bond. ## Proteins - The most abundant protein in mammals is: - Collagen - The number of helices present in a collagen molecule is: - 2 - Collagen has a triple helix structure in which every third amino acid is: - Glycine - Defects in collagen synthesis: - Results from deficiency of vitamin C - Gelatin is a simple protein characterized by: - It derived from collagen - Doesn't gel on cooling ## Lipids - All of the following are antioxidants EXCEPT: - Vitamin K - Which of the following is not an antioxidant: - Vitamin K - Which of the following has the highest antioxidant activity? - Vitamin E - The most potent antioxidant is: - Vitamin E - Esters of fatty acids with high molecular weight alcohols are: - Waxes - If the fatty acid is esterified with an alcohol of high molecular weight instead of glycerol, the resulting compound is: - Wax ## DNA Replication - The model for DNA replication first proposed by Watson and Crick's postulated that every newly replication double stranded duplex DNA molecule: - Contained two strands that are random mixtures of new & old DNA - within each strand - Given that DNA polymerases are unable to synthesize DNA without a primer, what molecule serve as the primer for these enzymes during replication? - A short RNA molecule - During DNA replication, The letter "P" in the diagram denotes: - DNA polymerase ## Proteins - Casein, the milk protein is a: - Phosphoprotein - Which of the following is an example of metalloprotein? - Ferritin - A protein rich in cysteine is: - Keratin - An example of a metalloprotein is: - Ferritin - Concerning hemoglobin, which statement is true: - Fe+2 binds to nitrogens of (tetra pyrrole rings)heme - It is monomeric protein - Its B-chain contains valine in position 6 - Fetal hemoglobin contains: - Two a and two y chains - Hemoglobin: - Is a conjugated protein ## DNA & RNA - In a DNA double helix, cytosine base in one strand forms a chemical bond with: - Guanine - They bind with the help of: - hydrogen bonds - The genetic code for each amino acid is formed of: - 3 nucleotides - Most of the RNA is found in: - Cytoplasm ## Transcription and Translation - mRNA is formed from DNA by an enzyme called: - Transcriptase - What disease is often associated with a breakdown of a cell's ability to regulate/control its own division? - Cancer - Match the following statements which explain the types of DNA mutations: | Mutation | Description | |---|---| | Transition | Replacement of a pyrimidine with another pyrimidine base | | Disturbed reading frame | Deletion of one or more bases from a DNA sequence| | Transversion | Replacement of a pyrimidine with a purine base | | Alkylation of DNA bases | | | Deletion | | | Formation of a T-T dimer | | - The mechanism through which RNAs are synthesized from DNA is: - Transcription - Match the following statements regarding the order of transcription steps: | Transcription Step | Order | |---|---| | Promoter recognition by sigma factor of RNA polymerase | 1 | | Local unwinding of DNA double helix | 2 | | Chain elongation | 3 | | Initiation of polymerization | 4 | | Chain termination | 5 | - The site to which RNA polymerase binds on the DNA template prior the initiation of transcription: - Promoter - The DNA segment from which the primary transcript is copied or transcribed is called: - Coding region - The enzyme that synthesizes RNA from a double stranded DNA template is: - DNA dependent RNA polymerase - The discontinues DNA replication that occurs during is catalyzed via the production of small DNA segments termed: - Okazaki fragments ## Protein Structure and Function - During denaturation of proteins, all of the following are destroyed EXCEPT: - Primary structure - During denaturation of proteins, there is a change in all of the following; except: - Primary structure - During denaturation of proteins, which of the following structure is not destroyed: - Primary structure - Denaturation of protein include break down of all structure EXCEPT: - Primary structure - Results of denaturation of proteins include the following except: - Loss of catalytic activity of enzymes - Loss of biological function as hormones - Decreased solubility and increased viscosity - Loss of the native primary structure of the protein - In Alzheimer's disease: - The protein a-amyloid is increased - The protein B-amyloid is increased - One of the following is considered a simple protein: - Gelatin - One of the following is considered a simple protein: - Albumin - Histones are: - Proteins rich in lysine and arginine - An example of scleroprotein is: - Keratin ## Lipids - Phospholipid is considered: - Complex lipid - In mammals, the major fat stored in adipose tissue is: - Triacylglycerol - Lipids are stored in the form of: - Triacylglycerol - Hydrogenation is: - to unsaturated - Deterioration of food (rancidity) is due to presence of: - Peroxidation of lipids - Unpleasant odour or taste in fat (rancidity) can be delayed or prevented by the addition of: - Vitamin E ## Glycosphingolipids - Glycosphingolipids are a combination of: - Ceramide with one or more sugar residues - Gangliosides derived from glucosylceramide contain in addition one or more molecules of: - Sialic acid - Gangliosides are complex glycosphingolipids found in: - Brain ## Protein Structure - The a-helix of polypeptide chain is stabilized: - By hydrogen bonds formed between peptide bonds of polypeptide chains - In proteins the a-helix and ẞ-pleated sheet are examples of: - Secondary structure - Tertiary structure of a protein describes: - The secondary structural arrangements to form domains - A tetrameric protein: - Has tertiary & quaternary structure - Types of protein bonds include the following: - Peptide bond - Hydrogen bond - Salt bridges - Denaturation of proteins results in: - Disruption of primary structure - Destruction of hydrogen bonds - Irreversible changes in the molecule - Denaturation of **except all of the following are disrupted except**: - Primary structure - A homodimeric protein: - Has 2 identical polypeptide chains ## Amino Acids - All amino acids contain negatively charged side chains: - False - A Zwitterion is: - None of these - Which statement describes a Zwitterion? - It has equal positive and negative charges - The net charge on a protein: - Is determined by the nature of ionizing groups on the protein. - Isoelectric point of amino acids is used for: - Crystallization - Precipitation - Solubility - At an acidic pH, the amino acid exists a: - Cation - All of the following are considered derived amino acids except: - Proline - All the following are true about Desmosine EXCEPT: - it is considered one of the normally existing 20 amino acids in the body - Which statement is not true regarding Desmosine: - it is not encoded by DNA genome ## Proteins - It is considered one of the normally existing 20 amino acids in the body: - False - Which of the following amino acid has no genetic code: - Hydroxy lysine - Globular proteins have completely folded, coiled polypeptide chain and the axial ratio (ratio of length to width) is: - Less than 10 - One of the following is a polypeptide in the primary and secondary structure: - Collagen - Regarding protein conformation: - Tertiary structure is formed by hydrogen bonds between peptide bonds- - Disulfide bonds stabilize primary structure - A dimer protein consists of one polypeptide chain - Quaternary structure is present in multi-chain proteins - Which of the following is a tripeptide: - Glutathione - What is the following is a dipeptide? - Glycylalanine - The polypeptide groups are the same distance apart in: - α-Helix ## Amino Acids - Which among the following is an essential amino acid? - Leucine - Non essential amino acids: - Can be synthesized in the body from essential amino acids - May be synthesized in the body in diseased states - an essential glucogenic amino acid is: Alanine - A high biological value protein should: - Contain all the essential amino acids - Regarding vegetable proteins, they are considered of low biological value due to: - Deficiency of one or more essential amino acids - All the following amino acids are essential Except: - Tyrosine ## Miscellaneous - Essential amino acids are characterized by: - They are synthesized in the body - Proteins containing all of them are called protein of high biological value. - They are synthesized in the body - The optically inactive amino acid is: - Glycine - All amino acids are optically active except: - Glycine - Proteins in human body contain: - Only L- amino acids - All of the following are considered derived proteins EXCEPT: - Collagen - They can't be precipitated in an electric field - The true statement about solutions of amino acids at physiological pH is: - All amino acids contain both positive and negative charges - The net charge on a protein is determined by the nature of ionizing groups on the protein - Which of the following is a pure ketogenic amino acid: - Leucine - All amino acids contain positively charged side chains: - False - Some amino acids contain only negative charge: - False