Unit+4+Practice+Test+Page+1

M1. Which molecule is not a ribonucleoside? (A) Guanosine (B) Cytidine (C) Thymidine (D) Uridine (E) None of the above

M2. What cofactor participates in the key regulating step in purine synthesis? (A) Glutamate (B) Glycine (C) Glutamine (D) Formyl tetrahydrofolate (E) None of the above

M3. Colchine is used to treat Gout by: (A) Increasing uric acid clearance (B) Increasing secretion of xanthine and hypoxathine (C) Blocking aminotransferase (D) Preventing synthesis of prostaglandin H2 (E) Inhibiting microtubule assembly in leukocytes

M4. Adenosine deaminase deficiency results in: (A) Accumulation of dGTP (B) Lack of B cells, but normal T cells (C) Lack of T cells, but normal T cells (D) Lack of T cells and B Cells (E) Autoimmune disease

M5. What amino acid does NOT participates in purine synthesis? (A) Glu (B) Gln (C) Gly (D) Asp (E) Asn

M6. How many urea units are in purines and pyrimidines, respectively? (A) 1, 0 (B) 0, 1 (C) 1, 2 (D) 2, 1 (E) None of the above

M7. What are the stages of prophase I in meiosis I in order? (A) Leptotene, pachytene, zytotene, diplotene, diakinesis (B) Leptotene, zytotene, pachytene, diplotene, diakinesis (C) Diplotene, pachytene, zytotene, leptotene, diakinesis (D) Pachytene, leptotene, diplotene, zytotene, diakinesis (E) None of the above

M8. How many chromosome and chromatids are present in the secondary oocyte when it is arrested at metaphase II? (A) 23 chromosomes, 46 chromatids (B) 46 chromosomes, 23 chromatids (C) 46 chromosomes, 46 chromatids (D) 23 chromosomes, 23 chromatids (E) 46 chromosomes, 92 chromatids

M9. Sertoli cells function in: (A) Formation of the blood-renal barrier (B) Mitotic formation of spermatogonia (C) Production of testosterone (D) General architecture of semineferous epithelium (E) None of the above

M10. Primary spermatocyte and oocytes are formed: (A) Enzymatically (B) By mitosis only (C) By meiosis only (D) By meiosis and mitosis, respecitvely (E) By mitosis and meiosis, respectively

M11. Primary oocyte meiosis is arrested at: (A) Prophase I (B) Metaphase I (C) Metaphase II (D) A and B (E) A and C

M12. Synaptonemal complex forms during: (A) Leptotene (B) Zytotene (C) Pachytene (D) Diplotene (E) B and C, only

M13. Pyrimidine synthesis is regulated by (A) ATP (B) UDP (C) UTP (D) CTP (E) GTP

M14. What enzyme is part of the CAD protein? (A) Aspartate transcarbamoylase (B) Carbamoyl phosphate synthetase (C) Dihyrdoorotase dehydrogenase (D) A and B (E) A, B and C

M15. What is the function of methotrexate? (A) Block donation of single amine groups (B) Prevent reduction of dihydrofolate (C) Inhibit thymine synthesis (D) Increase renal clearance of uric acid (E) Treat Lesch-Nyhan Syndrome

M16. Phosphoryl transferase does NOT form: (A) ADP (B) CMP (C) dAMP (D) A and B only (E) A, B and C

M17. Ribonucleotide reductase (A) has two allosteric sites (B) is regulated by UTP (C) is inhibited by thioredoxin (D) catabolyzes purines (E) is deficient in SCID

M18. All of the following is true EXCEPT: (A) Absence of hypoxanthine-guanine phosphoribosyl transferase causes increase purine synthesis (B) Hereditary orotic aciduria is treated with oral uridine monophosphate (C) Aminopterin is a folate analog (D) Beta-aminoisobutyrate is a product of thymine degradation (E) Salvage pathways for cytosine do not exist (F) UMP Synthase is composed of orotate phosphoribosyl transferase and orotidylic acid decarboxylase

M19. Nucleosomes are made of all of the following EXCEPT: (A) H1 (B) H2A (C) H2B (D) H3 (E) H4

M20. Size nucleosomes wound into a turn make a: (A) Histone (B) Solendoid (C) Loop (D) Miniband (E) Stacked-miniband

M21. If a doubled stranded DNA has 10% C, what is the relative content of A? (A) 10% (B) 20% (C) 30% (D) 40% (E) None of the above

M22. What is the complementary sequence for 5’-GATTACA-3’ (A) 5’-CUAAUGU-3’ (B) 5’-UGUAAUC-3’ (C) 5’-TGTAATC-3’ (D) 5’-CTAATGT-3’ (E) 5’-ACATTAG-3’

M23. Intercalating agents (A) disrupt hydrogen bonding (B) lengthens and unwinds DNA (C) fits between phosphoanhydride bonds (D) unwinds RNA (E) caused DNA to bend

M24. G4 DNA differ from B-form DNA in that (A) The phosphate-sugar backbone in G4 DNA is zigzagged (B) G4 DNA resembles duplex RNA (C) G4 DNA is only formed in vitro (D) Hoogsteen covalent bonding stabilizes G4 DNA (E) Maintained by G-G-G base triple

M25. All of the following are part of chromosome arms EXCEPT (A) p arm (B) telomeres (C) chromatids (D) centromere (E) q arm

1t. Which of the following does not have an adenine nucleotide component?
 * 1) GTP
 * 2) NAD
 * 3) FAD
 * 4) CoA
 * 5) None of the above.

2t. What is/are the non oxidative glycolytic intermediate(s) in purine ring synthesis?
 * 1) ribose 5 phosphate
 * 2) fructose 1 phosphate
 * 3) glyceraldehydes 3 phosphate
 * 4) fructose 6 phospohate
 * 5) Answer C and D

3t. What is the first committed step in purine synthesis?
 * 1) PRPP --> 5 Phospho B D ribosylamine
 * 2) 5 phospho BD ribosylamine --> glycinamide ribosyl 5 phosphate
 * 3) Alpha D ribose --->PRPP
 * 4) Glycinamide ribosylamine 5 phosphate --> formylglycinamide ribosyl 5 phosphate
 * 5) Inosine monophosphate --> xanthosine monophosphate

4t. What is the function of glutamine in purine synthesis?
 * 1) carboxyl donor
 * 2) amino donor
 * 3) oxygen donor
 * 4) carbon donor
 * 5) hydroxyl donor

5t. How is purine nucleotide synthesis regulated?
 * 1) IMP
 * 2) ATP
 * 3) GDP
 * 4) PRPP
 * 5) Ribose 5 phosphate

6t. What is the function of Allopurinol?
 * 1) Positive regulation of guanase
 * 2) Negative regulation of purine nucleoside phophorylase
 * 3) Inhibit xanthine oxidase
 * 4) Inhibit adenosine deaminase
 * 5) Inhibit adenylosuccinate synthetase

7t. Which of the following are major end products of pyrimidine biosynthesis?
 * 1) UDP
 * 2) PRPP
 * 3) UTP
 * 4) CTP
 * 5) Both C and D

8t. What is the committed step in pyrimidine biosynthesis?
 * 1) aspartate transcarbamoylase
 * 2) dihydroorotase
 * 3) carbamoyl phosphate synthetase II
 * 4) thymidylate synthase
 * 5) CTP synthetase

9t. What is the result of a defect in the gene encoding UMPsynthase?
 * 1) deficiency in orotidine 5 P pyrophosphorylase
 * 2) deficiency in ribonucleotide reductase
 * 3) deficiency in orotidine 5 P decarboxylase
 * 4) Both A and B
 * 5) Both A and C

10t. What inhibits regulation of ribonucleotide reductase at the specificity site?
 * 1) dGTP
 * 2) dATP
 * 3) dCTP
 * 4) dCDP
 * 5) ADP

11t. What appears to be the cause of Lesch-Nyhan Syndrome?
 * 1) APRT
 * 2) UPRT
 * 3) HGPRT
 * 4) ATP
 * 5) dTTP

12t. Why do high levels of thymidine arrest growth cells?
 * 1) thymidine added to tissue culture cells block DNA synthesis
 * 2) pools of dTTP, dGTP and dATP are decreased
 * 3) pools of dCTP increased 10-fold
 * 4) increase PRPP
 * 5) none of the above

13t. Name two unique events happening in meiosis?
 * 1) genetic recombination
 * 2) centromere divdes in each division
 * 3) no pairing of homologous chromosomes
 * 4) in somatic cells
 * 5) nucleus has diploid number of chromosomes.

14t. How many cells will result from the completion of meiosis (choose best answer)?
 * 1
 * 4
 * 3
 * 1) 1 and 3
 * 2) 1 and 4

15t. The meiotic divisions during spermatogenesis produce spermatids containing how many chromosomes?
 * 23
 * 30
 * 46
 * 92

16t. What hormone stimulates leydig cells to produce testosterone?
 * LH
 * 1) FSH
 * 2) ACTH
 * GH

17t. After about 4-6 hours after fusion, the two sets of haploid chromosomes each become surrounded by distinct membranes and are known as?
 * 1) Zona pellecida
 * 2) Perivitellince space
 * 3) Cortical granules
 * 4) Pronuclei
 * 5) Cell membrane

18t. What stage of meiosis is the primary oocyte in during the embryonic phase?
 * 1) metaphase I
 * 2) prophase I
 * 3) prophase II
 * 4) Interphase I
 * 5) Diplotene

19t. What is the complement of this sequence: 5’ ACCGCCA 3’? a. 5’ACCGCCT 3’ b. 5’ TGGCGGT 3’ c. 5’ TGGCGGT 3’ d. 5’ ATCGCCA 3’ e. 5’ TCCGCTA 3’

20t. What is **primarily** responsible for the stability of a DNA helix? a. hydrogen bonding b. sulfur bridges c. hydrophobic interactions between planar bases d. hydrophilic interactions between planar bases e. hydrophobic nature of phosphate groups

21t. Intercalating agents interact with DNA by: a. interacting with phosphate groups b. disrupting hydrogen bonds c. binding to histones d. fitting between bases and resulting in the unwinding and lengthening of DNA e. none of the above

22t. In Fragile X syndrome, how many CGG repeats would we expect in the 5’ untranslated region in the FMR1 gene to give a full mutation? a. 6-50 repeats b. 50-200 repeats c. > 200 repeats d. Fragile X syndrome does not contain CGG repeats e. none of the above

23t. Enzymes that recognize and cleave specific DNA sequences. Often a palindrome. a. restriction endonucleases b. helicase c. topoisomerase d. RFLP e. DNA cleavase

24t. Working hard in lab one night, Michael needed to identify specific DNA sequences in a mixture of DNA. What type of Blot would he use? a. Western Blot b. Southwestern Blot c. Northwestern Blot d. Far Western Blot e. Southern Blot

25t. Choose the correct sequence to prepare chromosomes for karyotyping. a. heparinize blood --> Add colchicines --> hypotonic solution --> stain b. separation of lympocytes --> add colchicines --> heparinize blood --> stain c. air dry --> hypotonic solution --> add colchicines --> stain --> heparinize blood d. culture --> heparinize blood --> culture --> air dry --> hypotonic solution e. stain --> air dry --> hypotonic solution --> culture --> add colchicines

Answer Key

M1. C (p.8) M2. C (p.10) M3. E (p.13) M4. D (p.14) M5. E (p.10) M6. D (p.8) M7. B (p.33) M8. A (p.36) M9. D (p.41) M10. E (p.40, 48) M11. E (p.45) M12. B (p.34) M13. C (p.18) M14. D (p.16) M15. B (p.22) M16. E (p.25) M17. A (p.21) M18. B (p.20) M19. A (p.65) M20. B (p.65) M21. D (p.69) M22. C (p.71-72) M23. B (p.76) M24. E (p.86) M25. D (p.123) M26. E (p.126) M27. C (p.133) M28. A (p.139-140) M29. D (p.130) M30. D (p.148)

t1. a pg 7 t2. e pg 9 t3. b pg 11 t4. b pg 11 t5. a pg 12 t6. c pg 13 t7. c pg 18 t8. c pg 18 t9. e pg 20 t10. a pg 21 t11. c pg 25 t12. a t13. a pg 32 t14. e t15. a pg 43 t16. a pg 43 t17. d pg 51 t18. b pg 45 19t. B pg 71 20t. C pg 74 21t. D pg 76 22t. C pg 99 23t. A pg 103 24t. E pg 108 25t. A pg 126 26t. E pg 129 27t. E pg 133 28t. B pg 150 29t. A pg 140 30t. E pg 148