Molecular Medicine Quiz 2014

Martin Nicklin

1. Which chemical element is not present in human DNA or RNA but is normally incorporated into growing protein chains during translation (or choose F)?

A. nitrogen (N)B. oxygen (O)C. phosphorus (P)D. chlorine (Cl)E. sulphur (S)F. Actually, all of the

above are present.

y

1. Which chemical element is not present in human DNA or RNA but is normally incorporated into growing protein chains during translation (or choose F)?

A. nitrogen (N)B. oxygen (O)C. phosphorus (P)D. chlorine (Cl)E. sulphur (S)F. Actually, all of the

above are present.

y

2. Which sugar moiety is the backbone sugar component present in DNA (or select F)?

A. ribuloseB. 2-deoxyriboseC. riboseD. 3-deoxyribuloseE. 2,3-dideoxyriboseF. none of the above are

present

a

2. Which sugar moiety is the backbone sugar component present in DNA (or select F)?

A. ribuloseB. 2-deoxyriboseC. riboseD. 3-deoxyribuloseE. 2,3-dideoxyriboseF. none of the above are

present

a

3. Which pair is odd man out (that is, has not the same internal relationship as the other pairs)? Choose F if all have the same relationship.

A. Glucose and glycogenB. Galactose and polysaccharideC. Thymidylic acid and DNAD. Alanine and proteinE. Adenine and mRNAF. All pairs are related in a similar way

b

3. Which pair is odd man out (that is, has not the same internal relationship as the other pairs)? Choose F if all have the same relationship.

A. Glucose and glycogenB. Galactose and polysaccharideC. Thymidylic acid and DNAD. Alanine and proteinE. Adenine and mRNAF. All pairs are related in a similar wayAdenine is a base, not a whole nucleotide subunit.

All of the other pairs are possible subunits and polymers that contain them (after condensation reactions involving the loss of water). b

4. Where, in this nucleoside, is the 5’-hydroxyl ? (Hint: it’s the hydroxyl that is usually phosphorylated)

a

<=D

A=>

<=C

<=B

E=>

<=F

4. Where, in this nucleoside, is the 5’-hydroxyl ? (Hint: it’s the hydroxyl that is usually phosphorylated)

a

<=D

A=>

<=C

<=B

E=>

<=F

1’2’3’

4’

5’ 98

76

1

24

5

3

23

5. The diagram shows a two base-pair segment of a DNA double helix. Which of the following is true (or select F)?

A. The orange ellipses mark bonds potentially cleaved by DNase I.B. The magenta bonds are base-stacking interactionsC. The sequence of one strand is 5’-T-G-3’D. The rings of the 2-deoxyribose moieties contain yellow circles.E. The blue carbon atom could be the site of CpG methylation.

F. Actually, none of the above are true.

5. The diagram shows a two base-pair segment of a DNA double helix. Which of the following is true (or select F)?

A. The orange ellipses mark bonds potentially cleaved by DNase I.B. The magenta bonds are base-stacking interactionsC. The sequence of one strand is 5’-T-G-3’D. The rings of the 2-deoxyribose moieties contain yellow circles.E. The blue carbon atom could be the site of CpG methylation.

F. Actually, none of the above are true.

6. Which of the following elements, as part of an amino acid, is never incorporated in human proteins during translation (or select F)?

A. sulphurB. oxygen C. iodine D. selenium E. carbonF. All of the above are incorporated during translation

e

6. Which of the following elements, as part of an amino acid, is never incorporated in human proteins during translation (or select F)?

A. sulphurB. oxygen C. iodine D. selenium [as selenocysteine at a few TGA codons]E. carbonF. All of the above are incorporated during translation

e

7. Mentally trace a route along the backbone of a DNA or RNA molecule. Which of the following sequence of atoms is connected by bonds in a continuous sequence? (or select F)?

A. -P-O-C-C-O-P-O-C-C-O-B. -O-P-O-C-C-C-O-P-O-C-C-C-C. -C-O-P-O-C-N-C-C-O-P-O-C-N-C-D. -H-C-C-O-N-H-C-C-O-N-E. -O-P-C-O-P-C-F. None of the above is correct

h

7. Mentally trace a route along the backbone of a DNA or RNA molecule. Which of the following sequence of atoms is connected by bonds in a continuous sequence? (or select F)?

h

A. -P-O-C-C-O-P-O-C-C-O-B. -O-P-O-C-C-C-O-P-O-C-C-C-C. -C-O-P-O-C-N-C-C-O-P-O-C-N-C-D. -H-C-C-O-N-H-C-C-O-N-E. -O-P-C-O-P-C-F. None of the above is correct

8. Which of the following is false (or select F)?

A. 18F is the synthetic radioactive isotope of fluorine used as a label in positron emission imaging.

B. Tritium, 3H, is a heavy radioactive isotope of hydrogen that has been traditionally used to label thymidine to demonstrate DNA replication.

C. 15N, a rare natural heavy stable isotope of nitrogen. It was used to label new strands of DNA, so they could be separated by their density in the original studies of the mechanism of DNA replication.

D. 12C is a radioactive isotope of carbon that may be used to trace any organic compound in which it has been incorporated.

E. 32P is a radioactive isotope of phosphorus that can be used to trace nucleic acids that are synthesised to contain it.

A. Actually, all of the above are true.

8. Which of the following is false (or select F)?

A. 18F is the synthetic radioactive isotope of fluorine used as a label in positron emission imaging.

B. Tritium, 3H, is a heavy radioactive isotope of hydrogen that has been traditionally used to label thymidine to demonstrate DNA replication.

C. 15N, a rare natural heavy stable isotope of nitrogen. It was used to label new strands of DNA, so they could be separated by their density in the original studies of the mechanism of DNA replication.

D. 12C is a radioactive isotope of carbon that may be used to trace any organic compound in which it has been incorporated. (It’s the predominant stable isotope!)

E. 32P is a radioactive isotope of phosphorus that can be used to trace nucleic acids that are synthesised to contain it.

A. Actually, all of the above are true.!!

9. Which description of an amino acid residue is incorrect (or select F)?

A. aromatic tyrosine (Tyr, Y)B. non-polar valine (Val, V)C. charged arginine (Arg, R)D. neutral and polar glutamine (Gln, Q)E. sulphur-containing cysteine (Cys, C)F. All of the descriptions are appropriate

28

Amino Acid Description

9. Which description of an amino acid residue is incorrect (or select F)?

A. aromatic tyrosine (Tyr, Y)B. non-polar valine (Val, V)C. charged arginine (Arg, R)D. neutral and polar glutamine (Gln, Q)E. sulphur-containing cysteine (Cys, C)F. All of the descriptions are appropriate

28

Amino AcidDescription

10. Which chemical element is present in all nucleic acid but absent from nascent polypeptides?

A. oxygen (O)B. sulphur (S)C. chlorine (Cl)D. phosphorus (P)E. nitrogen (N)F. Actually, all of the

above are present in both.

y

10. Which chemical element is present in all nucleic acid but absent from nascent polypeptides?

A. oxygen (O)B. sulphur (S)C. chlorine (Cl)D. phosphorus (P)E. nitrogen (N)F. Actually, all of the

above are present in both.

y

11. Which of the following is not required for a polymerase chain reaction reaction involving a thermophilic DNA polymerase (or select F)?

A. A DNA templateB. thermophilic DNA ligaseC. deoxy-nucleotide triphosphates or their

analoguesD. waterE. Divalent cationsF. All of the above are needed

j

11. Which of the following is not required for a polymerase chain reaction reaction involving a thermophilic DNA polymerase (or select F)?

A. A DNA templateB. thermophilic DNA ligaseC. deoxy-nucleotide triphosphates or their

analoguesD. waterE. Divalent cationsF. All of the above are needed

j

12. mRNA generation from primary RNA transcripts involves the removal of intron sequences. What is this process called (or select F)?

A. SplicingB. TranscriptionC. RecombinationD. CollusionE. Frame shiftingF. None of the above.

b

12. mRNA generation from primary RNA transcripts involves the removal of intron sequences. What is this process called (or select F)?

A. SplicingB. TranscriptionC. RecombinationD. CollusionE. Frame shiftingF. None of the above.

b

13. The segments of RNA that are lost after conversion of a pre-mRNA to a mature mRNA are called

A. CodonsB. PolymorphismsC. IntronsD. ExonsE. Splice boundariesF. None of the above.

b

13. The segments of RNA that are lost after conversion of a pre-mRNA to a mature mRNA are called

A. CodonsB. PolymorphismsC. IntronsD. ExonsE. Splice boundariesF. None of the above.

b

14. Which of the following does not happen to proteins post-translationally within the cell (or select F)?

A. Sugar moieties may be attached at the side-chain nitrogen of asparagine.

B. Peptide bonds may be selectively cleavedC. A phosphate may be added to the side-chain oxygen

of threonine.D. A methyl group may be added to the side-chain

nitrogen of lysine.E. Disulphide bonds –S-S- may be created by oxidising

pairs of -SH groups. F. Actually, all of the above occur, post-translationally.

c

14. Which of the following does not happen to proteins post-translationally within the cell (or select F)?

A. Sugar moieties may be attached at the side-chain nitrogen of asparagine.

B. Peptide bonds may be selectively cleavedC. A phosphate may be added to the side-chain oxygen

of threonine.D. A methyl group may be added to the side-chain

nitrogen of lysine.E. Disulphide bonds –S-S- may be created by oxidising

pairs of -SH groups. F. Actually, all of the above occur, post-translationally.

c

15. Molecular hybridisation of nucleic acids means (or select F)?

A. Mixing and joining of complementary DNA or RNA from different species of organism.

B. The non-covalent association of similar double stranded nucleic acid molecules.

C. The covalent joining of two complementary single-stranded DNA or RNA molecules.

D. The specific non-covalent association of two complementary or partially complementary single-stranded nucleic acid strands.

E. The molecular association of two single-stranded fragments of DNA or RNA with identical sequences.

F. None of the above.

m

15. Molecular hybridisation of nucleic acids means (or select F)?

A. Mixing and joining of complementary DNA or RNA from different species of organism.

B. The non-covalent association of similar double stranded nucleic acid molecules.

C. The covalent joining of two complementary single-stranded DNA or RNA molecules.

D. The specific non-covalent association of two complementary or partially complementary single-stranded nucleic acid strands.

E. The molecular association of two single-stranded fragments of DNA or RNA with identical sequences.

F. None of the above.

m

3

0

6

14

3

1

16. Which of the following DNA sequence pairs are complementary?

A. 5’-AACTACTGG and 5’-AACTACTGG.B. 5’-TCAGAATCG and 5’-CGATTCTGA.C. 5’-GACTGGACC and 5’-CCAGGTCAC.D. 5’-CCCGTAATA and 5’-GGGCATTAT.E. 5’-GACATAGTC and 5’-GACATAGTC.F. None of the above are complementary.

16. Which of the following DNA sequence pairs are complementary?

A. 5’-AACTACTGG and 5’-AACTACTGG.B. 5’-TCAGAATCG and 5’-CGATTCTGA.C. 5’-GACTGGACC and 5’-CCAGGTCAC.D. 5’-CCCGTAATA and 5’-GGGCATTAT.E. 5’-GACATAGTC and 5’-GACATAGTC.F. None of the above are complementary.

17. Which is the direction that DNA or RNA polymerases synthesises a new complementary

strand (or select F)?

A. from the 2’ end to the 5’ end.B. from the 3’ end to the 5’ end.C. from the 5’ end to the 2’ end.D. from the 5’ end to the 3’ end.E. from the 5’ end to the 5’ end.F. All of the above are incorrect.

k

17. Which is the direction that DNA or RNA polymerases synthesises a new complementary

strand (or select F)?

A. from the 2’ end to the 5’ end.B. from the 3’ end to the 5’ end.C. from the 5’ end to the 2’ end.D. from the 5’ end to the 3’ end.E. from the 5’ end to the 5’ end.F. All of the above are incorrect.

k

18. Which statement is not true? (or choose F)

What has been called the “universal” genetic code...

A. indicates how mRNA is transcribed into protein.

B. applies to triplets of nucleotides.C. does not apply to protein synthesis in

mitochondria.D. shows redundancy (there being more than

one codon for most amino-acids).E. always includes the de-coding of “AUG” as

methionine. F. All of these statements are true.

18. Which statement is not true? (or choose F)

What has been called the “universal” genetic code...

A. indicates how mRNA is transcribed into protein.

B. applies to triplets of nucleotides.C. does not apply to protein synthesis in

mitochondria.D. shows redundancy (there being more than

one codon for most amino-acids).E. always includes the de-coding of “AUG” as

methionine. F. All of these statements are true. (translated!!) L

19. Which of the following sets of codons would end the coding sequence of genes[they are “nonsense” (stop) codons] in humans and Escherichia coli?

A. UGA, UAA, UAGB. ATG, ATC, ATAC. TCA, TTA, CTAD. TAG, TAA, TGAE. AUG, TGA, TTTF. None of the above sets represent a set of

stop codons that might terminate the sense seqiuence of a gene.

o

19. Which of the following sets of codons would end the coding sequence of genes[they are “nonsense” (stop) codons] in humans and Escherichia coli?

A. UGA, UAA, UAG [gene, not mRNA]B. ATG, ATC, ATAC. TCA, TTA, CTAD. TAG, TAA, TGA [It’s DNA!]E. AUG, TGA, TTTF. None of the above sets represent a set of

stop codons that might terminate the sense seqiuence of a gene.

o

20. Which of the following is not a sequence-specific DNA location where transcription factors bind and regulate gene expression in human cells (or select F)?

A. A promoterB. A Shine-Dalgarno sequenceC. A TATAA boxD. A locus control elementE. An enhancerF. All of the above are involved in

transcriptional control

q

20. Which of the following is not a sequence-specific DNA location where transcription factors bind and regulate gene expression in human cells (or select F)?

A. A promoterB. A Shine-Dalgarno sequenceC. A TATAA boxD. A locus control elementE. An enhancerF. All of the above are involved in

transcriptional control

q

(SD is ribosomal entry site in prokaryotic RNA)

21. Which one of the following enzymes catalyses ribosomal RNA (rRNA) synthesis in the eukaryotic nucleus (or select F)?

A. RNA polymerase IIB. AMV reverse transcriptaseC. RNA polymerase ID. SP6 polymeraseE. RNA polymerase IIIF. None of the above catalyse rRNA synthesis

30

21. Which one of the following enzymes catalyses ribosomal RNA (rRNA) synthesis in the eukaryotic nucleus (or select F)?

A. RNA polymerase IIB. AMV reverse transcriptaseC. RNA polymerase ID. SP6 polymeraseE. RNA polymerase IIIF. None of the above catalyse rRNA synthesis

30

22. In which of the following situations may the polymerase chain reaction occur?

A. During the replication of retroviruses.B. During a DNA-replication cycle of a thermophilic

bacterium.C. In a test tube in a thermocycler.D. During a replication cycle of mitochondrial DNA.E. In ancient DNA.F. None of the above.

td

22. In which of the following situations may the polymerase chain reaction occur?

A. During the replication of retroviruses.B. During a DNA-replication cycle of a thermophilic

bacterium.C. In a test tube in a thermocycler.D. During a replication cycle of mitochondrial DNA.E. In ancient DNA.F. None of the above.

PCR is an entirely unnatural process!

23. Which of the following is not required for all natural template-directed DNA synthesis in vivo (or select F)?

A. A DNA polymeraseB. dTTPC. dATPD. A DNA templateE. A primer that hybridises to the templateF. Actually, all of the above are required.

w

23. Which of the following is not required for all natural template-directed DNA synthesis in vivo (or select F)?

A. A DNA polymeraseB. dTTPC. dATPD. A DNA template [Reverse transcriptases can

use an RNA template]E. A primer that hybridises to the templateF. Actually, all of the above are required.

24. Which of the following is not true of transcript processing in human cells (or select F)?

A. Introns usually represent the greater part of a primary transcript.

B. Exons are removed from pre-mRNA in the nucleus by splicing during and after transcription.

C. The 5’ nucleotide cap structure is added to all transcripts.

D. The poly-A tail is added when the mRNA is complete but before the completion of splicing.

E. replication-phase histone mRNA transcripts do not have a poly-A tail.

F. Actually, all of the statements above are true. ta

24. Which of the following is not true of transcript processing in human cells (or select F)?

A. Introns usually represent the greater part of a primary transcript.

B. Exons are removed from pre-mRNA in the nucleus by splicing during and after transcription.

C. The 5’ nucleotide cap structure is added to all transcripts.

D. The poly-A tail is added when the mRNA is complete but before the completion of splicing.

E. replication-phase histone mRNA transcripts do not have a poly-A tail.

F. Actually, all of the statements above are true. ta

25. Mentally trace a route along the main chain (the backbone) of a protein following only the atoms that make the chain. Which of the following sequence of atoms is connected (or select F)?

A. -N-H-C-C-O-N-H-C-C-O-B. -N-C-C-N-C-C-C. -N-C-C-O-N-C-C-O-D. -N-C-N-C-E. -N-C-C-O-H-N-C-C-O-F. None of the above are

correct

d

25. Mentally trace a route along the main chain (the backbone) of a protein following only the atoms that make the chain. Which of the following sequence of atoms is connected (or select F)?

A. -N-H-C-C-O-N-H-C-C-O-B. -N-C-C-N-C-C-C. -N-C-C-O-N-C-C-O-D. -N-C-N-C-E. -N-C-C-O-H-N-C-C-O-F. None of the above are

correct

d

26. Which of the following is false (or select F)?

The activity of transcription at a specific location in the genome can be regulated by localised…

A. methylation of cytosine basesB. methylation of lysine residues in

histonesC. acetylation of lysine residues in

histonesD. deamination of cytosine basesE. deacetylation of lysine residues in

histonesF. all of the above are true.

26. Which of the following is false (or select F)?

The activity of transcription at a specific location in the genome can be regulated by localised…

A. methylation of cytosine basesB. methylation of lysine residues in

histonesC. acetylation of lysine residues in

histonesD. deamination of cytosine basesE. deacetylation of lysine residues in

histonesF. all of the above are true.

27. Which of the following statements is most correct? A codon is a sequence of three nucleotides…

A. …present in an exposed loop of each amino-acyl tRNAs. The codon is used for recognising a complementary anti-codon of mRNA and thus specifying an individual amino acids for insertion by the translational machinery into a growing polypeptide chain.

B. …present in a mRNA molecule. A codon is involved in selecting a unique species of amino-acyl tRNA through its complementary anti-codon sequence for binding at the “A” site of a ribosome and thus specifies the amino acids that are inserted in a growing polypeptide chain.

C. …present in mRNA. A particular codon specifies a unique amino acids for insertion by the translational machinery into a growing polypeptide chain.

A. …present in a tRNA molecule. Each codon associates with the mRNA on a ribosome during translation. A codon, in effect, specifies an individual amino acid according to the mRNA sequence, for insertion by the translational machinery into a growing polypeptide chain.

A. …that is not correctly described by any of the statements above. te

27. Which of the following statements is most correct? A codon is a sequence of three nucleotides…

A. …present in an exposed loop of each amino-acyl tRNAs. The codon is used for recognising a complementary anti-codon of mRNA and thus specifying an individual amino acids for insertion by the translational machinery into a growing polypeptide chain.

B. …present in a mRNA molecule. A codon is involved in selecting a unique species of amino-acyl tRNA through its complementary anti-codon sequence for binding at the “A” site of a ribosome and thus specifies the amino acids that are inserted in a growing polypeptide chain.

C. …present in mRNA. A particular codon specifies a unique amino acids for insertion by the translational machinery into a growing polypeptide chain.

A. …present in a tRNA molecule. Each codon associates with the mRNA on a ribosome during translation. A codon, in effect, specifies an individual amino acid according to the mRNA sequence, for insertion by the translational machinery into a growing polypeptide chain.

A. …that is not correctly described by any of the statements above.

28. In human blood erythrocytes, which of the following statements is true (or select F)?

A. X-linked genes in women are present in a single copy.

B. The great majority of genes are present in two copies.

C. X-linked genes are absent from in male erythrocytes. D. There are two copies of the mitochondrial genome. E. Women have two copies of all human genes. F. All the statements above are wrong.

f

28. In human blood erythrocytes, which of the following statements is true (or select F)?

A. X-linked genes in women are present in a single copy.

B. The great majority of genes are present in two copies.

C. X-linked genes are absent from in male erythrocytes. D. There are two copies of the mitochondrial genome. E. Women have two copies of all human genes. F. All the statements above are wrong.

Less specifically-- all genes are absent!

f

29. In circulating human male leukocytes, which of the following statements is true (or select F)?

A. The Y chromosome in men is present in a single copy per nucleus.

B. Men’s leukocytes have no X chromosomes.C. All genes are present in two copies per nucleus. D. Men have two copies of each Y-linked gene. E. Mitochondrial genes are absent. F. All the statements above are wrong.

f

29. In circulating human male leukocytes, which of the following statements is true (or select F)?

A. The Y chromosome in men is present in a single copy per nucleus.

B. Men’s leukocytes have no X chromosomes.C. All genes are present in two copies per nucleus. D. Men have two copies of each Y-linked gene. E. Mitochondrial genes are absent. F. All the statements above are wrong.

30. Which of the following statements is in error by at least a factor of ten ? (or select F)?

A. Each human sperm nucleus contains 1 m of DNA.B. Free-living bacteria have 5,000 protein encoding

genes.C. A single copy of the human genome contains 3100

million base pairs of DNA.D. Humans have 300,000 protein-encoding genes.E. A single copy of a free-living bacterial genome

contains 10 million base pairs.

F. All of the above are fair estimates.

g

30. Which of the following statements is in error by at least a factor of ten ? (or select F)?

A. Each human sperm nucleus contains 1 m of DNA.B. Free-living bacteria have 5,000 protein encoding

genes.C. A single copy of the human genome contains 3100

million base pairs of DNA.D. Humans have 300,000 protein-encoding genes.E. A single copy of a free-living bacterial genome

contains 10 million base pairs.

F. All of the above are fair estimates.

31. Estimate the proportion of RNA in a human cell that is not mRNA?

A. 0.5%B. 5%C. 20%D. 50%E. 95%F. 99%

x

31. Estimate the proportion of RNA in a human cell that is not mRNA?

A. 0.5%B. 5%C. 20%D. 50%E. 95%F. 99%

x

32. In the organisation of genes in mammals, which statement is false (or F)?

A. The initiation codon must lie in an exon.B. A transcription promoter usually lies upstream of

or surrounds the transcription start.C. An enhancer for a gene can lie inside a

neighbouring geneD. The polyadenylation signal lies in the last exon.E. The stop codon of a functional coding sequence

cannot lie in an intron of the encoding gene.F. All of the above statements are true

x

32. In the organisation of genes in mammals, which statement is false (or F)?

A. The initiation codon must lie in an exon.B. A transcription promoter usually lies upstream of

or surrounds the transcription start.C. An enhancer for a gene can lie inside a

neighbouring geneD. The polyadenylation signal lies in the last exon.E. The stop codon of a functional coding sequence

cannot lie in an intron of the encoding gene.F. All of the above statements are true

33. A small molecule leaves a human cell that is suspended in culture medium. Which is the last cell-associated polymer that the molecule is likely to encounter (or F)?

A. cholesteryl estersB. polypeptide (protein)C. nucleic acidD. phospholipidsE. polysaccharideF. The molecule cannot encounter any of the above.

33. A small molecule leaves a human cell that is suspended in culture medium. Which is the last cell-associated polymer that the molecule is likely to encounter (or F)?

A. cholesteryl estersB. polypeptide (protein)C. nucleic acidD. phospholipidsE. polysaccharideF. The molecule cannot encounter any of the above.

34. Which of the following statements about the endoplasmic reticulum (ER) is false (or select F)?

A. Membrane-bound vesicles leave the ER to carry proteins into the Golgi apparatus.

B. Rough ER is the site of the synthesis of secreted proteins.

C. Signalase clips off signal peptides from secreted proteins in the lumen of the ER.

D. Smooth ER is so named because in electron microscopy it contains no ribosomes.

E. Rough ER is the site of synthesis of mitochondrial proteins.

F. Actually, all of the above statements are true.

34. Which of the following statements about the endoplasmic reticulum (ER) is false (or select F)?

A. Membrane-bound vesicles leave the ER to carry proteins into the Golgi apparatus.

B. Rough ER is the site of the synthesis of secreted proteins.

C. Signalase clips off signal peptides from secreted proteins in the lumen of the ER.

D. Smooth ER is so named because in electron microscopy it contains no ribosomes.

E. Rough ER is the site of synthesis of mitochondrial proteins.

F. Actually, all of the above statements are true.

35. Which answer does not correctly identify a function that is performed by the following organelles in human cells (or select F)?

A. The Golgi body modifies proteins for redirection to the plasma membrane.

B. Desmosomes are points of anchorage for cell membranes to the extracellular matrix

C. Chloroplasts harvest light energy to reduce NADP+ for photosynthesis.

D. Mitochondria release cytochrome c into the cytoplasm to trigger cell death.

E. Nucleoli are the sites for ribosomal RNA synthesis. F. All of the above are true in humans.

p

35. Which answer does not correctly identify a function that is performed by the following organelles in human cells (or select F)?

A. The Golgi body modifies proteins for redirection to the plasma membrane.

B. Desmosomes are points of anchorage for cell membranes to the extracellular matrix

C. Chloroplasts harvest light energy to reduce NADP+ for photosynthesis.

D. Mitochondria release cytochrome c into the cytoplasm to trigger cell death.

E. Nucleoli are the sites for ribosomal RNA synthesis. F. All of the above are true in humans.

36. Which is false? (or indicate F if all other answers are true)

A. Transporters carry molecules through impermeable cellular membranes.

B. Translation factors are involved directly in mRNA synthesis.

C. Growth factors signal cells to grow.D. Cell surface receptors bind to extracellular molecules.E. Apoptosis is programmed cell death.F. All of the above are actually true.

h

36. Which is false? (or indicate F if all other answers are true)

A. Transporters carry molecules through impermeable cellular membranes.

B. Translation factors are involved directly in mRNA synthesis.

C. Growth factors signal cells to grow.D. Cell surface receptors bind to extracellular molecules.E. Apoptosis is programmed cell death.F. All of the above are actually true.

37. Which of the following organelles are not included in the continuous sorting of proteins in lipid vesicles within the cell (or select F)?

A. endosomesB. the endoplasmic reticulumC. the Golgi apparatusD. the plasma membraneE. the mitochondrial membranesF. All of the above are linked by vesicular

membrane transport.

s

37. Which of the following organelles are not included in the continuous sorting of proteins in lipid vesicles within the cell (or select F)?

A. endosomesB. the endoplasmic reticulumC. the Golgi apparatusD. the plasma membraneE. the mitochondrial membranesF. All of the above are linked by vesicular

membrane transport.

s

38. Synapses are found between which of the following cells types?(or select F).

A. B cells and neurones. B. Dendritic cells and epithelial cells. C. Cortical neurones and dendritic cells. D. Skeletal muscle cells and motor neurones. E. Neutrophils and natural killer cells. F. None of the above cell types are associated

through synapses.

38. Synapses are found between which of the following cells types?(or select F).

A. B cells and neurones. B. Dendritic cells and epithelial cells. C. Cortical neurones and dendritic cells. D. Skeletal muscle cells and motor neurones. E. Neutrophils and natural killer cells. F. None of the above cell types are associated

through synapses.

39. Which one of the following chemical species diffuse rapidly through a biological membrane without using transporters or channels (or select F)?

A. waterB. oxygenC. chloride ionsD. citrate ionsE. potassium ionsF. None of the above

i

39. Which one of the following chemical species diffuse rapidly through a biological membrane without using transporters or channels (or select F)?

A. waterB. oxygenC. chloride ionsD. citrate ionsE. potassium ionsF. None of the above

i

40. Which of the following statements is not correct (or select F)?

A. The overwhelmingly common class of cell surface signalling receptors, the “serpentine” receptors contain seven sequential alpha-helical domains that snake through the membrane.

B. Ras, Rac and Rho are “small” GTPases.C. Serpentine receptors, for their activity, associate with

specific GTPases.D. Hydrolysis of ATP and GTP are often used in biological

systems to drive unfavourable reactions, in metabolism and protein interactions, respectively.

E. Some pharmacologically important receptors are protein kinases, which use ATP to phosphorylate proteins.

F. Actually, all of the statements above are correct.

40. Which of the following statements is not correct (or select F)?

A. The overwhelmingly common class of cell surface signalling receptors, the “serpentine” receptors contain seven sequential alpha-helical domains that snake through the membrane.

B. Ras, Rac and Rho are “small” GTPases.C. Serpentine receptors, for their activity, associate with

specific GTPases. [‘large” GTPases]D. Hydrolysis of ATP and GTP are often used in biological

systems to drive unfavourable reactions, in metabolism and protein interactions, respectively.

E. Some pharmacologically important receptors are protein kinases, which use ATP to phosphorylate proteins.

F. Actually, all of the statements above are correct.

4

36

3

1

10