A. Incorrect! This feature does help with it suitability as genetic material.

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1 College Biology - Problem Drill 08: Gene Structures and Functions No. 1 of Which of the statements below is NOT true in explaining why DNA is a suitable genetic material? #01 (A) Its double helix structure enables its physical stability. (B) Double strand structure enables its repairing capacity. (C) The coding capacity is enormous. (D) It cannot be damaged by radiation. (E) The information can be copied easily and processed. This feature does help with it suitability as genetic material. This feature does help with it suitability as genetic material. This feature does help with it suitability as genetic material. D. Correct! DNA can be destroyed by radiation. This feature does help with it suitability as genetic material. DNA is the cellular genetic material. It is made up from deoxyribose-phosphate and 4 bases. It contains two strands based on base pairing between A and T, C and G. The two strands are anti-parallel and form double helix structure. DNA is highly organized in cells (final form: chromosome). One chromosome contains one DNA molecule. One chromosome contains many genes. One gene is defined as one functional section of DNA. Genes (DNA) only carry genetic information, which needs to be processed into RNA or protein to perform its biological function. The correct answer is (D).

2 No. 2 of If a gene has the following DNA sequence, what is its protein sequence? ATACAGGTTCTGACTCCTCAGGACTAAAAA #02 (A) Met-ser-lys-glu-glu-glu-ser (B) Met-ser-lys-trp-gly-gly-ser (C) Ser-met-lys-cys-glu-glu-cys (D) Met-ser-lys-thr-glu-glu-ser (E) Lys-ser-thr-glu-glu-ser-met A. Correct! This is the correct sequence of amino acids. This is not the correct sequences of amino acids. This is not the correct sequences of amino acids. This is not the correct sequences of amino acids. This is not the correct sequences of amino acids. mrna is read from an initiation codon. The initiation codon is AUG. The mrna is then read in triplet code; every three bases encode one amino acid or a stop codon. One amino acid can be encoded by multiple codons. The base sequence is read consecutively. Translation stops when the ribosome reaches the stop codon. The correct answer is (A).

3 No. 3 of Which of the following is NOT correct about DNA function? #03 (A) Serves as genetic material. (B) Directs synthesis of mrna. (C) Maintains cell shape. (D) Forms chromosome structure. (E) Found in the nucleus. DNA does serve as the genetic material for the cell. DNA does control and direct mrna synthesis. C. Correct! DNA does not help to maintain cell shape. DNA does form the chromosomal structure. DNA is found in the nucleus. DNA (deoxyribonucleic acid) is made up of genes. Genes code for the physical development and phenotype of an organism. Genes are considered the unit of genetic inheritance. Chromosomes are made up of genes and are associated with proteins. They are located in the nucleus. DNA direct mrna synthesis and mrna control protein synthesis. The correct answer is (C).

4 No. 4 of Which RNA molecule is responsible for carrying the amino acid to the ribosome? #04 (A) mrna (B) rrna (C) trna (D) snorna (E) snrna mrna carries the information for the amino acid sequence of a polypeptide (protein) chain. rrna are pieces of RNA that form complexes with ribosomes (protein) to facilitate the transfer of amino acid from trna to the polypeptide chain. C. Correct! trna carries amino acids to the ribosome and transfers them to the growing polypeptide chain. snornas are small nuclear RNAs used to process and chemically modify rrnas. snrna forms complexes with proteins used in eukaryotic RNA processing (e.g. exon splicing and intron removal). RNA is a molecule made of a stretch of bases on a sugar-phosphate backbone and it is different from DNA. The sugar is ribose instead of deoxyribose, like in DNA. The bases are AUCG instead of ATCG like in DNA. RNA is smaller molecules and single-stranded. There are four Classes: mrna: Copies information from DNA through base-pairing mechanism and serves as a messenger from DNA to protein. trna: Carries amino acid to protein synthesis place. rrna: Component for ribosome ncrna: Regulate cellular processes snornas small nuclear RNAs are used to process and chemically modify rrnas. snrna forms complexes with proteins used in eukaryotic RNA processing (e.g. exon splicing and intron removal). The correct answer is (C).

5 No. 5 of Which of the following can cause a genetic disease? #05 (A) A chromosome mis-segregation in blood cells. (B) Skin cells that have extensive exposure to UV light. (C) A spontaneous mutation in germ line DNA. (D) Exposure of one s digestion system to over-dosed chemicals, which may cause extensive mutations. (E) All of the above This can cause a genetic disease. It is not the only choice here that can cause disease. This can cause a genetic disease. It is not the only choice here that can cause disease. This can cause a genetic disease. It is not the only choice here that can cause disease. This can cause a genetic disease. It is not the only choice here that can cause disease. E. Correct! All of these can cause genetic disease. The sequence of bases in DNA makes up a gene. Gene mutations occur in two ways: they can be inherited from a parent or they are acquired during a person s lifetime. Acquired (or somatic) mutations occur in the DNA of individual cells at some time during a person s life due to environmental factors. Acquired mutations in somatic cells cannot be passed on to offspring. Mutations that are passed from parent to child are hereditary mutations or germline mutations. Mutations that are only in egg or sperm or those that happen immediately after fertilization are de novo mutations. The correct answer is (E).

6 No. 6 of Which of the following statements is incorrect? #06 (A) DNA strands run antiparallel. (B) The bases in DNA are G, C, A, T. (C) The backbone of the DNA molecule is made of a phosphate backbone. (D) DNA nucleotides are joined together by phosphodiester bonds. (E) All of the above are correct. The DNA strands are antiparallel. This is not the only characteristic listed here. The bases are G, C, A, T. This is not the only characteristic listed here. The backbone is made of phosphate backbone. This is not the only characteristic listed here. DNA nucleotides are held together by phosphodiester bonds. This is not the only characteristic listed here. E. Correct! All of the above are characteristics of DNA. DNA is the cellular genetic material. It is made up from deoxyribose-phosphate and 4 bases. It contains two strands based on base pairing between A and T, C and G. The two strands are anti-parallel and form double helix structure. DNA is highly organized in cells (final form: chromosome). One chromosome contains one DNA molecule. One chromosome contains many genes. One gene is defined as one functional section of DNA. Genes (DNA) only carry genetic information, which needs to be processed into RNA or protein to perform its biological function. The correct answer is (E).

7 No. 7 of Which of the following is NOT a difference between DNA and RNA? #07 (A) DNA has T base and RNA has U base. (B) DNA use ribose sugar and RNA uses deoxyribose sugar. (C) DNA remains in the nucleus and RNA is translocated out. (D) DNA is double stranded and RNA is single stranded. (E) There are different types of RNA molecules. There is a T base in DNA and a U base in RNA. B. Correct! DNA uses deoxyribose sugar and RNA uses ribose sugar. DNA remains in the nucleus, and RNA is translocated out of the nucleus. DNA is double-stranded and RNA is single-stranded. There are different types of RNA. RNA is a molecule made of a stretch of bases on a sugar-phosphate backbone and it is different from DNA. The sugar is ribose instead of deoxyribose, like in DNA. The bases are AUCG instead of ATCG like in DNA. RNA are smaller molecules and single-stranded. There are four Classes: mrna: Copies information from DNA through base-paring mechanism and serves as an messenger from DNA to protein trna: Carries amino acid to protein synthesis place rrna: Component for ribosome ncrna: Regulate cellular processes snornas small nuclear RNAs are used to process and chemically modify rrnas. snrna forms complexes with proteins used in eukaryotic RNA processing (e.g. exon splicing and intron removal). The correct answer is (B).

8 No. 8 of Which of the following statements is incorrect? #08 (A) Exons are regions of RNA that code for protein. (B) A 5 cap is added to the mrna transcript after transcription. (C) RNA polymerase directs transcription. (D) Bacteria use polyadenylation to terminate transcription. (E) All of the statements are correct. Exons are regions of RNA that code for proteins. A cap is added to the transcript after transcription. RNA polymerase does direct transcription. D. Correct! Bacteria do not use polyadenylation to terminate transcription. Eukaryotes do this. Of the choices listed, not all of them are correct. In post-transcriptional modification, precursor mrna from eukaryotes is converted into mature mrna (this is not post-translational modification). The three main modifications are 5 capping, 3 polyadenylation and RNA splicing cap occurs while the RNA molecule is being transcribed after about 30 nucleotides have been added. 2. Cleavage of the 3 end is followed by adding polyadenosine (poly-a) tail. 3. RNA splicing: introns (regions of RNA that do not code for protein) are removed from the premrna leaving exons connected. The splicing is catalyzed by a large protein complex called the spliceosome. There are many ways to splice an mrna allowing for a large variety of proteins from a limited amount of DNA. The correct answer is (D).

9 No. 9 of Which of the following statements is incorrect? #09 (A) AUG is the start codon for translation. (B) One amino acid can only be coded for by one codon. (C) The amino acid sequence is degenerative. (D) The anticodon on the trna recognizes the codon on the mrna. (E) UGA is one of three stop codons. AUG is the correct start codon. B. Correct! Some amino acids can be coded for by more than one codon. The amino acid sequence is degenerative because there are 64 codons for 20 amino acids. The anticodon of the trna matches up with the codon on the mrna transcript. UGA is one of the three stop codons. In translation, mrna is read in a sequential manner starting from a fixed point (initiation codon, AUG) and it stops at stop codons. Every three bases on mrna determine one amino acid. Each of 64 combinations (43) of triplet bases encodes an amino acid or a stop codon. One amino acid may be encoded by multiple codons. The amino acid sequence is said to be degenerative because there are 64 codons for 20 amino acids. The correct answer is (B).

10 No. 10 of Which of the following statements is true about DNA replication? #10 (A) During semi-conservative replication, the new DNA molecule is made of one parental strand and one newly synthesized strand. (B) DNA replication is bidirectional. (C) Helicase is the enzyme that helps to separates the DNA double helix. (D) Primase generates a short RNA primer used for replication of the lagging strand. (E) All of the statements are true. Replication is semi-conservative. DNA replication is bidirectional from the replication fork. Helicase does unwind the DNA double helix. Primase is used to make a short RNA primer that helps with lagging strand replication. This is not the only true statement. E. Correct! All of these statements are correct. The parent double helix opens and a complementary daughter strand synthesized. The product of semi-conservative replication is two double helices, each having one new strand and one parent strand. DNA strands separate at the origin and replication proceeds in opposite directions along the DNA. Helicases are enzymes that move directionally along a nucleic acid phosphodiester backbone, separating two annealed nucleic acid strands. At the origins of replication, a replication fork emerges opening the double helix. DNA replication is bidirectional. The strands are primed and replication proceeds from, the 5 to 3 direction. In DNA replication, the lagging strand is the strand opposite of the replication fork of the leading strands. Replication is in the 3 to 5 direction. The leading strand is done in a single unit, not fragments as it is in the lagging strand. Replication is in the 5 to 3 direction. 1. On the leading strand, Pol II reads the DNA and adds nucleotides continuously. 2. On the leading strand, DNA polymerase III is able to synthesize DNA using free 3 OH group donated by a single RNA primer. 3. Continuous synthesis occurs in the direction the replication fork is moving. The correct answer is (E).