EOC 23 Molecular Genetics

Which of the following results from an incorrect base pairing during DNA replication?

• complementary RNA strand

• complementary DNA strand

•  mutated RNA strand

•  mutated DNA strand 

If a single DNA strand contains 40 adenines prior to replication, what conclusion can be made about its complementary strand after replication, assuming no mutations occurred? 

• The complementary strand would contain a total of 40 guanines

• The complementary strand contains a total of 60 cytosines.  

• The complementary strand contains a total of 40 uracils.

• The complementary strand would contain a total of 40 thymines.

During the process of DNA replication, the nitrogen bases pair in a specific way.  Which of the following statements correctly describes the pairing of the nitrogen bases during this process?

• Cytosine pairs with uracil. 

• Guanine pairs with thymine. 

• Adenine pairs with guanine.

• Adenine pairs with thymine.

Genetically modified crops are foods that have had specific changes introduced into their DNA. Using genetic engineering, scientists can take genes that control a trait from one organism and insert the genes into another organism's genetic code. This process creates an organism with the desired characteristics. Which statement describes how scientists are able to use genes from one organism on another?

• Similarities in the physical characteristics of organisms are due to common ancestors.

• Different species exchange DNA during reproduction.

• The basic components of DNA are universal in all organisms. 

• Organisms that are closely related have identical genetic information. 

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During the process of DNA replication, a complementary DNA strand is formed.  If the original strand of DNA is 5’ ATA GTG CCC AAC GGT 3’, which of the following would be the correct complementary DNA strand?

• 3’ TAT CAC GGG TTG CCA 5’

• 3’ TAT CAA GGG TTG CCA 5’

• 3’ ATA GTG CCC AAC GGT 5’

• 3’ TAT CAC GGG TTG CCT 5’

During transcription the DNA base sequence is transcribed into a complimentary mRNA sequence. A codon table like the one shown below lists the amino acids coded for by particular triads of mRNA bases. A segment of DNA has undergone a mutation in which one nucleotide has been changed. The original sequence was ACG and the new sequence is ACA. Use the codon table to determine whether or not this mutation will cause a change in the phenotype of the organism.

• Yes, the phenotype of the organism would change because any change in the DNA sequence will cause a change in phenotype.

• Even though the DNA sequence changed, the sequence still codes for the same amino acid, so no change in phenotype will occur.

• Yes, the phenotype of the organism would change because a new amino acid will be coded for

• It is impossible to determine if a change in phenotype will occur using only the DNA sequence.

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 DNA replication results in:

• 1 new molecule of RNA

•  2 completely new DNA molecules

• 1 new DNA molecule, 1 old molecule is conserved

• 2 DNA molecules that each contain a strand of the original

Sickle-shaped red blood cells result from a mutation in the gene that codes for hemoglobin.  This mutation results in sickle-cell anemia.  A partial sequence of bases from a normal hemoglobin gene and sequence that results in sickle-cell anemia are shown below.

What type of mutation is depicted in this sequence?

• Deletion

• Insertion

• Frameshift

• Substitution

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NGSS.HS-LS3-2

A diagram of a cellular process is shown below. Which of the following identifies the process shown at point Y?

• Translation

•  Replication

• Transcription

• Translocation

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The sequence of DNA below is part of a gene.  How many amino acids are coded for by this segment?

5' ATCAGCGCTGGC 3'

• 20

• 4

• 12

• 8

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