EOC Review DNA

Genes for medically important proteins can be cloned and inserted into bacteria, as shown in the diagram below. Why can bacteria recognize a human gene and then produce a human protein?

•  DNA replication in bacteria and humans is the same.
•  Bacterial cells contain the same organelles as human cells.
•  The basic components of DNA are the same in humans and bacteria.
• Bacterial cells and human cells contain the same kind of chromosomes.

Which choice describes DNA after replication has taken place?

• one molecule with two original strands and one molecule with two new strands
•  two molecules, each with one original and one new strand
•  two molecules, each with two new strands
•  two molecules, each with two old strands

At what point in the cell cycle does DNA replication occur and why?

•  before a cell divides, to provide each of the two resulting cells with a complete set of DNA instructions
•  before a cell divides, to ensure that the DNA will fit into the resulting cells
• during cell division, to ensure that the DNA will fit into the resulting cells
• after a cell divides, to provide each of the two resulting cells with a complete set of DNA instructions

Four different segments of a DNA molecule are represented below. There is an error in the DNA in which molecule?

• segment 1 only
• segment 3 only
• segment 2 and 3
• segment 2 and 4

The sequence of DNA below is part of a gene. How many amino acids are coded for by this segment?  
 5' ATCAGCGCTGGC 3'

• 4
• 8
• 12
• 20

A scientist puts nucleotide chains of UUUUUU in a test tube under conditions allowing protein synthesis. Soon the test tube is full of polypeptide chains composed only one the amino acid phenylalanine. What does this experiment indicate?

•  The amino acid phenylalanine is composed of uracil.
• UUU codes for the amino acid phenylalanine.
• Protein synthesis malfunctions in test tubes.
• Most proteins contain only one type of amino acid.

Which of the following would most likely cause a mutation?

•  the placement of ribosomes on the endoplasmic reticulum
•  the insertion of a nucleotide into DNA 
•  the movement of transfer RNA out of the nucleus
•  the release of messenger RNA from DNA

Which of the following identifies the process shown at point Z?

• Translation
•  Translocation
• Replication
•  Transcription

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 a new amino acid will be coded for.
• 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.
•  It is impossible to determine if a change in phenotype will occur using only the DNA sequence.

Which of the following carries amino acids to the site of protein synthesis?

• mRNA
•  rRNA
•  tRNA
•  nRNA