MCAS Biology Ms. Chen Name:
Date:
Do Now 1/15/15 Directions: For each question, underline KEY words in the question. Explain why you picked your answer.
1. An enzyme moves along a strand of DNA and produces a new nucleic acid strand. Part of the new strand is shown below. GUACUCGGCAAUUUCGCA Which of the following cellular processes created the new strand? A. active transport B. crossing over C. replication D. transcription
2. Which of the following is an example of a mutation? A. A red blood cell loses its nucleus. B. A zygote receives two X chromosomes. C. A strand of mRNA is produced from DNA. D. A nucleotide is missing in a replicated DNA strand.
3. Which of the following processes relies directly on the complementary base pairing of nucleotides? A. synthesis of ATP B. replication of DNA C. formation of peptide bonds D. pairing of chromosomes in meiosis
4. The table below presents a variety of mRNA three-base sequences (codons) and the amino acids for which these sequences code. First Base of mRNA G
Second Base of mRNA A
Third Base of mRNA A C G U
G
U
A C G U A C G U
Amino Acid glutamic acid aspartic acid glutamic acid aspartic acid glycine glycine glycine glycine valine valine valine valine
Based on the information in the table, which of the following changes is least likely to produce a phenotypic change in an organism? A. GAU to GGU B. GAU to GUU C. GAU to GAA D. GAU to GAC
