lab 11

Question 1

open reading frames

Answer 1

spans of DNA sequence between the start and stop codons

must be at least 100 amino acids long

must end with one of the three termination signals

Question 2

first amino acid residue of one ORF

Answer 2

translated sequence must begin with a methionine (typically the first amino acid in a protein)

Question 3

how ORF stops after the last amino acid residue

Answer 3

it’s a stop codon??? signals a halt to protein synthesis in the cell

tells the ribosome and transfer DNA that the process can stop and the new polypeptide chain can be released

Question 4

BLAST function

Answer 4

searches the databases for DNA sequences similar to the DNA sequence of interest, which is called the query sequence

Question 5

bioinformatics

Answer 5

integrates biology with information science

Question 6

identification of proteins

Answer 6

proteins with similar function often have conserved amino acid sequences, it is often possible to identify the probable function of an ORF if it has a high degree of similarity to another protein whose function has been determined

Question 7

microarrays

Answer 7

determining if and when a gene is expressed is Northern analysis

Each ORF in the genome is separately amplified and bound as a minute spot to a slide in an organized array of up to 20,000 separate genes. This is called a microarray

used to identify genes that are expressed only under one particular physiological condition

Question 8

BLAST steps

Answer 8

Paste your query DNA sequence into the BLAST search box

look at the graphical view of all the sequences that are similar to the query sequence

look at the E value for each sequence (you want a negative E value or 0) and determine your possible matches