Micro Lab 3 Questions

Small circular pieces of prokaryotic or eukaryotic DNA that is not associated with the cell's DNA is called __________.

extrachromosomal DNA

Prokaryotic DNA is found in the __________ region and eukaryotic DNA is located in the ___________.

nucleoid, nucleus

Determine if the properties listed on the left-hand side column are describing DNA or RNA.

- the sugar ribose: RNA

- nucleotides A,U,C,G: RNA

- used as a template for transcription: DNA

- nucleotides A,T,C,G: DNA

- translated to synthesize a polypeptide: RNA

- the sugar deoxyribose: DNA

- double stranded: DNA

- single stranded: RNA

Which nitrogenous base is not found in RNA?

thymine

What are the three component parts of a nucleotide?

- 5-carbon sugar

- phosphate group

- nitrogenous base

What type of bonds are formed between nitrogenous bases on opposite strands of the DNA double helix?

hydrogen bond

What mRNA sequence is synthesized using the DNA template strand AAT CCG AGG?

UUA GGC UCC

What type of RNA codes for proteins?

mRNA

What enzyme is used for transcription?

RNA polymerase

Eukaryotic mRNA has non-coding sequences called _______ that are spliced out before the RNA leaves the nucleus.

introns

Transcription occurs in the _________ of prokaryotes and the __________ of eukaryotes.

cytoplasm/nucleus

What type of RNA makes up a portion of the ribosome?

rRNA

What type of RNA is used to bring amino acids to a growing protein chain?

tRNA

What direction is RNA made?

5' to 3'

What is the anticodon sequence of a tRNA molecule for the mRNA codon UCA?

AGU

The fact that more than one codon can code for a single amino acid is referred to __________ in the genetic code.

redundancy

What type of bond joins amino acids to a growing protein chain?

peptide bond

What type of codon ends translation once it is positioned in the ribosome's A site?

stop codon

The start codon AUG codes for _________ in prokaryotes.

formyl methionine

The start codon AUG codes for _________ in eukaryotes.

methionine

Which of the following is NOT a stop codon?

UGG

How many codon sequences code for the amino acid serine? (Be very careful--look at all of the columns)

6

Translate the mRNA sequence ACA CAG AUG GUG CCC

threonine-glutamine-methionine-valine-proline

Sometimes during DNA replication, a change in the DNA nucleotide sequence occurs; this is called a mutation. There are several reasons why mutations occur. In certain instances, a chemical called _______ increases the mutation rate.

a mutagen

There are two main types of mutations: base-substitution and frameshift mutations. Match the type of base substitution mutation located in the left-hand side column with the result of that mutation.

- missense mutation: a change in the wild type amino acid to a different amino acid
- silent mutation: no change in the amino acid sequence
- nonsense: premature stop codon introduced

If a nucleotide is inserted or deleted from the DNA sequence, the resulting mutation is known as a _________________ mutation.

frameshift

Thymine dimer mutations cause by ultraviolet light can be repaired using ___________.

photolyases and excision-repair enzymes

Mismatch-repair enzymes cannot repair a DNA mutation once it becomes ______________.

methylated