Chapter 14 AP Test review
Know how to read the genetic code chart.
->
Given: A -> B -> C how many genes are necessary for this pathway? Assuming an enzyme is used to get from A to B and B to C.
2
RNA polymerase moves in which direction along the DNA?
5' - 3'
Know the movement of tRNA's during translation to through active sites. EPA sites?
A Site- holds the tRNA with the next amino acid to be added to the chain P site- holds the tRNA carrying the growing polypeptide chain E site- releases tRNAs from the ribosome
Define gene.
A gene is a region of DNA that can be expressed to produce a final functional product that is either polypeptide or an RNA molecule
What is a codon? Know all about them.
A three-nucleotide sequence of DNA or mRNA that specify a particular amino acid or termination signal; the basic unit of the genetic code
What is the anticodon for DNA that is AAA
AAA - > mRNA= UUU -> tRNA= AAA ... If there is a T in this case, you have to do the mRNA complementary first TTT -> mRNA= AAA-> tRNA= UUU
Which molecules contain adenine? (3)
ATP, DNA, RNA
What does it mean to say that the Genetic Code is universal?
All living organisms use the genetic code
What is an anticodon?
An anticodon is the three unpaired bases on a tRNA that is complementary to one mRNA. CCGACG-> GGCUGC ... tRNA has to code for the same amino acid, this is redundant one.
Who was Garrod? What was his hypothesis?
He was a physician and hypothesized that each gene codes for a single, specific enzyme
Describe alternative RNA splicing
It can allow the production of proteins of different sizes and functions from a single mRNA.
A transfer RNA (#1) attached to the amino acid lysine enters the ribosome. The lysine binds to the growing polypeptide on the other tRNA (#2) in the ribosome already. Which enters the exit tunnel through the large subunit of the ribosome?
It is going to the E site
How could a point mutation in DNA make a difference in the function of a protein?
It might substitute a different amino acid in the active site.n amino acid in the active site. D
Be able to take an amino acid sequence and give a DNA strand.
Phe: UUU&UUC DNA strand: AAA & AAG
What is the function of GTP in translation?
Provides energy for the formation of the initiation complex
Where does the promoter attach at the beginning of transcription on the DNA molecule?
The right of the template strand
When the genome of a particular species is said to include 20,000 protein-coding regions, what does this imply?
There is additional genes for RNA other than mRNA
When does transcription begin in a eukaryotic cell? What must be there?
When a promoter is present; promoter, RNA polymerase, several transcription factors
In order for a eukaryotic gene to be engineered into a bacterial colony to be expressed, what must be included in addition to the coding exons of the gene?
a bacterial promoter
Cystic fibrosis cause?
a polypeptide missing an amino acid
When are exons spliced out?
after transcription inside the nucleus
What is a ribozyme?
an RNA with enzymatic activity
When the ribosome reaches a stop codon on the mRNA, no corresponding tRNA enters the A site. If the translation reaction were to be experimentally stopped at this point, which of the following would you be able to isolate from the cell?
an assembled ribosome with a polypeptide attached to the tRNA in the P site
Which types of mutations could result in a frameshift mutation?
any base deletion or insertion
What does the accuracy of translation of mRNA into the amino acids in a polypeptide depend upon?
bonding of the anticodon to the codon and the attachment of amino acids to tRNA
When does the spliceosome bind to a pre-mRNA transcript?
certain sequences along an intron
What is the anticodon complementary to?
corresponding codons in mRNA
Know which mutations are the most negative given a list to choose from a. Substitution b. Codon substitution c. Codon deletion d. Base pair deletion
d. Base pair deletion
What small-scale mutation effect would have the greatest negative effect on the functioning of a protein?
deletion of a base primarily at the start of a gene
What type of bonding is responsible for maintaining the shape of the tRNA molecule?
hydrogen bonding between base pairs
A eukaryotic transcription unit that is 8,000 nucleotides long may use 1,200 nucleotides to make a protein consisting of approximately 400 amino acids. This is best explained by the fact that?
many noncoding stretches of nucleotides are present in eukaryotic DNA
What does a TATA box do?
recognition site for a specific transcription factor
What is needed in transcription in Eukaryotes along with RNA polymerase?
several transcription factors
For a newly made polypeptide, what must happen to it before it can be secreted from the cell?
signal sequence must target it to the ER and then to the Golgi
Which mutations are most likely to cause a phenotypic change?
single nucleotide deletion in an exon coding for an active site protein
There are 61 mRNA codons that specify an amino acid, but only 45 tRNAs. This is best explained by the fact that
tRNAs are flexible
Know the anatomy of the tRNA molecule. What happens at the 3' end projecting beyond its 5' end?
the amino acid binds covalently
Transcription and translation both go on at the same time in a prokaryote a. true b. false
true
A deletion of a single codon usually causes what in the protein product?
unmutated protein, a protein with a codon missing
