Chapter 15 and 16 (Test 2 Study) Flashcards
What is the name for any genes coding proteins?
structural genes
What are the encoding products that interact with other sequences and affect the transcription?
regulatory genes
DNA sequences that are not transcribed but play a role in regulating nucleotide sequences are ____ _____.
regulatory elements
Describe constitutive expression.
It is continued expression under normal cellular conditions.
Within constitutive expression, there are two type of controls. Which one inhibits gene expression and which stimulate gene expression?
inhibits: negative control
stimulates: positive control
Most regulation happens at the transcription level, what is a region within DNA called? (has generally 60-90 amino acids)
domains
What is the structure that fits into the major groove of DNA called?
motif
Name three different types of DNA-binding proteins based on the motif.
- helix-turn-helix
- zinc fingers
- Leucine zipper
What are genes controlled by a single promoter called (non-coding)?
operon
What structure has products that affect the operon but are not apart of it?
regulator gene
In positive transcription, the regulator protein involved is an _____.
activator
What type of process uses glucose when available and represses the metabolite of other sugars?
catabolite repression
In catabolite repression, which factor has a concentration that is inverse to glucose availability?
cAMP; cyclic AMP
Describe an inducible operon.
Occurs when transcription is off and needs to be on.
Describe a repressible operon.
Occurs when transcription is normally on and needs to be turned off.
Which type of operon occurs when the control is negative and can be switched on and off?
negative inducible operon
Which type of operon occurs when transcription is on and needs to be turned off?
negative repressible operon
What is a small molecule that binds to the repressor and makes it capable of binding to the operator to turn off transcription?
corepressor
- Has 5 structural genes
- Found in E.coli
- Is a negative repressible operon
What is it?
trp operon
Which structural genes of the trp operon combine to make tryptophan?
trp E, trp C, trp B, and trp A = tryptophan
(1) The ___ operon collectively works to _____ tryptophan (an amino acid).
(2) The ___ operon collectively works to _____ lactase (an amino acid).
(1) trp; synthesize
(2) lac; break down
‘
_____ affects the continuation of transcription, not its initiation. This action terminates the transcription before structural genes.
attenuation
List 4 characteristics or parts of attenuation.
- attenuator
- anti terminator
- stopping of transcription in downstream region
- uuuuuu
What increases the rate of transcription at genes that are distant from the enhancer in bacteria?
bacterial enchancers
What is complementary to the targeted partial sequence of mRNA?
**This is also a way of blocking mRNAs you do not want to be translated.
antisense RNA
What are the molecules that influence the formation of secondary structures in mRNA?
**They form a binding site for small molecules, regulatory proteins or molecules close theses off when bonded.
riboswitches
What are the mRNA molecules with catalytic activity?
**When bound to small regulatory molecules, they can induce the cleavage and degradation of mRNA.
ribozymes (enzyme + ribosome)
Under low osmolarity, _____ genes are created, but during high osmolarity, both _____ genes and _____ genes can also be created.
ompF
ompF; micF
Amino acids are joined together by ____ bonds.
peptide
Label the following as either: primary structure, secondary structure, tertiary structure, quaternary structure.
(1) two or more polypeptide chains associated together
(2) sequence of amino acids
(3) sequences of amino acids folded or pleated (DNA helix)
(4) one bundle of folded amino acid sequences, condensed
(1) quaternary
(2) primary
(3) secondary
(4) tertiary
What kind of code is when an amino acid may be specified by more than one codon?
degenerate code
Describe the Wobble Hypothesis.
Sometimes the 3rd position on the anticodon is not complementary.
This results in variability and non-Watson-Crick interaction.
Codons that specify the same amino acid are called ______ codons.
synonymous
There are ___ possible codons.
There are ___ stop codons.
There are ___ sense codons.
64
3
61
True or False: The Wobble hypothesis may exist in the pairing of a codon and anticodon.
True
A polypeptide chain can be attached to a ribosome moving along the mRNA. On the polypeptide chain, which is the amino end (N) and which is the carboxyl end (C).
The amino end (N) is not attached to the ribosome, it is floating about.
The carboxyl end (C) is attached to the ribosome.
Where is the amino acid acceptor stem located on the tRNA?
At the 3’ end
Which position is the start codon first added during elongation?
P
Whenever a new tRNA anticodon attaches to the codon during elongation, which position is it added to?
A
When the tRNA is expelled from the ribosome during elongation, which position is it expelled from?
E
A ________ can be represented in three ways in which the sequence can be read in groups of three. Each different way of reading encodes a different amino acid sequence.
reading frame
Eukaryote or Prokaryote Translation: Multi-factor, multiple step process, highly regulated and controlled.
eukaryotes
Eukaryote or Prokaryote Translation: Can begin while part of the mRNA is still being transcribed, polycistronic, no nuclear membrane separating transcription and translation, Shine-Dalgarno sequence directly recruits the small subunit of the ribosome to the start codon.
prokaryotes
What are the three elongation factors?
Tu, Ts, G
List a few things that happen once release factors bind to the termination codon.
- the polypeptide releases from the last tRNA
- the tRNA releases from the ribosome
- The mRNA releases from the ribosome
Different stop codons are
recognized by different release
factors.
Because UAG is the termination
codon in this illustration, the
release factor is _____.
RF-1
What is an mRNA with several ribosomes attached?
polyribosome
