Chapter 17 Flashcards
In most cases one gene codes for one
Polypeptide hypothesis
Transcription is the process by which ___ is produced, using ___ as a template
RNA
DNA
Translation is the process by which ___ is produced, using ___ as a template
Polypeptide
mRNA
Translation takes place in cellular structures called
Ribosomes
Draw the central dogma
DNA ➡️ RNA ➡️ protein
No membrane bound nucleus
DNA not separated by nuclear membrane
Prokaryotes
Membrane bound nucleus
Separated by space and time
Eukaryotes
Each set of ___ nucleotides of DNA specifies one amino acid
3
____ stran(s) of DNA is/are read during the transcription of a gene
One
The mRNA nucleotide triplets
Codon
There are three codons that do not code for amino acids and undead signal
Stop
The codon AUG codes for the amino acid methionine (met) or for
Start
Gene expression typically includes two stages
Transcription and translation
Why do tobacco plants and fireflies genes use the same codons?
Bc many forms of life share the same genetic code
2 similarities between RNA polymerase and DNA polymerase
Add nucleotides to 3’ end
Enzymes
Proteins
Found in cells
2 differences between RNA polymerase and DNA polymerase
Adding DNA vs RNA nucleotides
DNA polymerase needs a primer
The DNA sequence where RNA polymerase attaches to begin transcription is called the
Promoter
What happened during ignition of transcription?
RNA polymerase attaches to the promoter
Briefly describe what happens during the elongation phase of transcription
RNA polymerase moves along the DNA, using it as a template to build RNA strand
RNA polymerase falls off
Termination
The job of transfer RNA is to bring ____ from the cytoplasm to attach to a growing polypeptide chain
Amino acids
If mRNA contained the codon UGG the complementary tRNA molecule would have the anticodon
ACC
Charged tRNA molecule
See chapter notes
Aminoacyl-tRNA synthetases match tRNA molecules w the correct amino acids. This process requires energy from
ATP
Ribosomes are made up of proteins and
rRNAs
Within the ribosome, a new tRNA molecule (charged w an amino acid) arrives in the ____ site, where its anticodon pairs w the next codon of mRNA
A-arrival
The new amino acid is added to the growing polypeptide chain, and the tRNA moves to the ____ site, holding the polypeptide in one place
P - polypeptide
Once the polypeptide is attached to the next incoming amino acid, the tRNA moves to the ____ site before leaving the ribosome
E - exit
Name four components that must be in place for the initiation of translation to occur
sm ribosomal subunit
Lg ribosomal subunit
mRNA strand
Initiator tRNA (charged with methionine)
Elongation requires energy in the form of
GTP
Termination of translation occurs when a stop codon binds to a
Release factor
____ ribosomes can bind to a single strand of mRNA during translation
More than 3
After undergoing post-translation modifications, a polypeptide becomes a
Functional protein
Some polypeptides begin w a ___ that directs them to a particular location in the cell
Signal peptide
A change in a single nucleotide pair is called a
Point mutation
If one nucleotide pair in a gene is changed to a different pair, it’s referred to as a ____ . If and extra pair is added that’s an ___. And if a pair is deleted then it’s a ____
Substitution
Insertion
Deletion
A missense mutation changes one amino acid to another, but a nonsense mutation changes the codon for an amino acid to ____
Stop codon
A mutation that changes the reading frame of a gene is called a
Frame shift mutation
Why is a deletion of one nucleotide pair worse than a deletion of three nucleotide pairs?
Frameshift
