Genetics #2 Flashcards
Gene structure is…
Linear sequence of nucleotides with a fixed start point and an end point
Evolution of genes (3 steps)
- Gene (DNA or RNA)
- RNA (mRNA, tRNA, rRNA)
- Polypeptide (protein/amino acid)
The nucleotide sequence in a gene that has the information for amino acid placement on a polypeptide
Coding Sequences
The entire gene is a continuous coding sequence in…
Prokaryotes
The gene is split into coding and noncoding regions in…
Eukaryotes
In Eukaryotes, the nucleotide that codes for amino acids
Exons
In Eukaryotes, the nucleotide that does not code for amino acids and need to be removed by splicing?
Introns
What is the advantage of alternative splicing of introns?
- Provides for more than one polypeptide per gene
The process of making an RNA copy of a gene sequence
Transcription
The template is READ in the…. direction?
3’ to 5’ direction
The template strand of the DNA directs?
mRNA synthesis
The complimentary DNA strand is also called?
The coding strand, same nucleotide sequence of the mRNA
-This is located at the start of a gene
Promoter
Functions of the Promoter? (2)
- The recognition and binding site for the RNA polymerase
2. Helps orient the polymerase
Coding sequence begins with what DNA sequence?
3’- TAC- 5’
What is the start codon? (RNA sequence)
AUG
What signals the end of the coding region?
- The stop codon
What 2 things follow the stop codon?
- A trailer sequence
- This contains a terminator sequence that is used to stop transcription
T or F: Genes that code for tRNA may code for more than a single tRNA molecule or type of tRNA?
True
t or F: Genes that code for rRNA sequence are transcribed as a single, large precursor.
True
Special ribonucleases that remove spacers between the coding regions after transcription?
Ribozymes
3 Types of RNA that are produced during transcription?
- mRNA
- tRNA
- rRNA
Function of mRNA
Carries the message for protein synthesis
Function of tRNA
Carries the amino acids during protein synthesis to the ribosomes
Function of rRNA
Molecules that are components of ribosomes
In bacteria, this has information for 1 polypeptide?
Monocistronic
In bacteria, this has information for more than one polypeptide?
Polycistronic
In Bacteria, this has no catalytic activity but it helps the core enzyme recognize the start of genes (aka the promotor)
Sigma Factor
Holoenzyme=
A core enzyme + sigma factor
T or F: Only the core enzyme can begin transcription
True
- This is the site of transcription
- Site where DNA polymerase binds to the initiate transcription
Promotor
The sigma factor recognizes…
The specific sequences located before the transcription starting point which is recognized by specific amino acids and it helps the binding factor of the RNA polymerase to correctly position the RNA polymerase