Chapter 7 Flashcards
Definition: Central Dogma
the fundamental principle of molecular genetics, which states that genetic information flows from DNA to RNA proteins
Definition: TransCription
Mechanism by which the information coded nucleic acids of DNA is copied into the nucleic acids of RNA ; something rewritten in the same language
Definition: TranSlation
Mechanism by which the information coded in nucleic acids of RNA is copied into the amino acids of proteins
How does RNA and DNA differ?
Single; double
AU; AT
OH on 2’ carbon for RNA; instead of deoxyribose
Definition: mRNA
The end product of the transcription of a gene; mRNA is translated by ribosome into a protein.
It is the intermediate between DNA -> cytosol-> to nucleus
Definition: (trasnfer) tRNA
A carrier molecule that binds to a specific amino acid and adds the amino acid to the growing polypeptide chain
It is a block ‘t’ shaped works like converter belt as it matches the codons to the appropriate amino acids.
It is short and loops itself to form antiparallel double strands that complement each other
Is tRNA antiparallel?
It is short and loops itself to form antiparallel double strands that complement each other in terms of base pairs in between each loops
Definition: ribosomal RNA (rRNA)
An RNA molecule within the ribosome that bonds the correct amino acid to the polypeptide chain ( A P E)
Defintion: RNA polymerase
An enzyme that reads a DNA strand and creates a complementary strand of RNA
If the DNA template strand is read form 3’ to 5’ what will the mRNA strand read?
Since mRNA is complementary to the DNA strand it will read 5’ to 3’
Definition: Template strand
The DNA strand that is copied into an mRNA molecule during gene transcription . This DNA strand is read by RNA POLYMERASE
What reads the DNA template strand?
RNA polymerase
Why is the first step of DNA replication called transcription
The template strand is a DNA strand that is transcribed into a precursor mRNA molecule
Defintion: pre-mRNA
- Cannot be used to produce a protein
As a result needs to be modified to become an mRNA strand
Where does transcription occur?
DNA and mRNA are found in the nucleus
What is translation for dummies !
- mRNA associates with a ribosome
- the amino acids coded by the mRNA are delivered to tRNA, then to the ribosome
- The amino acids join together to from polypeptides chains
Definition: Genetic code
The specific coding relationship between bases and the amino acids they specify; the genetic code can be expressed in terms of either DNA or RNA bases
Defintion: codon
A group of THREE base pairs that code for and individual amino acid
Definition: start codon
The codon that signals the start of a polypeptide chain and initiates translation. First codon translated in any mRNA in both prokaryotes and eukaryotes
AUG
Defintion: stop codon
A codon that signals the end of a polypeptide chain and causes the ribosome to terminate translation
UAA, UAG, and UGA
How does protein synthesis actually stop using the stop codon?
Unlike, the other codon the THREE stop codons are not affiliated with amino acids therefore when used there is NO amino acid for the ribosome to read therefore the polypeptide chain is released.
Defintion: Promoter
A nucleotide sequence that lies just before a gene and allows for the binding of the RNA polymerase
Definition: TATA box
A region of the promoter that enables the binding of RNA polymerase. The RNA polymerase is able to recognize this region by the amount of thymine and adenine bases, since they contain only a double bond it takes less energy to break.
How does the process of transcription begin?
It starts as the enzyme RNA polymerase binds to the DNA and unwinds it near the beginning of a gene.
Is the TATA box on the DNA or RNA
ASK MRS
Transcription- Initiation
Defintion: Coding strand
The DNA strand that is not being copied by contains the same sequence as the new RNA molecule
Definition: Termination sequence
A sequence of bases at the end of gene that signals the RNA polymerase to stop transcribing
Definition: Poly (A) tail (hair and makeup)
A chain of adenine nucleotides that are added to the 3’ end of the pre-mRNA molecule to protect it from enzymes in the cytosol
Definition: 5’ cap
A sequence of seven Gs that is added to the start of a pre-mRNA molecule; ribosomes recognize this site and use it as the sit of initial attachment
Definition: Exon
A sequence of DNA and RNA that codes for part of a gene
Definition: Intron
A non-coding sequence of DNA or RNA. Prokaryotes do not contain introns