1C Gene Expression Flashcards
What is the phenotype determined by ?
The proteins produced as the result of gene expression.
Are all genes in a cell expressed?
No.
The regulation of both transcription and translation leads to what?
Gene expression
Describe the structure of RNA
Single stranded
Contains uracil instead of Thymine
Contains ribose instead of deoxyribose
What is the function if mRNA?
To carry a copy of the genetic code from the nucleus to the ribosome.
What forms the ribosome?
rRNA (ribosomal RNA) and proteins
Describe the process of transcription
RNA polymerase unwinds and unzips the DNA strand, breaking hydrogen bond between the strands.
Complementary RNA nucleotides align with their complementary DNA nucleotides on one strand.
Hydrogen bonds form between the complementary base pairs.
Strong chemical sugar-phosphate backbone forms.
RNA polymerase joins RNA nucleotides to the frowning strand of the mRNA at the 3’end.
The primary transcript is now formed.
Where does transcription take place?
The nucleus.
What are promoter sequences?
DNA sequences that define.
What are introns?
The non-coding regions of a gene.
What are extrons?
The coding regions of a gene.
Are introns or expos removed from the primary transcript?
Introns are removed.
What is the process or removing the exons called?
Splicing.
Explains why it’s important that the non-coding regions are removed from the primary transcript.
To ensure the correct protein is made.
Exons are joined together to form what?
The mature transcript.
Explain how a different protein can be produced from the same gene?
Different regions of the primary transcript are treated as exons and introns and therefore different mature transcripts are formed from the same primary transcripts.
What is the process of producing different mature transcripts from the same primary transcript called?
Alternative splicing.
Where does translation take place?
The ribosome.
What is the triplet of bases called on a DNA and mRNA strand?
Codon.
What is the function of tRNA?
To transfer specific amino acids to the ribosome (To align specific amino acids in the correct sequence in the protein).
What two sites does the tRNA have?
An amino acid attachment site and an anticodon.
What is the anticodon of the tRNA complementary to?
An mRNA codon.
Describe the method of translation.
mRNA joins to the ribosome.
tRNA transfers specific amino acids to the ribosome and aligns the correct amino acids in the sequence by aligning its anticodon with the complementary codon on the mRNA strand.
Hydrogen bonds form between the bases.
Peptide bonds form between adjacent amino acids.
Polypeptide is formed.
How is it possible that different proteins are expressed from one gene?
Alternative splicing and post- translational modification.
What is post-translational modification?
The process of cutting and combing polypeptide chains OR
By adding phosphate OR
Adding carbohydrate groups of protein.
