Unit 1-Gene Expression Flashcards
Ways that RNA differs from DNA
RNA is single-stranded while DNA is double-stranded.
RNA has a sugar called ribose while DNA has a sugar called deoxyribose.
RNA has the base uracil while DNA has the base thymine.
What does RNA stand for?
Ribonucleic acid
What are the three types of RNA?
Messenger RNA (mRNA)
Transfer RNA (tRNA)
Ribosomal RNA (rRNA)
What is the function of messenger RNA?
Carries the genetic code from the nucleus to the ribosome.
What is the function of transfer RNA?
Picks up a specific amino acid from the cytoplasm and brings it to the ribosome
What is the function of ribosomal RNA?
Ribosomal RNA (rRNA) and proteins form the ribosome
Where is mRNA made?
In the nucleus
In RNA what are the four types of bases?
Adenine, cytosine, guanine, and uracil
What is the complementary base pair for adenine in RNA?
Uracil
How are proteins made?
Proteins are made by joining together amino acids in a specific sequence.
What determines the type of protein formed?
The order of amino acids (which depends on the order/sequence of the bases in the DNA
Gene expression is made up of which two processes?
Transcription and translation
Synthesis of the primary RNA molecule from a DNA template
Transcription
Synthesis of a polypeptide chain from a mRNA
Translation
What are the stages of transcription?
- DNA unwinds
- Primary transcript of mRNA using RNA nucleotides.
- The primary transcript of mRNA is processed to produce a mature transcript of mRNA.
- The mature mRNA transcript is now ready to leave the nucleus and travel to the ribosome.
What is the strand of mRNA produced by transcription called?
The Primary Transcript
What does the primary transcript contain?
Exons and introns
What are the introns of the primary transcript?
Introns are non-coding regions that have to be removed.
What are the exons of the primary transcript?
Exons are coding regions and are joined together to form the mature transcript.
What is DNA splicing?
DNA splicing is where introns are removed and the exons are joined together to form a mature transcript of mRNA.
What happens once the mature transcript of mRNA is produced?
The mature mRNA leaves the nucleus and enters the cytoplasm.
Where is tRNA found?
In a cell’s cytoplasm
What is translation?
Translation is the synthesis of a protein in the form of a polypeptide chain of amino acids.
What does each codon contain?
Each codon contains the code for one amino acid.
Where does translation occur?
Translation occurs on the ribosome.
What does the start codon indicate?
The start codon indicates to the tRNA where to add the first amino acid.
What happens to the tRNA after the polypeptide is formed?
It leaves the ribosome once the polypeptide has been formed.
What are amino acids linked by and what does this form?
Amino acids are linked by peptide bonds to form polypeptides.
What does the polypeptide fold to form and how is this held together?
Polypeptide chains fold to form the three-dimensional shape of a protein, held together by hydrogen bonds and other interactions between individual amino acids.
What is the phenotype determined by?
Phenotype is determined by the proteins produced as the result of gene expression.
How can different proteins be expressed from one gene?
Different proteins can be expressed from one gene, as a result of alternative RNA splicing.
What is gene expression?
The switching on or off of a gene to make a specific protein.
