Unit 1 - KA 3: Control Of Gene Expression Flashcards
Name the type of bonds that hold amino acids together.
Peptide bonds
Name the structure created when many amino acids are joined together.
A polypeptide
Describe how the polypeptide chain is altered to create a 3D protein shape.
Polypeptide chains fold to form the three-dimensional shape, held together by hydrogen bonds.
Define the term gene.
A gene is a sequence of DNA that codes for a protein.
Define the term phenotype.
The visible characteristics
State how phenotype is determined.
Phenotype is determined by the proteins produced as the result of gene expression.
State another factor that can influence phenotype.
Environmental factors.
State another factor that can influence phenotype.
Environmental factors.
State 3 differences between DNA and RNA.
DNA is double stranded; RNA is single stranded
DNA has thymine bases; RNA has uracil
DNA has deoxyribose sugar; RNA has ribose sugar
State 3 differences between DNA and RNA.
DNA is double stranded; RNA is single stranded
DNA has thymine bases; RNA has uracil
DNA has deoxyribose sugar; RNA has ribose sugar
What is mRNA?
Messenger RNA carries a copy of the DNA code from the nucleus to the ribosome.
What is mRNA?
Messenger RNA carries a copy of the DNA code from the nucleus to the ribosome.
What is tRNA?
Transfer RNA carries a specific amino acid to the ribosome.
What is rRNA?
Ribosomal RNA combines with protein to form the ribosome.
What is rRNA?
Ribosomal RNA combines with protein to form the ribosome.
Define the term codon.
A triplet of bases on mRNA which codes for a single amino acid.
Define the term codon.
A triplet of bases on mRNA which codes for a single amino acid.
Define the term anticodon.
A triplet of exposed bases on a tRNA molecule.
Describe transcription.
The genetic code on the DNA is used to create a complementary base sequence of mRNA called the primary transcript.
Describe the order of events during transcription.
- The enzyme RNA polymerase moves along the DNA molecule unwinding the double helix and breaking hydrogen bonds between bases.
- RNA polymerase attaches RNA nucleotides to their complementary DNA bases on the template DNA strand. Hydrogen bonds form.
- RNA nucleotides are then joined together into a strand by strong chemical bonds forming the primary mRNA transcript.
Define the terms introns and exons.
Introns are non-coding regions.
Exons are coding regions.
Describe what happens to the introns following transcription of the mRNA.
The introns are removed from the primary mRNA transcript.
Describe what happens to the exons during RNA splicing.
The exons are joined together, the order of exons always stays the same.
Name the molecule that is formed after RNA splicing.
The mature mRNA transcript.
What is translation?
Translation is a process that results in the formation of a polypeptide.
State how translation starts and ends.
Translation begins at a start codon and ends at a stop codon.
Explain how the mRNA determines the sequence of amino acids in the polypeptide.
The order of bases on mRNA determines the sequence of amino acids in a polypeptide.
Describe how anticodons and codons join together.
They bond by complementary bade pairing, translating the genetic code into a sequence of amino acids.
State what happens to each tRNA molecule as the polypeptide is formed.
The tRNA molecule leaves the ribosome to collect another specific amino acid
Name the process that results in one gene producing many different proteins.
Alternative RNA splicing.
Explain how different mature mRNA strands can be produced from the same primary transcript.
Different combinations of exons can be retained in the mature mRNA transcript. The order remains unchanged.
