Gene Expression Flashcards
what is meant by a genotype
sequence of DNA bases
what is meant by a phenotype
physical and chemical characteristics of an organism determined by its genotype
what is gene expression
involves the DNA sequences being transcribed and translated to make a protein
what are proteins made of
amino acids
what is a polypeptide
a chain of amino acids joined together by peptide bonds
what gives a protein it’s shape
the order of amino acids determines a proteins shape and therefore their function
what determines the order of amino acids
the sequence of DNA bases in the gene the proteins codes for
what are the 3 types of RNA
what do they do?
- mRNA (messenger RNA): carries a copy of code from DNA in the nucleus to ribosome
- tRNA (transfer RNA): carries specific amino acids to ribosome where they can be linked together into a polypeptide
- rRNA (ribosomal RNA): ribosome is site of protein synthesis, made up of rRNA and proteins
which enzyme is required to make a molecule of mRNA
RNA Polymerase
what are the differences between DNA and RNA?
DNA - Double stranded
RNA - Single Stranded
DNA - Adenine + Thymine
RNA - Adenine + Uracil
DNA - Deoxyribose Sugar
RNA - Ribose Sugar
What is transcription
makes a copy of DNA using mRNA
stages of Transcription
- RNA Polymerase unzips DNA
- Free RNA nucleotides line up with complementary base pairs in DNA
- A-U G-C
- Hydrogen bonds form
what is a codon?
a triplet of bases on mRNA molecule which codes for a specific amino acid
what is an anticodon?
a triplet of based on tRNA molecule that matches up with a codon on mRNA
which process allows the formation of a mature mRNA transcript?
RNA splicing
what happens during RNA splicing?
the introns are removed, and the exons are joined together to form the mature mRNA transcript
what is an intron
a non coding region of mRNA primary transcript which is removed during RNA splicing
what is an exon?
a coding region of dna
what is a ribosome made of?
rRNA abs proteins
where does translation begin?
at a start codon
where is mRNA translated into proteins?
by ribosomes in the cytoplasm
what is the structure of tRNA molecule?
an anticodon at one end and an attachment site for a specific amino acid at the other.
Folded due to complementary base pairing
what is the process which makes a protein using the information carried in mRNA?
Translation
stages of translation
- tRNA picks up an amino acid and takes it to the nucleus
- anti codons + codons pair up using complementary base pairing
- peptide bonds form between amino acids
- tRNA released to pick up new amino acid
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