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what is gene expression?
the process by which dna directs protein synthesis TERM 2
how many stages are there to gene
expression and what are they?
DEFINITION 2 two stages. transcription and translation TERM 3
in 1909
DEFINITION 3 archibald garrod suggsted that genese dictated phenotype through enzymes that catalyze specific chemical reactions in the cell and that mendels laws apply to humans as well as plants TERM 4
what happened in the 1930's and iwth whom
DEFINITION 4 george beadle and boris ephrussi speculated that each mutation affecting eye color in drosophila blocks pigment synthesis at a specific step by prevent production oftheenzyme that catalyzes that step TERM 5
what did progress in linking genes and
enzymes rest on?
DEFINITION 5 the growing understanding that cells synthesize most organic molecules by a series of steps; a metabolic pathway
what is the one gene - one enzyme
experiement
they used neurospora (bread mold) to do the experiement testing wild type vs irradiated neurospora (that had been pounded with x-rays) and checked how well the mutants that survived can live in minimal amounts of agar (food) TERM 7
what are the links between genotype and
phenotype?
DEFINITION 7 proteins TERM 8
whas is the central dogma of how information
flows in cells?
DEFINITION 8 DNA -> RNA -> Proteins TERM 9
the flow of info from gene to protein is based
on a triplet code called:
DEFINITION 9 codons. they are a series of non-overlapping three nucleotide words. one codon specifies one amino acid. TERM 10
how many triplets are there and how many
code for amino acids?
DEFINITION 10 64 triplets total and 61 code for amino acids
in RNA what is subsituted for what
Uracil is subbed for Thymine TERM 17
what is the promoter?
DEFINITION 17 the dna sequence where rna polymerase attaches TERM 18
what is the stretch of dna that is transcribed
called?
DEFINITION 18 the transcription unit TERM 19
what signals the initiation of RNA synthesis?
DEFINITION 19 promoters TERM 20
what is the completed assembly of
transcription factors and RNA polymerase
bound to a promoter called?
DEFINITION 20 transcription initiation complex
a promoter called a _____ box is crucial in
forming the initiation complex in eukaryotes
TATA
TERM 22
what are transcription factors
DEFINITION 22 they mediate the binding of RNA polymerase and initiation of transcription TERM 23
what is template strand?
DEFINITION 23 start point at which RNA synthesis occurs on the DNA TERM 24
how fast does transcription progress ( in
eukaryotes)?
DEFINITION 24 60 nucleotides per second in eukaryotes TERM 25
waht are introns?
DEFINITION 25 long noncoding stretches of nucleotides that lie between coding regions
what is a ribozyme?
an RNA molecule that has enzymatic activity due to the fact that it is single stranded and can help form various secondary structures and specially modified bases that contribute to catalytic activity TERM 32
what is alternative RNA splicing?
DEFINITION 32 when genes can encode more than one kind of polypeptide depending on which segments are treated as exons during RNA splicing.because some codons can subsitute for one another. TERM 33
what is thalassemia?
DEFINITION 33 a form of anemia common in the mediterranean countries that is caused by errors in splicing process. red blood cells are distroted due to a point mutation in teh beta-globin gene, which cuases an error in splice site selection. a faulty beta- globin protein is made. TERM 34
what are "domains" on a protein?
DEFINITION 34 proteins often have a modular architecture consisting of discrete regions called domains that impart a particular structure and/or function TERM 35
what are domains typically encoded by
DEFINITION 35 discrete exons and structurally/functionally related proteins that most likely arose via exon shuffling during evolution
define
Translation
the process of protein synthesis using an mRNA template to specify the order of amino acids TERM 37
translation require the function a large # of
molecules that include...
DEFINITION 37
- components of ribosomes - 50 proteins 3-5 RNA molecules2. at least 20 amino acid activating enzymes3. 40- 60 tRNA's4. at least 9 soluble proteins involved in a polypeptide initation elongation and termination TERM 38
what is the rate of protein translation @ 37
degrees Celsius
DEFINITION 38 20 amino acids per second TERM 39
what do tRNAs act as/what are
tRNA's?
DEFINITION 39 they function as adaptors. they bring amino acids to the ribosome by the appropriate base pairing between the codon of the mRNA and hte anti-codon of the tRNA TERM 40
what does it mean that tRNA's act as
adaptors?
DEFINITION 40 They attach to the mRNA template and convert its function. The anti-codon attaches to the codon. on the other end of the tRNA it has an amino acid and after a couple of interactions between the tRNA and the mRNA template they form a polypeptide chain out of it.
