Chapter 16 Flashcards
gene expression
process of converting information in DNA into functioning molecules within the cell
messenger RNA (mRNA)
- carry information from DNA to site of protein synthesis
- interacts with DNA and grabs specific information needed
central dogma analogy
DNA= novel
mRNA= spark notes
protein= summary
RNA polymerase
synthesizes RNA
- uses DNA strand as template
what is the central dogma of biology
summarizes flow of information in cells
DNA—>RNA—>proteins
transcription
process of using a DNA template to make complementary RNA
- making copy of information
what is the transcription analogy
transcribe hieroglyphs (DNA) into modern day Egyptian
what is the flow of genetic information in a eukaryotic cell
DNA
transcription
RNA
translation
PROTEIN
where does transcription occur in eukaryotes
nucleus
where does translation occur in eukaryotes
cytoplasm
what is translation
process of using information in mRNA to synthesize proteins
- switching from nucleotide “language” to amino acid “language”
what is the analogy for translation
translate what Egyptian text says
analogy for protein product
translated text
codon
series of nonoverlapping three bases that specifies a particular amino acid
what does a codon specify
amino acids
can some amino acids have more than one possible codon
yes
what is a reading frame
sequence of codons
how many codons are there
64 total
- one start codon (AUG)
- three stop codons (UGA, UAA, & UAG)
- other 60 codons for amino acids
what dictates how codons are translated into amino acids
genetic code
genetic code
specifies how a sequence of nucleotides codes for a sequence of amino acids
what is a start and stop codon
start- signals where protein synthesis starts
stop- signal end of protein coding sequence
mutation
any permanent change in DNA
point mutation
result from one or a small number of base changes
what are the types of point mutations
- missense
- silent
- frameshift
- nonsense
missense mutation
change an amino acid
silent mutation
do not change sequence due to redundancy in code
frameshift mutation
shift reading frame altering the meaning if all subsequent codons
nonsense mutations
change a codon that specifies amino acid into a stop codon
- early stop
what are the three different impacts point mutations can have on fitness
- beneficial: increase fitness
- neutral: do not affect fitness
- deleterious: decrease fitness
chromosome mutations
may change chromosome number
what are the types of chromosome mutations
- inversion: segment of chromosome breaks off, flips around, and rejoins
- translocation: section of chromosome breaks off & becomes attached to another chromosome
- deletion: segment of chromosome lost
- duplication: segment of chromosomes present in multiple copies
the genetic code is
redundant
unambiguous
nearly universal
without punctuation
what did Francis Crick propose
sequence of DNA acted as a code
- DNA is information storage molecule
- particular stretch of DNA specifies amino acid sequence of protein
Jacob & Monod
suggested that RNA links genes in the nucleus to protein synthesis in cytoplasm
who determined which codon coded for each amino acid
Nirenberg & Leder
- made chains of specific codons & determined which amino acid was bound to ribosome
what is the relationship between genotype & phenotypes
genotype is determined by sequence of bases in DNA & phenotype is a product of the protein produced
- differences in genotype may cause differences in phenotype
triplet code
genetic instructions for the amino acid sequence of polypeptide chain
how are triplet codes written
DNA and RNA as codons
