DNA to PROTEIN 2 step process of transcription and translation.
-
Upload
kelley-fletcher -
Category
Documents
-
view
222 -
download
1
Transcript of DNA to PROTEIN 2 step process of transcription and translation.
Protein Synthesis:>Transcription & Translation
DNA contains all the information for your traits – in the form of genes
These genes are blueprints and need to remain safe – kept inside the nucleus
Copies can be made through – a messenger Form proteins (polymers) from the building
blocks – amino acids (monomers)
Transcription – making mRNA from DNA in the nucleus mRNA – stands for messenger RNA
it is the copy of the DNA message for making a protein
Occurs in the nucleus only
RNADNA
RNApolymerase
TranscriptionSection 12-3
Adenine (DNA and RNA)Cystosine (DNA and RNA)Guanine(DNA and RNA)Thymine (DNA only)Uracil (RNA only)
Transcription (Steps)
DNA “unzips” – helicases separate DNA molecule
Free-floating RNA w/in the nucleus attach to complementary DNA base pairs
Covalent bonds form b/w sugar-phosphate backbone
mRNA is released DNA zips back up
DNA RNA
A U
T A
C G
C G
mRNA Transcribes DNA message and carries it to
ribosomes RNA polymerase is the enzyme that matches up
the base pairs No T (thymine) so when it reads the nucleotide A
on DNA it matches it with U (Uracil).
CLICK ON PICTURE FOR ANIMATION ON TRANSCRIPTION
Translation – using mRNA and tRNA to make proteins Ribosomes are the site
of protein synthesis
Click here to see mRNA and tRNA work together at that ribosome to build a protein
mRNA base
codon
tRNA base
anticodon
A U
U A
C G
G C
from to to make up
Concept MapSection 12-3
also called which functions to also called also called which functions towhich functions to
can be
RNA
Messenger RNA Ribosomal RNA Transfer RNA
mRNA Carry instructions
rRNACombine
with proteins tRNABring
amino acids toribosome
DNA Ribosome Ribosomes
Review – by now you should know…
structure of DNA How DNA replicates Differences b/w DNA & RNA Steps of Transcription & Translation Parts of tRNA 3 types of RNA
Messenger RNA
Messenger RNA is transcribed in the nucleus.
mRNA Start codon
Ribosome
Methionine
Phenylalanine
tRNA
Lysine
Nucleus
TranslationSection 12-3
mRNA
Go to Section:
Mutation – permanent change in DNA
Important: source of new variation
important for evolution. Causes:
viruses, high temps, chemicals, radiation
Germ-cell Mutations
Somatic-cell
Mutations
Occurs in gametes
Occurs in body cells
Don’t affect organism, but affects offspring
Affects organism itself
Ex: skin cancer, leukemia
2 categories of mutations
1) Gene mutations – may involve large segments of DNA or a single nucleotide
2) Chromosome mutations – either changes in the structure of a chromosome or loss or gain of an entire chromosome
Gene Mutations (large segments or a single nucleotide)
Point mutations: change in 1 nitrogen base
*Can do 1 of 3 things* Change a.a. being coded
for the protein Change a.a. to a start
and stop codon Not change the a.a. or
the protein at all Example: sickle cell
anemia
http://www.intelihealth.com/i/P/PointMutationGEN.gif
Gene Mutations (large segments or a single nucleotide)
Frameshift mutation: addition or deletion of a nitrogen base Changes EVERY triplet &
a.a. after the insertion or deletion of a nitrogen base
More severe since more a.a. are affected
Chromosome mutations – either changes in the structure of a chromosome or loss or gain of an entire chromosome
Inversion: chromosome segment breaks off and then reattaches in reverse orientation to the same chr
Translocation: chr segment breaks off and attaches to different chr Causes sterility in plants
Chromosome mutations – either changes in the structure of a chromosome or loss or gain of an entire chromosome
Deletion: loss of a piece of chr due to chr breakage
Nondisjunction: a pair of homologous chr or single chr fails to separate during meiosis 2 kinds of gametes result
1) trisomy (extra chr…3 homologous chr’s ) Down Syndrome (trisomy 21)
2) monosomy (missing a chr…1 homologous chr instead of 2)
Ex: Turner’s Syndrome (X monosomy)