bio protein synthesis + mutations (brennan)

synthesis occurs...

in ribosomes

amino acids

blocks of proteins

primary structure

sequence of amino acids

info about how to make proteins stored...

in DNA

gene

sequence of DNA that controls the synthesis of a specific

sequence of nucleotides in DNA provides...

a code for constructing

presence and of proteins determine

of

3 types of RNA (protein synthesis)

1. rRNA

2. mRNA (messenger)

3. tRNA (transfer)

2 stages of synthesis

1. transcription

2. translation

transcription

DNA transcribed to mRNA

DNA strands in transcription...

separate

one strand in transcription used to...

produce the RNA chain (using complementary pairing)

_____ catalyzes the reaction in transcription

RNA polymerase

stages of transcription

1. initiation

2. elongation

3. termination

stage of transcription; 1. initiation

RNA polymerase binds to a promoter, then helix unwinds

stage of transcription; 2. elongation

RNA nucleotides are added to chain

stage of transcription; 3. termination

RNA polymerase reaches terminator sequence, then detaches from template

central dogma

order of events in biology: DNA -> RNA -> protein

genetic code; triplet

3 nucleotides of DNA specify 1 amino acid

codon

- on mRNA

- specifies an amino acid

codon chart

used to determine which amino acid is coded for each mRNA codon (64 codons)

translation

proteins are produced using RNA molecules as templates

ribosomal subunits during translation...

come together & have binding sites for mRNA & tRNA

in translation, transfer RNA molecules...

match an amino acid to its corresponding mRNA codon

anticodon

allows tRNA to bind to a specific mRNA codon

A pairs with

U

G pairs with

C

T pairs with

A

mutation

a change in the nucleotide sequence of DNA

mutations can be...

- spontaneous: errors in DNA replication

- induced: by mutagens (high energy radiation or chemicals)

- neutral, harmful, or beneficial

mutations are...

random events & can be inherited

types of mutations

1. base substitutions (point mutations)

2. deletions/insersions (frameshift mutations)

3. chromosomal mutations (during meiosis crossing over)

base substitutions mutation(point mutations)

replacement of one nucleotide with another

base substitution mutation effects:

- depends on if there's an amino acid change that alters protein's function

- can be silent mutation (no effect)

deletion/insersion mutation (frameshift mutations)

alters mRNA reading frame so nucleotides are grouped into different codons

deletion/insersion mutation effects:

- lead to significant changes in amino acid sequence

- can cause nonfunctional polypeptide

some mutations can cause...

a premature stop during translation

chromosomal mutations

1. deletion

2. duplication

3. inversion

4. translocation

chromosomal mutations; 1. deletion

loss of a chromosome segment

chromosomal mutations; 2. duplication

repeat of a chromosome segment

chromosomal mutations; 3. inversion

reversal of a chromosome segment

chromosomal mutations; 4. translocation

attachment of a segment to a non-homologous chromosome (can be reciprocal)