Protein Synthesis Part II: Genetic Code and

Translation

Which is single stranded?

93%

7% 1. DNA2. RNA

Where in the cell does transcription take place?

Cyt

oplasm

Mito

chond

ria

Nucl

eus

Golg

i Body

Vac

uole

0% 0% 0%0%

100%1. Cytoplasm2. Mitochondria3. Nucleus4. Golgi Body5. Vacuole

If a DNA strand has the following sequence of base pairs – A C T G G T C C A A , then the mRNA strand would have what sequence?

0%

100%

0%0%

1. T G A C C A G G T T2. A C T G G T C C A A3. T G U C C U G G T T4. U G A C C A G G U U

mRNA is synthesized in the nucleus and travels to the cytoplasm to meet up with which organelle?

Mito

chond

ria

Rib

osom

e

Golg

i Body

Lys

osom

e

Nucl

eus

7%

80%

0%0%

13%

1. Mitochondria2. Ribosome3. Golgi Body4. Lysosome5. Nucleus

Genetic Code

Quick Review of Proteins…

Monomer: Amino Acid 20 different amino acids! The properties of proteins are determined

by the order of the amino acids

The Genetic Code!

RNA contains 4 different bases: A, G, C, U The genetic code is read three letters at a

time Each “word” of the coded message is

three base pairs long These “words” are called codons

RNA Sequence:UCGCACGGU

Read sequence 3 bases at a time

UCG – CAC – GGU

Each set of three bases is a codon. Each codon represents a different amino

acid

…more genetic code AUG is the start codon In addition there are 3 different stop

codons. Stop codons are like the period at the end

of a sentence.

Using your mRNA codon chart, what amino acid would a ribosome call for if the codon was A A C ?

Phen

ylal

anin

e

Glu

tam

ine

Asp

arag

ine

Lys

ine

Tyr

osine

0%7%

13%

0%

80%1. Phenylalanine2. Glutamine3. Asparagine4. Lysine5. Tyrosine

Translation

RNA and Ribosomes work together to produce proteins

Transfer RNA

For translation we need a new type of RNA

Transfer RNA (tRNA) is responsible for carrying different amino acids to the ribosome.

tRNA has a three base sequence called an anticodon

Steps in Translation mRNA attaches to the ribosome tRNA brings in the amino acids Anticodons match with codons Peptide bonds form between amino acids

Translation Translation continues until a stop codon is read The newly formed protein is released

Where in the cell does translation, the second part of protein synthesis, take place?

Mito

chond

ria

Nucl

eus

Golg

i body

Cyt

oplasm

0% 0%0%0%

1. Mitochondria2. Nucleus3. Golgi body4. Cytoplasm

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23 24 25 26 27 28 29 30

Molecules called tRNA’s are floating around the cytoplasm carrying what?

mRNA’s

Glu

cose

DNA

Nucl

eotid

es

Am

ino A

cids

0% 0% 0%0%0%

1. mRNA’s2. Glucose3. DNA4. Nucleotides5. Amino Acids

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23 24 25 26 27 28 29 30

An mRNA codon is made up of how many nitrogen bases?

1 3 6 24

0% 0%0%0%

1. 12. 33. 64. 24

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23 24 25 26 27 28 29 30

What protein would be synthesized from the following mRNA strand?A C U U U C G A A U A C

Thre

onine

– ph...

Phen

ylal

anin

e ...

Tyr

osine

– glu

...

Thre

onine

– cy

...

0% 0%0%0%

1. Threonine – phenylalanine – glutamate – tyrosine

2. Phenylalanine – leucine – methionine – valine

3. Tyrosine – glutamate – phenylalanine – threonine

4. Threonine – cysteine – arginine – histidine

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23 24 25 26 27 28 29 30