Protein Synthesis

Review… DNA:

Found in the nucleus Double stranded Contains the instructions for controlling

the cell (including instructions for making proteins)

Has the bases A, T, C, G RNA:

Can go outside the nucleus Single stranded Has the bases A, U, C, G

Ribosomes: Make proteins

Steps of Protein Synthesis: Transcription Translation

Transcription DNA is “unzipped” by RNA

polymerase RNA polymerase breaks the

Hydrogen bonds between the DNA bases to separate the two strands

RNA polymerase makes a copy of RNA from the DNA that has been separated

The strand of RNA that is made is called mRNA (messenger RNA)

Transcription

Transcription Animation

Translation mRNA leaves the nucleus and

enters the cytoplasm Ribosomes attach to the mRNA

strand and “reads” the information on the mRNA strand Ribosomes also have RNA, called

rRNA (ribosomal RNA), that does the “reading”

The information that is being “read” is called codons Codons – a set of 3 bases

Translation When the RNA is “read”, tRNA

(transfer RNA) attaches to the mRNA strand

tRNA will have complementary bases that will match up with the mRNA These complementary bases on the

tRNA are called anticodons Anticodons match up with the correct

codons tRNA also has an amino acid

attached to the bottom of it

Translation As more tRNAs attach to the mRNA,

a bond will form between the amino acids on the tRNA These bonds are called polypeptide

bonds As bonds form, tRNA detaches from

the amino acids and mRNA

Translation Animation

Proteins!!! When all the amino acids have

bonded together, they are in a chain

This chain is a protein Amino acids are the building blocks

of proteins The protein chain will fold in to

itself so that it is more compact to travel within and outside the cell