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RNA AND PROTEIN SYNTHESIS... Before making proteins, Your cell must first make RNA • Question: • How does RNA RNA ribonucleic acid ribonucleic acid differ from DNA deoxyribonucleic ac

RNA AND PROTEIN SYNTHESIS

How your cell makes very

DNA → RNA RNA → Protein

Before making proteins, Your

cell must first make RNA

• Question:

• How does RNA RNA (ribonucleic acid) (ribonucleic acid) differ

from DNA (deoxyribonucleic acid) DNA (deoxyribonucleic acid) ?

RNA differs from DNA DNA

1 RNA RNA has a sugar ribose sugar ribose

DNA has a sugar deoxyribose sugar deoxyribose

2 RNA RNA contains uracil (U) uracil (U)

DNA has thymine (T) thymine (T)

3 RNA RNA molecule is single-stranded single-stranded

DNA is double-stranded double-stranded

1 Transcription

• Then moves along one of the DNA strands DNA strands

and links RNA RNA nucleotides together

1 Transcription OR RNA production

• RNA molecules are produced by copying part of DNA into a complementary

sequence of RNA

• This process is started and controlled by

an enzyme called RNA polymerase.

1 Transcription

DNA

pre-mRNA

RNA Polymerase

• What would be the complementary

RNA strand for the following DNA DNA

sequence?

• DNA 5’-GCGTATG-3’

Types of RNA

• Three types of RNA RNA :

A messenger RNA (mRNA)

B transfer RNA (tRNA)

C ribosome RNA (rRNA)

• Remember: all produced in the nucleus nucleus !

• Carries instructions from DNA to the

rest of the ribosome.

• Tells the ribosome what kind of

protein to make

• Acts like an email from the principal

to the cafeteria lady.

A Messenger RNA (mRNA)

methionine glycine serine isoleucine glycine alanine stop

codon

protein

A U G G G C U C C A U C G G C G C A U A A mRNA

start codon

Primary structure of a protein

peptide bonds

codon 1

If the cell is a school…

office

principal to the cafeteria lady

QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture.

• Part of the structure of a ribosome

• Helps in protein production

tRNA

A go-getter

Gets the right parts to make the right protein according to mRNA instructions

B Transfer RNA (tRNA)

amino acid

attachment site

U A C anticodon

methionine amino acid

2 RNA Processing

• Introns are pulled out and exons exons

come together.

molecule that leaves the nucleus nucleus

• Introns bad…… Exons good!

2 RNA Processing

pre-RNA molecule

Mature RNA molecule

intron intron

splicesome splicesome

P Site

A Site

3 Translation

• Three parts:

1 initiation initiation: start codon (AUG)

2 elongation elongation:

3 termination termination: stop codon (UAG)

• Let’s make a PROTEIN!!!! PROTEIN!!!!

3 Translation

P Site

A Site

of a protein aa3

terminator

or stop codon

Termination

End Product

• The end products of protein synthesis is

a primary structure of a protein primary structure of a protein

• A sequence of amino acid amino acid bonded

together by peptide bonds peptide bonds

aa1

aa5

aa200 aa199

• tRNA - UAC (anticodon)

• mRNA - AUG (codon)

• DNA - TAC