Protein Synthesis

RNA

(Ribonucleic Acid)

Structure of RNA

RIBONUCLEIC ACID
• a nucleic acid

• Single stranded

• Ribose – sugar

• CHONP

• Nitrogen bases:
A,C,G, andURACIL (U)

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.

Three Types of RNA

•Messenger RNA (mRNA)
carries genetic
information

•Transfer RNA (tRNA)
transfers amino acids

•Ribosomal RNA (rRNA)
assembles the proteins

How does RNA differ from DNA?

RNA

DNA

1. Ribose (sugar)

1. Deoxyribose (sugar)

2. A, C, G, and Uracil

2. A, C, G, and Thymine

3. Single stranded

3. Double stranded

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Making a
Protein

Protein Synthesis

▪ The production of proteins
using the genetic code
▪ Separated into Two phases:

1. Transcription

2. Translation

DNA → mRNA →Protein

Nuclear
membrane

Transcription

RNA Processing

Translation

DNA

Pre-mRNA

mRNA

Ribosome

Protein
Eukaryotic

Cell

Protein Synthesis:2 Main Phases

1. Transcription

▪DNA 🡪 mRNA

▪Occurs in nucleus

2. Translation

▪mRNA 🡪 Proteins

▪Occurs in the cytoplasm (ribosome)

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Phase 1: Transcription

- occurs inside the nucleus
- The genetic code is

transcribed
(copied/changed) to
mRNA.

- DNA → mRNA

Question:

▪What would be the
complementary RNA strand
for the following DNA
sequence?

DNA 5’-GCGTATG-3’

Answer:

•DNA
5’-GCGTATG-3’
•RNA
3’-CGCAUAC-5’

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Phase 2: Translation

- Occurs in the

cytoplasm/ribosome

- tRNA brings a

corresponding amino acid to
the ribosome to make
proteins according to the
mRNA code.

- Translates a language of

letters to a language of
words.

Genetic Code

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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

aa1

aa2

aa3

aa4

aa5

aa6

peptide bonds

codon
2

codon
3

codon
4

codon
5

codon
6

codon
7

codon
1

methionine

End Product –The Protein!

• The end product of a sequence of amino acids

bonded together by peptide bonds is a protein.

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aa1

aa2
aa3
aa4

aa5

aa200

aa199

The End

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