Transcription - Translation.ppt

8/10/2019 Transcription - Translation.ppt

1/34

RNA ANDPROTEIN SYNTHESIS


2/34

How your cell makes very

important proteins The production (synthesis) of proteins.

3 phases:

1. Transcription

2. RNA processing

3. Translation

DNA RNA Protein


3/34

DNA RNA Protein

Nuclear

membrane

Transcription

RNA Processing

Translation

DNA

Pre-mRNA

mRNA

Ribosome

Protein

Eukaryotic

Cell


4/34

Before making proteins, Your

cell must first make RNA Question:

How does RNA(ribonucleic acid) differ

from DNA (deoxyribonucleic acid)?


5/34

RNAdiffers from DNA

1. RNAhas a sugar ribose

DNAhas a sugar deoxyribose

2. RNAcontains uracil (U)

DNAhas thymine (T)

3. RNAmolecule is single-stranded

DNAis double-stranded


6/34


7/34

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.


8/34

1. Transcription Then moves along one of the DNA strands

and links RNAnucleotides together.Nuclear

membrane

Transcription

RNA Processing

Translation

DNA

Pre-mRNA

mRNA

Ribosome

Protein

Eukaryotic

Cell


9/34

1. Transcription

DNA

pre-mRNA

RNA Polymerase


10/34

Question:

What would be the complementary

RNAstrand for the following DNA

sequence?

DNA 5-GCGTATG-3


11/34

Types of RNA

Three types ofRNA:

A. messenger RNA (mRNA)

B. transfer RNA (tRNA)

C. ribosome RNA (rRNA)

Remember: all produced in thenucleus!


12/34

mRNA

Carries instructions from DNA to the

rest of the ribosome.

Tells the ribosome what kind ofprotein to make

Acts like an email from the principal

to the cafeteria lady.


13/34

A. Messenger RNA (mRNA)

methionine glycine serine isoleucine glycine alanine stop

codonprotein

A U G G G C U C C A U C G G C G C A U A AmRNA

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 7codon 1


14/34

If the cell is a school

The Nucleus is the school office

The Nucleolus is the principalsoffice

The DNA is the principal

Ribosomes are the cafeteria ladies mRNA is the email from the

principal to the cafeteria lady


15/34


16/34

B. Transfer RNA (tRNA)amino acid

attachment site

U A C

Anticodon attaches to mRNA

methionine amino acid

tRNA linksamino

acids with

codons


17/34

2. RNA Processing

Nuclear

membrane

Transcription

RNA Processing

Translation

DNA

Pre-mRNA

mRNA

Ribosome

Protein

Eukaryotic

Cell


18/34

2. RNA Processing

Intronsare pulled out and exonscome together.

End product is a mature RNAmoleculethat leaves the nucleusto the cytoplasm.


19/34

2. RNA Processing

pre-RNA molecule

intron intronexon exon exon

exo

n

exon exon

Mature RNA molecule

exon exon exon

intron intron

splicesomesplicesome


20/34

RibosomesEach ribosome contains 3 binding sites A +

P + E

PSite

ASite

Large

Subunit

49 proteins

+3 RNA

molecules

Small subunit 33 proteins +1 RNA molecule

mRNA

A U G C U A C U U C G


21/34


22/34

3. Translation

Three parts:

1. initiation: start codon (AUG)

2. elongation:3. termination: stop codon (UAG)

Lets make a PROTEIN!!!!.


23/34

3. Translation

PSite

ASite

Large

subunit

Small subunit

mRNA


tRNA is held tightly at A+P

sites only if anticodon

forms base pairs with theattached mRNA.

The A&P sites are

close enough so

the 2 tRNA areforced to form base

pairs with the

adjacent codons on

the mRNA


24/34

Initiation

mRNA


2-tRNA

G

aa2

A U

A

1-tRNA

U A C

aa1

anticodon

hydrogen

bonds codon

The A&P sites are

close enough for the

2 tRNA are forced toform base pairs with

the adjacent codons

on the mRNA

Each amino acid is added is

selected by complementary base

pairing between the anticodon on

its attached tRNA and the next

codon on the mRNA


25/34

mRNA


1-tRNA 2-tRNA

U A C G

aa1 aa2

A U

A

anticodon

hydrogen

bonds codon

peptide bond

3-tRNA

G A A

aa3

Elongation


26/34

mRNA


1-tRNA

2-tRNA

U A C

G

aa1

aa2

A U

A

peptide bond

3-tRNA

G A A

aa3

Ribosomes move over one codon

(leaves)


27/34

mRNA


2-tRNA

G

aa1

aa2

A U

A

peptide bonds

3-tRNA

G A A

aa3

4-tRNA

G C U

aa4

A C U


28/34

mRNA


2-tRNA

G

aa1aa2

A U

A

peptide bonds

3-tRNA

G A A

aa3

4-tRNA

G C U

aa4

A C U

(leaves)



29/34

tid b d


30/34

mRNA

G C U A C U U C G

aa1

aa2

A

peptide bonds

3-tRNA

G A A

aa3

4-tRNA

G C U

aa4

A C U

U G A

5-tRNA

aa5


5


31/34

mRNA

A C A U G U

aa1

aa2

U

primarystructure

of a protein

aa3

200-tRNA

aa4

U A G

aa5

C U

aa200

aa199

terminator

or stop

codon

Termination


32/34

End Product The end products of protein synthesis is

a primary structure of a protein.

A sequence of amino acid bondedtogether by peptide bonds.

aa1

aa2 aa3 aa4

aa5

aa200

aa199


33/34

Question:

The anticodon UACbelongs to a tRNAthat

recognizes and binds to a particular amino

acid.

What would be the DNA base code for this

amino acid?


34/34

Answer:

tRNA - UAC (anticodon)

mRNA - AUG (codon) DNA - TAC

Date post:	02-Jun-2018
Category:	Documents
Upload:	ezgi-tanil
View:	229 times
Download:	0 times

Transcription - Translation.ppt

Documents