DNA and Protein Synthesis

Protein Synthesis

• It’s a process– DNA -> RNA -> Amino Acids (Protein)

RNA

• Sugar is Ribose NOT what…• Has nitrogen base Uracil

instead of Thymine– Also contains the other 3

bases…what are they?• Only single stranded

RNA

Three processes in this unit…

• 1. Replication (DNA DNA)• 2. Transcription (DNA mRNA)• 3. Translation (RNA Protein)

A. DNA Replication

1. Occurs in the nucleus prior to any cell division

2. Enzyme is used to “unzip” or “unwind” the DNAa. Forms a bubble at the origin site

DNA Replication (cont.)3. Another enzyme is used to build a

complementary strand of DNA from the template piece of original DNAa. Nitrogenous bases pair up

1. A – T

2. C - G

4. As a result, you create two identical strands of DNA

Let’s Practice

• Replicate the following strand of DNA using the correct nitrogenous bases:

ATCGGCTATTAGGCATATCCGACGGTC

TAGCCGATAATCCGTATAGGCTGCCAG

Let’s Build A Protein

Transcription

• 1.) DNA strand unzips– The bonds between the nitrogen bases are broken– Initiated by RNA polymerase (enzyme) binding to

promoter site on DNA• 2.) A single strand of mRNA (messenger RNA) is

made– Pair up the bases

• A• T• C• G

The mRNA then travels from nucleus to cytoplasm

Transcription

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. Cytoplasm

2. Mitochondria

3. Nucleus

4. Golgi Body

5. Vacuole

Any given segment of DNA has directions that make unique what?

Glu

cose

Pro

tein

s

Lip

ids

Blo

od cel

ls

0% 0%0%

100%1. Glucose

2. Proteins

3. Lipids

4. Blood cells

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?

T G

A C

C A

G G

T T

A C

T G

G T

C C

A A

T G

U C

C U

G G

T T

U G

A C

C A

G G

U U

4%

96%

0%0%

1. T G A C C A G G T T

2. A C T G G T C C A A

3. T G U C C U G G T T

4. U G A C C A G G U U

Why is mRNA called messenger RNA?

• Because it carries the directions to make a protein to the ribosome like a message

Actually 3 types of RNA

• mRNA- messenger – Brings message from nucleus to ribosomes in

cytoplasm• rRNA- ribosomal

– Make up a ribosome• tRNA- transfer

– “transfers” amino acids from the cytoplasm to the ribosome to be added to the chain

The difference between RNA and DNA is what?

The

phosphat

es

The

sugar

s

The

nitrogen

bas

es

The

way

the

mon

ome.

..

0%

36%

82%73%

1. The phosphates

2. The sugars

3. The nitrogen bases

4. The way the monomer units bond

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

0%

95%

5%0%0%

1. Mitochondria

2. Ribosome

3. Golgi Body

4. Lysosome

5. Nucleus

Translation

1. mRNA meets up with a ribosome…why??– Ribosomes are the site for protein production

2. tRNA molecules bring amino acids to ribosomes

3. An mRNA codon will pair with a tRNA anticodon– Codon: 3 Nitrogen base sequence in mRNA

that specifies a specific amino acid – Anticodon: 3 Nitrogen base sequence in

tRNA

Translation (cont.)

4. As tRNA’s are added, amino acids are bonded together and will be released as a fully functional protein.

That’s the process, Now how do you know what amino acids make up a particular protein

• We use an mRNA codon chart

Where in the cell does transcription, the first part of protein synthesis, take place?

Mito

chond

ria

Nucl

eus

Rib

osom

es

Cyt

oplasm

0% 0%0%0%

1. Mitochondria

2. Nucleus

3. Ribosomes

4. 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

DNA has the directions to make what?

Glu

cose

Nucl

eotid

es

Pro

tein

s

Mono

sacc

harid

es

0% 0%0%0%

1. Glucose

2. Nucleotides

3. Proteins

4. Monosaccharides

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

After a strand of mRNA is made where does it go?

Rib

osom

e

Mito

chond

ria

Lys

osom

e

Vac

uole

0% 0%0%0%

1. Ribosome

2. Mitochondria

3. Lysosome

4. Vacuole

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

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. Mitochondria

2. Nucleus

3. Golgi body

4. 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

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’s

2. Glucose

3. DNA

4. Nucleotides

5. 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

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

1 3 6 24

0% 0%0%0%

1. 1

2. 3

3. 6

4. 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

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% 0% 0%0%0%

1. Phenylalanine

2. Glutamine

3. Asparagine

4. Lysine

5. Tyrosine

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

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

Thre

onine

– phen

ylal

...

Phen

ylal

anin

e –

leuci

..

Tyr

osine

– glu

tam

ate.

.

Lys

ine

– cy

stei

ne –

a...

0% 0%0%0%

1. Threonine – phenylalanine – glutamate – tyrosine

2. Phenylalanine – leucine – methionine – valine

3. Tyrosine – glutamate – phenylalanine – threonine

4. Lysine – 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

What protein would be synthesized from the following DNA segment?T A A G T A C G C T A G

Isole

ucine

– al

anin

e –.

..

Isole

ucine

– his

tidin

e ...

Phen

ylal

anin

e –

leuci

..

Isole

ucine

– le

ucin

e –.

..

0% 0%0%0%

1. Isoleucine – alanine – histidine – alanine

2. Isoleucine – histidine – alanine – isoleucine

3. Phenylalanine – leucine – valine – arginine

4. Isoleucine – leucine – threonine – lysine

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

How would you assess your comprehension of DNA and Protein Synthesis?

A B C D

0% 0%0%0%

1. A

2. B

3. C

4. D

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