1. summarize each of the 6 steps of transcription 2. make an mrna copy from the dna gene:...

TRANSLATION

BELLWORK 1. Summarize each of the 6 steps

of transcription.2. Make an mRNA copy from the

DNA gene:GCATATGCAATGATAGATTGACGTATACGTTACTATCTAACT

3. How did you know whether the gene was on the top or bottom strand?

1. Grade hmw.2. Review the Gel Electrophoresis Lab, complete

conclusion, and hand in. (no make-up, go on class website and look up

directions for alternative assignment)3. Binder organization (to be left behind this weekend for

grading)4. Slate review on RNA types & transcription5. New notes & hand-out on translationNO HOMEWORK. Congrats on finishing science fair

project!!!

No late boards will be accepted AT ALL after today. Go on the class website to get the alternative assginment (not worth as many points, but you still pass if done well)

http://fwsciencejohnson.wikispaces.com

Grade homework: ___/15

#1 = 3 pts for completion #2 = 3 pts for completion #3= 3 pts for completion #4= all 6 drawings done= 6 pts

(at least 3 done= 3 pts)

Look at the gel below

Which colors are negative? Positive?Which are large? Small?

+ _

Make a record of what goes where!!1. Draw a picture of your gel and indicate

where each sample will go (remember there are 8 wells and 6 samples) Measure the distance each dye traveled using the ruler provided.

X

Sample

ObservationsQualitative Quantitative

At least 5

=20 total

Load and run YOUR gels!!1. Use the yellow pipettor with a fresh tip to

load each dye sample.2. Raise your hand to have a biotech student

add the buffer when you are done3. Connect cables and run the gel at 125 volts

for 15 minutes. Note the starting time.4. While you wait, make observations and lab

notes. (Note any dye spills or over flow. Did your pipettor tip puncture the gel? Can you see any thing happen in the box?)

5. While you wait, start writing the answers to the questions in complete sentences.

Conclusions—Write these on the back of your DNA lab!1. Which dye is the smallest? Largest? Which dyes

are positive? Negative?2. What dyes make up the unknown (X sample)?3. Compare the relative size of one of the positively

charged dyes, to one of the negatively charged dyes. Identify dyes in this comparison by number and color. Use the side (+ or -) the dye move towards, and measure the distance from the center for this analysis.

4. How about your hypothesis?...Was it correct? Why?Hand into box when finished and get out

notebook and binder, make sure all notes/hmw. Is finished

Binder Check On top: Translation hand-out (from today) Transcription homework (15)* Transcription simulation (10) Transcription In-class practice (10) History of DNA-scientists (10) DNA Worksheet (10)

Get slates out *MUST LEAVE BINDER BEHIND FOR GRADING THIS

WEEKEND Notebook check next week (all even pages filled

in, 3 ?s, summary at the bottom)

Protein Synthesis

To get from a DNA gene to a protein, the cell has to perform protein synthesis.

It requires 3 types of RNA: mRNA rRNA tRNA

It happens in 2 parts: Transcription Translation

Open binder to Transcription homework. Make SURE YOUR NAME IS ON the homework.Put binder on lab bench in order of last names:

RNAi (chefs, tower, recipes)

Translation

Translation is the process of making an amino acid chain from the instructions coded in the mRNA. Occurs in cytoplasm.

Translation Video Clip

http://www.youtube.com/watch?v=41_Ne5mS2ls (start @ 1:56)

http://www.youtube.com/watch?v=41_Ne5mS2ls

http://www.youtube.com/watch?v=41_Ne5mS2ls

Translation- step 1 Initiation

1. mRNA binds to the ribosome & the ribosome begins reading at the START codon AUG

Mature mRNA

Practice

GCG AUG CUG GGU CGU UAA

Which codon above is the START codon?

On your worksheet, find the START codon in each of the 8 mature mRNA strands

GCG AUG CUG GGU CGU UAA AUG GGU AGC AUC GAU UCU GAU UAA

AUG CGA UUC GAC UGG GAC CCA UAU UAG AUG CGC CGU UUG UGA

GAU CUG AUG CCU AAC UGC AUC UAG GCA AUG CAU AGA UCA GUC CCG UGA

AUG GAC CGA GUU AGC UGA GAU CUG GGC AUG CGA UAC CUC UAA CGA

Translation- step 2tRNA matching

2. The ribosome move along mRNA & reads each codon, matching it up with a tRNA that has the complementary anti-codon

Mature mRNA

Practice

What is the anticodon ontRNA that will match with

the START codon on mRNA?

AUG CCG GCA UGC GGA CUG

On your worksheet, fill out the tRNA anticodons for each codon in the mature mRNA strand

Translation- step 3Elongation

3. Each tRNA that enters the ribosome adds an amino acid to the growing chain. A peptide (protein) bond is formed between each amino acid in the chain.

FYI

There are 20 amino acids Each tRNA can only carry ONE type

of amino acid

tRNA w/ anticodon “UAC” can ONLY

carry methionine (M)

Translation- step 4Termination

3. When a STOP codon (UAA, UAG, or UGA) on mRNA enters the ribosome, the large & small rRNA subunits fall apart and translation ends

Practice

How many amino acids are coded for in the mature mRNA strand below? (hint: think about start & stop codons)

GAU CUG AUG CCU AAC UGC AUC UAG GCA

On your worksheet circle the START codon, Box the STOP codon, and record how many amino acids will be in the chain after translating each of the 8 mRNA strands.

Start:1

2 3 4 5

STOP (no

amino acid)

AUG CGA AUG GAC UGG GAC CCA UAU UAGWhat if there are 2 “start” codons??

Start at the FIRST one and keep going until you hit a STOP!

Practice Putting It All Together

Which of the following am I showing/describing?

DNA mRNA rRNA tRNAProteinThe central dogma

of biology says that ______ RNA

Protein



DNA mRNA rRNA tRNAProteinMade

with Uracil (U) instead of

T:___________



DNA mRNA rRNA tRNAProteinAmino

Acids are the small subunits

of ___________



DNA mRNA rRNA tRNAProtein



DNA mRNA rRNA tRNAProteinTransports

amino acids to the ribosome:

___________


Which colors are negative? Why?

+ _



DNA mRNA rRNA tRNAProtein



DNA mRNA rRNA tRNAProteinReads mRNA

and assembles amino acids into a chain:

___________


Which colors are the largest? Why?

+ _



DNA mRNA rRNA tRNAProteinA copy of the

information in DNA that can be taken

out of the nucleus:___________

Open binder to Transcription homework. Make SURE YOUR NAME IS ON the homework.Put binder on lab bench in order of last names:

Bellwork 2-6-13

1) Summarize the four steps of translation.

2) What carries the anti-codon?

Translation Simulation

You and your partner will receive an envelope full of mature mRNA transcripts

Take the mRNA out of the nucleus & into the cytoplasm (lab table) for translation

Pull the mRNA through the ribosome, & match up the correct tRNA

Record the amino acids that would be added to the growing chain

Figure out the secret phrase!

**If you finish early, work on your translation HW probs

Simulation Run-down

Each tRNA can only carry ONE amino acid (UAC always carries Methionine)….but were there some amino acids that were carried by multiple tRNAs?

Why might this overlap be beneficial?

Short-cut

mRNA Codon Wheel

Determine an amino acid

sequence from the mature

mRNA…without having to

match up tRNA anticodons!

AUG =Methionine

(M)

Try it out!

Mature mRNA: AUG GAC CGA GUU AGC UGA GAU CUG

Amino Acids: _ _ _ _ _ _ _ _M D R V T stop

Complete the amino acid

sequence on your worksheet using the codon

wheel

Closure- do it backwards

Write a short message using amino acid abbreviations: CAR

Work backwards to write the mRNA:

Add a start & stop codon

Write the complementary DNA gene & make it double stranded:

UGU CGA AGA

AUG UGU CGA AGA UGATAC ACA GCT TCT ACTATG TGT CGA AGA TGA

Closure- do it backwards

Write a short message using amino acid abbreviations: CAR

Work backwards to write the mRNA:

Add a start & stop codon

Write the complementary DNA gene & make it double stranded:

UGU CGA AGA

AUG UGU CGA AGA UGA

TAC ACA GCT TCT ACT

Write the DNA gene onto an index card to

trade with another class

tomorrow! Don’t forget to put your name!

Dear p.2,

Can you figure out the se

cret messa

ge? It’s

on the top strand…

TAC ACA CGT TCT ACT

ATG TGT GCA AGA TGA

Sincerely,

Carlos Caballero

ATG TGT CGA AGA TGA

1. summarize each of the 6 steps of transcription 2. make an mrna copy from the dna gene:...

Documents