Name ____________________________________ Date __________Mrs. Geithner-Marron Bio 200 Period _________

Unit 6: DNA & Protein SynthesisCh. 28 DNA—Life’s Code

Describing DNA

• Who first described DNA?

– ________________________ & ________________________

• What shape did they use to describe DNA?

– _____________________________ (which looks like a ______________________)

DNA is a Polymer…

• What is the monomer that repeats to make DNA

– _____________________________________ (Sketch & label one in the box below.)

What are the parts of a nucleotide?

• ______________________________________

• ______________________________________

• ______________________________________

– 4 kinds:

• _______________________________

• _______________________________

• _______________________________

• _______________________________

– ____________________ gives name to _____________________________________

A Model of DNA

• Is a DNA molecule single-stranded or double-stranded?

Name ____________________________________ Date __________Mrs. Geithner-Marron Bio 200 Period _________

– __________________________________-stranded

• What parts make up the strands?

– “backbone”/sides

• __________________& __________________

– “rungs”/steps

• ______________________________________

– Always paired as:

» _______________________________

» _______________________________

• Strands are ___________________________________________________ (A-T & G-C) & _____________________________________________ (opposite directions/upside down)

Where is DNA found in eukaryotic cells?

• DNA is contained in ________________________________________________ within the _______________________________________________________________________

Name ____________________________________ Date __________Mrs. Geithner-Marron Bio 200 Period _________

DNA Replication

• What is another word for replication???

– ____________________________________

• Why must DNA replicate?

– so when cell divides, each new cell __________________________________________

• When does DNA replicate?

– ___________________________ the cell divides (________________________ mitosis or meiosis)

• Where does DNA replicate?

– inside the _______________________________

• How does DNA replication occur?

– 1. DNA molecule ____________ between bases forming 2 new _____________ "strands"

– 2. The “parent” strands act as ____________________________________________…

• "new" ______________________ are paired up with the ____________________ ________________ on the “parent” strand

– forming a ________________________________________________ strand

Name ____________________________________ Date __________Mrs. Geithner-Marron Bio 200 Period _________

» Ex. ________ pairs up with ________

• 3. Now, there are ___________________________________ of the original DNA molecule.

• And, when the cell divides, each daughter cell _____________________________.

Finish the replications…

Name ____________________________________ Date __________Mrs. Geithner-Marron Bio 200 Period _________

Deoxyribonucleic Acid vs. Ribonucleic Acid

DNA RNA• sugar = • sugar =

• stranded

• stranded

• leave nucleus • between nucleus & cytoplasm

• N bases = • N bases =

The DNA Code & Protein Synthesis

• What is a gene?

– a ______________________________________ that ______________________ for the synthesis (making) of a specific _______________________

• Which part of DNA actually carries the code?

– the ___________________________________

Name ____________________________________ Date __________Mrs. Geithner-Marron Bio 200 Period _________

• & their ________________________

– If the _______________________________________________ is changed the ___________________________________________ (usually) changes & the _____________________________________ made (usually changes)

• So, the big question is… How does the DNA code in a cell’s nucleus get to the ribosomes where proteins are synthesized?

– _____________________________ & _____________________________

Transcription

• What is transcription?

– DNA code is "transcribed"/________________ into __________________________

• When does transcription happen?

– when a _______________________________________________________ is needed

• Where does transcription happen?

– in the _______________________________________________________________

• What does transcription make?

– a single-stranded ______________________________________________________

• made from instructions/order of the ___________________ in the ____________

Name ____________________________________ Date __________Mrs. Geithner-Marron Bio 200 Period _________

• What are the steps in transcription?

– 1. DNA _____________________________

– 2. free _________________________ pair with _______________________ on DNA

• until a ___________________________________________________ is reached

– 3. mRNA _____________________________________________________________

• & moves __________________________________________________________

– to ___________________________________________________________

– 4. DNA strands rejoin

mRNA Carries DNA's Code Using Codons

• What is a codon?

– ____________________ consecutive bases on mRNA that codes for a particular _______________________________

• 64 possible combinations, so some amino acids ________________________________________________________________

• How can we figure out the amino acid coded for by a codon?

– a codon chart (You will be given 2 types & can use them on quizzes/tests.)

• What amino acid does the AUG codon code for?– ________________________________

Name ____________________________________ Date __________Mrs. Geithner-Marron Bio 200 Period _________

Translation

• What is translation?

– process of reading ________________________ ______________________________________ ______________________________________

• with help of _________________________ ___________________________________

• When does translation occur?

– when ______________ from the nucleus ____________________________________

• Where does translation happen?

– at ____________________________________ in the _________________________

What are the steps in translation?

• 1. ______________ comes from the nucleus & joins with __________________ in cytoplasm

• 2. ________________________________ the codon until it finds the ________________

• 3. _____________________________________________________________________

______________________________________________________________________

– _______________________________________________ specified by the mRNA codon

Name ____________________________________ Date __________Mrs. Geithner-Marron Bio 200 Period _________

• 4. Ribosome moves along mRNA reading each codon ________________________________ _______________________________________________________________________

– tRNA brings each amino acid

• 5. _______________________ line up & ______________ to ______________________

• 6. Polypeptide chain ___________________________________________________ (3-D)

– Shape of protein is related to its function

Let's Practice...

Given the following DNA sequence:

• What would the mRNA strand look like?

• What amino acids would be coded for using this mRNA?

• What would the anticodons on the tRNA be for each amino acid?

Name ____________________________________ Date __________Mrs. Geithner-Marron Bio 200 Period _________

• Given the following DNA sequence determine the:1. mRNA codon sequence2. The amino acids that would be coded for by each codon3. anticodons on each tRNA which "allowed" it to bring that amino acid (using mRNA

codons)

DNA = TAC CCA TTG GAT CCG ACT

1. mRNA codon =

2. amino acid (a. a.) =

3. anticodon (on tRNA) =

Mutations

• What are mutations?

1. ____________________________________ in a ________________ on a chromosome

• can occur spontaneously during __________________________________________

• can be caused by ______________________________ (such as radiation, high temperatures, or chemicals)

• often corrected, but not always

– once occurs, ________________________ as if ______________________________________

– can cause a different ________________________ to be formed

Types of Mutations

• What are the 3 types of mutations?

Name ____________________________________ Date __________Mrs. Geithner-Marron Bio 200 Period _________

1. _______________________________________

• What happens in a deletion mutation?

– a nucleotide (base) is ___________________

» causes a _____________________________________

~___________________ nucleotides after the deletion to the ____________ causing a different ___________________________________ to be formed

2. ________________________________________

• What happens in an insertion mutation?

– a nucleotide (base) is __________________

» causes a _____________________________________

~___________________ nucleotides after the insertion to the ____________ causing a different ___________________________________ to be formed

3. ________________________________________

• What happens in an point mutation?

– one nucleotide (base) is _____________________________________________

» affects only ______ amino acid & ___________________ cause “frame shift”

» sometimes amino acid & protein can be the same (“_____________________”)

» protein may be able to ___________________________________________

Sickle Cell Mutation

• What does the sickle cell mutation do?

– affects __________________________ (a protein in red blood cells that carries oxygen)

• What type of mutation causes sickle cell?

– a _____________________________ mutation

Name ____________________________________ Date __________Mrs. Geithner-Marron Bio 200 Period _________

• changes one ________________________________________________________

– changes the _____________________________________________________

“___________________________________________” mutation (no change in polypeptide)