Download ch10 GN

10.1 - DNA
A.
B.
C.
D.
Found in the ________________ of the cell
Control _____________ synthesis and thus controls cell activities
Has shape of a ____________________
Building block is a _______________
Nucleotide
1) _______________________________ group – PO4
2) 5-C ________________________________ = deoxyribose
3) a ____________________________________ base (one of the four)
b) _____________________ – single ring
thymine (T) “Tut & Cleopatra
cytosine (C)
= Pyramids”
a) _____________________ =double ring
adenine (A) “Another Guido
guanine (G)
Pumps”
DNA People:
1) 1951 – ________________________determines that the number of A=T and G=C
2) 1952 - __________________________ used x-ray to observe the structure of
DNA. She worked with Maurice W ilkins.
3) 1953 - _______________________________________ examined Franklin’s work and
they had determined the structure of DNA by building a model.
The Watson-Crick Model of DNA
Double Helix = like a twisted ladder
a) backbone = __________________
rungs = _____________________
(always a purine to a pyrimidine, A-T or C-G)
b) 2 sides held together by weak ________________________ bonds
c) backbone held together by ______________________________ bonds
DNA REPLICATION
1) _________________________________________ a portion of the DNA molecule.
2) __________________________ attach to the DNA molecule, move along the molecule
and “_____________________” the two strands of DNA by breaking the H bonds
3) New complimentary bases from the cell’s _____________________ are added to the
unraveled DNA strands by DNA _________________________________, and hew
hydrogen bonds are formed between the bases. “zips up” strands
4) Bonds form between the phosphates and sugars of copied strands.
5) 2 identical double helices of DNA are formed; each consists of one “old” strand of DNA
and one “new” strand of DNA
 Replication starts at ______________________________________ along the helix, to
go much FASTER!
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10.2 RNA
a) Same as DNA except: it is _______________________-stranded
b) ____________________________ replaced thymine
(bonds with _________________________)
c) sugar = ____________________________
Types of RNA
mRNA – ______________________________ RNA
- copies DNA (gets transcript) to leave nucleus
has a _________________________ to code for an amino acid (3 nucleotides)
rRNA = ________________________________RNA
- makes up most of ribosomes
tRNA= ________________________ RNA
- translates mRNA to the amino acid
- carries the amino acid to ribosome
has an ______________________
to match the mRNA
has an ______________________
to pick up the correct amino acid.
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TRANSCRIPTION (mRNA) – “written across”
• RNA ______________________________attaches to a special place (certain base
sequence called ____________________________) on the DNA molecule and moves
along the strand, unwinding and separating the strands.
• The RNA polymerase then begins reading and copying the DNA as it goes along. “zips
up” an RNA copy of DNA - (A-U, C-G)
• Pairing of the nucleotides continues until the enzyme reaches a sequence of nucleotides
on the DNA that represents a ______________________________________________.
• mRNA separates from the DNA as it grows, resulting in a new mRNA strand that will
carry the genetic information out of the nucleus to the ribosome.
Replication vs Transcription
These two processes are similar except:
1) URACIL replaces THYMINE in mRNA
2) The RNA completely detaches from the DNA strand
TRANSLATION (tRNA)
•
amino acids are assembled into a polypeptide chain at the ribosome
•
____________________ anticodons translates from _____________________ codons
REVIEW
What is the difference between the following?
1.
Replication
Transcription 2.
Translation
3.
List 3 differences.
DNA
RNA
4.
5.
6.
7. What does RNA polymerase also do that DNA polymerase does not?
8. What are the base pair rules for DNA---DNA? A --- ________ , G --- _________
9. G & A are purines or pyrimidines?
T & C are purines or pyrimidines?
10. Who took an Xray of DNA to view it? ___________________________________
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Lecture 10.3 - PROTEIN SYNTHESIS (MAKING PROTEINS)
Why are proteins important?
They literally MAKE UP _____________________ & ___________________
 Monomers of protieins 
 AA + AA 
 AA + AA + AA (or more) 
 2 or more polypeptides 
Overview of Protein Synthesis:
- an organism’s genotype is translated into its phenotype.


I. Genetic Code
A. Link between: gene (______________ sequence) to protein (______________ sequence)
B. genetic code for amino acids:
________ nucleotides = TRIPLET CODE = ____________________________
– Set of 64 base triplets
– Codon – found on ________________________________
– Start codon 
– Stop codon 
– ____________ kinds of amino acids are directed by 61 codons
– Most amino acids can be specified by more than one codon
Ex. 6 codons specify leucine - UUA, UUG, CUU, CUC, CUA, CUG
II. Translation
Once the mRNA reaches the _____________________, the cell can begin to build a protein.
A. The ________________ translates the mRNA’s code into a particular protein.
STRUCTURE:
•
____________________-strand of RNA looped back on itself
•
Has ________________________ on 1 side (matches up with mRNA codons)
•
Has ___________________________ of amino acid on the other side
FUNCTION: to carry proper ___________________________ to mRNA at the ribosome
Ex: tRNA with anticodon GCU codes for Arginine (mRNA codon is: ______________ )
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B. Process of Translation
– A __________________________ attaches to the mRNA at a start codon - AUG
–
The “AUG” codon pairs with the anticodon “UAC” on a specific tRNA.
–
This tRNA carries the amino acid ___________________________________
–
2nd codon is now ”read” by the _______________________________.
Then a ______________________________
Then its ___________________________________ is attached to the polypeptide chain
–
An enzyme joins the first two amino acids in the chain by a __________________ bond.
The first tRNA is now empty and the second is holding both amino acids. The 1st tRNA
leaves the ribosome
–
The _________________________ continues to grow until the ribosome reaches a
STOP CODON on the mRNA
Three Stages of Translation
Initiation - start codon
Elongation – addition of AA
Termination – stop codon
What Happens to the New Polypeptides?
 Some just enter the ______________________________
 Many enter the __________and move through the cytomembrane system where they are
processed, packaged, and transported out of cell
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REVIEW
1. Where is a codon found? ___________________________________
2. Where is an anticodon found? _______________________________________
3. What are the 2 steps to protein synthesis?
–
–
4. What tells a ribosome to start translating mRNA? _______________________________
5. What tells a ribosome to stop translating mRNA? ________________________________
6. How many Nitrogen bases are a part of a codon? ___________________
7. Look up at the mRNA Codon Chart. What amino acid do you make with GUG?
________________________________________
8. Proteins are important because they make ________________________ & ________________
9 Fill in the matching RNA Nitrogen bases in the box to the right
10 Recopy the mRNA bases in the rectangle with the circle (ribosome) Fill in tRNA’s anticodon in
the circle. Do you know the amino acid these 3 bases will be translated to?
T
A
C
A
G
T
C
T
A
A
T
T
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