Download DNA and RNA DNA: Important scientist: Frederick Griffith: Oswald

DNA and RNA
I. DNA: ______________________________________
a. Important scientist:
1. Frederick Griffith: __________________________________________________________
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2. Oswald Avery: ____________________________________________________________
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3. Alfred Hershey Martha Chase: ______________________________________________
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b. Components of DNA: made up of units called ___________________________________,
each unit has 3 basic components; a 5-carbon sugar called __________________________, a
phosphate group, and a nitrogenous base there are 4 of them: two known as purines (which
have 2 rings in their structures) called: _____________________________ and
__________________________________. Two others called pyrimidines (which have 1 ring
in their structure) called ____________________________________ and
___________________________________. __________ and ___________ pair up and
__________ and __________ pair up . Refer to page __________. Watson and Crick are the
scientist who identified the general shape of DNA and created a model of DNA which was a
___________________________________ in which two strands were wound around each
other. DNA is reproduced in a process called DNA________________________________.
Refer to page _________. DNA is “unzipped” and base pairs broken apart, each part serves
as a template, the DNA polymerase enzyme joins individual nucleotides to produce a DNA
molecules.
II. RNA: ___________________________________________
a. Structure: RNA is also made up of long chains of ___________________________________.
There are 3 main differences between DNA and RNA:
1. ________________________________________________________________________
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2. ________________________________________________________________________
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3. ________________________________________________________________________
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b. Types of RNA, there are 3 main types of RNA they are:
1. mRNA___________________________________________________________________
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2. rRNA____________________________________________________________________
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3. tRNA____________________________________________________________________
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c. Transcription:
d. Translation:
e. Roles of DNA & RNA:
III. Mutations and Gene expressions:
a. Mutations: may occur in many types of cells ; however, only mutations occurring on/in the
gametes (sex cells egg and sperm)may be passed on from one generation to another. If the
mutation occurs in the body cells it may affect the individual. Look at Fig 13-11
1. Types:
Point mutations: occur at a single point on DNA
a. Substitution; on gene replaces another causing the mRNA to change form CCC
becomes ACC, both codons still specify for the amino acid proline therefore no
change. If the first base were changed CCC to ACC the amino acid theronine would be
produced this could cause a change.
b. Insertion and deletions: referred to as a frameshift mutations, can change the entire
sequence of the amino acids coded to produce, not only at one codon but many
others. This is a more “serious”type of mutation.
c. Chromosomal mutation: changes in the number of chromosomesor the structure of
the chromosome seen in figure 13-12. Cri-du Chat is an example of deletion of a part
of a chromosome.
There is no one cause for mutations either by natural events or through artificial means.
Mutagens, chemical or physical agents in the environment can produce changes in DNA. Some of
these changes are vary in their effect, some are helpful while others are harmful. Figure 13-13
b. Gene regulations:
1. Prokaryotes DNA binding proteins regulate genes by controlling transcription, these
genes wich are regulated together are called operons . The lac operonturns on at the
promoter and operator sites, the Lac repressor blocks transcription. Figure 13-16
2. Eukaryotes transcription factors control the expression of those genes Gene regulation
allows for cell specialization. This not only allows cell specialization but also for cells
differentiation (become specialized in structure and function). This can be associated with
the homeotic genes and the “Hox genes” (master genes which are like switches that
trigger particular patterns of development and differentiation in cells and tissue).
Figure 13-20 & 21