Nucleic Acids And Protein Synthesis

1
Nucleic Acids And Protein Synthesis
2
I. What are Nucleic Acids?
3
A. Nucleic acids are organic compounds that
control all the activities of a cell.
4
B. The cells of all organisms, except viruses,
contain both types of nucleic acids.
5
C. 2 types of nucleic acids
6
DNA(Deoxyribonucleic Acid)known as the code of
life
7
a. The structure of DNA was discovered by James
Watson and Francis Crick in 1953.
8
b. The structure of DNA is a double helix (looks
like a spiral staircase). If uncoiled DNA would
look like a ladder.
9
c. Each side of the DNA ladder made of
alternating phosphate groups and sugar molecules.
Each rung of the DNA ladder is made of 2 nitrogen
bases held together by hydrogen bonds.
10
1. Each sugar, phosphate and base make up a
nucleotide.
11
d. DNA is made of 4 bases
12
Adenine2. Guanine(both called purines and made
of a double ring carbon and nitrogen atoms)
13
3. Thymine4. Cytosine(both called pyrimidines
and made up of single ring carbon and nitrogen
atoms)
14
e. Each rung of the DNA ladder is made up of one
purine and one pyrimidine.
15
Adenine bonds only with thymine.2. Guanine bonds
only with cytosine.
16
f. DNA has the ability to build an exact copy of
itself.
17
1. A complete copy of DNA must be made before a
cell can divide.
18
2. During replication the ladder splits down the
middle (unzips) and a matching nucleotide joins
on each nucleotide of the original.
19
2. RNA (Ribonucleic Acid)
20
a. There are 3 major structural differences
between DNA and RNA
21
1. RNA is a single strand It does not bond to a
complimentary strand like DNA (It makes ½ a
ladder).
22
2. RNA has a 5 carbon ribose sugar (it has one
more oxygen molecule than a deoxyribose sugar).
23
3. RNA uses the base uracil instead of the base
thymine. The bonding rule stays the same with
this exception) (AU GC)
24
b. 3 different types of RNA.
25
1. Messenger RNA (mRNA) carries the
information(or message) from the nucleus to the
ribosome.
26
The message is the instruction as to how amino
acids are put together to build specific protein.
It serves as a template for amino acid assembly.
27
2. Transfer RNA (tRNA) picks up and carries amino
acids to the ribosomal RNA at the ribosome.
28
Made in 20 or more varieties that bond to only
one type of amino acid.
29
3. Ribosomal RNA (rRNA) makes up part of the
ribosome.
30
II. Protein Synthesis (The making of proteins
from amino acids)
31
A. Important process because without proteins
there would be no life.
32
B. Steps of protein synthesis
33
1. Transcription (making RNA from DNA)
34
a. DNA unzips just like in replication except
this time the nucleotides that pair up have a
ribose sugar and thymine is replaced by uracil.
35
1. This strand now unzips, leaves the nucleus and
attaches to a ribosome the original DNA will
bond back together.
36
b. On the mRNA each combination of 3 bases is
called a codon (a 3 letter code word for a
specific amino acid (ex. AGC, GUC)
37
1. There are 64 possible codons. Most code for
amino acids, but a few are start and stop
signals.
38
2. Translation assembling amino acids to make
protein.
39
a. Each combination of 3 bases on transfer RNA is
called an anticodon (bases that pair up with a
codon on the mRNA)
40
b. Transfer RNA pairs up with the mRNA bringing
an amino acid with it. These amino acids bond
together to form a protein.
41
c. Proteins can be several amino acids long or
just a few.
42
(No Transcript)