DNA  RNA  Proteins

pumpkincentersulkyBiotechnologie

16 déc. 2012 (il y a 4 années et 9 mois)

175 vue(s)

Unit 4a.


DNA


RNA


Proteins

DNA/ RNA/ Proteins Word Meanings


Deoxy

-
a molecule containing less oxygen than another


ribose

-
A pentose sugar, C
5
H
10
O
5


Complementary


to “match up”


Subunit


a piece or small part of a larger unit.



replication




the act of duplicating, copying, or reproducing


transcription


the act or process of rewriting in a different script.


translation


to rewrite in a second language having the same meaning as the original
source.

I.
DNA:
D
eoxyribo
n
ucleic
A
cid

i.
Complete instructions for manufacturing all the
proteins for an organism. (which determine all your
other characteristics)

ii.
The “recipe” for life!

iii.
structure of DNA proved that it was in fact the
molecule of heredity


iv.
Analogy:1000 textbooks= all the info (DNA/genes) of
1 single organism

a.
Structure

i.
Watson & Crick


1.
proposed that DNA is made of chains

2.
nucleotides held together by nitrogenous bases
(teeth of zipper)

3.
proposed that DNA is shaped like a long zipper that is
twisted into a coil like a spring

helix

4.
DNA is a double helix

b.
Nucleotide = monomer of DNA

i.
Subunits

of DNA

ii.
3 parts

1.
phosphate

group

2.
simple sugar:
deoxyribose

3.
nitrogenous
base

a)
A= adenine

b)
G= guanine

c)
C=cytosine

d)
T=thymine


Complementary

base pairs

A
-
T & C
-
G

iii.
Phosphate groups &
Deoxyribose

sugar form backbone of
DNA

iv.
Chargaff’s Rule:

i.
The number of
Adonines

= number of
ii.
The number of
Guanines

= number of
Cytosines

The Base pairing rules
:

(
A binds to T

and
G binds to C
).

II.
Replication

a.
Helicase

unzips the
double helix
, forming
replication forks
.

b.
DNA polymerase

is an
enzyme that joins
individual nucleotides to
produce a new strand of
DNA
.

c.
New bases are added
,
base pairing rules:
(
A with T

and
G with C
).

d.
This is a
Semi
-
Conservative

process =
One old strand of DNA with
one new strand of DNA


DNA

DNA

III.
Mutations

i.
Any changes in the DNA
sequences

ii.
This could be:

1.
Deletion of bases

2.
Duplicating bases

3.
Ceratain

bases changing
places

4.
New bases being inserted
where they do not belong.

iii.
Mutations can result in:

a.
Genetic diseases

b.
Cancer

c.
New genetic traits

d.
No harm at all



Genetic Disorders caused by mutations to the DNA:



IV.
Manipulating DNA


How do we manipulate DNA?


We can literally cut the DNA into pieces.


This is done through the use of
proteins

known as
restriction
enzymes


They cut the DNA at certain Base Pair sequences









We use the cut up DNA for all sorts of things.



Paternity test


Criminal
Investigation


Genetic
Engineering


Cloning


Paternity Test and Criminal Investigations


Cut up fragments of certain DNA segments are put
into a gel electrophoresis.


Depending on how big the segment of DNA, the
further down the gel a fragment of DNA will move.


Doctors and scientist can then compare one
persons DNA to another persons to see if they’re
related.


Genetic Engineering


Cut up fragments of DNA segments with specific genes can
be added to the DNA of a fertilized egg.


This can give rise to organisms with new traits.


Ex. Mice that can glow



Here the gene for insulin is being put
into the plasmid of a bacterial cell.

The bacteria will now produce insulin
for human use.


Cloning


Theoretically, any organism can be cloned to make a
genetically identical organism.


This is done by a process called
Nuclear Transfer

1.
Extract the nucleus of an unfertilized egg.

2.
Insert a nucleus (DNA) from a cell of the organism you want
to clone.

3.
Cause the egg cell with the novel nucleus to start dividing by
stimulating the egg with a shock of electricity.

4.
After the embryo grows for a few days it is placed inside a
serogate

mother and allowed to develop there until birth.

These two cats are clones: But they look
different. This is because different genes
on the same DNA can be activated by the
different environments the organism grew
up in.

V.
RNA

a.
Ribonucleic Acid

b.
Single stranded

c.
RNA is a special copy of DNA used to make proteins.


Single RNA strand

a.
RNA Nucleotides
(monomer)

i.
Subunit of RNA

ii.
3 parts:

1.
phosphate

group

2.
simple sugar=
ribose

3.
nitrogenous
base

a.
U=
uracil

(Replaces T)

b.
A= adenine

c.
G= guanine

d.
C=cytosine


Complementary

base pairs

A
-
U & C
-
G

b.
Transcription

(DNA
→RNA)

i.
Creating RNA from DNA

1.
RNA polymerase

is an enzyme that

1.
uses only one side of DNA (one DNA strand) to create a single strand
of RNA.

2.
Uses DNA as a template to lay RNA nucleotides in a specific order
according to the DNA code.

2.
New bases are added

according to the base pairing rules:


(
A with U
,
G with C
,
T with A
).

Ex. DNA = ATTCGCATT


RNA = UAAGCGUAA


c.
3 Types of RNA

i.
mRNA

messenger


carries a
copy of the DNA’s instructions

(code) for the
creation of proteins.


ii.
rRNA


ribosomal


Makes up
ribosomes

-

structures where proteins
are assembled.


iii.
tRNA


transfer


carries amino acids

to the ribosome and
matches them to the coded mRNA message.

d.
Translation

(
mRNA
→ proteins)

i.
Converting
mRNA

into
amino acids

then into a
protein

1.
To
begin Translation the
rRNA

must binds to the mRNA

2.
translation begins at the start
codon
[AUG]
-
(three bases
in a row) on the mRNA.


3.
tRNA

contains an
anti
-
codon

that binds to the mRNA’s
codon

and carries one kind of amino acid.

4.
The amino acids bond together and stop when a
“stop
codon
” is reached.

5.
The newly formed polypeptide (protein) is then
released.

e.
Amino Acids

i.
Basic building blocks of proteins carried by
tRNA

ii.
Codon
: 3 bases on mRNA code for 1 amino acid

iii.
64 different combinations can create 20 different
amino acids.

What does a Protein look like?

Transcription

Replication

RNA polymerase used

DNA polymerase used

RNA nucleotides linked

(
A U C G
)

DNA nucleotides linked

(
A T C G
)

A single stranded RNA
molecule is made

A double stranded DNA
molecule is made

Only 1 DNA strand is used
as a template.

Both DNA strands get
replicated.

DNA
-
RNA Differences

DNA
→RNA

DNA
→DNA