Genetic Transfer - Get Biotech Smart

lessfrustratedBiotechnology

Oct 23, 2013 (3 years and 10 months ago)

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1

Welcome

A key factor in creating genetically modified organisms is
understanding the principles associated with how genetic
information is transferred. We’ve all heard these terms, but how
do they relate to biotechnology?



2

Objectives

By the end of today’s lesson, you will be able to…


Identify the components involved in the creation of the
genetic code


Differentiate between the two main nucleic acids


Determine the role transcription and translation play in
protein synthesis


Recognize the importance of genetic transfer to biotechnology




3

DNA/Protein Complex

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Deoxyribonucleic Acid (DNA)


DNA is a nucleic acid
composed of units called
nucleotides


Each nucleotide is made up of
a
sugar
,

a
phosphate
, and a
nitrogen

molecule


The nitrogen molecules, called
bases, are:


Adenine (A)


Guanine (G)


Cytosine (C)


Thymine (T)



5

DNA’s Structure

The structure of DNA is a called a double helix, which resembles
a twisted, ladder like structure.

6

Backbone

Base pairs form the
rung of the ladder

Genetic Code

The sequence of the nucleotides controls the characteristics of
traits or how they are expressed in the organisms. This
sequence, that controls a given trait, is known as a gene.

7

Gene

Three Minute Checkup

1.
On a sheet of paper draw a DNA nucleotide and correctly
label each part

2.
Next, in the image below, complete the DNA sequence on
the other side of the DNA strand


8

Ribonucleic Acid (RNA)

RNA is another type of nucleic acid and is central to protein
synthesis, or the process by which cells build proteins.

9

DNA

strand

What differences do you
notice between DNA and
RNA?


1.
RNA is single
-
strained

2.
RNA contains uracil
instead of thymine

3.
RNA has a different sugar,
ribose

4.
RNA has three different
types, or classes

Transcription and Translation

Protein synthesis involves both DNA and
RNA. Protein synthesis is a two step process.


Transcription

The process of coping segments of DNA to
complementary segments of RNA.


Translation

The process of taking the complementary
RNA segments from transcription to decode
and sequence to produce specific
polypeptides, or proteins.


10

Classes of RNA


Ribosomal RNA
, or rRNA, is the largest of the three classes of
RNA. It plays a key role in the synthesis of proteins by
decoding messenger RNA and interacting with transfer RNA
during translation.



Messenger RNA,
or mRNA, carries the information that is
necessary to sequence amino acids in a protein to the
ribosome where translation will occur.



Transfer RNA,
or tRNA, is the smallest of the RNA classes. Its
role is to bring, or carry, the amino acid to the ribosome
during protein synthesis.


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Transcription Overview

12

Nucleus

Plant Cell

Initiation

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During initiation, an enzyme called RNA polymerase unzips the
DNA strand and attaches to a promoter.

RNA Polymerase

DNA template

Inactive
template

T

A

A

T

Elongation

Next, RNA polymerase travels the DNA template strand and uses
complementary base pairings of the DNA template to create an
RNA copy.

14

mRNA

RNA Polymerase

DNA template

Termination

15

Nucleus

Translation Overview

16

Nucleus

Plant Cell

mRNA

mRNA

Amino Acid

Codons

Genes are organized according to the genetic code. The genetic
code functions through a sequence of amino acids, which occurs
in groups of three. The groups of three are called a
codon
.

17

17

mRNA

Codon

Three Minute Checkup

1.
On an index card (or a sheet of paper) write down the steps
in transcription

2.
Describe each transcription step in five words or less

3.
Using the genetic code card, write the amino acid for each
codon

below

1.
AUG

2.
UCG

3.
GCU

4.
UGA



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Initiation

Translation initiation begins by using a start codon. In prokaryotes,
the initiation codon of mRNA is AUG, which is a modified amino
acid, fromylmethionine.

19

mRNA

Start
Codon

tRNA Roles

tRNA contains three complementary nucleotides called
anticodons. Once tRNA finds the start codon, a large piece of
ribosome containing a “P” and an “A” site are attached to mRNA.


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Anticodon

mRNA

Elongation

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“A” Site

“P” Site

Termination

Termination is initiated by one of three stop codons (UAA, UAG,
or UGA). At this point, the ribosome splits and the completed
protein is released.


22

Stop
Codon

What Does This Mean to Biotechnology?

Gene cassettes
are built to regulate when a new gene is
activated or deactivated in a genetically modified plant.

23

Promoter

Gene

Terminator

The terminator
sends a signal
to stop the
transcription
process.

The promoter
causes RNA
polymerase to
begin reading the
DNA sequence.

What Does This Mean to Biotechnology?

24

Plasmid

Donor gene

Isolated gene
from the plant

Recombinant DNA

Plasmid Vector

Bacterium

Donor gene

Transcription

Translation

Protein

Questions

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