fis0414_week 9 & 10

Genetic Control And Genetic Engineering

(Week 9 & 10)

Last Updated:April 18, 2023

Biology IBiology I

PowerPoint® Slides by M. Lokanathan

2© I-Station Solutions Sdn Bhd

Learning Objectives


The objectives of this topic are to:

Know the parts of a nucleotide and state how they are linked together to make DNA.Understand how DNA is replicated and what materials are needed for replication.Express how the structure and behaviour of DNA determine the structure and behaviour of the forms of RNA during transcription.Know how the structure and behaviour of the three forms of RNA determine the primary structure of polypeptide chains during translation.Know what plasmids are and how they may be used to insert new genes into recombinant DNA molecules.Know how DNA can be cleaved, spliced, cloned and sequenced.Be aware of several limits and possibilities for future research in genetic engineering.


Learning Outcomes


At the end of this topic, you should be able to:

Identify the parts of a nucleotide and state how they are linked together to make DNA.State how DNA is replicated and what materials are needed for Replication.Express how the structure and behaviour of DNA determine thestructure and behaviour of the forms of RNA during transcription.Explain how the structure and behaviour of the three forms of RNA determine the primary structure of polypeptide chains duringTranslation.Indicate what plasmids are and how they may be used to insert new genes into recombinant DNA molecules.Express how DNA can be cleaved, spliced, cloned and sequenced.Indicate the several limits and possibilities for future research ingenetic engineering.


Introduction


Humans are made up of

trillions of cells.

Fig. 1Fig. 2


Each cell have:

Introduction


46 human

chromosomes46 human

chromosomes2 metres of

DNA

2 metres of DNA

3 billion DNA subunits

(A,T,G,C)

3 billion DNA subunits

(A,T,G,C)

Approximately

30,000 genesApproximately

30,000 genes

WHAT IS DNA?


Deoxyribonucleic Acid (DNA)


Deoxyribonucleic Acid (DNA) is the hereditary molecule controlling the activities of the cell.

Deoxyribonucleic Acid (DNA) is the hereditary molecule controlling the activities of the cell.

Fig. 3


DNA Structure


WATSON and CRICK proposed the DNA structure in 1952.

Fig. 3


DNA Structure


DNA is made up of nucleotides.

Nucleotides is the building block of the DNA ladder.

Fig.5


DNA Structure


Nucleotides composed of:

• Prosphate

• Deoxyribose Sugar

• Nitrogenous Base

Base

Sugar molecule

Phosphate group

NucleotideNucleotide

Fig.6


DNA Structure


Example of Nucleotide Structure


DNA Structure


There are four types of nitrogenous bases:

Adenine (A)Adenine (A)

Guanine (G)Guanine (G)

PURINESPURINES

Thymine (T)Thymine (T)

Cytosine (C)Cytosine (C)

PYRIMIDINESPYRIMIDINES


DNA Structure


Purines

Contains 2 rings

Purines

Contains 2 rings

Pyrimidines

Contain 1 ring

Pyrimidines

Contain 1 ring


DNA Structure


Adenine (A) always pairs with Thymine (T).

Guanine (G) always pairs with Cytosine (C).


DNA Structure


Adenine (A) pairs with Thymine (T) with two hydrogen bonds.

Guanine (G) pairs with Cytosine (C) with three hydrogen bonds.


DNA Shape


DNA consists of two strands of nucleotides twisted (ladder shape) into double helix.

On the outside of the ladder is phosphate and sugars, and in the middle are the rungs of bases.

Fig.7

Sugar Phosphate Backbone

Bases


DNA Replication


The process of making an exact copy of a DNA molecule.

SELF doubling.


DNA Replication


Example of DNA Replication


Protein Synthesis


Protein synthesis is the process of making proteins.

The path from genes to proteins has two steps:

TranscriptionTranscription1

TranslationTranslation2


Protein Synthesis


TranscriptionTranscription

TranslationTranslation

Transcription

The process of changing the DNA pattern into messenger RNA.

DNA RNA

Transcription

The process of changing the DNA pattern into messenger RNA.

DNA RNA

[ Click on button for more details.]

Translation

The process of changing the information of messenger RNA into proteins.

RNA protein

Translation

The process of changing the information of messenger RNA into proteins.

RNA protein


Protein Synthesis


TranscriptionTranscription TranslationTranslation


Protein Synthesis


RNARNA

RNA differs from DNA in five ways:

Single stranded helix

Contains the Ribose Sugar

The base uracil substitutes for the thymine of DNA

RNA found in the nucleus and cytoplasm

Smaller in size


Protein Synthesis


RNARNA

Example of DNA structure vs RNA structure


Protein Synthesis


RNARNA

There are three types of RNA:

Messenger RNA (mRNA)

Brings coded information from DNA to the ribosomes.

Messenger RNA (mRNA)


Fig.8

Ribosomal RNA (rRNA)

Combines with proteins to form ribosomes upon which polypeptides are assembled.

Ribosomal RNA (rRNA)

Combines with proteins to form ribosomes upon which polypeptides are assembled.

Transfer RNA (tRNA)

Carries the amino acids to the ribosomes and pairs with mRNA.

Transfer RNA (tRNA)

Carries the amino acids to the ribosomes and pairs with mRNA.


Genetic Code


The sequence of bases in DNA forms the Genetic Code.

Fig.9


Genetic Code


The genetic code based on three letter 'words‘.

Codon is a combination of three nucleotides bases of mRNA that determines the order of amino acids.

Fig.10


Genetic Engineering



Purpose of Genetic Engineering


It allows genes from one organism to be inserted into a cell of a different organism of a different species.

Human genes can be inserted into a bacterium.

Human genes can be inserted into cells from other animals.

Bacterium genes can be inserted into plant cells.

Human genes can be inserted into a bacterium.

Human genes can be inserted into cells from other animals.

Bacterium genes can be inserted into plant cells.

Examples


Steps in Genetic Engineering


Basic steps in genetic engineering are:


Process of Genetic Engineering


There are four process of genetic engineering:




Isolation1

a) Isolation of a specific gene from donor. Example: human

• Cells broken open using chemicals and enzymes. • Genetic probe added.

• Reveals position of the gene of interest.

a) Isolation of a specific gene from donor. Example: human

• Cells broken open using chemicals and enzymes. • Genetic probe added.

• Reveals position of the gene of interest.

[ Click on button for more details.]STEP 1STEP 1 STEP 2

Fig.11


b) Isolation of plasmid from a bacterial cell.

• A plasmid is a bacterial cell contains a circular loop of DNA.• The plasmid will act as a vector for carrying a new gene.

b) Isolation of plasmid from a bacterial cell.

• A plasmid is a bacterial cell contains a circular loop of DNA.• The plasmid will act as a vector for carrying a new gene.



Isolation1

[ Click on button for more details.]STEP 1 STEP 2STEP 2

Fig.12




Restriction (Cutting) 2

The donor DNA and plasmid DNA are cut using enzymes called restriction enzymes.Restriction enzymes act as molecular scissors and cut DNA at specific sites called restriction sites.The cut ends have sticky ends.

Restriction site

Restriction site Restriction

ezymes

Plasmid

Plasmid cut with enzyme

Sticky ends


Plasmid DNAwith sticky

ends



Transformation (Ligation)3

The donor DNA is now inserted into the plasmid DNA.Enzyme DNA ligase bonds sticky ends together.Recombinant DNA formed.

Recombinant DNA

Donor DNAwith sticky

ends




Transformation (Ligation)3

Animation of enzyme DNA Ligase

Animation 1




Expression4

The recombinant DNA serves as a cloning gene to deliver the

DNA into a bacterium cell that can divide rapidly to produce many identical copies of the DNA.

Fig.13




Summary of Process




[ Click on button to see the animation of genetic engineering.]

Animation 2


Application of Genetic Engineering


AnimalsAnimals

Sheep have been genetically modified to carry the gene.

For the production of a human blood clotting protein.

This protein is then used to treat haemophiliacs.

Fig.14




PlantsPlants

Genetically modified corn.

Can resist infection by an insect European corn borer.


Fig.15



Micro-organismsMicro-organisms

Production of Humulin.

Humilin is a genetically modified form of insulin.


Ethical Issues in Genetic Engineering



Pros and Cons in Genetic Engineering


ProsPros

Reduces costs of production. This means that the poor can afford more food.

Cheaper and safer source of human medicine

Higher productivity

Can reduce the World hunger

ConsCons

Unnatural

Crosses species barriers which would never occur in nature.

A high danger might be the “gene-flow”-transfer of genes from crops to weedy relatives by cross-pollination


References


Cecie Starr & Bevery McMillan (2007). Human Biology (7th Ed).Thomson Brooks/Cole

Sylvia S. Mader (2004). Human Biology (8th Ed). McGraw Hill

Collen Belk and Virginia Borden Maier (2010). Biology: Science for life with Physiology (3rd Ed). Benjamin Cummings


Key Terms


Term Definition

Deoxyribonucleic Acid (DNA)

The hereditary molecule controlling the activities of the cell.

Nucleotides The building block of the DNA ladder consisting of a nitrogenous base, a sugar, and a phosphate group.

DNA replicationThe process of making an exact copy of a DNA molecule.

TranscriptionThe process of changing the DNA pattern into messenger RNA.

TranslationThe process of changing the information of messenger RNA into proteins.

messenger RNA (mRNA)


ribosomal RNA (rRNA)

Type of RNA molecule that plays a structural role in ribosomes


Key Terms


Term Definition

transfer RNA (tRNA)

RNA molecule that temporarily carries a specific amino acid to a ribosome during translation

CodonA combination of three bases of mRNA that determines the order of amino acids.

Genetic EngineeringThe process of manipulation and alteration of genes.


Appendix


Figure Source

Fig.1http://zazenlife.com/wp-content/uploads/2012/02/human-body.jpg

Fig.2

http://www.corporatewellnessmagazine.com/upload/articles/61509D50E1171AD9AD222506A93CC110-main.jpg

Fig. 3http://hst102.pbworks.com/f/1324031362/Watson-Crick.jpg

Fig.4http://bookbuilder.cast.org/bookresources/40/40654/153493_1.gif

Fig.5http://campus.murraystate.edu/academic/faculty/eweber/bio101/images/mirkov_fig63.jpg

Fig.6http://www.buzzle.com/img/articleImages/387160-1237-22.jpg


Appendix


Figure Source

Fig.7http://www.daviddarling.info/images/DNA_diagram.jpg

Fig.8http://www.vcbio.science.ru.nl/images/cellcycle/mcell-transcription-translation_eng_zoom.gif

Fig.9https://cepmed.dnadirect.com/img/content/common/geneticCode.gif

Fig.10http://www.brooklyn.cuny.edu/bc/ahp/BioInfo/graphics/GP.GeneticCode.GIF

Fig.11-13http://www.biologiedesynthese.fr/images/biotechnologie-en.gif

Fig.14http://2.bp.blogspot.com/_AD9W-Tx6g8E/SS0RTRuxGwI/AAAAAAAAJ8M/rlIHNuhUmno/s400/sheep_1.jpg


Appendix


Figure Source

Fig.15http://www.mims.com/resources/drugs/Malaysia/pic/Humulin%2030_70%20susp%20for%20inj%20%28vial%29_50819.gif

Animation 1http://www.bios.niu.edu/johns/bios103/DNA_files/v3_slide0036_image058.gif

Animation 2

http://www.bbc.co.uk/schools/gcsebitesize/science/aqa_pre_2011/evolution/reproductionrev6.shtml

fis0414_week 9 & 10

Documents

behaviour of dna

dna ladder

dna subunits

recombinant dna molecules

forms of rna

new genes

genetic engineeringweek

genetic control