molecular biology bch 361fac.ksu.edu.sa/sites/default/files/introduction-1-2018_1.pdf · molecular...

Introduction -1

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Lecture no. 1

Recommended Text books

1- Molecular Biology: Principles and Practice - 5th edition.

By Michael M. Cox., Jennifer Doudna & Michael O'Donnell.

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2- Biochemistry - 7th Edition. By Jeremy M. Berg, John L. Tymoczko, & Lubert Stryer

Lecture Outline

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Lecture no. 1

• Definition

• What Is Life Made Of?

• What Is Central Dogma?

• What Is Genetic Material?

• Some Terminologies

• History: Major Events in Molecular Biology

Molecular Biology

• It is the study of biology at a molecular level.

• The field overlaps with other areas of biology, particularly genetics and

biochemistry

Molecular biology

Biochemistrygenetics

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Biochemistry is the study of molecules such as enzymes, lipids and DNA,

Genetics is the study of the effect of genetic

differences on organisms

Molecular biology concerns understanding the interactions between various systems of a cell, such as the interrelationship of DNA, RNA and protein synthesis and how these interactions are regulated

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Definition

Broadly speaking, molecular biology is the study of essential

cellular macromolecules, including DNA, RNA, and proteins, and

the biological pathways between them.

Molecular biology associated with the structure, function, and

regulation of information pathways at the molecular level.

All of the processes required to reliably pass genetic information

from one generation to another and from DNA to RNA to protein are

included in this area of study.

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Lecture no. 1

Importance

Molecular biology may have a relatively short history, BUT its

impact on the human experience is already considerable.

Medicine, modern agriculture, forensic science, and many other

endeavors rely on technologies developed by molecular biologists.

Examples….

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Lecture no. 1

Classical genetics showed that genes control the transmission ofphenotype from one generation to the next.

Biochemistry showed that within one generation, proteins had adetermining effect on phenotype.

Molecular biology is the hereditary information passed betweengenerations in a form that is truly, digital.

Understanding how that digital code directs the creation of life isthe goal of molecular biology.

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Continue…Lecture no. 1

What is life?

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Characteristics of living systems: Each characteristic distinguishes living organisms from inanimate matter.

Lecture no. 1

Life begins with Cell

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• Every organism is composed of one of two radically different types

of cells: prokaryotic cells or eukaryotic cells.

• A cell is a smallest structural unit of an organism that is capable of

independent functioning

Lecture no. 1

Prokaryotes and Eukaryotes, continued

Prokaryotes Eukaryotes

Single cell Single or multi cell

No nucleus Nucleus

No organelles Organelles

One piece of circular DNA Chromosomes

No mRNA post transcriptional

transcriptional modification

Exons/Introns splicing

All Cells have common Cycles

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Lecture no. 1

Signaling Pathways:

Control Gene Activity

• Instead of having brains, cells make decision through complex

networks of chemical reactions, called pathways

– Synthesize new materials

– Break other materials down for spare parts

– Signal to die

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Lecture no. 1

Cell signaling

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Lecture no. 1

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Example of cell signaling

Lecture no. 1

Cells Information

• Cells store all information to replicate itself

– Human genome is around 3 billions base pair long

– Almost every cell in human body contains same set of genes

– But not all genes are used or expressed by those cells

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Lecture no. 1

Overview of organizations of life

• Nucleus = library

• Chromosomes = bookshelves

• Genes = books

• Almost every cell in an organism contains the same libraries

and the same sets of books.

• Books represent all the information (DNA) that every cell in

the body needs so it can grow and carry out its various

functions.

Lecture no. 1

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All Life depends on 3 critical molecules

DNAs

Contains the genetic instructions used in the development and functioning of living organisms

RNAs

Provide templates to synthesize into protein

ProteinsThe workhorses within

cells , participating in all processes

Lecture no. 1

DNA: The Code of Life

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continued

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• DNA has a double helix structure which composed of – sugar molecule

– phosphate group

– and a base (A,C,G,T)

• DNA always reads from 5’ end to 3’ end for transcription replication 5’ ATTTAGGCC 3’

3’ TAAATCCGG 5’

Lecture no. 1

DNA, RNA, and the Flow of Information

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Lecture no. 1

These 3 molecules can link together By Central Dogma

Information in RNA is passedto proteins. It never passes fromproteins to nucleic acids

Overview of DNA to RNA to Protein

• A gene is expressed in two steps

1) Transcription: RNA synthesis

2) Translation: Protein synthesis

Lecture no. 1

Basic Molecular Biology Terminology

Lecture no. 1