Molecular Biology Arises From a Structure-Function Tradition

triteritzyBiotechnology

Dec 14, 2012 (4 years and 7 months ago)

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Biotechnology

Biotechnology


Literally translated means “life technology”


Applying knowledge about living things for the
practical use of human kind


How long do you think biotechnology has
existed?

Buzz Words in Biotechnology


Genetic Engineering


Stem Cell Research


Cloning


Bioterror


Forensic Science


GMO (genetically modified
organsim
)


Pharmacogenomics


Personalized Medicine


Human
Genome Project

Place to following in order from
smallest to largest

Atom

Cell

Ecosystem

Organ

Organism

Biosphere


Molecule
(DNA)

Population

Electron

Organelle

Community

Proton

Tissue

Organ system

Virus

Electron

Proton & neutron

Atom

Molecule (DNA)

organelle

virus

Cell

Tissue

Organ

Organ system

Organism

Population

Community

Ecosystem

biosphere

In Your Journal


Can all forms of technology be
used to study all of these aspects
of biology?

Explain!

3 Main Types of Experiments


in vitro: experiments done in glass,
testubes
,
or
petri

dishes. Not in living
multicellular

organisms


in vivo: in a living cell or organism


in
silico
: experiments done through computer
simulation or programming


Biotechnology demands synthetic thinking
that incorporates knowledge from all 3 types
of experiments

Biotechnology


The technical aspects of life involve the
complex chemical interactions that take place
among the several thousand different kinds of
molecules found in any living organism


Macromolecules in living things can be
classified into 1 of 4 categories


Protein




Nucleic Acid


Carbohydrate


Lipid

Biotechnologies Macromolecules

Protein


Essential parts of organisms
that participate in virtually
every process within cells.


Cell structure


Signaling


Transport


Biological catalysts


Immune response


Nucleic Acids


Contain the genetic
instructions used in the
development and
functioning of all known
living organisms
and
viruses
.


2 types :


DNA


RNA

Proteins: Essential Parts of Organisms


Many proteins are
enzymes

that catalyze
biochemical reactions and are vital to
metabolism.


Some have structural or mechanical functions


actin

and myosin in muscle


proteins in the cytoskeleton maintains cell shape.


Other proteins are important in cell signaling,
immune responses, cell adhesion, and the cell
cycle.

DNA: the Master Molecule


Of the several thousand macromolecules
needed to keep living things alive, DNA is the
master molecule in whose structure is
encoded all the information needed to create
and direct the chemical machinery of life
(mainly proteins)


DNA: the Master Molecule


DNA accomplishes this by providing a
template to make RNA, which in turn acts is
the instructions to build proteins, which are
essentially the building blocks and machinery
that allow for life


Analysis of the flow and regulation of this
genetic information from


DNA


剎䄠


偲潴敩e





is the subject of molecular genetics

Molecular Genetics


aka: molecular biology


Has blurred the lines between biology,
physics, and chemistry


It arose from a confluence of disciplines from
both the physical sciences and the natural
sciences


Genetics



Biochemistry


Physical chemistry


Microbiology


Quantum mechanics

Virology


Biotechnology & Molecular Biology


Bio = Life


Molecular biology studies the relationship
between DNA


RNA


Protein


Technology :


Technology is a term with origins in the Greek
technología



téchnē

= 'craft'


logía

= the study of something


Molecular Biology
Arises
F
rom a
Structure
-
Function
Tradition

Structure & Function


Natural scientists have always tried to find
relationships between structure & function



This pursuit began with the examination
of obvious physical attributes



Physicians from the earliest civilizations
tried to relate their knowledge of the
human body to the treatment of illness

Matthias
Schleiden

& Theodor
Schwann


Advanced part of the cell theory in the
1830’s


Individual cells are the basic units of structure
and function in both plants and animals


Organs were now seen to be composed of tissues


Tissues are groups of cells with similar structures
that perform similar functions


Moved structure functionalism beyond
systems directly observable with the
naked eye

Determined all
plants are made of
cells

Determined
all animals
are made of
cells

Cells


Cells in turn were found to be composed
of organelles, each of which has its own
specific function


Mitochondria produce energy


Lysosomes

digest waste and cellular debris


Ribosomes

make protein


Chloroplast do photosynthesis to make sugar



By the 1930’s the stage was set for
structure functionalism to move to the
level of biologically important molecules

4 Characteristics of Life


Reproduction


Organized structure composed of 1 or
more cells


The ability to respond to your
environment and maintain homeostasis


The ability to transform energy

Molecular Biology


Molecular biology arose from the quest to
define the nature of heredity


Reproduction

is perhaps the most
distinctive attribute of life


Replication of
multicellular

organisms all
begin the same way, with replication of a cell


To explain replication of cells and inheritance
of traits over successive generations is, in
large measure, to define life

The Biotechnology Revolution


We now understand the nature of heredity
and so have answered many of the
questions of the genomic era



As we move into the post
-
genomic era the
question is not about how things are
inherited, but rather can we manipulate
them!


This is the subject of this class

Bear in Mind…


100 years ago there was no explanation
why some siblings have brown eyes and
other blue


75 years ago the physical structures of
simple organic molecules were unknown


50 years ago we did not know the correct
# of human chromosomes


25 years ago we did not know any of the
genes behind cancer


We still do not know how many genes are
in the human genome!

Heredity


Scientific study of heredity


Heredity: the transmission of genetic
characters from parents to offspring:


it is dependent upon the segregation and
recombination of genes during meiosis and
fertilization


it results in the creation of a new individual
similar to others of its kind but exhibiting certain
variations


How are Traits passed on from 1
Generation to the Next



Enter Austrian Monk
Gregor

Mendel


Crossed different varieties of garden pea plants
and using mathematical analysis provided a
basis for inheritance


Brought the hereditary process down to the
individual organism


Provided a mechanism to drive evolution

Types of Hybridization


P generation = parental
generation


True breeding parents



F
1

generation = 1
st

filial
or 1
st

generation of
offspring



F
2

generation = 2
nd

filial,
or 2
nd

generation of
offspring


Vocabulary


Gene: sequence of DNA that codes for a
protein and thus determines a trait



Allele: 1 of a number of different forms of
a gene



Gamete
: A reproductive cell having the
haploid number of chromosomes,
especially a mature sperm or egg capable
of fusing with a gamete of the opposite
sex to produce the fertilized egg


Homozygous: pair of identical alleles for a
trait

Heterozygous: Having 2 different alleles for a
trait

Genotype
: an organisms genetic makeup

Phenotype
: an organisms outward
appearance

How are Traits passed on from 1
Generation to the Next


Mendel showed that “traits” are inherited
in a predictable manner through what we
now know are “genes”


Genes governing individual traits do not
“blend” but rather are maintained as discrete
bits of hereditary information


Useful traits can be accentuated through
controlled mating


Mendels

Hypothesis

1.
Genes can have alternate versions called
alleles
.

2.
Each offspring inherits two alleles, one from
each parent

3.
If the two alleles differ, the
dominant

allele

is expressed. The
recessive allele

remains hidden unless the dominant allele is
absent. from each parent

4.
The two alleles for each trait separate
during gamete formation


Mendelian

inheritance has its physical
basis in the behavior of chromosomes



Chromosome Theory of Inheritance


States: Genes have specific loci
(locations) along chromosomes, and it is
the chromosomes that undergo
segregation and independent
assortment, rather than the individual
genes


Developed in 1902 by Walter
Sutton

&
Theodor
Boveri




Thomas Morgan Hunt


Chose to use fruit flies as a test organism
in genetics.


Allowed the first tracing of traits to
specific chromosomes


There are many genes, but only a few
chromosomes.


Therefore, each chromosome must carry
a number of genes together as a
“package”.


Traits that are located on the same
chromosome, and so tend to be inherited
together, are called
Linked Genes



Linked Genes


All genes found on the same chromosome
are said to be linked


If genes on the same chromosome are
100% linked, you would only produce the
parental phenotype for that chromosome,
and as you can see in the previous
picture, that is not the case


Genetic Recombination


The production of offspring with
combinations of traits that differ from
those found in either parent


3 Types of Genetic Recombination


Recombination of unlinked genes due to
independent assortment


Recombination of linked genes due to crossing
over


Recombination of genes due to human
manipulation


DNA: The Genetic Material


Learning about DNA contributes to our
knowledge of…


genetic disorders


viral diseases


cancer


aging


genetic engineering


criminal investigations

Why its important

Objectives


Relate

Griffith’s conclusions to the
observations he made during the
transformation experiments.



Summarize

the steps involved in Avery’s
transformation experiments, and state the
results.



Evaluate

the results of the Hershey and
Chase experiment.


New Vocabulary


Vaccine


Virulent


Transformation


Bacteriophage


DNA


What does DNA stand for?



What subunits make up


DNA?



What three parts do the


subunits consist of?




deoxyribonucleic acid

nucleotides

phosphate group,

Pentose (5 carbon) sugar,

& a nitrogenous base

Friedrich
Miescher


DNA was first identified as far back as
________ by a Swiss scientist named
Friedrich ____________



He extracted DNA from the _________ of
pus cells found on surgical bandages



At first DNA was called __________
because it was a substance found in the
nucleus



1868

Miescher

nuclei

nuclein


Miescher

was also able to separate the
substance into two basic parts…



The phosphate groups, also called phosphoric
acid,were

slightly acidic, so DNA belongs to a
class of substances called nucleic acids



Throughout the next century, scientists
made many exciting discoveries about the
function and structure of DNA


Transformation

Griffith’s Experiments



In 1928, Frederick Griffith, a bacteriologist,
carried out an experiment that led to an
accidental discovery about DNA



He was actually trying to prepare a vaccine
against the bacteria,
Streptococcus
pneumoniae
, which causes pneumonia



Griffith was working with two strains
of S.
pneumoniae



One enclosed in a capsule of
polysaccharides, that protects the
bacterium from the body’s defense
system


This helps make the bacterium



virulent, or able to cause



disease


Smooth
-
edged S strain


The other strain lacks the
polysaccharide capsule and is unable
to cause disease


Rough


edged= R strain




In Griffith’s experiment, he injected mice with…




S bacteria



R bacteria



Heat
-
killed S bacteria



Heat
-
killed S bacteria and normal R bacteria



Note about “heat
-
killing”…



During Griffith’s time, it was
not

understood
that DNA can tolerate temperatures around
90
°
C without being altered, but ___________
are altered at around 60
°
C



So “heat
-
killing” damages a cells proteins and
_______________, but leaves DNA intact


proteins

enzymes

Griffiths Discovery of
Transformation


Somehow, the harmless R bacteria had
changed and become ______________



Griffith had discovered what is now called
____________________


Occurs when a cell picks up new DNA from it’s
_____________, changing its combination of
genes, called a _________________


virulent

transformation

environment

genotype

Heat
-
killed S bacteria

is ____________ down

and its DNA escapes to

the environment


A receptor protein on the

R bacteria receives the S

bacteria DNA


Receptor


protein


broken

Then restriction enzymes _________ and _________

the two pieces of DNA together


Restriction


enzyme


cut

paste


But during Griffith’s time, scientists really
didn’t understand transformation



During the 1940s and 1950s, scientists
were still debating over what cell part
contained genetic information


Many scientists actually thought that
___________ contained our genetic
information, and not DNA.

proteins

Oswald Avery


In 1944, a scientist named Oswald __________
conducted a transformation experiment under 4 different
conditions…


Condition 1: Added an enzyme that destroyed ________


Condition 2: Added an enzyme that destroyed ________


Condition 3: Added an enzyme that destroyed ___
Condition 4: Added an enzyme that destroyed ________


Result?


Transformation was only stopped by the enzymes that
destroyed DNA, so it must contain the genetic material!

Avery

proteins

DNA

lipids

Carbs


Despite Avery’s results, scientists
remained _____________



Since proteins are so important to
many cell _____________ and
_______________, most scientists still
thought that proteins contained the
genetic material

skeptical

structures

metabolism

Hershey and Chase


In 1952, Alfred ___________ and
Martha _____________ set out to
settle the controversy.



Their experiments made use of a
bacteriophage

which is a type of virus
that attacks and infect bacterial cells



A virus is much
smaller than
a cell
and consists
of a nucleic acid.
Either
________ or ________
(never both) surrounded
by a
protective protein coat called
a

DNA

Capsid

Hershey

Chase

DNA

RNA

capsid


A special type of virus that
infects
________________ cells
is called a
__________________ or
a _________ for short



The viral DNA is contained
in the ________ and the
tail __________ attach to
the bacteria cell



After attachment, the DNA
is injected into cell, almost
like a _________

Capsid with DNA

Tail Fibers

bacteria

bacteriophage

phage

capsid

fibers

shot


The
bacteriophage

made the perfect
test subject, because it was a simple
substance that contained both
________ and ____________



Scientists knew that DNA contained a
____________ group



They also knew that proteins often contain
the element __________

DNA

proteins

phosphate

sulfur


So Hershey and Chase labeled the
phages with one of the following
radioactive isotopes…


______, which would


be found in DNA


______, which would


be found in the


protein coat

32
P

35
S


These radioactive isotopes will
__________ or break down into stable
particles that can be ____________ with
machines




Next the labeled phages


were allowed to


___________ the


bacteria cells

decay

detected

infect


Hershey and Chase then checked to see
which
parts of the phage entered
the
bacteria cells



First the phages that


were still attached to


the bacteria cells were


removed with a


__________________

blender


Then the bacteria cells
and the phages were
placed in test tubes
and
spun in
a
machine
called a centrifuge


Which spins, causing


the different
substances


settle out by
_________

weight


The heavier bacteria cells settled at the
__________ of the test tubes while the
lighter phages
remained suspended in
the supernatant at the top of the tube


Only the ______ isotope was found
inside of the bacteria cells

35
S test tube


(protein)

32
P test tube


(DNA)

Bacteria


cells

Phages

35
S

32
P

bottom

32
P


So based on these results… which
substance, proteins or DNA, would you
conclude is responsible for
transformation?

35
S test tube


(protein)

32
P test tube


(DNA)

Bacteria


cells

Phages

35
S

32
P

DNA

Time Line


1866
-

Mendel's Paper


1875
-

Mitosis worked out


1890's
-

Meiosis worked out


1902
-

Sutton,
Boveri

et. al
. connect
chromosomes to Meiosis.


1907
-

Morgans

“fly room” provides
support for chromosomes as the
hereditary material