Human Biology (BIOL 104)

Talk one:Biological Perspective

To get you thinking and talking

Living Things are Alike• Common Characteristics like:• Cells:

Fundamental unit of life is the cell – all

living things are made up of cells.

• Tissues:– Similarly specialized cells that perform a

common function.

• Organs:– Similarly specialized tissues that perform a

common function.

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OH H

CH2OH

Levels ofBiological Organization I

SubatoSubatomicmic ElectronElectronNeutronNeutronProtonProton

NitrogenNitrogenCarbonCarbonHydrogenHydrogen OxygenOxygen

DNADNAGlucoseGlucoseWaterWater

NucleusNucleusChloroplastChloroplastMitochondrionMitochondrion

Nerve CellNerve Cell

AtomicAtomic

MolecularMolecular

OrganelleOrganelle

CellularCellular

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Levels ofBiological Organization II

TissueTissue NervousNervousTissueTissue

BrainBrain

NervousNervousSystemSystem

PronghornPronghornAntelopeAntelope

OrganOrgan

Organ SystemOrgan System

OrganismalOrganismal

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Levels ofBiological Organization

III

PopulationPopulationHerd of PronghornsHerd of Pronghorns

HawkHawk

WaterWater

Earth’sEarth’ssurfacesurface

CommunityCommunity

EcosystemEcosystem

BiosphereBiosphere

PronghornsPronghorns

HawkHawk GrassGrass

PronghornsPronghornsSnakeSnakeBushesBushes

SoilSoilAirAir

SnakeSnake

Scientific theories• Animals, plants, and bacteria are examples of living systems

that share many properties distinguishing them from nonliving things. These properties are branched into theories.

Cellular organizationFundamental unit of life is the cell – all living things

are made up of cells.Metabolism

Living things take up energy-rich materials and give out waste to environment. Some energy fuels life processes some accumulates and is released after death.Selective response

Living things respond selectively to stimulation in the environment. Organisms recognize certain chemicals as nutrients while ignoring others.

Scientific theoriesHomeostasis

Living systems have some capacity to change harmful conditions into conditions more favorable to their continuing existence – the conversion of chemical compounds.Growth and biosynthesis

Living systems go through phases during which they make more of their own material. Genetic material

Living systems contain genetic material (DNA and RNA) to allow inherited traits.Reproduction

Living systems can reproduce & pass on genetic material.Population structure

Organism form populations. Of these organism capable of sexual processes, a population is all those organisms that can interbreed with one another.

The Experimental Approach!

• Lederbergs experiments on bacterial genetics

• Most bacteria are killed by streptomycin

• The Lederbergs exposed E. coli to streptomycin and were able to isolate streptomycin-resistant E. coli strains.

• They allowed these bacteria to reproduce and showed that resistance to streptomycin was inherited by their offspring

The Experimental Approach!

• This gave the Lederbergs two hypothesis to test

– The mutation was caused by exposure to streptomycin

– Bacteria mutated before exposure to streptomycin

So they conducted an experiment to test both of these hypotheses.

Figure 1.3 (1)

Figure 1.3 (2)

Figure 1.3 (3)

Figure 1.3 (4)

Paradigms• A paradigm is much more than a theory

– It includes a strong belief in the truth of one or more theories and shared opinions as to what problems are important and unimportant

– What techniques and research methods are useful

• Over time a paradigm shift occurs– Better technologies and scientific instruments lead

scientists to look and old data in a different way– Younger scientists look at old data in a new way– In this way ideas and definitions of theories alter

over time an new data is collected and explained.

Paradigm Shifts• OLD PARADIGM• Natural Theology, Lamarckism, and

several other competing paradigms• Blending inheritance and various

folk ideas• Various beliefs: bad humors, bad air

or water, evil spirits, and many others

• Competing paradigms, including Darwinism, mutationism, population

• genetics, neo-Lamarckism• Classical Mendelian genetics• Various theories of territorial

behavior, sexual behavior, etc.; also• psychological theories (gestalt,

behaviorism, ethology)• Descartes’ mechanistic theories and

dualism• Classic germ theory: pathogenicity

as a characteristic of pathogen only

NEW PARADIGMDarwinism (since 1859)Classical Mendelian genetics (since 1865 or 1900)Germ theory of disease (Pasteur, Koch, since 1880)

Modern evolutionary theory (since 1940)

Molecular genetics (since 1950s)

Sociobiology (since 1975)

Mind–body connections (since 1980s)

Pathogenicity as an interaction of pathogen and host (since 1990s)

Science has Improved our Lives!

• Antibiotics--Penicillin, others?• Vaccines--Polio, Measles, Smallpox,

others?• Cell Biology--Cancer Research, others?• Genetics--Basis for Disease, others?• Physics--Electricity!, others?• Engineering--Roads, Bridges, Buildings,

Planes, Trains, Bikes, others?• Fermentation--Civilization!

Science has also opened up “Pandora’s Box”

• Bio-warfare-, Anthrax letters, Current worries?

• Nuclear Weapons--Does North Korea really have them?

• Genome--Insurance issues, Selecting offspring?

• Others?

Ethical thinking• Ethics is a discipline

dealing with the analysis of moral rule and the ways in which moral judgments are made and justified.

• Would you park your car in this space?

• Why?

Ethical thinking• What benefits could

come from nuclear power?

• At what cost?

• At what risk?

• Remember Chernobyl?

Chernobyl Nuclear Disaster • April 26, 1986 in the Ukraine,

• It is regarded as the worst accident in the history of nuclear power.

• A plume of radioactive fallout drifted over parts of the western Soviet Union, Eastern and Western Europe, Scandinavia, the British Isles, and eastern North America. Large areas of Ukraine, Belarus, and Russia were badly contaminated

• Resulted in the evacuation and resettlement of over 336,000 people. About 60% of the radioactive fallout landed in Belarus, according to official post-Soviet data From the wikimedia free licensed

media file repository

Chernobyl Nuclear Disaster• Two hundred people were

hospitalized immediately, of whom 31 died (28 of them died from acute radiation exposure).

• Most of these were fire and rescue workers trying to bring the accident

under control

• At least 8,000 people have died, most from radiation-related diseases.

• About 2,000 people have been diagnosed with thyroid cancer and between 8,000 and 10,000 cases are expected to develop over the next 10 years.

From the wikimedia free licensed media file repository

Chernobyl Nuclear Disaster

From the wikimedia free licensed media file repository

Chernobyl Nuclear Disaster

forum.prisonplanet.com  thepurebar.com 

Rights• Do animals have rights?

• Nearly all new drugs, cosmetics, food additives, new forms of surgery are tested on animals first

• Many societies have historically denied even the most basic of rights to classes of persons on the basis of economics, gender, race, ethnicity, or religious beliefs

Experiments without consent

• Humans as experimental subjects

• Experiments on twins

• Bone, muscle, and nerve transplantation experiments

• Head injury experiments

• Freezing experiments

• Malaria experiments

• High Altitude and pressure experiments

From the wikimedia free licensed media file repository

Experiments without consent

• 1932 The Tuskegee Syphilis Study begins.

• 200 African-American men infected with syphilis are never told of their illness, are denied treatment, and instead are used as human guinea pigs in order to follow the progression and symptoms of the disease.

• 95% all subsequently die from syphilis, their families never told that they could have been treated.

• Voluntary informed consent– Both a moral and legal issue

• As there are lawyers under every rock!

Charlie Pollard

Herman ShawFrom the wikimedia free licensed media

file repository

Thalidomide• Gender bias

– What happens if this is not considered

– It was only in 1992 that women were included in medical trials of new drugs by law!

• Thalidomide (Kevadon®)– Developed as a morning

sickness drug in the 1950s– BUT – never tested on

women

• Led to a generation of deformities

From the wikimedia free licensed media file repository

So, how did Thalidomide affect DNA?

• So, things to remember:

• All genes are coded for at the genetic level by four nucleotide bases (A, C, G, and T) and each gene has a unique coding and relative ratio of these bases.

• Gene expression is highly regulated:– Promoters, enhancers, and repressors

• In limb development, the genes involved have a VERY HIGH relative ratio of guanine (G).

Thalidomide• The structure of

thalidomide is similar to that of the DNA purine bases adenine (A) and guanine (G).

• In solution, has almost no affinity for the other nucleotides, cytosine (C) and thymine (T).

• Furthermore, thalidomide can intercalate into DNA, presumably at G-rich sites.

From the wikimedia free licensed media file repository

Thalidomide• Thalidomide or one of its

metabolites intercalates into these G-rich promoter regions, inhibiting the production of proteins and blocking development of the limb buds.

• This intercalation would significantly affect the genes that rely primarily on guanine (G) sequences.

• Most other developing tissues in the embryo rely on pathways without guanine, and are therefore NOT affected by thalidomide

From the wikimedia free licensed media file repository

Thalidomide• In UK alone there were

12,000 victims.

• Sometimes functional feet and hands were amputated to allow the fitting of lower- and upper-limb Prosthesis in order for the children to appear “normal”.

• Special school were set up too, in an attempt to keep the children out of sight and out of the minds of the public.

From the wikimedia free licensed media file repository

Thalidomide• Victims of the 1970s

Thalidomide scandal have passed their deformities on to their children.

• Thalidomide altered the coded regions for limb development in the G-rich promoter regions of the victims to replication of these regions during the production of gametes during Meiosis

• – so arms and legs are not developed! From the wikimedia free licensed media

file repository

Thalidomide, Still?!!!!!!• Still in use today

• Cancer treatments– by cutting off the flow of blood

to tumors

• Leprosy– is an infectious disease caused

by a DNA plasmid – invades human nerves.

– If untreated can eventually cause a variety of skin problems, loss of feeling, and

paralysis of the hands and feet .

From the wikimedia free licensed media file repository

Genetically modified crops• All plant characteristics, such as size, texture, and

sweetness, are determined on the genetic level.

• Also:• The hardiness of crop plants.• Their drought resistance. • Rate of growth under different soil conditions. • Dependence on fertilizers.• Resistance to various pests and diseases.

• Used to do this by selective breeding

Genetically modified crops• Agrobacterium method

– Uses the natural infection mechanism of a plant pathogen

– Agrobacterium tumefaciens naturally infects the wound sites in dicotyledonous plant causing the formation of the crown gall tumors.

– Capable to transfer a particular DNA segment (T-DNA) of the tumor-inducing (Ti) plasmid into the nucleus of infected cells where it is integrated fully into the host genome and transcribed, causing the crown gall disease.

• So the pathogen inserts the new DNA with great success!!!

What people think of using GM Plants!

• Survey carried out by: – The Scientist Magazine.

• Feb 2004, No/15401

• 302 readers responded to survey

• Yes, a small group, as there are seven billion people on the planet

• Interesting questions!

• What to YOU think? From the wikimedia free licensed media file repository

Genetically modified crops• Issues:• Destroying ecosystems – tomatoes are

now growing in the artic tundra with fish antifreeze in them!

• Destroying ecosystems – will the toxin now being produced by pest-resistance stains kill “friendly” insects such as butterflies.

• Altering nature – should we be swapping genes between species?

Genetically modified crops• Issues:• Vegetarians – what about those

tomatoes?

• Religious dietary laws – anything from a pig?

• Cross-pollination – producing a super-weed

• Human health – what of the antibiotic marker gene?

The End.Any Questions?