Notesale: Turn your study into money

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Chapter 1
Science
A systematic approach to answering questions about things that are observed
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Make observations and ask a question about the observations
Begin with an observation that prompts a question
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Questions should be reasonable and consistent with existing knowledge
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2
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Prediction based on your hypothesis, and test it in a controlled experiment
Make a prediction regarding what should occur if the hypothesis is
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correct
Prediction will determine the experiment or observations that are
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necessary to test the hypothesis
Controlled experiment
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Control group
Experimental group
4
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3
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Hydrophilic heads facing inside the cell interact with cytoplasm
o
Within the phospholipid bilayer, the hydrophobic tails point toward each other
and hold the plasma membrane together
Functions
o
Maintains the cell's structural integrity
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Regulates the movement of substances into and out of the cell (selectively
permeable)
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Cell-cell recognition
Recognize invaders such as bacteria
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Communication between cells
Relies on receptors (proteins in the plasma membrane)
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Binding pairs or groups of cells together
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Movement across plasma membrane
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Simple diffusion - Fig
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7 page 47
Movement of a substance from higher to lower concentration
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Result: equal distribution of the substance in two areas - eliminate the
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concentration gradient
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Facilitated diffusion - Fig
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8 page 47
Movement of a substance through the plasma membrane from higher
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to lower concentration with the aid of a carrier or channel protein
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Osmosis
Water moves across a plasma membrane or any other selectively
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permeable membrane from a high to low concentration
Passive transport
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Hypertonic solution
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A solution whose solute concentration is higher than that inside
the bag, more water moves out the bag than in, causing it to shrivel
Isotonic solution
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One with the same solute (sugar) concentration as inside the
bag, no net movement of water in either direction, bag maintains
original shape
Hypotonic solution
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Concentration of solute is lower than that inside the bag, more
water moves into the bag than out, bag swells and possibly bursts
o
Active transport
Substances moves across plasma membrane with the aid of a carrier
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protein and energy supplied by the cell, from low to high concentration
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Endocytosis
A region of plasma membrane engulfs the substance to be ingested and
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then pinches off from the rest of the membrane
It encloses the substance in a saclike structure called a vesicle and
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travels through the cytoplasm
2 types:
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Phagocytosis: cells engulf large particles or bacteria
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o

Pinocytosis: cells engulf droplets of fluid, which bring all the
substances dissolved in the droplet into the cell
Exocytosis
When large molecules leave cells
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Chapter 20
Gene
Segment of DNA
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Located in a specific site on a specific chromosome that contains information for
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producing a particular protein (polypeptide)
Gene-determined protein can influence whether a certain trait will develop
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Genes for the same trait are found at the same specific location on homologous
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chromosomes
Trait
A phenotypically expressed characteristic
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Alleles
Different forms of a gene
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Produce different versions of the trait they determine
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Alleles for each gene segregate during gamete formation, half gametes bear one allele,
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half bear the other
Somatic cells carry two alleles for each gene, one allele on each homologous
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chromosome
Homologous pair
Each member caries genes for the same traits
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One member of each pair was inherited from the mother, and one from the father
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Homozygous
Individuals with two copies of the same allele of a gene
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Heterozygous
Individuals with different alleles of a given gene
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Dominant allele
Effects of a certain allele can be detected regardless of an alternative allele is present
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Recessive allele
An allele whose effects are masked in the heterozygous condition
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Ex
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Orientation of paternal and maternal homologues to
the poles is entirely random
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Freckles
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Dihybrid cross
A mating of individuals who are both heterozygous for 2 traits of interest
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Ex
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Inheritance of blood type AB
Incomplete dominance
Expression of a trait in a heterozygous individual somewhere between the expression of
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the trait in a homozygous dominant individual and the expression of the trait in a
homozygous recessive individual
Dominant allele produces a functional protein product, recessive allele does not
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produce that product
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Sickle cell hemoglobin
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Pleiotropy
One gene leading to many effects
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Ex
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ABO blood types
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Polygenic inheritance
The involvement of 2 or more genes, often on different chromosomes, in producing a
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trait
Inheritance in which several independently assorting or loosely linked genes determine
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the expression of a trait
The more genes involved, the smoother the gradations and the greater the extremes of
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trait expression
Ex
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Male pattern baldness
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o
Depends on allele for baldness and presence of testosterone
Breaks in chromosomes
Breakage can be caused by chemicals, radiation, viruses, in crossing over
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Deletion: the loss of a nucleotide or segment of a chromosome
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o
Most common type: tip of chromosome breaks off, during cell division, does not
move into same daughter cell as rest of the chromosome
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Ex
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Fragile X Syndrome: certain sequences of DNA duplicated many times

Detecting gene disorders
Amniocentesis: needle inserted through the lower abdomen into uterus and small
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amount of amniotic fluid withrdrawn
Chorionic villi sampling: removes and analyzes a small amount of tissue containing
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chorionic villi

DNA and biotechnology - Chapter 21
A
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Recombinant DNA technology
o
Definition: form of gene manipulation, cut DNA from 1 species and put into
another creating a transgenic organism: DNA from 2 sources; itself and foreign DNA
o
Natural genetic manipulation
Ex
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DNA review:
o
Structure
Basic molecule
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Term for non-coding (protein) is junk DNA (no genes)
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Replication
View: semi conservative
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Old and new DNA
Specific enzymes used to break and re-make the hydrogen
bonds
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Central dogma
Transcription and translation
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Translation: 3 steps
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Initiation
Elongation
Termination
D
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Use of bacterial plasmids
• Method: extract plasmid, open plasmid, insert foreign genes, put back into
bacteria
• Step 1
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cut both dnas with the same restriction enzyme
• Step 3
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dna ligase links the new gene into the plasmid
• Step 5
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bacteria clones contain many copies of the donor genes
• Step 7
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Double-stranded DNA is unzipped by gentle heating, forming single strands that serve as
templates for new strands
2
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The mixture is cooled to allow for base pairing
4
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The amount of DNA is now
doubled
Repeat procedure: the amount of DNA is doubled again - procedure repeated many
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times
Uses of gene amplification
1
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To produce large amounts of gene products
Practical uses of recombinant DNA technology
A
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Human insulin; growth hormone; EPO (erythropoietin);
herceptin
Immune system proteins
Ex
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Tobacco plants
Ex
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Created high salinity tolerant oats to grow in saline soils
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o
Controlling via monsanto terminator
Environmental benefits to transgenic plants
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Decrease pesticide/fertilizer use on crops
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Increased production
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Increased nutrition on crops
Ex
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Pigs that produce growth hormone
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Ex
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Mice, cows, goats, chickens
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Biosteel
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1
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Implant cell into host mother
3
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The gene of interest is expressed in the cells of mammary glands and the protein is
secreted in milk
5
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Separate the milk proteins
7
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Bovine growth hormone
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Cellulase production enhanced in guts?
Double muscled beef
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Belgian blue bull - blocked antigrowth factor myostatin
Transgenic plants
New tool - the DNA gun
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Benefits
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Plants resist pests (we use less pesticides)
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Better nutrition
Ex
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Cotton - recently engineered to be edible
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GMFs accelerated artificial selection
Pros
Better nutrition - golden rice
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Increase crop yields - enhanced growth
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Herbicide resistant - target weeds
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Disease and pest resistant - use less chemicals
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Lower allergens and increase shelf life
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Cons
Cost - GMF's are expensive
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Pollen drift - contamination of non-GMF crop with pollen
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Monoculture - tendency to grow only 1 type of GMF
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Superweeds/pests - these might evolve
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Alter expression of plant's own genes - by inserting new genetic material
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Long term environmental impacts are unknown
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New allergens are possible, must monitor research
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How to decrease risk of pollen drift
Make plants sterile - Monsanto terminator
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Use borderfields - isolates GMF's
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Isolate crops - grow indoors
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Greenhouses
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GMF's have a brief pollination verses wild so they often don’t overlap ecologically
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Wild plants often self-pollinate and don’t accept GMF pollen
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What we still have to do
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Label GMF's - under debate/review, where to begin?
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Do environmental impact studies
Gene Therapy
Gene therapy is the use of nucleic acid polymers as a drug to treat disease by
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therapeutic delivery into a patient's cells
They are expressed as proteins so they interfere with the expression of proteins
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Correct genetic mutations
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Methods
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Insert genes into bone marrow via transplants
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Use liposomes or microspheres filled with new gene sequences
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Transplantation of genetically engineered cells (first removed, modified, then
put back in)
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Viruses as vectors
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Fig
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19
Medical potential
It has been used to treat:
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Severe combined immunodeficiency disease - Duchenne's muscular dystrophy
Parkinson's disease
Cystic fibrosis
Hypercholesteremia (excessively high cholesterol)
Hemophilia
Other applications of recombinant DNA
Technology
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1
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Bacteria that eat oil, heavy metals
Bioremediation
The use of biological agents, such as bacteria, fungi, or green plants, to remove or
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neutralize contaminants, as in polluted soil or water
Alternative source of energy
Bacteria that produce electricity
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Fungi that can be used as fuel
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Cloning copies of an organism
What can we currently do in science?
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We can: clone - DNA, cells, entire organism
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Cloning an entire organism
1
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Somatic cell nuclear transfer (nuclear transplantation)
Historical overview - Somatic cell nuclear transfer
July 5, 1996 - Dolly the sheep
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Medical potential
It has been used to treat
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Gene therapies:
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Severe combined immunodeficiency disease - Duchenne's muscular dystrophy
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Parkinson's disease (loss of dopiame nerves
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Cystic fibrosis
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Hypercholestremia (excessively high cholesterol)
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Hemophilia
Other applications of recombinant DNA
Technology
1
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Get DNA sample
B
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Compare with (gel electrophoresis)

Environmental-engineered organisms:
Ex
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Pollution - waste of ?
Bioremediation
The use of biological agents, such as bacteria, fungi, or green plants, to remove or
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neutralize contaminants, as in polluted soil or water
Alternative source of energy
Bacteria that produce power-electricity
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Fungi that can be used as fuel
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Cloning copies of an organism
What can we currently do in science?
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o
We can clone DNA, cells, entire organism
Cloning an entire organism
1
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Somatic cell nuclear transfer
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For nuclear transplantation
Historical overview - somatic cell nuclear transfer
Sheep Dolly
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Was somatic cell nuclear transfer
Cloning (kion = "twig", greek):
Process of producing similar populations of genetically identical individuals
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Natural in bacteria, plants, and some insects
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Human cloning are:
A
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Reproductive cloning
A
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Ex) Progress to date
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Earlier overview
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Human cloning
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(The bizarre and cultish) Dec 2002 (clonaid project)
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Also claimed to clone dead

In reality or evidence based…
First cloned human embryo (Nov 2001) (Scientific American)
This had no organs
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Came from parthenogenetically (growth and development without fertilization by male)
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Formed blastocysts
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Mice have been cloned from the dead
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Uses
Therapeutic vs reproductive
Therapeutic
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Clone to get stem cells used to repaired ?Own cells
Reproductive
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Implant cloned embryo in female uterus in hopes of producing offspring
Human genome project
Started in 1990; took 13 years to complete
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Major goals:
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Sequence all 3 billion base pairs
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Two approaches (cut vs shot gun)
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Identify approximately 20000-25000 genes
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Store and use information from genome
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Address ethical and legal issues
Controversies
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A misuse of genome information
Ex
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Patented genetic code
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B
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D
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Put AIDS virus into flu to create more deadly Anthrax
Agriculture
Will we apply our genome knowledge to engineer transgenic animals related to our
nutrition?
Larger ethical concerns

Ex
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Internal chemical signals
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Cycling of cytoplasmic enzymes controls cell cycle
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Ex
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External signals - influence internal signals
o
Ex
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Skin cells normally produce growth inhibiting factor
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G1 - restriction point
Is located before entry into S phase, making the key decision of whether the cell should
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divide, delay division, or enter a resting stage
Cyclins (functional proteins - enzymes) produce cell cycle progression
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Gene regulatory proteins increase cyclins expression
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High amount of growth factors determines expression of cyclin proteins
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Cell would not move into the S phase if: insufficient cell growth, damaged DNA, or other
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preparations have not been completed
G1 phase is affected, it is generally because gene regulatory proteins of the E2F family
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have become unrestrained and increase G1/S cyclin gene expression, leading to
uncontrolled cell-cycle entry
Cure for some forms of cancer also lies in the G1 phase of the cell cycle
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Breast cancer and skin cancer have been prevented from proliferating by causing the
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tumor cells to enter G1 cell cycle arrest, preventing the cells from dividing and spreading
Apoptosis
Programmed cell death (PCD) - death of a cell in any form, mediated by an intracellular
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program (necrosis is caused by external factors)
In a developmental context, cells are induced to positively commit suicide (homeostatic
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context, tissue differentiations)
o
Sometimes taking place in younger tissues
Cancer (chapter 21a)
Uncontrolled cell division
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A
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Block passages; steal nutrients
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B
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Proto-oncogenes may have many different functions in the cell
(some provide signals that lead to cell division, other regulate programmed cell death)
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Gene products are abnormally high (makes too much protein)
2
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Missense mutation - a change in the amino acid sequence
2
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Chromosomal translocation
o
Ex
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Retroviral insertion
Tumor suppressor genes
Tumor suppressor genes represent the opposite side of cell growth control, normally
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acting to inhibit cell proliferation and tumor development
Functions of suppressor genes
Inhibiting cell division
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DNA repair proteins
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Coupling (as long as there is damaged DNA in the cell, it should not divide; if the damage
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can be repaired, the cell cycle can continue)
Induces apoptosis
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Cell adhesion (suppress metastasis)
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Play important role to keep cells together
When these genes mutate to cause a loss or reduction in their function, the cell can progress to
cancer, usually in combination with other genetic changes
Tumor protein (also known as p53)
Is crucial in multicellular organisms, where it regulates the cell cycle, and thus, functions
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as a tumor suppressor, preventing cancer
In humans, the TP53 gene is located on the short arm of chromosome 17
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Functions:
•
o
It can activate DNA repair proteins when DNA has sustained damage

It can arrest growth by holding the cell cycle at the G1/S regulation point
It can initiate apoptosis - programmed cell death - if DNA damage proves to be
irreplaceable
Problem: The mutant p53 protein itself can inhibit normal p53 protein levels
o
A missense mutation in p53 have ben shown to disrupt p53 stability and
function

o
o
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Normal p53
When cellular damage occurs, P53 arrests the cell cycle until the damage is repaired
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The damaged cell continues to divide •
spreading the cancer
C
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Rapid spread of malignant melanoma formation
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Tumor suppressor genes inhibit cell division, proto-oncogenes stimulate cell division
Promosters or co-carcinogens or Epigenetic carcinogens
Stimulate cell division by other mechanisms than directly mutating DNA
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Mismatch repair genes
Normal genes that repair DNA
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Problem: Defects in repair genes can cause cancer
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Ex
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DNA methylation; hormonal; weakened immune; chronic injury
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Risk factors and prevention
Do not use tobacco; reduce amount of saturated fat in diet; eat atleast 5 servings of
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fruit and vegetables a day, etc

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Skin cancer
Know diagnoses and information about it
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Lung cancer

Highest type of cancer
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Breast cancer
A tumor grows from single cancer cell
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Cancer cells invade neighboring tissue
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Cancer cells spread through lymphs and blood vessels to other parts of body
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How else to prevent:
Antioxidants
1000's of types
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Ex
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Herceptin
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Treatments for cancer
Drug delivery: drugs inside
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o
As time-release capsules
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To enhance specificity - coat of the tablets make it able to attach to part of the
body
A
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Radiation
C
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Immunotherapy
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Cytotoxic T cells search body for abnormal cells and kill any they find
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Boost patients immune system
E
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Inhibit of blood vessel formation

Blood (chapter 11)
Functions
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1
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Protection (blood clotting, phagocyte action of neutrophils, antibodies and antitoxins)
3
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1):

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Platelets - play room in blood clotting
White blood cells (leukocytes) - two types:
1
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Agranulocytes
Monocytes
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Lymphocytes (B and T)
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T: destroy cancer cells
Problem: tumor is usually growing too fast
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o
Cells working against pathogens
Red blood cells (erythrocytes)

Antigen (Ag), or antibody generator
Is any substance which provokes an adaptive immune response
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Antibody, also called immunogobulin, is a protective protein produced by the immune
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system in response to the presence of a foreign substance (an antigen)
Antibodies recognize and latch onto antigens in order to remove them from the body
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A wide range of substances are regarded by the body as antigens, including disease•
cause organisms and toxic materials such as venom
*Blood types*

The immune system (Chapter 13)
A
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A
virus cannot replicate outside a living host cell
Bacteria
Larger versus viruses
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Reproduce by binary fission (splitting)
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Commonly called prokaryotes
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Other: fungi, protozoans, parasites
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Lines of defense - Fig 13
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Skin
Second line: body has to take measures against foreign pathogens before it spreads
o
Consistent through white blood cells
Third line: specific and internal
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White blood cells
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To recognize what type of bacteria it is
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•
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2
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Inflammatory response (2nd line of defense)
Inflammatory response: a local response of chemical and biological (cell) warfare on
invader
Local
1
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Histamine released
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2
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Pyrogens (cause fever): chemicals released by macrophages (MO) during
inflammation that increase temperature
4
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Infected cell produces interferon
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Interferon protects other cells that become
infected with a virus by stimulating the cell to produce antiviral proteins
that prevent the virus from making copies of itself
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Bacteria) but also toxins (ex
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IL - 1 stimulates Thelper cells
IL - 2 stimulates Tcytotoxic and B cells
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Antigen-presenting cells (APC)
Can be MO and/or B cells that recognize Ag, endocytose the Ag and display it on their
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surface

THE IMMUNE SYSTEM
Three lines of defence
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