Transcript Biology COS PPT for Review part 1

Science Review for Graduation
Exam
1.) Select appropriate laboratory glassware,
balances, time measuring equipment, and optical
instruments to conduct an experiment.
• Graduated cylinders
measure liquid
volume.
• 10 ml—volume of ink
pen
• 20 ml– volume of
marble
Beakers
• Beakers are used to mix, measure, or
heat liquids, but they are not designed for
accurate measurements.
Erlenmeyer Flask
• An Erlenmeyer flask is used for boiling
liquids and helps prevent liquids from
splashing or giving off nauseous fumes.
Test Tubes
• Test tubes are used to mix, measure, or
heat liquids. Test tubes are not usually
marked with measurements, so they are
only used to make approximate
measurements.
Microscope slide
• Used to see microscopic unicellular
organisms.
pipette
• A pipette is a
laboratory instrument
used to transport a
measured volume of
liquid.
Petri dish
• Used to grow bacteria on a nutrient agar.
Balance
• A triple-beam
balance is used to
determine the mass
of heavier materials to
the nearest gram.
stopwatch
• A stopwatch is a
handheld timepiece
designed to measure
the amount of time
elapsed from a
particular time when
activated to when the
piece is deactivated.
microscope
• A microscope enables us to see very
small objects or organisms too small to
see with the unaided eye.
Compound microscope
• The compound
microscope uses
multiple lenses to
further increase
magnification.
Electron microscope
• An electron microscope is
a type of microscope that
uses electrons to
illuminate a specimen
and create an enlarged
image. Electron
microscopes have much
greater resolving power
than light microscopes
and can obtain much
higher magnifications.
Magnifying glass
• Simple Magnification
• A magnifying glass is a
bi-convex lens. It is
convex on both sides,
meaning that the glass is
curved outward to form a
dome. Things look bigger
looking through convex
lenses.
Using appropriate SI units for
measuring length, volume, and
mass
Scientific Measurement
• SI System of Measurement —a measurement
of matter based on units of ten.
• Mass—amount of matter in an object
• Volume—amount of space an object occupies
• Length– distance from one point to another.
• The basic unit of length is the meter.
• The basic unit of
liquid volume is the
liter.
• A meniscus is the
curve you see at the
surface of a liquid.
Liquids are always
measured from the
bottom of the
meniscus.
• kilogram—basic unit
of mass in the metric
system
• Describing the steps of the
scientific method
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Make an observation.
Ask questions.
Form the hypothesis.
Set up an experiment
to test the hypothesis.
Collect and record the
data.
Analyze the data.
Draw a conclusion.
Make a prediction.
Comparing controls, dependent
variables, and independent variables
• A control group is used so that results can
be compared.
• A variable is the part of the experiment is
changed.
• The dependent variable always depends
on the independent variable.
• • Identifying safe laboratory
procedures when handling chemicals and
using Bunsen burners and laboratory
glassware
• Never smell any
chemical directly from
its container. Always
use your hand to waft
some of the odors
from the top of the
container toward your
nose, and only when
instructed to do so.
• Keep all lids closed
when chemicals are
not in use.
• Dispose of all
chemicals as
instructed by your
teacher.
Chemical Safety
Bunsen burners
• Procedure
Bunsen burner safety guidelines:
• PLACE the Bunsen burner away from any overhead shelving, equipment or
light fixtures.
• REMOVE all papers, notebooks, combustible materials and excess
chemicals from the area.
• TIE-BACK any long hair, dangling jewelry, or loose clothing.
• INSPECT hose for cracks, holes, pinched points, or any other defect and
ensure that the hose fits securely on the gas valve and the Bunsen burner.
• REPLACE all hoses found to have a defect before using.
• NOTIFY others in the laboratory that the burner will be in use.
• UTILIZE a sparker / lighter with extended nozzle to ignite the Bunsen burner.
Never use a match to ignite burner.
• HAVE the sparker / lighter available before turning on gas.
• ADJUST the flame by turning the collar to regulate air flow and produce an
appropriate flame for the experiment (typically a medium blue flame).
• DO NOT leave open flames unattended and never leave laboratory while
burner is on.
• SHUT-OFF gas when its use is complete.
• ALLOW the burner to cool before handling. ENSURE that the main gas
valve is off before leaving the laboratory.
Lab Glassware
• When heating or rinsing a container such
as a test tube, point it away from yourself
and others.
• Inform the teacher immediately of any
mishap, such as fire, bodily injuries or
burns, electrical shock, glassware
breakage, and chemical or other spills.
Describe cell processes necessary for achieving
homeostasis, including active and passive transport,
osmosis, diffusion, exocytosis, and endocytosis.
Endocytosis (active)
Exocytosis (active)
homeostasis
• The ability of an organism or cell to
maintain internal balance and stability by
adjusting its physiological processes.
Active Transport
• Movement of a substance across a
biological membrane against its
concentration or electrochemical gradient
with the help of energy input and specific
transport proteins.
Passive transport
• The diffusion of a substance across a
biological membrane.
osmosis
• Movement of water across a selectively
permeable membrane.
Diffusion
• The spontaneous tendency of a substance
to move down its concentration gradient
from a more concentrated to a less
concentrated area.
Exocytosis
• The cellular secretion of macromolecules
by the fusion of vesicles with the cell
membrane.
Endocytosis
• The cellular uptake of
macromolecules and
particulate
substances by
localized regions of
the cell membrane
that surround the
substance and pinch
off to form an
intracellular vesicle.
•
• Comparing
the reaction of plant and
animal cells in isotonic, hypotonic, and
hypertonic solutions
• A cell in a sugar solution will be smaller
because water left the cell by osmosis.
• A paramecium
achieves homeostasis
when water enters the
cell by osmosis and
contractile vacuoles
eliminate excess
water by active
transport.
• In passive transport,
There is a
concentration
gradient across a
semi-permeable
membrane where
molecules move from
an area of high
concentration to an
area of low
concentration.
• Osmosis movement of water
• Diffusion movement of substance other
than water.
• Explaining how surface area, cell size,
temperature, light, and pH affect cellular
activities
Temperature, concentration,
Surface area
• In both chemical and physical reactions,
increasing temperature or concentration
increases the rate of the reaction.
• Also, increasing the surface area between
reactants gives more opportunity for
interaction, and this speeds up reaction
rate.
• Identifying functions of
carbohydrates, lipids, proteins, and
nucleic acids in cellular activities
carbohydrates
• WHAT'S IT USED FOR?
• A carbohydrate is called an organic
compound because it contains carbon.
Sugars provide living things with energy
and act as substances used for structure.
Some examples of structures might be the
shell of a crab or the stem of a plant.
Lipids
• Lipids are another type of organic molecule (contains
carbon). When you think of fats, you should know that
they are lipids. Lipids are also used to make steroids and
waxes. So if you pick out some ear wax and smell it,
that's a lipid, too!
GET THE WAX OUT OF YOUR EARS
• Waxes are used to coat and protect things in nature.
Bees make wax. Your ears make wax. Plant leaves even
have wax on the outside of their leaves. It can be used
for structures such as the bees' honeycombs. Waxes
can also be used for protection. Plants use wax to stop
evaporation of water from their leaves.
Proteins
• Proteins are made of amino acids. Even though a protein can be
very complex, it is basically a long chain of amino acids, all twisted
around like a knot.
•
Proteins are very important molecules in our cells. They are involved
in virtually all cell functions. Each protein within the body has a
specific function. Some proteins are involved in structural support,
while others are involved in bodily movement, or in defense against
germs.
Proteins vary in structure as well as function. They are constructed
from a set of 20 amino acids and have distinct three-dimensional
shapes.
Nucleic Acids
• THE NUCLEIC ACIDS
•
The nucleic acids are the building blocks of living organisms. You
may have heard of DNA described the same way. Guess what?
DNA is just one type of nucleic acid. Some other types are RNA,
mRNA, and tRNA. All of these "NA's" work together to help cells
replicate and build proteins. NA? Hold on. Might that stand for
nucleic acid? It might.
• THE BASICS
• We already told you about the biggie nucleic acids (DNA, RNA,
mRNA, tRNA). They are actually made up chains of base pairs
stretching from only a few to millions. When those pairs combine in
super long chains (DNA), they make a shape called a double helix.
The double helix shape is like a twisty ladder. The base pairs are
the rungs.
• • Applying the concept of fluid pressure to
biological systems
Examples: blood pressure, turgor pressure
(water pressure against cell walls of
plants), bends, strokes
Blood pressure
• What is blood pressure?
Blood pressure is the pressure of the blood
against the walls of the arteries.
• Blood pressure results from two forces. One is
created by the heart as it pumps blood into the
arteries and through the circulatory system. The
other is the force of the arteries as they resist
the blood flow.
Turgor pressure
• turgor pressure or turgidity is the main
pressure of the cell contents against the
cell wall in plant cells, determined by the
water content of the vacuole, resulting
from osmotic pressure.
The Bends
• Nitrogen seeps into the bloodstream. It
blocks blood flow.
Strokes
• A stroke is an interruption of the blood
supply to any part of the brain. A stroke is
sometimes called a "brain attack."
• 3.) Identify reactants and products
associated with photosynthesis and
cellular respiration and the purposes of
these two processes.
•Photosynthesis (CO2-O2 cycle)
6H2O + 6CO2 -----> C6H12O6+ 6O2
Water + carbon dioxide = glucose +oxygen
(reactants)
(products)
Cellular Respiration
• Relationship between photosynthesis and
respiration:
• CO2  O2 cycle
• They are the reverse of each other!!
Learn one and you know the other!!!
• Photosynthesis is
affected by light,
water, and
temperature.
• The main purpose of photosynthesis is to
use light energy from the sun, water, and
carbon dioxide to make food.
• The primary purpose of cellular respiration
is to use chemical energy from glucose
molecules.
4.) Describe similarities and differences of cell
organelles, using diagrams and tables.
• Nucleus—control center of the cell; DNA
stored here
• Mitochondria—”powerhouse” of the cell
– Where ATP is produced
– Conducts respiration
– More in muscles because need more energy
• Ribosomes—synthesizes proteins
Ribosomes are the small dots.
• Golgi Apparatus– packages proteins
• Endoplasmic
reticulum —transport
system of cell
– Smooth (no
ribosomes)
– Rough (ribosomes
attached to it)
• Nucleolus—produces ribosomes
Cell membrane
• The cell membrane (also called the
plasma membrane) is a semipermeable
lipid bilayer found in all cells.
vacuole
• Vacuoles are found in
the cytoplasm of most
plant cells and some
animal cells. Vacuoles
are membrane-bound
compartments within
some eukaryotic cells that
can serve a variety of
secretory, excretory, and
storage functions.
Organelles found ONLY in plant
cells
• Central vacuole
• Chloroplasts
• Cell wall
Cell wall
• A cell wall is a fairly
rigid layer
surrounding a cell,
located external to the
cell membrane, which
provides the cell with
structural support,
protection, and acts
as a filtering
mechanism.
chlorophlast
• Conducts photosynthesis
• Chloroplasts are
organelles found in plant
cells and eukaryotic algae
that conduct
photosynthesis.
Chloroplasts absorb light
and use it in conjunction
with water and carbon
dioxide to produce
sugars, the raw material
for energy
Central vacuole
• Found only in plant cells.
• Identifying scientists who contributed to the cell
theory
Examples: Hooke, Schleiden, Schwann, Virchow, van
Leeuwenhoek
Schleiden
(plants)
Schwann
(animals)
Robert Hooke (cork)-named
“cells”
Anton van Leeuwenhoek
given credit for viewing the first LIVING
cells under a microscope
Virchow helped develop the cell
theory
• Distinguishing between prokaryotic and eukaryotic
cells
• Prokayote—has no true nucleus or
membrane bound organelles
• Eukaryote—has a true nucleus and
membrane bound organelles.
Identifying various technologies used to observe
cells
Examples: light microscope, scanning electron
microscope, transmission electron microscope
•
Light microscope
• The light microscope,
so called because it
employs visible light
to detect small
objects, is probably
the most well-known
and well-used
research tool in
biology.
Scanning electron microscope
• The scanning electron
microscope (SEM) is a
type of electron
microscope that creates
various images by
focusing a high energy
beam of electrons onto
the surface of a sample
and detecting signals
from the interaction of the
incident electrons with the
sample's surface.
Transmission electron microscope
• Transmission electron
microscopy (TEM) is a
microscopy technique whereby
a beam of electrons is
transmitted through an ultra
thin specimen, interacting with
the specimen as it passes
through it. An image is formed
from the electrons transmitted
through the specimen,
magnified and focused by an
objective lens and appears on
an imaging screen, a
fluorescent screen in most
TEMs, plus a monitor, or on a
layer of photographic film, or to
be detected by a sensor such
as a CCD camera.
9.) Differentiate between the previous five-kingdom and
current six-kingdom classification systems.
• Sequencing taxa from most inclusive to least inclusive in the
classification of living things
Taxonomy Hierarchy
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Kingdom(most inclusive)
Phylum
Class
Order
Family
Genus
Species (least inclusive)
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•
King
Phillip
Came
Over
For
Good
Spaghetti
King
Phillip
Crapped
On
Forest
Gump’s
Shirt
Classification Systems
5 Kingdom System
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•
•
•
•
Kingdom
Kingdom
Kingdom
Kingdom
Kingdom
Monera (Pro)
Protista (Euk)
Fungi (Euk)
Plantae (Euk)
Animalia (Euk)
6 Kingdom System
Kingdom
Kingdom
Kingdom
Kingdom
Kingdom
Kingdom
Archabacteria (Pro)
Eubacteria (Pro)
Protista (Euk)
Fungi (Euk)
Plantae (Euk)
Animalia (Euk)
Monera in the 5-kingdom system is divided into Eubacteria and
Archaebacteria in the 6-kingdom system
Archaebacteria
– Cell membranes have lipids (this is not found
in any other organism)
– No peptidoglycan in their cell walls
– Prokaryotic
– Unicellular
– Unique ribosomal RNA (used to
differentiate between Archaebacteria and
Eubacteria
– Commonly found in harsh environments
– Commonly found in anaerobic environments
• Identifying organisms using a dichotomous key (two
choices)
•
Writing scientific names accurately
by using binomial nomenclature
(Genus species)-Homo sapien
Binomial nomenclature
• Uses the Genus and species to give the
scientific name of an organism.
• Genus is capitalized and species is
lowercase
• Both should be either written in italics or
underlined.
• Written in Latin
• Example: Panthera leo
• Carolus Linnaeus—
binomial
nomenclature
5.) Identify cells, tissues, organs, organ systems,
organisms, populations, communities, and ecosystems
as levels of organization in the biosphere.
Cells—tissues—organs—organ systems—organism
• Cells—smallest unit of life
• Tissues—group of cells that work together
for a common function
• Organs– group of tissues that work
together for a common function
• Organ systems —group of organs that
work together for a common function
• Tendon is a tissue
• species– organisms
• Population—all the species in an area
• Community—all the populations in an area
(different populations/organisms)
• Ecosystem—all the biotic (living) and
abiotic (nonliving) parts of an environment.
»
organism
»
populations
»
communities
»
ecosystem
Least complex
--same species
Most complex
Community or Ecosystem?
• All parts of area—abiotic (water) included
is an ecosystem.
• If only asking about “living” organisms in
an area, then the answer is community.
Organismpopulationcommunityecosystem
Least
complex
Same
species
Most
Complex
(abiotic
And biotic)
• Recognizing that cells differentiate to perform
specific functions
Examples: ciliated cells to produce movement, nerve
cells to conduct electrical charges
cilia
Cilia
6.) Describe the roles of mitotic and meiotic
divisions during reproduction, growth, and repair of
cells.
• Mitosis---2n2n
• Meiosis---2n  n
Meiosis and variation
• Meiosis leads to variation in a species.
Meiosis and reproduction
• Meiosis produces haploid cell used in
reproduction.
Mitosis in cell repair
• During respiration, mitosis helps replace
cells that are destroyed or damaged.
• Mitosis in growth
• Meiosis and mitosis are reproductive
processes.
• Crossing-over occurs in Prophase I of
meiosis.
• Meiosis is a way to create diversity.
• Mitosis is NOT.
• Meiosis—
• Oogenesis—production of eggs
• Spermatogenesis—production of sperm
• Stages of mitosis:
prophase,
metaphase,
anaphase, telophase.
Meiosis
• Spermatogenesis—production of sperm
• Oogenesis– production of eggs
• Sexual reproduction
• If homolog or homologous is mentioned, it
is Meiosis I
Meiosis I (four phases)
• Cell division that reduces the chromosome
number by one-half.
• four phases:
a. prophase I
b. metaphase I
c. anaphase I
d. telophase I
Crossing over occurs in Prophase I
Meiosis I : the reduction division
Spindle
fibers
Nucleus
Nuclear
envelope
Prophase I
(early)
(diploid)
Prophase I
(late)
(diploid)
Metaphase I
(diploid)
Anaphase I
(diploid)
Telophase I
(diploid)
Meiosis II : the equational division
Prophase II
(haploid)
Metaphase II
(haploid)
Anaphase II
(haploid)
Telophase II
(haploid)
Four
nonidentical
haploid
daughter cells
Results of meiosis
Gametes
Four haploid cells
One copy of each
chromosome
One allele of each gene
Different combinations of
alleles for different genes
along the chromosome
Spermatogenesis
• Occurs in the testes
• Production of sperm
Spermatogenesis
n=23
human
sex cell
sperm
n=23
n=23
2n=46
haploid (n)
n=23
diploid (2n)
n=23
n=23
meiosis I
meiosis II
Oogenesis
• Occurs in the ovaries
• Production of the egg
Oogenesis
First polar body
may divide
(haploid)
a
a
X
a
X
a
Meiosis I
A
Oogonium
(diploid)
X
X
Mitosis
X
Primary
oocyte
(diploid)
Polar
bodies
die
Meiosis II
(if fertilization
occurs)
A
X
A
X
Secondary
oocyte
(haploid)
Ovum (egg)
A
X
Second
polar body
(haploid)
Mature
egg
• Comparing sexual and asexual
reproduction
Asexual Reproduction
• Asexual reproduction is the ability of an
organism to reproduce without the need of
the production of eggs and sperm.
– Takes place in the lower forms of animals
• Phylums:
– Porifera --sponges
– Coelenterara (Cnidarians)--jellyfish
– Platyhelminthes—planaria, tapeworms
• All these can reproduce asexually by cell division,
budding, regeneration, or fission.
• Prokaryotes—usually reproduce asexually
• Eukaryotes—asexually, sexually, or both
depends on the organism
Asexual Reproduction
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•
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ONLY ONE ORGANISM IS NEEDED!!
One parent
Copies of all genes to each offspring
Actually a clone—genetically identical
Prokaryotes—binary fission
Asexual reproduction
• Simplest method of reproduction
– Some ways:
• Fission
• Fragmentation
• budding
Binary fission
• Parent separates into two or more
individuals of approximately equal size
• Example: amoeba
Fragmentation
• Mulitcellular eukaryotes
• The body breaks into several pieces
• The fragments develop into complete
adults when missing parts are regrown.
• Example: sea star
Budding
• New individuals split off form existing
ones.
• Can break off or remain attached.
• Examples: hydra
• In a stable environment, asexual
reproduction allows organisms to produce
many offspring in a short period of time.
– Not necessary to use energy to produce
gametes or find a mate
• Comparing sperm and egg formation in
terms of ploidy
Example: ploidy-haploid, diploid
7.) Apply Mendel's law to determine phenotypic and
genotypic probabilities of offspring.
• Defining important genetic terms, including dihybrid
cross, monohybrid cross, phenotype, genotype,
homozygous, heterozygous, dominant trait, recessive
trait, incomplete dominance, codominance, and allele
Monohybrid cross
Dihybrid cross
• Click on the words below to see an
animation
Punnett Squares
• Practice LOTS of Punnett Squares!!
• See your teacher!!
• The set of alleles that an individual has is
called its genotype.
• The physical appearance of a trait is called
a phenotype.
• A gene can be dominant or recessive.
• To express a recessive trait, an individual
must have two recessive allelles.
• If the dominant allele is present, it will be
expressed.
• If an individual receives two like alleles for
a characteristic, the individual is
homozygous. (AA, aa)
• If an individual receives two different
alleles for a characteristic, the individual is
heterozygous. (Aa)
Incomplete dominance
In Caucasians, the child of a straight-haired
parent and a curly-haired parent will have wavy
hair. Straight and curly hair are homozygous
dominant traits. Wavy hair is heterozygous and
is intermediate between straight and curly hair.
Codominance
• Both traits are displayed.
• Example: cattle– A cross between a
homozygous red horse (cow) and a
homozygous white horse (cow) results in
heterozygous offspring with both red and
white hairs in about the same number.
– Called a roan.
Some traits are caused by
mutations
• Mutations are changes in genetic material.
– Harmful effects produced by inherited
mutations are called genetic disorders.
Interpreting inheritance patterns
shown in graphs and charts
• Pedigrees are
particularly helpful if
the trait is a genetic
disorder and the
family members want
to know if they are
carriers.
• Carriers are
individuals who are
heterozygous for an
inherited disorder but
do not show
symptoms of the
disorder.
– They can pass the
allele to their offspring.
Pedigree
• • Calculating genotypic and phenotypic
percentages and ratios using a Punnett
square.
T = Tall (dominant)
t = Short (recessive)
Genotypes: tt & tt
Phenotypes:short
tt = 100%
Short = 100%
Genotypes: Tt & tt
Phenotypes: Tall &
short
Tt = 50%
tt = 50%
Tall = 50%
Short = 50%
Genotypes: TT & Tt
Phenotypes: tall
TT = 50%
Tt = 50%
Tall = 100%
Genotypes: TT, Tt, tt
Phenotypes: Tall &
short
TT = 50%
Tt = 25%
tt = 25%
This Punnett
Square is wrong. Tall = 75%
Short = 25%
WHY??
8.) Identify the structure and function of
DNA, RNA, and protein.
•
I. Structure of DNA
A. Each DNA strand
consists of many
nucleotide monomers
linked by covalent
bonds
B. Each nucleotide has
three parts:
1. a phosphate group
2. a nitrogen base
3. a sugar (deoxyribose)
IV. Structure of RNA
A. A nucleic acid consisting of one strand of
nucleotides
B. Contains the bases A, C, G, and U
C. Contains the sugar ribose
•
•
•
•
•
Amino acids make up proteins
Proteins can function as enzymes
Production of protein
Patterns of base pairingDNA & RNA
DNA makes up genes and chromosomes
• Proteins serve as enzymatic catalysts.
• RNA transports amino acids.
Base Pairing
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•
•
•
DNA Replication
Thymine (T) pairs with Adenine (A)
Cytosine (C) pairs with Guanine(G)
In RNA– Uracil (U) pairs with (A)—There
is NO THYMINE IN RNA!!
• DNA replication preserves the genetic
code from one generation to the next.
• Explaining relationships among DNA, genes, and
chromosomes
Chromosomes
• The DNA and the proteins associated with
the DNA coil into a structure called a
chromosome as a eukaryotic cell prepares
to divide.
DNA in Eukaryotic Cells
A gene is a segment of DNA that codes for a
protein or RNA molecule.
Genes play an important role in determining how a
person’s body develops and functions.
• Each chromosome contains thousands of genes
that play important roles in determining how a
person’s body develops and functions.
• Relating genetic disorders and disease to
patterns of genetic inheritance
• Examples: hemophilia, sickle cell anemia,
Down's syndrome, Tay-Sachs disease, cystic
fibrosis, color blindness, phenylketonuria (PKU)
•
Sickle Cell Anemia
Recessive
Symptom: Poor blood circulation
Defect: Abnormal hemoglobin
molecules
Frequency in human births: 1 in
500 African Americans
Tay-Sachs
disease
• recessive
• Symptom: deterioration of central
nervous system in infancy; affected
individuals die in early childhood
• Defect: defective form of a brain
enzyme
• Frequency in human births: 1 in 3,500
(Jews)
Cystic Fibrosis
• recessive
• Symptom: mucus clogs many organs,
including the lungs, liver, and pancreas;
affected individuals usually do not
survive to adulthood
• Defect: defective chloride-ion transport
protein
• Frequency in human births: 1 in 2.500
(whites)
Hemophilia A
• Sex-linked recessive
• Symptom: failure of blood to clot
• Defect: defective form of a blood-clotting
factor
• Frequency in human births: 1 in 10,000
(white males)
Huntington’s disease
• dominant
• Symptom: gradual deterioration of brain
tissue in middle age; shortened life
expectancy
• Defect: inhibitor of brain-cell metabolism
is made
• Frequency in human births: 1 in 10,000
• Listing significant contributions of
biotechnology to society, including
agricultural and medical practices
Examples: DNA fingerprinting, insulin,
growth hormone
• So what is biotechnology and genetic
engineering? There are three major
developments that act as the signature of
biotech, with many more surprises coming
down the road:
Biotechnology in Agriculture
• Modification of plants to change their
response to the environment, disease or
pesticides. For example, tomatoes can gain
fungal resistance by adding chitinases to
their genome. A chitinase breaks down
chitin, which forms the cell wall of a fungus
cell. The pesticide Roundup kills all plants,
but crop plants can be modified by adding
genes that leave the plants immune to
Roundup.
Biotechnology in Medicine
• Bacterial production of substances like
human interferon, human insulin and
human growth hormone. That is, simple
bacteria like E. coli are manipulated to
produce these chemicals so that they
are easily harvested in vast quantities
for use in medicine. Bacteria have also
been modified to produce all sorts of
other chemicals and enzymes.
• Relating normal patterns of genetic
inheritance to genetic variation
Example: crossing-over
•
• Gel electrophoresis
Crossing over
(genetic recombination)
Variation
• Caused by
– Crossing over
– Random fertilization
– Independent assortment
Relating ways chance, mutagens, and genetic
engineering increase diversity
Examples: insertion, deletion, translocation, inversion,
recombinant DNA
Deletion
• A piece of
chromosome breaks
off completely.
• The new cell will lack
a certain set of genes.
• Many times is fatal.
duplication
• A chromosome
fragment attaches to
its homologous
chromosome, which
will then carry two
copies of a certain set
of genes.
inversion
• Chromosome piece reattaches to the
original chromosome but in a reverse
orientation.
translocation
• If the piece reattaches
to a nonhomologous
chromosome.