Transcript Test of Essential Academic Skills (v. 5)

Science Section
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Scientific Reasoning
Human Body Science
Earth and Physical Science
Life Science
Scientific Reasoning
Conducting an Investigation
• Proper scientific investigation involves critical
thinking which leads to sound procedures
and creates solutions to problems.
• A systematic inquiry into a technical problem
may establish an entirely new method of
solution not previously considered.
• Proper investigations have led to radically
new designs that improve the quality of life.
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Concepts Guiding a Scientific Investigation
An inquiry starts with identifying a problem
and asking questions.
Next, carefully define the terms of the
question being asked, using qualitative and
quantitative assessment.
Afterwards, formulate a hypothesis, which is
an explanation generated to answer the
question being investigated.
Finally, test the hypothesis with experiments,
analyzing the data and drawing conclusions.
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Formulation of a Scientific Explanation
Any scientific investigation demands that a
logical procedure be followed.
Logic follows rules that are independent of
the subjective fallacies of the investigator
(sophistry v. dielect v. philosophy – Aristotle).
The rules of logic follow a path of inductive or
deductive reasoning (i.e. sunrise and Earth
rotation).
Inductive: arrive at a principle from fact(s).
Deductive: draw prediction from principle(s)
Use of Technology and Math in an Investigation
• Investigation is dependent on the application of
various mathematical and technical skills,
employing computers and measuring devices to
obtain the most precise and timely data.
• These data are then related to one another
through relationships often established by
graphs and empirical formulas, thus generating
a model which is applied to a theory and
communicated.
• Refinements in data collection and analysis lead
to a further understanding of the subject and a
refinement of the prior scientific model.
Example: Cellular and Molecular Systems Biology
Outer membrane
and cell surface
Cytoplasm
Nucleus
Advances are due to:
1. “High-throughput” technology, which
yields enormous amounts of data
2. Bioinformatics, which is the use of
computational tools to process a large
volume of data
3. People: Interdisciplinary research teams
Human Body Science
Anatomy & Physiology – Structure & Function
Hierarchy of human body structure
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Tissue types
Epithelial: tissue providing covering (i.e. skin)
or producing secretions (i.e. glands). Avascular
(diffusion dependent for blood). Regenerative
(cuts on skin heal quickly). 2 Layer types
(simple vs. stratified). 3 Shapes (squamous,
cuboidal and columnar).
Connective: tissue connecting different body
structures. Types: bone, cartilage, fat.
Muscle: dedicated to providing movement.
Types: skeletal, cardiac, smooth.
Nervous: structure for brain, spine and nerves.
Types: neurons and support cells.
Anatomical Terminology
Organ Systems and Functions
Circulatory System
4 Chambers
4 Valves
Atria v. Ventricle
Left v. Right
Systemic v. Pulmonary
Circulatory Pathway
Artery – Capillary – Vein
Respiratory System
Inhale O2 – Exhale CO2
Anatomy of Air Flow
Muscles and Air Flow
Inhale-Active/Exhale-Passive
Alveoli and Capillaries
Mucociliary Escalator
Nervous System
Digestive System
Alimentary Canal
Accessory Structures*
Gastrointestinal (GI) Tract
Process of Digestion
Mechanical and Chemical
Bolus in the Mouth
Peristalic Movement Thru
Chyme in Stomach
Absorb in Duodenum
Water in Colon
Villi increase absorption
Sphincters stop backflow
Immune System
• Innate (nonspecific) mechanisms include
physical (i.e. skin), chemical (i.e. Lysozyme) and
cellular (i.e. killer cells produce Perforin)
barriers.
• Cytokines stimulate Leukocytes (WBC) and
promote their chemotaxis.
• Adaptive (specific) mechanisms are antibodymediated, involving B-cells and antibodies
against a pathogenic antigen, or cell-mediated,
involving T-cells which trigger other immune
system cells to kill the pathogen.
…and there is more! 
Primary and Secondary
Exposure to Antigen
Vaccines (time & scale)
Active Immunity
Passive Immunity
Birth and Fertility, Population Growth and Decline
• Fertility rates refer to the average number of
children a woman will have and coincide with the
replacement rate of a population.
• Less developed countries have a higher rate
than more developed countries (due to death),
contributing to resource depletion (i.e. Haiti).
• Fertility is affected by religious, cultural, medical
economic, financial and education factors.
• The population is dependent on birth and death
rates, and immigration and emigration rates.
• Population dynamics are affected by economic,
political, medical, natural and climatic changes.
Life Science
Biological Classification
Taxonomic Hierarchy of human body structure
Binomial Nomenclature
Species Genus Family Order
Class Phylum Kingdom Domain
Ursus americanus
(American black bear)
Ursus
Ursidae
Taxonomy Tool:
Drunk
King
Philip
Came
Over
From
Greece
Stoned
Carnivora
Mammalia
Chordata
Animalia
Eukarya
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Natural Selection and Adaptation
Natural selection occurs when some
individuals of a species are better able to
survive in their environment and reproduce.
Some of the characteristics that enable those
individuals to survive and reproduce are
inherited and passed on to offspring.
Through genetic mutation, these individuals
are better able to survive and adapt to
environmental pressures (called adaptation).
As this process repeats itself, that species
evolves or changes genetically over time.
Insect-eaters
Gray warbler finch
Certhidea fusca
Bud-eater
Seed-eater
Warbler finches
COMMON
ANCESTOR
Green warbler finch
Certhidea olivacea
Sharp-beaked
ground finch
Geospiza difficilis
Vegetarian finch
Platyspiza crassirostris
Mangrove finch
Cactospiza heliobates
Insect-eaters
Tree finches
Woodpecker finch
Cactospiza pallida
Medium tree finch
Camarhynchus pauper
Large tree finch
Camarhynchus
psittacula
Cactus-flowereaters
Seed-eaters
Ground finches
Niche’ driven
modifications
Small tree finch
Camarhynchus
parvulus
Large cactus
ground finch
Geospiza conirostris
Cactus ground finch
Geospiza scandens
Small ground finch
Geospiza fuliginosa
Medium ground finch
Geospiza fortis
Large ground finch
Geospiza
magnirostris
Chromosomes and Genes
• The human genome contains 23 pairs of
chromosomes, one derived from the mother
and one from the father.
• Chromosomes contain areas called genes,
which contain information that ultimately
specifies the production and type of proteins
which control the heredity of particular traits.
• Each individual has 2 alternative forms of a
gene, called alleles. Each allele is located
on a chromosome and thus, each allele is
inherited from each parent.
from dad
from mom
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Nucleic Acids
The job of nucleic acids is to store and
transmit hereditary information.
Structurally, a nucleic acid is a chain of
nucleotides (a polynucleotide). Each
nucleotide consists of a pentose sugar, a
phosphate group and a nitrogenous base.
A pentose is a type of sugar.
A phosphate group is the backbone of
nucleic acids linking adjoining bases.
A nitrogenous base encodes the genetic
information in cells.
2 Nucleic Acid Sugar types:
They can form DNA or RNA
Deoxyribonucleic Acid (ds)
Ribonucleic Acid (ss)
Differ in C2 Oxygen
Differ in function (later…)
2 Nucleic Acid Base types:
Pyrmidines or Purines
Thymine is in DNA only
Uracil is in RNA only
DNA is double helical structure
2 nucleic acid strands interact
Hydrogen bond between bases
Adenine bonds with Thymine
Cytosine bonds with Guanine
The Central Dogma of Molecular Biology
DNA
TRANSCRIPTION
Inside a cell
mRNA
TRANSLATION
Protein
ribosome
DNA is the blueprint
RNA is the messenger (TS)
Protein is the worker (TL)
How is a protein specifically produced from DNA?
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Protein Synthesis
Genes contain coded information controlling
the heredity of traits (i.e. eye or hair color).
The genetic code is composed of sequences
of the bases of DNA (A, T, C or G). Each
piece of the code is called a codon and is
composed of 3 of the bases.
Some 64 codons specify 20 amino acids.
A specific sequence of amino acids forms a
chain which is called a protein.
Protein is the cell’s workhorse, responsible
for the expression of genetic traits.
Third mRNA base (3’ end of codon)
First mRNA base (5’ end of codon)
• Of the 64 codons, 61
code for amino acids
• 1 codon is the “start”
sequence and encodes
Methonine
• 3 codons are the “stop”
sequence to end
translation
• The genetic code is
degenerate; no codon
specifies more than one
amino acid but 1 amino
acid can be encoded
several codons
• Codons must be read in
the correct reading
frame (correct
groupings) in order for
the specified polypeptide
to be produced
Second mRNA base
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DNA Mutation
Genome mutation occurs by two mechanisms:
DNA replication error or mutagenesis, which is
caused by mutagens (i.e. smoke or UV).
Cells have repair mechanisms which greatly
reduce the overall mutation rate (frequency).
DNA polymerase not only replicates DNA, it
also corrects errors which are inherent in the
process by proofreading the replicated strand.
Another mechanism, called excision repair,
scans DNA constantly to find errors in the
sequence and correct them back to normal.
Cancer is caused by mutation
EFFECTS OF MUTATIONS
p53 – tumor suppressor
Ras - oncoprotein
Protein
overexpressed
Cell cycle
overstimulated
Protein absent
Increased cell
division
Cell cycle not
inhibited
Somatic vs. Germ line mutation
Differentiation and Developoment
• Differentiation produces a more-specialized
cell from a less-specialized one. The original
cell (progenitor) is called a stem cell.
• The genes of each cell regulate the process
of cell differentiation and ultimately, the
development of an organism.
• A fertilized egg begins dividing and becomes
a mass of cells called a zygote. Ultimately,
the zygote forms an embryo which in turn,
becomes a fetus.
2 influences in differentiation and development
Unfertilized egg cell
Sperm
Fertilization
Nucleus
Two different
cytoplasmic
determinants
Zygote
Mitotic
cell division
Two-celled
embryo
Cytoplasmic determinants in the egg
(internal signals)
Early embryo
(32 cells)
NUCLEUS
Signal
transduction
pathway
Signal
receptor
Signal
molecule
(inducer)
Induction by nearby cells
(external signals)
Microbiology, Cell Biology and Organelles
Bacterial Cell
Prokaryote (pro – before)
Most generalized cell type
Very small in size
Leads independent life
Has no organelles
Has a rigid cell wall
Has plasmid DNA
Possess flagellar motion