Transcript Biology Notebook Semester Two

By: Zack White
Table of Contents
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Chapter 10
Chapter 11
Chapter 14
Chapter 16
Chapter 15.3 and 17.1
Chapter 17.4
Chapter 19
Nervous System Notes
Chapter 10
Limits to Cell Growth
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DNA Overload!
Inefficient exchange of materials!
Cell volume increases too rapidly!
The solution: Cell Division
Cells that do not divide throughout
life would not encounter the issues
above. DNA determines cell decline
and death!
What are Chromosomes?
 Strands of DNA
 Every organism has a specific number
of chromosomes.
 Before cell division occurs, DNA must
be copied so each new cell will have
DNA.
 Once copied, the two identical stands
(or Chromatids) are held together by
a Centromere
Cell Cycle
 Interphase – growth period of cell, longest
stage of cell life.
1. G1 phase – growth
2. S phase – DNA replication
3. G2 phase – preparation for mitosis
 Cell Division – division of the cell into 2
1. Mitosis – division of the cytoplasm
2. Cytokinesis – division of the cytoplasm
Mitosis
 Prophase – chromatin condenses, centrioles
separate to opposite sides of cell (animal
cells only), spindle forms, nuclear
membrane breaks down
 Metaphase – Chromosomes line up in the
middle
 Anaphase – Sister chromatids separate
 Telophase – chromosomes gather at
opposite ends, new nuclear membranes
form
Cytokinesis
 Division of the cytoplasm
 In animal cells: cleavage of cell
membrane.
 In plat cells: a cell plate forms
midway between the divided nuclei.
Table of Contents
Cancer
 Uncontrolled cell division
 DNA or proteins damaged by
carcinogens or genetically inherited.
 Carcinogens: radiation, chemicals,
viral
End of Chapter 10 Notes!!!!!!!!!!!!!!!!!!!!!!!!!
Chapter 11 Notes
Chromosome Number
 Each organism inherits 1 set of
chromosomes from “mom” and 1 set
from “dad”. (ex. In humans…)
 A homologous pair = 1 chromosome
pair
 A diploid cell = 2 whole sets
 A haploid cell = 1 set (ex: sex cells)
Meiosis
 Reduction division What is it!?
 Two stages: Meiosis I and Meiosis II
 Meiosis I: Important events that take
place:
a. Pairing of tetrads What is tetrad?
b. Crossing over What happens?
c. Reduction division
 Meiosis II: same process as mitosis (no
real interphase II thus no 2nd S-phase)
Table of Contents
Gamete Formation
Males
 Produce 4 sperm from 1 cell
 Each are haploid
Female
 Produce haploid eggs
 Cell divisions are uneven
 Only one cell receives most of the
cytoplasm
 Other smaller cells are called polar bodies
End of Chapter 11 Notes
Chapter 14 Notes
Human Chromosomes
 Karyotype: picture of chromosomes
that are arranged in 23 pairs.
 Autosomes are pairs #1-22.
 Sex chromosomes are pair #23
-Males have one X and one Y (XY)
-Females have two X’s (XX)
 Human chromosome number is
written as: 46XX for a female and
46XY for a male
Autosomal Genetic Disorders
 Recessive alleles – two recessive alleles
to show disorder
Ex: PKU, cystic fibrosis, albinism
 Dominant alleles – only one dominant
allele needed to show disorder.
Ex. Huntington’s disease, achondroplasia
 Codominant alleles – only one
codominant allele needed to show disorder.
Ex. Sickle cell anemia
Sex-Linked Traits
 Location: Sex chromosomes, pair #23
 Most sex chromosome disorders are found on the “X”
chromosome of pair #23
 Males only need 1 allele for the trait.
 Females need 2 alleles for the trait.
 Colorblindness – lack of ability to distinguish certain
colors
 Hemophilia – lack of a clotting factor in blood.
 Duchenne Muscular Dystrophy – defective muscle
protein that causes progressive weakening and loss of
skeletal muscle.
Table of Contents
Chromosomal Mutations
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2.
3.
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Meiosis goes wrong at Anaphase I.
Homologous pairs don’t separate
Called: Nondisjunction
Down Syndrome – 57XX or 47XY
Klinefelter’s Syndrome – 47XXY
Turner’s Syndrome – 45XO
Metafemale – 47XXX or 48XXXX
Jacob Syndrome – 47XYY
~!End of Chapter 14 Notes!~
Chapter 16 Notes
Gene Frequencies
and HardyWeinberg
 Gene frequencies can be high or low
no matter if the allele is dominant or
recessive.
 Frequencies can change depending on
the conditions that exist in the
environment.
 It is the changes in gene frequencies
over time that results in evolution.
Hardy-Weinberg
 In 1908 Hardy-Weinberg made a
principle that provides a way to
determine whether gene frequencies
have changed in a population, and
thus, whether evolution has occurred.
Hardy-Weinberg Principle
 This principle will be maintained in
nature only if all five of the following
conditions are met:
1. Very large population
2. Isolation from other populations
3. No net mutations
4. Random mating
5. No natural selection
Hardy’s Equations
P+q=1
P = frequency of dominant allele
Q = frequency of recessive allele
P2 + 2pq + q2 = 1
P2 = frequency or % homozygous dominant
genotype
2pq = frequency or % heterozygous genotype
Q2 = frequency or % homozygous recessive
genotype
Evolution
 Definition: Change over time
 Occurs on populations, not individuals.
(Individuals do note evolve, but are part of
populations which do.)
 Evolution is the genetic change occurring in
a population of organisms over time.
 Darwin’s Natural Selection is the
mechanism that runs evolutionary theory…
Evolution by Natural Selection
 The Struggle for Existence (compete
for food, mates, space, water, etc.)
 Survival of the Fittest (strongest able
to survive and reproduce)
 Works upon the PHENOTYPES not the
genotypes of any population.
Darwin’s Observations
 In any population, there is variation
with no two individuals being exactly
alike.
 Much of this variation between
individuals is inheritable
What are the Sources of Variations?
 Gene shuffling and crossing over from
Meiosis.
 Zygote production or fertilization
 Mutations
What is a Gene Pool?
 All the alleles or genes for all the
traits for a given population.
 How common is a particular allele in a
gene pool is its: GENE FREQUENCY
What is an adaptation?
 Any trait that increases an animal’s
chance for survival in a particular
environment.
 Those with the best adaptation for
the environment are the FITTEST and
will reproduce more.
Patterns for Natural Selection
 Single-Gene trait – only two alleles,
with two distinct phenotypes; show
all-o-nothing pattern from natural
selection.
 Polygenic Traits – many allele
possibilities with several phenotypes;
show continuous variation just shifts
in distribution
 Ex: directional, stabilizing,
Artificial Selection
 Humans slelect those traits they
found most useful
 Domesticated animals
Dog breeds
Milk production in cows
 Genetically engineered crops
What if natural selection does not
play a role in gene frequency?
 GENETIC DRIFT
Notes 16.3
 In the process of evolution, natural
Selection and genetic drift can lead to
the ultimate
differentiation…Speciation
What is a species?
 A group of similar organisms that can
breed and produce fertile offspring.
 So, once members of two populations
cannot interbreed and produce fertile
offspring, they are considered 2
different species
 They are reproductively isolated
How could this happen!?!?!?!?
Some Isolating Mechanisms
 Geographical – barriers such as
rivers, mountains or bodies of water
separate a population
 Behavioral – different courtship
rituals
 Temporal – reproduce at different
times of the year
Darwin’s Finches is an example of
speciation
 Finches on the islands resembled a
mainland finch
 More types of finches appeared on
the islands where the available food
was different (seeds, nuts, berries,
insects)
 Finches had different types of beaks
adapted to their type of food
gathering
Table of Contents
Speciation of Darwin’s Finches
 Founders Arrive – few finches from the
island from the South American mainland
reach island.
 Separation of Populations – Geographic
isolation by being on different islands
 Changes in gene pools – by natural
selection
 Reproductive isolation – do not recognize
behaviors or physical traits etc.
Continued evolution over many generations
End of Chapter 16 Notes!!!!
What Evidence is there for
Evolution?
 Sections 15.3 and 17.1
Fossil Record
 The Fossil Record – incomplete record of
life on earth
-sedimentary rock forms most fossils
-proves life on earth has changed over time
 Relative Dating – estimating a fossil’s age
by comparing it with other fossils
 Radioactive Dating – calculation of sample’s
age based on the amount of radioactive
isotope it contains.
Geographic distribution of species
 Unrelated species share similarities
because of similar adaptations to the
environment.
Biochemical Similarities
 All organisms use DNA or RNA; cell
respiration process
Homologous Structures
 Same embryonic origin but have
different mature forms.
 Vestigial organs are useless
structures that many have been used
by ancestors.
Embryology
 Embryonic cell development patterns
are the same in all vertebrates
Descent with modification
 Species today look different from
their ancestors because they have
similar traits
 Each living species has:
-descended
-with changes
-from other species
-over time
Table of Contents
Common Descent
 All living things were derived from
common ancestors
 Cladograms can help to show this
End of 15.3 and 17.1 Notes
Evolution patterns
 17.4
Macroevolution
 Large-scale evolutionary patterns and
processes that occur over long
periods of time
Microevolution
 Small-scale changes in allele
frequencies over a few generations at
or below the species level
A Driving Force of Evolution:
Extinction
 More than 99% of all species that had
ever lived on earth are now extinct.
 Usual reasons: competition,
environmental changes
 Mass extinctions account for large
changes wiping out entire ecosystems
 Leaving many open niches to be filled
by those that survived.
Divergent Evolution
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Many species developing from one.
A.k.a. Adaptive Radiation
Example: Darwin’s finches
Evolving through natural selection
Usually a slow process
Disappearance of dinosaurs cleared
the way for adaptive radiation of
mammals.
Convergent Evolution
 Process where unrelated organisms
come to resemble each other or have
similar looking traits.
 Environmental conditions are the
same.
 Convergent evolution may lead to the
formation analogous structures
Table of Contents
Coevolution
 Two species evolve in response to
changes in each other over time.
 Formation of symbiotic relationships
 Advantages: less competition
 Disadvantages: too specific
End of 17.4 Notes!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Chapter 19
 Viruses and Bacteria
What is a virus?
 Ultramicroscopic infectious agents
that replicates itself only within cells
of living hosts.
 Many are pathogenic
 Composed of a piece of nucleic acid
wrapped in a thin coat of protein.
Virus Genetic Material
DNA
fairly stable from radical mutations
Ex: polio, small pox
RNA
Mutations are common
Retroviruses
Ex: influenza, HIV
Viral Reproduction Types
Lytic Cycle
 Quick in process
 Takes over host cell
 Forces host to make more virus
 Uses host’s materials
 Destroys host cell
Lysogenic
 Slower process
 Prophage inserted into host’s DNA
 Hides in host’s DNA until activated
 Once activated, continues with lytic cycle
How fast can they replicate
 A virulent virus may complete its
lifecycle in 30 minutes, producing 200
new viruses.
 Flu of 1918 killed people over 24
hours.
How can a viral infection be cured
 There is no cure for a viral infection
 Vaccines must be taken before you
are infected
 Once infected, body must fight off the
infection
 Antiviral drugs are available to treat
only a few viral diseases
Prion
 Protein infectious particles
 No genetic material
 Diseases: Mad Cow, scrapie and
Creutzfeldt-Jacob
 Nervous tissue with prions must be
ingested
Diseases
 See Textbook Figure 19-5
What is a Prokaryote
 An organism with no nucleus and
unicellular.
ALL BACTERIA!!!!!!!!!!!!!!!!!!!!!!!!!
Classification
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Movement
Non-Motile
Flagella
Slime
Bacteria Shapes
 Three basic – Bacillus (rod), coccus
(sphere), and spirillum (spiral)
Gram Staining Technique
 Cell Walls: thick or thin peptidoglycan
walls. Gram staining is used to
identify.
Metabolic Diversity
 Heterotrophs
Chemoheterotroph
Photoheterotroph
 Autotrophs
Photoautotrophs
Chemoautotrophs
Energy Release
 Two ways: respiration and
fermentation
 Classified based on how they release
energy from food:
Obligate aerobes
Obligate anaerobes
Facultative anaerobes
Growth and Reproduction
 Binary Fission – simple mitosis
 Conjugation – Swapping genetic
material
 Endospore Formation – thick coat for
dormant times.
Bacterial Importance
Photosynthesis
Decomposers – sewage treatment
Nitrogen Fixers – fertilizer for plants
Biological – vitamin K production,
fiber breakdown
 Genetic Engineering – production of
hormones for medical purposes
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Disease
 Pathogen – disease causing agent
 Cell and tissue destruction of infected
organism. Food consumption of
bacteria
 Releases toxins that poison the host
and cause symptoms of disease.
Prevention and Control
 Vaccines – given to prevent illness
 Antibiotics – given after infection to kill
bacteria
-Over usage problems
-Conjugation
 Sterilization – exposure to high heat
 Disinfectants – chemical solutions
 Refrigeration
 Cooking
 Canning and Preservatives
Chapter 40 Notes
 The Immune System
Immune System Function
 To recognize, attack, destroy, and
remember pathogens that invade our
body.
Two types of defense systems
 Nonspecific defense
 Specific defense
Nonspecific Defenses
 Does not discriminate between any
type of threat – Attacks all
 Provided by physical or chemical
barriers
1st Line of Defense
 Skin and Mucus membranes
(skin pH and stomach, saliva, tears,
sticky mucus traps)
2nd line of defense: inflammatory
response and fever
 Blood vessels dilate from histamine
release, phagocytes move in
 Body temperature increase slows
down pathogen growth and speeds up
WBC response.
 Interferon – chemical secreted by
infected cells to protect other cells
from infection.
Specific Immune Defense
 Two pathways that will occur
1. Humoral – antiobodies are made
2. Cell Mediated – destruction of
infected cell or pathogen
 Key players: Lymphocytes
 Both pathways are activated when a
pathogen invades the body.
Humoral
 Antibodies are made to attach to a specific
pathogen’s antigens. Immobilizing
pathogen.
 Antigens are identifying surface markers.
 Key players: B cells
 Key steps:
1. B cells recognize antigen
2. B cell differentiates into plasma cells
3. Plasma cells make/release antibodies.
4. B cell differentiates into memory B’s
Antibodies
 Y structured molecule made of
protein.
 Specific receptor sites made to bind
to specific antigens.
 Binds to the pathogen, flagging it for
death
Cell-mediated Immune Response
 Key players and steps:
1. Killer (cytotoxic) T-cells will multiply and
attack cells with antigen markers.
2. Helper T’s will activate killer T’s and
differentiate into memory T’s for future
exposures.
3. Suppressor T’s will slow or stop the killer
T’s when the attack is under control.
4. Macrophages clean up the mess
The Germ Theory
What is a disease
 Any change that disrupts normal functions
of the body.
What are some agents that produce disease?
 Bacteria, viruses, fungi, helminths, protists
How can agents be transmitted?
 Physical contact, contaminated food, water,
and infected animals (vectors)
What methods do we use to fight infections
disease?
 Antibiotics, vaccines, sanitation, pesticides
Germ theory of Disease
 Idea that microorganisms can cause
disease
 Based on observations from Louis
Pasteur and Robert Koch.
 Robert Koch developed a set of rules
“Postulates” for testing whether or
not an organism caused disease.
Koch’s Postulates
1. The pathogen should always be found in
the body of a sick organism and not in a
healthy one.
2. The pathogen must be isolated and grown
in the lab in a pure culture.
3. When purified pathogens are placed in a
new host, they should cause the same
disease that infected the host.
4. The very same pathogen should be reisolated from the second host. And it
should be the same as the original
pathogen.
Immunity Types
 Active Immunity – injection of a weak
or mild form of pathogen; may make
you a little sick. Attenuated form of
disease. Natural exposure to
pathogen. Long-term immunity.
 Passive Immunity – injection of
antibodies from another organism;
temporary immunity or treatment.
Allergies
 An overreaction of the immune
system
 Mast cells release histamines when
allergic antigens attach to it.
 Result: itchiness, mucus production,
sneezing, watery eyes etc.
Asthma
 Narrowing of the air passages by the
spasm contractions of the smooth
muscle.
 Chronic disease
 Reaction to antigens or stress related.
Other diseases
Autoimmune Disorders
 Your own immune system is attacking
yourself
 Production of “antiself” antibodies.
 Ex. Multiple Sclerosis, Rheumatoid arthritis,
Lupus
Immunodeficient Diseases
 Failure of the immune system to develop
normally.
 Pathogen could be destroying WBC’s
 Ex: AIDS, boy in the bubble
Chapter 18
 Classificiation
Why classify
 To organize living things into groups
with biological meaning
 Taxonomy: the study of classification
Assigning a name
 Problem: common names can vary among languages
 Solution: Latin and Greek words are commonly used
to avoid any language issues
 Problem: When naming by specific traits too many
words are used
 Solution: Carolus Linneaus developed 2-part naming
system used today called Bionomial Namenclature
 Rules:
1. Always italicized
2. 1st word cap, 2nd lowercase
3. Genus is 1st word, species 2nd
Kingdoms and Domains
 Modern tree contains six kingdoms
and their phyla: Eubacteria,
archaebacteria, protista, fungi,
plantae, animalia
 Domains – newest larges inclusive
category devloped from comparing
rRNA subunits. Bacteria, Archaea,
Eurkarya
Modern Classification
 Just using appearance can be
misleading
 New system uses:
1. Fossil
2. 2. Dissections/Comparative anatomy
3. 3. Molecular
similarities/DNA/enzymes
4. 4. Evolutionary similarities or
developmental milestones
Molecular Clocks
 Comparing DNA segments and
looking for mutations in similar
genes.
 The more dissimilar the genes the
longer ago they shared a common
ancestor.
Nervous System Notes
CNS
 Consists of the brain and spinal cord
 Recieves sensory input, integrates
and relays information for a response.
Peripheral Nervous System
 All nerves from spinal cord and cranial
region.
1. Sensory nerves pick up stimuli
2. Motor nerves send response to muscle
organs
 Motor functions are controlled by
a. Somatic nervous system, conscious
control, skeletal system
b. Autonomic nervous system, involuntary
actions, heart, glands etc.
Meninges
 Membranous coverings of the CNS
 CSF (cerebrospinal fluid) flows here
Cerebrum
 Two hemispheres
 Connected by the Corpus Callosum
 Wrinkles or folds (gyri) increase
neuron space.
 Four lobes: frontal, parietd, temporal,
occipital
 Cerebral cortex – gray matter,
outermost
Cerebellum
 Beneath the occipital lobes of
cerebrum
 Function – coordination of voluntary
movements, maintains posture,
integrates balance, information
(equillbrium)
Brain Stem
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1.
2.
3.
Connects the cerebrum to spinal cord
Primary life functions
Three sections
Midbrain
Pons
Medulla Oblongata
Other structures
 Thalamus – main relay station for
sensory impulses; general awareness
 Hypothalamus – regulates HR, BP,
temperature, hunger, sleep,
waterfullness, stimulate pituitary
 Pituitary gland – major endocrine
glands secretes hormones to control
other glands/organs.