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Cell

growth

• To maintain homeostasis (balanced internal

environment, cells must

have a large_large surface area compared to their volume so that raw materials can

enter

enter the cell and

Vocabulary

• Chromosomes are segments of DNA wrapped around

proteins

– The entirety of the DNA is split between the

chromosomes

• Found in Eukaryotes

• Prokaryotes don’t have

chromosomes – their DNA is in a plasmid

• Each organism has a specific number of chromosomes

– Humans have 46 chromosomes

•

A diploid cells has

two copies of

each chromosome

•

A haploid cell has

only one copy of

each chromosome

• Different forms of a gene are called alleles

• Because diploid organisms have two copies of every gene – one on each

chromosome – we may have two copies of the same allele OR two

different alleles of the same gene

• Diploid organisms have two of each chromosome.

These are homologous

chromosomes because they have the same genes but are not identical (the

alleles are different)

• Prior to cell division, each chromosome replicates

(DNA replication), forming sister chromatids

• Sister Chromatids are identical (same alleles)

Mitosis

Cell division in body

(somatic) cells.

Mitosis is asexual

reproduction because

the cells produced by

mitosis are identical to

Uncontrolled

Cell Growth

• Cancer is a disorder

where cells lose control of cell growth

• Tumors can form that disrupt function

MEIOSIS

• Cell division resulting in sex cells or gametes.

• Nuclear division in which the

diploid number of chromosomes is reduced to the haploid number of chromosomes by separating

homologous chromosomes.

• 2n  1n

–

Only diploid cells can

undergo meiosis.

–

Through meiosis, the

initial diploid cell

produces 4 haploid cells

Meiosis I

• Two non-identical haploid cells are produced by

meiosis I

• The new cells are no longer diploid – they do not have a copy of each chromosome from each parent.

• Each new cell has ½ the

Meiosis

•

The final products of

meiosis are 4 haploid

gametes (n).

Each gamete has ½ the

GENETIC

VARIATION

• Meiosis causes genetic

variation. Genetic variation is the raw material for

evolution.

• What causes genetic variation:

– Crossing over

– Independent assortment

– Random fusion of gametes

• Necessary for a species survival in a changing

Independent

assortment

• During meiosis I, there are many ways that the

chromosomes can line up in pairs

• Depending on how they align, the assort independently

Crossing Over

–Reminder – during prophase I,

the duplicated homologous

chromosomes form tetrads

–Review of Homologous

chromosomes

•They are not identical

Crossing

Over

•

Crossing over occurs

when segments of one

chromosome

interchanges with the

corresponding segments

from its homologous

chromosome – alleles

switch

•

Chiasma (plural

chiasmata) are places

where chromosomes are

experiencing crossing

Genetic

Variation

•

Random fusion of gametes

also increases genetic

variation

•

Every gamete is unique,

and during sexual

GENETICS

•

Genetics is the study

_{of heredity.}

•

Heredity is the

transmission of

biological information

from parent to

• A trait is a specific characteristic that varies from one individual to another

– Plant height – Eye color

• A gene is the factor that determines traits

– There are genes for plant height – There are genes for eye color

• The chromosomal theory of inheritance states that genes are located on

chromosomes

• Alleles are the

different forms of genes

– Tall vs. short plants – Blue eyes vs. brown

eyes

• Because Mendel noticed that only traits from one parent were

expressed, he came up with the Principle of Dominance

• The principle of dominance states that some alleles are dominant and others are

recessive

• Principle of Dominance

–

The allele expressed in

the F

is dominant.

(capital letter)

–

The allele that is

hidden is recessive.

(lower case letter)

• The principle of segregation states that alleles separate during gamete formation.

• This means that each F1 plant produces 2 types of gametes: those with the

• The genotype of an

organism is the genetic makeup of an organism

• Tt

• The phenotype is the physical traits of an organism

– Tall

• Homozygous means both alleles are the same

– Homozygous tall: TT

• Heterozygous mean the alleles are different

– Heterozygous tall: Tt

Punnett Square

R r

RR Rr

Rr rr

R

• A cross involving an

individual with a dominant phenotype mated with an individual with a recessive phenotype.

• Test crosses are

performed to determine the genotype of an

organism exhibiting the dominant phenotype.

• An F1 plant that is homozygous for shortness is crossed with a

heterozygous F1 plant. What is the

Dihybrid Cross

•

Cross involving individuals that

differ in two different genes.

• These crosses demonstrate that

alleles assort independently

Dihybrid Cross

X-linked Inheritance

• Chromosome 23 is the sex chromosome

• XX are females

• XY are males

• Dominant and recessive rules still apply • Males are much more likely to carry

X-linked recessive traits than females because they only have one

Practice

Failingmr.solomon’sclass is a serious

disease that affect several 10th graders

at BTW. It is an X-linked recessive

disease. Suppose a normal female and a male with the disease have a child –

Incomplete Dominance

Incomplete Dominance

R

R R_R

W

W RWRW RWRW

W

W RWRW RWRW

Codominance

Both phenotypes of

parents are

expressed in the

heterozygote.

Punnett Square for

Punnett Square for

Codominance

Codominance

Blood

Type

• Blood types A and B are codominant to each other

• Blood type O is recessive to both A and B

• Suppose a mother with blood type AB claims a man is the father of her

Multiple

Alleles

•

Occurs if there are

more than two alleles

in a gene pool

• Never more than two

alleles, however, for any one individual within that population

Polygenic

Inheritance

• Involves many genes affecting one phenotypic trait.

• Each gene has an additive

effect resulting in continuous variation.

• Results in a bell curve or

normal distribution if graphed

Pleiotropy

•

A single gene affects

more than one

characteristic.

• PKU is caused by a mutation that codes for a defective

enzyme  brain damage, small

Pedigrees

• A family tree describing the heritable characteristics in parents and offspring across as many generations as

possible.

Effect of

Environment

•

Gene expression

is always the

result of the

interaction of

genetic potential

with the

Genetic

Disorders

• A genetic disorder is a an

abnormality in a person’s DNA.

• THIS IS NOT AN INFECTION

Genetic

Disorders

• Some genetic disorders are

simply caused by

basic dominant and recessive

Other Causes of

Genetic

disorders:

• Nondisjunction • Duplication

• Deletion • Inversion

Nondisjunction

•

Homologous

chromosomes fail to

separate during

meiosis.

– Euploidy is the normal number of chromosomes.

– Aneuploidy is an abnormal number of chromosomes

Deletion

Deletion: portions of

DNA are deleted.

– Chromosome 5 – Cri Du Chat: meow cry, small round head, wide set eyes with epicanthic folds, slow growth and severe mental

retardation

Duplication

•

Duplication: extra

pieces of

chromosomes (extra

DNA)

– Less severe

effects.

– May accelerate

evolution providing

extra DNA for

mutation.

Translocation

• Translocation occurs when

chromosome or fragment of a chromosome joins with a

nonhomologous chromosome.

• Crossing over between non-homologous chromosomes

Inversion

breaks in two places then attaches itself in reverse

Mutation

• Your DNA is made up a specific sequence of nucleotides

• A mutation occurs when the specific DNA

sequence is altered

– Point mutation: change in single nucleotide

• Genetic Engineering is the transfer of genes from one

organism to another. This new DNA is referred to as

recombinant DNA

• Stanley Cohen and Herbert Boyer in 1973 were the first scientists to

successfully do genetic engineering. • Only possible because all living

organisms use the same genetic cods – universal code!

Restriction enzymes

•

A restriction enzyme

cuts DNA at a

specific nucleotide

sequence

Biotechnology

Gel electrophoresis

•

Gel Electrophoresis

separates DNA

fragments created by

restriction enzymes

based on size

•

The smaller the

 Taxonomy is the science of

classifying organisms

 Taxonomy is used to name and

group organisms according to their evolutionary relationships

 Why do we classify organisms? ◦ _{Common Language}

◦ Easy to find information

 _Domain  _Kingdom  _Phylum  _Class  Order  Family  Genus  Species

“King Philip Came Over For Good Songs”

As you go down, the number of organisms…?

• Originally, organisms were classified by physical

similarities

• Now species are classified by their evolutionary relationships

• Organism classification

changes as new evolutionary evidence is found

Domain: Archea Bacteria Eukarya Kingdom: Archeabac

teria

Eubacteria Protista Fungi Plantae Animalia

Cell Type Prokaryote Prokaryote Eukaryote Eukaryote Eukaryote Eukaryote

Number of cells

Unicellular Unicellular Mostly unicellular Mostly multicellular Multicellular multicellular Structure of cell Wall Cell wall without peptidoglycan

Cell wall with petidoglycan

Some have cell walls, some do not

Cell walls made of chitin Cell walls made of cellulose

No cell wall

Mode of Nutrition Autotrophs and heterotrophs Autotrophs and heterotrophs Autotrophs and heterotroph s Heterotroph s, absorb nutrients with filaments Autotrophs, perform photosynthe sis Heterotroph s, ingest nutrients Other Characteristics Live in extreme places

Very diverse   Decomposer s in ecosystems Immobile, producers     Examples Organisms that live in extreme places bacteria Algae, protozoa Mushrooms, mold, yeast

Origin of the First Cells

Evolution of Cells

• The early Earth’s atmosphere did not contain oxygen. The early prokaryotes were anaerobic consumers and got their energy through glycolysis and

Evolution of Cells

• Heterotrophs mutated and gained

the ability to make their own food – photosynthesis and chemosynthesis

Evolution of Cells

• The buildup of oxygen in the atmosphere allowed for the evolution of aerobic

respiration. OXYGENATION OF THE ATMOSPHERE WAS VERY IMPORTANT

Evolution of Cells

Evolution of Cells

• Endosymbiotic hypothesis proposes that eukaryotic cells arose from living communities of prokaryotic organisms

Evolution

• Evolution is any change across generations in the inherited characteristics of an organism • Evolution is a change in gene

frequency, and therefore the traits, of a species over time • Evolution is a result of

differential reproductive success

• Today we are talking about how organisms adapt to their

Theory of Evolution by Natural Selection

• 1859 publication of Charles

Darwin’s On Origin of Species. – Proposed that organisms

alive today “descended” from a common ancestral species.

– Proposed a mechanism for evolution (change through time) called natural

Requirements for Evolution by Natural Selection

1. Individuals of

a population

2. All species produce

more offspring than the environment can support (overpopulation).

– Houseflies produce so many offspring in a single season, if they all survived they would cover an area the size of Germany to a depth of 47 feet.

Requirements for Evolution by Natural

3. This

overpopulation leads

to a struggle for

existence among

individuals of a

population, with

only some surviving

each generation.

Requirements for Evolution by Natural

4. Survival of the fittest

Those individuals with

inherited characteristics best fit to their

environment are likely to leave more offspring than less fit individuals. These individuals are selected for by nature

Requirements for Evolution by Natural

Evolutio

n

• Evolution is a direct result of differential reproductive success

• Organisms that inherited better genes are more likely to survive and reproduce.

Organisms that inherited worse genes are less likely to survive and reproduce.

• Over time, a higher percent of individuals will have better genes – this is evolution!!!

• Environmental limitations cause natural

Evolution

• Evolution is only possible because of genetic variation– genetic

variation causes offspring to have different traits and therefore

allows natural selection to occur!

• The greater the genetic diversity, the more likely a species is to

Evolution caused

by factors other

than Natural

Selection

• Genetic Drift: the

random change in gene frequency not as a

• Gene Flow: the transfer of genes from population to another as a result of migration

• Mutations: randomly increase genetic

variation and may produce organisms better suited to the environment. Natural selection acts on the

mutated individuals, but the root cause of the

evolution is the mutation not the selection

Evolution caused

by factors other

Cladograms

• A cladogram shows the evolutionary

relationships among species

• Cladograms show how closely related

organisms are

Patterns of

Evolution

•

Convergent Evolution

occurs when distantly

related organisms

inhabiting a similar

environment come to

resemble each other

•

Coevolution occurs

when two or more

populations interact

so closely that

each is a strong

selective force on

the other.

– Bees and flowers

Patterns

of

• Divergent Evolution: a

population becomes isolated from the rest of the species and follows a different

evolutionary course.

• An extreme type of divergent evolution is adaptive radiation. A.R. is rapid speciation (one

species quickly turns into many species)

– Bone structure in vertebrate forelimbs

– Darwin’s Finches

Speciation

• Species is a group of organisms that share a common gene pool and can breed to produce

fertile offspring

• Two different species cannot interbreed

Speciation

– If gene flow (exchange of genes between populations) occurs,

then no new species is formed. The species may evolve, but no new species will form

– If gene flow is prevented by some barrier, then a new

species can form.

– A new species is formed when two populations are

Why does speciation occur

after isolation?

• Two groups have different initial gene frequencies

• Two groups will experience different mutations

• Two groups will have different selective forces

• These changes can cause such differences in the populations that they become

Punctuated Equilibrium

arise rapidly after long periods of non-speciation.

• During this period of non-speciation,

the genes of the species are diverging until speciation occurs

Evidence for

the Theory

of Evolution

•

All evidence for

the theory of

evolution

•

Fossils

– Provide evidence that organisms have changed

through time. (dinosaurs, trilobites, horse)

– Can date using Law of

Superimposition (relative age) or Radioisotopes (absolute age)

• Radioactive isotopes are

unstable and break down at a steady rate called ½ life.

– 14C = 5,600 years and 40K =

1.3 billion years

Evidence

for the

• Biogeography

– Study of past and

present distribution of species. Gives us

clues to the evolution of species.

•Flightless birds in South America,

Africa and Australia. •Island flora and

fauna more similar to mainland species than other island species.

Comparative anatomy – organisms with

anatomical similarities are closely related

Homologous structures – structures that are

similar because of common ancestry.

Evidence

for the

– Analogous

structures –

similarities are due to adaptation to

similar

environments not common ancestry.

– Vestigial structures –structures of little or no use to the

organism.

• Comparative embryology

– Closely related

organisms go through similar stages in their embryonic development.

• Vertebrate embryos have gill slits and tails. Vertebrates have

descended from a common ancestor.

•

Molecular

biology –related

species have a

DNA and

proteins in

common

– The more similar the organisms, the more similar their DNA and proteins

• Observed change in gene/trait

frequency

– Remember the black squirrels?!

•

Bipedalism – walking on

two feet

•

Decreasing jaw bone and

jaw muscle size

•

Decreasing “eyebrow

bone” size

•

Increasing brain size

– Led to development of language and of useful tools

Catalyst

• 1.Write the structure and function of each macromolecules

• 2.Write the equations for photosynthesis and cellular respiration

Factors that

affect blood

flow:

• Resistance:

Increased Resistance = decreased blood

flow

– Misshapen blood cells

– Increased volume

– Disease

– Increased viscosity

Factors that affect blood

flow:

• Disease: narrows blood vessels and decreases blood flow. Heart must work harder to deliver blood

– Atherosclerosis occurs when arteries become less

elastic (harder) causes increase in blood pressure but decrease in blood flow

– Smoking causes constriction and therefore increased pressure and decreased blood flow

• Exercise: decreases pressure and resistance while increasing blood flow. Heart does not have to

Heart attack

FPOT

Immune System

Specific

(Specific Defense, Active, Acquired, evolved later)

Non-Specific

(General Defense, inborn, evolved earlier)

 Primary Response: First

exposure causes build-up of antibodies to attack a specific pathogen.

Caused by environment or vaccines

 Secondary Response:

Second exposure, does not cause illness because body has defenses from primary response

 First Defense: Passive

defense that is always protecting

◦ Skin, mucus, hair, sweat

 Second Defense: Active

defense, only active after infection. Does not target specific pathogen –

generally tries to destroy

◦ Interferon

Vaccines and

Antibiotics

• Vaccine: injection with an inactive virus/small amount of virus to trigger primary response. Body builds

defenses so if you get infected, secondary

response prevents illness

• Antibiotics: destroys bacteria in your body

Fertilization and

Implantation

1. An egg (n) is fertilized by a sperm (n) in the oviduct (an egg must have been released into the fallopian tubes for this to occur).

A fertilized egg is called a zygote (2n)

2. As the zygote travels through the oviduct, it develops and gets implanted in the uterus. After implantation, it is referred to as an embryo

Developmental Structures

• Placenta: exchanges

maternal and fetal blood (oxygen, waste)

• Umbilical Cord: connects placenta to fetus

• Amniotic Sac: protective sac where fetus

First Trimester

• Major organs develop • Heart beats

• Highest chance of causing harm to embryo

• By the end of the first trimester, ALL major organs and body systems have

Second Trimester

• Movement

• Reflexes develop, such as swallowing and sucking

Third Trimester

• Languno disappears • Lungs develop

• Body fat forms (warmth after birth) • Fetus arranges itself to prepare for

Birth

– Cervix thins

– Amniotic sac breaks (water breaking)