Asexual Reproduction

1
AsexualReproduction
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• Reproduction not involving the union of gametes
• Ex mitosis
• Ex Budding and Binary fission

3
Binary Fission
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• An asexual cell division of prokaryotes that
  produces identical offspring
• Ex, bacteria dividing by mitosis.

A budding Yeast cell
A dividing bacterium
5

• Sexual Reproduction

6

• Combination of two set of DNA to form
• a diploid organism.

• Can be external as in fish, amphibians or
• internal as in mammals.

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• DNA Replication

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• An exact DNA copy is made.
• A process called semiconservative
• replication because the DNA has one old
• strand on one new strand.

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• The process of DNA Replication

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1. DNA separates at the base pair/hydrogen bond
2. DNA polymerase attaches the complementary DNA
   nucleotides
3. Two identical strands are made, one new and one
   is the old.

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• DNA replication animation

http//www.tracy.k12.ca.us/thsadvbio/OnlineLessons
.htm
http//207.207.4.198/pub/flash/24/menu.swf
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Mitosis
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• A process where chromosomes replicate and are
  separated to separate cells.
• One cell divides into two identical cells
• Diploid number of chromosomes
• Phases of mitosis are prophase, metaphase,
  anaphase and telophase. Two cells result after
  cytokinesis or the divison of the cytoplasm

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• The Cell Cycle

15

• When a cell first is formed to when it divides (
  either by mitosis or meiosis)
• Stages include Interphase
• (growth and DNA replication), Mitosis and
  Cytokinesis

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• Interphase

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• Stage of the cell cycle where the cell is
• G1(first growth) growing in cytoplasm
• S( Synthesis) DNA replication
• G2(second growth) organelles, especially
  centrioles
• replicate.

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• Prophase

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• Phase of mitosis where the nucleus and nucleolus
  begin to disintegrate, the DNA condenses into
  chromosomes and cenrioles begin to separate to
  opposite ends of the cell.

(centrioles)
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• Metaphase

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• Phase of mitosis where the chromosomes ( already
  replicated and look like X) line up ion the
  center ( metaphase plate)

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• Anaphase

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• Phase of Mitosis where the sister chromotids
  separate ( replicate chromosomes) and move to
  opposite ends of the cell. They are moved by the
  spindle fibers retracting into the centriole

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• Telophase

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• Phase of mitosis where the cell begins to pinch
  into two ( animal cells form a cleavage furrow
  and plant cells begin to form a new cell plate).
  Two identical cells are produced. The nucleus and
  nucleolus reform.

Animal cell
Plant cell
Cytokinesis is when there are actually two cells
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• Animal cell Mitosis compared to
• Plant cell mitosis

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Animal Plant

• -Centrioles present - no
  centrioles
• -Centrioles produce spindles -Cytoskeleton
  produces spindles
• -Cleavage furrow (pinching in) -new cell
  plate/wall formed
• to produce 2 cells to
  produce 2 cells

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• Mitosis animation

http//www.ai.mit.edu/lab/olympics/98/events/MITos
is/mitosis-animation.gif http//web.grcc.edu/bios
ci/pictdata/mitosis/planmito.htm (plant)
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Diploid
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• A cell that contains both chromosomes of a
  homologous pair.
• One set of chromosomes from each parent
• Union of an egg (23 chromosomes) and a sprem (23
  chromosomes) results in a zygote with 46
  chromosomes or the diploid number of chromosomes
  ( for humans)

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Somatic
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• Body cells (all except gametes)
• Produced by mitosis
• Have the diploid number of chromosomes or 46 in
  humans
• Ex Skin, muscle, nerve

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Gamete
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• A reproductive cell
• Eggs and sperm cells
• These cells contain the haploid number of
  chromosomes ( half the full set)
• In humans this is 23 chromosomes
• These cells are produced by Meiosis of
• special somatic cells (eggs by oogonia and
  sperm by spermatogonia).
• The Cell Cycle for these
• cells ends with
• gamete formation.

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Haploid
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• Having only one chromosome of each homologous
  pair
• Gametes are haploid or contain 23 chromosomes
• Haploid cells combine to form diploid cells
• as in fertilization ( egg combines with sperm)

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Meiosis
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• The process of nuclear division that reduces the
  number of chromosomes in a cell by half
• In humans, the parent cell of the gametes has 46
  chromosomes (diploid number). This cell divides
  by Meiosis to produce four halpoid cells with 23
  chromosomes.

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• First Division of Meiosis

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• The replicated sets of chromosomes pair up into
  tetrads, the tetrads line up on the metaphase
  plate and are separated. This division results
  in two cells with replicate sets of chromosomes.
  They still need to separate (the second division)

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• Second division of Meiosis

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• From the first division where there are two cells
  with replicate sets of the haploid number of
  chromosomes, the two cells now divide similar to
  MITOSIS and four cells with one copy of a haploid
  set of chromosomes is the result.

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Crossing Over
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• The exchange of genes by reciprocal segments of
  homologous chromosomes during meioses
• This occurs during prophase and metaphase of
  meiosis I.

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• Meiosis animation

http//www.sumanasinc.com/webcontent/animations/co
ntent/meiosis.html
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Fertilization
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• Joining of two gametes to produce a diploid zygote

egg
sperm
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Zygote
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• The diploid cell that results from the fusion of
  gametes

DNA from sperm
zygote
DNA from egg
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RNA
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• A nucleic acid composed of a single strand and
  distinguished form DNA by containing ribose and
  Uracil
• Can be rRNA (ribosomal), mRNA (messenger) and
  tRNA (transfer)
• The function of RNA is to read the code of DNA
  and produce a protein.

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rRNA (ribosomal RNA)
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• The type of RNA found in a ribosome that is
  necessary for the messenger RNA to bind to the
  ribosome for protein synthesis

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tRNA(Transfer RNA)
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• the RNA that match amino acids to the mRNA
• They are free floating in the cytoplasm
• Contain an anticodon ( complement to the
• mRNA codon) that allows it to bind to the
• mRNA.

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mRNA (Messenger RNA)
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• The type of RNA that carries genetic information
  from the nucleus to the ribosome
• DNA is transcribed in the nucleus to mRNA that
  leaves the nucleus to be translated on a
  ribosome.
• DNA A T T A T A T C G C T G
• mRNA U A A UA U A G C G A C

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Ribosome
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• An organelle that functions in the synthesis of
  proteins

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Transcription
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• The process in which RNA is made from DNA
• Ex DNA TTATGCGCTA makes the
• mRNA AAUACGCGAU

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Translation
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• The process of converting the mRNA into the amino
  acid sequence that makes up a protein
• Occurs on the ribosome as the ribosome reads the
  mRNA and finds the start codon AUG to start
  protein synthesis

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Protein Synthesis
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• The formation of proteins using information coded
  on DNA and carried by RNA

• DNA separates
• RNA made from the DNA
• 3. mRNA moves out of
• nucleus to a ribosome
• in the cytoplasm
• 4. Ribosome reads the
• mRNA, finds AUG to
• start protein synthesis
• 5. tRNA bring the right
• amino acid to the mRNA
• 6. The amino acids
• attach to make a protein
• 7. The proteins affect the
• structure and function
• of the cell traits

translation
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• Protein synthesis animation

http//www.tracy.k12.ca.us/thsadvbio/animations/Pr
otein.swf
http//learn.genetics.utah.edu/units/basics/transc
ribe/ Practice protein synthesis
67
Mutations
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• Any change in the genetic message (DNA and RNA)
• Mutations lead to genetic diversity
• Can be a change in only one base (addition,
  deletion, substitution)
• Can be changes in chromosomes
• Can be changes in chromosome
• number.

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Turners Syndrome
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• Genetic disorder caused by a mistake in meiosis.
• A female with only one X-chromosome.
• Missing the second X
• Designated as XO

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Downs Syndrome
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• Genetic disorder caused by a mistake in meiosis.
• Three chromosome 21s, called triosomy 21

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Karyotype
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• A picture of an individual's chromosomes
• Aligned in homologous pairs, by size and location
  of the centromere.

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Dominant
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• An allele that masks the presence of another
  allele
• Ex. Aa is a heterozygous dominant genotype
• Ex. AA is a homozygous dominant genotype
• A is the dominant allele and a is the
  recessive allele

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Recessive
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• An allele that is dominated by the other
• ex. aa is recessive
• A is the dominant allele and a is the
  recessive allele

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Phenotype
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• The external appearance of an organism that is
  determined by the individual genotype

Different phenotypes of the shells
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Genotype
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• The pair of alleles that determine a specific
  trait.
• Ex Aa the allelles are A and a

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Offspring
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• Product of fertilization

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Punnett Square
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• A model used to establish the probabilities of
  the results of a genetic cross

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Homozygous
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• Referring to a gene pair in which the two alleles
  code for the same trait
• AA or aa are homozygous genotypes

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Heterozygous
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• Referring to a gene par in which the two alleles
  do not code for the same trait
• Ex Aa is a heterozygous genotype

91
Monohybrid Cross
92

• A cross between individual that involves one pair
  of contrasting traits

93
Dihybrid Cross
94

• A cross between individuals that involves the
  pairing of contrasting traits

95
Sex Linked
96

• A trait carried on only the x chromosomes

97
Incomplete Dominance
98

• The inheritance relationship that occurs when
  both alleles influence the phenotype

If this was not an incomplete Trait, there would
have been 3 tall and 1 short
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Codominance
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• When neither of two alleles of the same gene
  totally masks the other, they are both expressed
  at the same time.
• More than one dominant allele
• Ex Blood types
• AA type A
• BB type B
• OOType O recessive
• AB Type AB (both are dominant)

101
Polygenic
102

• A trait controlled by multiple genes
• Ex eye color. There is not one gene that
• Determines eye color, but several

103
Multiple alleles
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• When more than alleles code for one trait
• Ex Blood types
• Alleles are A, B , and o Three alleles

105
Alleles
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• Alternative form of a gene, there are two
• Dominant A
• Recessive a

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Pedigree
108

• A diagram of the genetic history of an
  individual, a family tree

109
Gene Splicing
110

• Splicing of two genetic codes
• Taking a piece of DNA and moving it, removing it,
  or replacing it.

111
Electrophoresis
112

• Using electricity to separate DNA on an agarose
  gel. DNA can be visualized a a set of bands that
  were cut by enzymes.
• DNA is cut with enzymes to produce fragments.
• The band run through the getl according to size.
  Small bands travel faster than larger ones.

113
Cloning
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• Process of removing DNA from one organism and
  putting it into another.
• EX the gene for insulin is removed from a pig or
  human and inserted into E.coli bacteria. The E.
  coli then produce the insulin that is purified ,
  bottled, and distributed to people in need. The
  insulin was cloned

115
Biotechnology
116

• Technology used to manipulate DNA, proteins,RNA
  and such.
• EX cloning, DNA fingerprinting, DNA and protein
  sequencing.

117
Genetic engineering
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• A form of applied genetics in which scientists
  directly manipulate genes

119
DNA Fingerprinting
120

• A pattern of bands made up of specific fragments
  from a individual's DNA. The bands are produced
  by putting enzymes or moleculer scissors in
  with the DNA. These enzymes cut the DNA at
  specific sequences producing smaller fragments.
  These fragments can be visulaized by DNA
  electrophoresis.
• http//www.biotech.iastate.edu/biotech_info_series
  /bio6.html