Asexual Reproduction

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

Binary Fission

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

A dividing bacterium A budding Yeast cell

Sexual Reproduction

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

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

DNA Replication

• An exact DNA copy is made.

• A process called “semiconservative replication” because the DNA has one old strand on one new strand.

The process of DNA Replication

1.

2.

3.

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

DNA replication animation

http://www.tracy.k12.ca.us/thsadvbio/OnlineLessons.htm

http://207.207.4.198/pub/flash/24/menu.swf

Mitosis

• • • • 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

The Cell Cycle

• 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

Interphase

• 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.

Prophase

• 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)

Metaphase

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

Anaphase

• 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

Telophase

• 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

Animal cell Mitosis compared to Plant cell mitosis

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

Mitosis animation

http://www.ai.mit.edu/lab/olympics/98/events/MITosis/mitosis-animation.gif

http://web.grcc.edu/biosci/pictdata/mitosis/planmito.htm

(plant)

Diploid

• • • 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)

Somatic

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

Gamete

• • • • • 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.

Haploid

• 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)

Meiosis

• • 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.

First Division of Meiosis

• 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)

Second division of Meiosis

• 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.

Crossing Over

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

Meiosis animation

http://www.sumanasinc.com/webcontent/animations/content/meiosis.html

Fertilization

• Joining of two gametes to produce a diploid zygote egg sperm

Zygote

• The diploid cell that results from the fusion of gametes DNA from sperm = zygote DNA from egg

RNA

• • • 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.

rRNA (ribosomal RNA)

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

tRNA (Transfer RNA)

• • • 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.

mRNA (Messenger RNA)

• • 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

Ribosome

• An organelle that functions in the synthesis of proteins

Transcription

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

Translation

• • 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

Protein Synthesis

• The formation of proteins using information coded on DNA and carried by RNA translation 1. DNA separates 2. 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

Protein synthesis animation

http://www.tracy.k12.ca.us/thsadvbio/animations/Protein.swf

http://learn.genetics.utah.edu/units/basics/transcribe/ Practice protein synthesis

Mutations

• • • • 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.

Turner’s Syndrome

• • • • Genetic disorder caused by a mistake in meiosis.

A female with only one X-chromosome.

Missing the second X Designated as XO

Down’s Syndrome

• • Genetic disorder caused by a mistake in meiosis.

Three chromosome 21s, called triosomy 21

Karyotype

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

Dominant

• 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

Recessive

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

Phenotype

• The external appearance of an organism that is determined by the individual genotype Different phenotypes of the shells

Genotype

• The pair of alleles that determine a specific trait.

• Ex: Aa the allelles are A and a

Offspring

• Product of fertilization

Punnett Square

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

Homozygous

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

Heterozygous

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

Monohybrid Cross

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

Dihybrid Cross

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

Sex Linked

• A trait carried on only the x chromosomes

Incomplete Dominance

• 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

Codominance

• • 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 OO=Type O recessive AB = Type AB (both are dominant)

Polygenic

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

Multiple alleles

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

Alleles

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

Pedigree

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

Gene Splicing

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

Electrophoresis

• • • 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.

Cloning

• • 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”

Biotechnology

• • Technology used to manipulate DNA, proteins,RNA and such.

EX: cloning, DNA fingerprinting, DNA and protein sequencing.

Genetic engineering

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

DNA Fingerprinting

• 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