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157 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Interphase has sometimes been called a "resting stage". Why is this inaccurate? |
During interphase, a cell is still undergoing its normal cell functions. It is growing and duplicating its contents. It is resting from mitotic division but it is not resting altogether, |
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Most general functions of a cell occur during G1 of interphase. What events that occur during other phases of the cell cycle might inhibit general metabolism? |
During S phase DNA synthesis occurs; this would impede the metabolic process since the cell would be synthesizing instead of breaking down a substance |
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List the fundamental cellular/structural differences between prokaryotic and eukaryotic cellular replication. What is the basis for these differences? |
poop |
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Some specialized cells such as neurons and red blood cells lose their ability to replicate when they mature. Which phase of the cell cycle do you think is terminal for these cells and why? |
poop |
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Which process is more accurately referred to as nuclear division: meiosis or mitosis? Explain. |
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What special event does does interkinesis lack compared to premeiotic interphase? What would happen if this event did occur? |
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How old is an ovulated oocyte of a 40 year old woman? What consequences does this have? |
40 years old. It's been in her body for forty years so it's more likely to have diseases
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Briefly describe how three different processes that occur during a sexual life cycle increase the genetic diversity of offspring. |
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What determines how often a phenotype occurs in a population? |
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Are dominant characteristics always more frequent in a population than recessive characteristics? Why or why not? |
No. If a dominant allele is selected more often than a recessive one then it will become more common in the gene pool and vice versa. For example, having six fingers is dominant and having five fingers is recessive. However, it is more common for people to have five fingers than six.
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Is it possible to determine the genotype of an individual having a dominant phenotype? How? |
If the individual were to have a child with a recessive individual then their genotype could be determined. |
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What blood types are not expected for children to have if their parents have AB blood? O blood? Explain showing punnet squares. |
AB- can't have O
O- can't have AB, A, or B |
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cell cycle |
-life of a cell -formation of cell -> cell division |
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cell division (mitosis) |
-duplication of chromosomes -sorting chromosomes and other cellular parts into daughter cells |
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functions of mitosis |
-reproduction in single-celled organisms -growth in multi-cellular organisms -repair |
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reduction-division (meiosis) |
-reducing the number of chromosomes in a cell -produces specialized daughter cells- gametes (egg and sperm) |
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Function of meiosis |
gamete production for cellular reproduction |
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eukaryotic cell division |
-larger, more complex than prokaryotes -many genes -multiple chromosomes stored in nucleus -Ex: rice ~ 51,000 genes |
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eukaryotic chromosomes |
-made of chromatin |
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chromatin |
-one long DNA molecule and proteins (structural, packing, and regulatory/ turns genes on and off) -dispersed when cell is not dividing -becomes condensed before cell division |
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chromatin continued |
-visible as chromosomes -before cell division, chromosomes replicate -two copies called sister chromatids form, joined together at centromere |
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cell cycle |
-ordered sequence of events -gradual transitions described as stages |
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Eukaryotic cell cycle stages |
-stage one: interphase -stage two: mitotic phase |
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interphase |
-normal cell functions -majority of cell cycle time -duplication of cell contents |
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mitotic phase |
division of chromosomes |
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Interphase continued |
-G1- cell grows in size -S- chromosomes replicated, centrosomes formed -G2- prepares for division |
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Stages of mitosis |
-prophase -prometaphase -metaphase -anaphase -telophase |
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prophase |
-microtubules emerge from centrosomes, forming spindle fibers -centrosomes move to opposite poles -chromatin condenses into visible chromosomes |
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prometaphase |
-nuclear envelope disappears -spindle fibers attach to centromeres -chromosomes begin to be moved to center |
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metaphase |
-miotic spindle fully formed -chromosomes lined up along metaphase plate -sister chromatids face opposite poles |
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anaphase |
-centromeres come apart -sister chromatids separated and pulled to opposite poles -cell elongates |
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telophase |
-chromosomes unwind -mitotic spindle breaks down -nuclear envelope reforms around the chromosomes at opposite poles -cell begins to divide |
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cytokinesis |
-cells physically separate into two cells -differs in animal and plant cells -animal cells-cell membrane pinches in the middle to form the cleavage furrow -plant cells-cell plate forms between cells -beginnings of new cell wall |
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mitosis is carefully regulated: |
-checkpoints in cell cycle -failure to follow checkpoints can result in uncontrolled mitosis (cancer) |
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asexual reproduction
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-offspring are identical to the original cell or organism
-ex: hydra budding, plant clones |
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sexual reproduction
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-offspring are similar to parents but have variation
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chromosomes in human cells
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-chromosomes are matched in homologous pairs
-somatic (body) cells of each species contain specific number of chromosomes -Ex: humans have 46 chromosomes, 23 homologous pairs |
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chromosomes continued
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-22 pairs are autosomes (regular chromosomes/each member of a pair is same size and same in genetic composition) -1 pair are sex chromosomes (differ in size and genetic composition) (x and y) |
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cells with two sets of chromosomes |
-diploid -somatic cells -skin, liver, etc |
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one set of chromosomes |
-haploid -gametes |
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fertilization restores ___ |
diploid number |
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meiosis |
-reduces chromosome number from diploid to haploid -gamete production -proceeded by chromosome duplication in interphase -cell divides 2 times to form 4 haploid cells |
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prophase 1 |
-chromatin condenses, nuclear envelope breaks down, spindle fibers form -homologous chromosomes become paired in synapsis -exchange segments via crossing over, then separate |
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metaphase 1 |
-spindle microtubules attach to each centromere -sister chromatids still attached at centromere -joined pairs of homologous (tetrads) line up on metaphase plate -orientation of each pair is random |
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anaphase 1 |
-spindle fibers begin to shorten and pull whole centromeres toward poles -tetrads split, each pole receives a member of each homologous pair -chromosomes still exist as replicated sister chromatids -random orientation results in independent assortment -each pole gets a complete set of haploid chromosomes |
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telophase 1 |
-chromosomes are segregated into two clusters, one at each pole -sister chromatids no longer identical due to crossing over -nuclear membrane may reform around each daughter -cytokinesis |
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meiosis II |
-no replication of chromosomes between meiosis I and II -meiosis II resembles normal miotic division |
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prophase II |
nuclear envelope breaks down and second meiotic division begins |
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metaphase II |
spindle fibers bind to both sides of centromere and line up on metaphase plate |
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anaphase II |
spindle fibers contract and sister chromatids move to opposite poles |
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telophase II |
nuclear envelope reforms |
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cytokinesis |
physical separation into two cells |
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final result of meiosis II |
four haploid cells |
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both meiosis and mitosis: |
-start with diploid cells -chromosomes replicate during previous interphase |
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differences between meiosis and mitosis: |
-mitosis--> two genetically identical diploid somatic daughter cells -meiosis--> four genetically unique haploid gametes |
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meiosis and fertilization generate |
diversity |
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diversity due to: |
-synapsis and crossing over in prophase I -random alignment of chromosomes during metaphase I -random fertilization of eggs by sperm |
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total number of combinations of chromosomes in gametes= |
-2n -( n= haploid number) - ~ 8 billion possible combos |
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genetic diversity is raw material for |
evolution |
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asexual reproduction
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-involves mitosis
-creation of genetically identical offspring |
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types of asexual reproduction
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-budding- individual grows off parent
-fission- parents splits into two ~ equal halves -fragmentation and regeneration- small portion breaks off and regrows missing parts -parthnogenesis- development from unfertilized egg |
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advantages of asexual reproduction
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-produce many offspring rapidly
-reproduce without finding mate -individuals genetically suited to environment produce offspring identical to parent (if you do well, offspring will do well) |
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disadvantages of asexual reproduction
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-no genetic variation
-if environment changes, individual may be less suited to new environment |
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sexual reproduction
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-creation of offspring by fertilization
-two haploid gametes fuse --> diploid zygote |
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advantages of sexual reproduction
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-genetically diverse offspring -if environment changes, chance that some individuals well suited to new conditions |
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disadvantages of sexual reproduction |
-genetically diverse offspring (if environmental conditions don't change, offspring may not do as well as you) -risk of disease transmission -must find another individual (usually) |
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some animals alternate between asexual and sexual reproduction in life cycle: |
-ex: water flea -stable summer water conditions/asexual/only females produced -fall unstable water conditions/sexual/males and females produced |
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reproductive tactics in sexually reproductive animals |
-monoecious- both male and female reproductive organs in same individual (hermaphrodites) -may outcross with another individuals (ex: earthworms) -may fertilize own eggs (ex: tapeworms) -advantageous to solitary/less mobile animals -dioecious- male and female reproductive organs in different individuals |
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tactics continued |
-external fertilization: -ex: fish, amphibians -gametes released to environment -fertilization takes place externally -internal fertilization: -ex: mammals, birds -sperm deposited in female -fertilization takes place internally |
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gametogenesis |
-requires meiosis -only occurs in specialized cells in gonads -testes-spermatogenesis -ovaries-oogenesis |
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spermatogenesis |
-testis filled with coiled semineforous tubules -walls of tubules have 2n spermatogonia -spermatogonia --> mitosis --> more spermatogonia + 2n primary spermatocytes (germ cell) |
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spermatogenesis continued |
-primary spermatocytes --> meiosis --> 2 1n secondary spermatocytes at end of meiosis 1 -secondary spermatocytes finish meiosis II --> 1n spermatids -2 spermatids from each secondary spermatocyte -spermatids mature and differentiate into spermatozoa (sperm) |
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oogenesis |
-ovary structure: -2n oogonia (germ cell) -contained in a packet- follicle |
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oogenesis continued |
-oogonia --> mitosis --> 2n primary oocytes packaged in follicles -primary oocytes --> meiosis I to produce a 1n secondary oocyte and a 1n polar body -secondary oocyte gets majority of cytoplasm -polar body disintegrates or may finish meiosis II |
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oogenesis continued |
-secondary oocyte contained in a large, mature (Graafian) follicle -secondary oocyte released during ovulation -if sperm enters finishes meiosis II to produce a haploid ovum (egg) and another polar body |
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spermatogenesis summary |
-produces 4 haploid gametes -gametes are small, motile |
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oogenesis summary |
-produces 4 haploid cells -only 1 becomes the egg -gamete is large, nonmotile |
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Fertilization |
-haploid nuclei of sperm and ovum fuse -form diploid zygote -zygote --> mitosis --> embryo -empty follicle becomes a corpus luteum, producing hormones to support embryo -corpus luteum- "yellow body" -disintegrates if no fertilization |
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asexual reproduction in flowering plants |
-modified roots, stems, leaves -ex: aspen tree roots -ex: strawberry stolons (roots) -ex: kalanchoe plantlets (leaves) |
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sexual reproduction in flowering plants |
-flowers are reproductive organs -typically have four rings (whorls) of parts: -sepals -petals -stamens -carpels |
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sepals |
-outermost, usually green and leaf-like -protection |
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petals |
-usually colorful -attract pollinators -protection |
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stamens |
-pollen formation -anther contains germ cells in pollen sacs -filament-supports anther |
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carpels |
-ovules develop inside ovary -stigma (pollen receptive surface) supported by style |
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plant life cycle
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-alteration of generations:
-multicellular 2n sporophyte --> multicellular 1n gametophyte |
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male gametophytes
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-microgametophytes
-pollen grains |
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female gametophytes
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-megagametophyte
-embryo sac |
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gametophyte generation
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makes gametes --> fertilization --> 2n sporophyte
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pollen formation (male gametogenesis in flowering plants)
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-anthers contains pollen sacs -each pollen sac contains specialized chambers with 2n microspore mother cells -meiosis --> 4 1n microspores -each microspore will divide by mitosis to form a 1n pollen grain (microgametophyte) -2 cells: tube cell + generative cell |
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female gametogenesis in flowering plants |
-embryo sac: -2n megaspore mother cell found within each ovule in ovary -meiosis -> 4 1n megaspores -one survives and the rest are absorbed -remaining megaspore divides by mitosis --> 8 1n nuclei in a 1 celled embryo sac (megagametophyte) |
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pollination |
-pollen placed on stigma -wind, animal pollinators -pollen tube grows through style to reach ovary -2 sperm cells formed from generative cell |
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fertilization |
-occurs in ovule -two fertilizations in flowering plants |
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double fertilization |
-1 sperm nucleus + ovum --> zygote -other sperm nucleus + 2 1n nuclei in embryo sac --> triploid (3n) endosperm ( nutritive tissue for embryo) |
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seed |
-embryonic plant -surrounded by nutritive tissue and protective outer layer -surrounded by mature ovary tissue (fruit/protection and dispersal of embryo) |
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gergor mendel's 1866 experiment |
-used peas because they are easy to grow, have distinguishable characteristics, easy to control crosses |
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experimental design |
-allowed pea plants to self fertilize for several generations (pure-breeding traits) -crossed varieties with alternative forms (ex: crossed purple and white) -permitted hybrid offspring to self fertilize for several generations -kept detailed notes |
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mendel's results
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-parental generation (P):
-monohybrid cross- 1 characteristic at a time (ex: purple X white) -F1 generation (first fillial): -flower color resembled one parent only -all purple -F2 generation (second fillial): -cross between seeds of F1 -3 p: 1 w: -monohybrid cross ratio -1/4 of purple were true breeding -disguised 1:2:1 ratio |
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mendel's model of heredity
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-parents transmit discrete info (factors) to offspring
-each individual receives two factors that may code for same, or alternative, character traits (alleles) -homozygous- two copies of same allele -heterozygous- one copy of two different alleles |
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genotype vs phenotype
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G- totality of an individual's alleles
P- physical appearance |
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Dominant vs recessive allele
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D- always expressed if at least one allele is present
R- only expressed if homozygous (need two copies) (masked by dominant allele in heterozygous) |
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genotypes use same letter for :
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same trait
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F1 generation:
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PP x pp (parental generation) --> all Pp purple
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F2 generation:
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-Pp x pp --> 1:2:1 ratio
-1 PP purple: 2 Pp purple: 1 pp white |
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punnet squares
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show predicted ratios |
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law of segregation |
-inheritance of single character -each individual inherits two alleles, one from each parent -alleles can be same or different |
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law of independent assortment |
-inheritance of two characters -inheritance of one has no effect on inheritance of another -ex: flower color, pea color -allele pairs segregate independently of other allele pairs during meiosis |
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test cross |
-cross of an individual with dominant phenotype -but unknown genotype with a homozygous recessive individual -ex: purple can be PP or Pp -one of two possible predicted results: -pp x PP = 100% (Pp) -pp x Pp = 50% pp : 50% Pp -any recessive phenotype offspring = unknown genotype is heterozygous |
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complete dominance vs incomplete dominance |
C- dominant allele completely masks recessive in heterozygote I- offspring's phenotype is intermediate to the phenotypes of its parents (ex: red x white = pink) |
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multiple alleles |
-many genes have more than two alleles -ex: human ABO blood types -three alleles: I a, I b, i |
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codominance |
-no single allele is dominant -each allele has its own effect, is shown, and is shown fully ex: ABO blood types |
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A blood |
-(I a) (I a) or (Ia i) -A antigens -Anti B antibodies |
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B blood
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-I b Ib or Ib i
-B antigens -Anti A antibodies |
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AB blood
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-I a I b
-make A and B antigens -no antibodies |
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O blood
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-ii
-make no antigens -Anti A and B antibodies |
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A single gene may affect many phenotypes
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-Pleitropy
-Ex: sickle cell anemia -one change in gene --> changes shape of hemoglobin --> RBC shape --> organ damage |
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A single characteristic may be influenced by multiple genes |
-polygenic inheritance -creates range of phenotypes (continuous variation) -ex: human height |
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physical environment can affect phenotype |
-ex: temp affects fur color in siamese cats -only genetic influences are inherited |
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chromosome theory of inheritance |
-principles: -genes occupy specific loci (positions) on chromosomes -chromosomes undergo segregation and independent assortment during meiosis -movement during meiosis and fertilization accounts for inheritance patterns |
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human chromosomes |
-human somatic cells have 23 pairs of chromosomes -22 pairs of autosomes -1 pair of sex chromosomes -Y chromosome has genes for the development of testes -absence of Y chromosomes allows ovaries to form |
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genes on sex chromosomes |
-sex-linked -X chromosome carries genes unrelated to sex (ex: colorblindness, hemophilia, etc) -most sex-linked human disorders are recessive and affect males more often than females |
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a male receiving a single x-linked allele from mom: |
-will have the disorder |
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a female: |
has to receive the allele from both parents to be affected |
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discovery of genetic material |
-proteins or DNA? -both make up chromosomes -1000s different proteins |
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key experiments: |
-frederick griffith -alfred hershey and martha chase |
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griffith's experiment |
-live pathonogenic bacteria injected into mice --> mice died -live harmless bacteria injected into mice --> mice lived -live harmless + dead pathonogenic injected into mice --> mice died -harmless bacteria transformed into pathonogenic |
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Hershey Chase experiment |
-used bacteriophage (viruses that use bacteria as hosts) (viral structure: protein shell with DNA inside) -viral protein shell labeled with radioactive sulfur -viral DNA labeled with radioactive phosphorous |
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hershey chase continued |
-allowed virus to infect bacteria -bacterial host cells make viruses, eventually releasing them -followed fate of radioactively labeled protein and DNA |
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results of hershey chase |
-new viruses had no radioactive proteins -had radioactive DNA -viral DNA was copied to make more viruses -protein shell wasn't used to make new viruses |
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DNA and RNA |
-nucleic acids -polymers of nucleotides bonded together |
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nucleotides consist of: |
-5c sugar (deoxyribose in DNA, ribose in RNA) -phosphate group (same for DNA and RNA) -nitrogenous base (different in DNA and RNA) |
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pyrimidines vs purines |
-pyrimidines-single ring -purines-double ring |
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DNA |
-double stranded -deoxyribose sugar (lacks O2) -nitrogenous bases: adenine, cytosine, thymine, guanine |
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RNA |
-single stranded -ribose sugar -nitrogenous bases: adenine, cytosine, uracil, guanine -3 main types of RNA: -mRNA -rRNA -tRNA |
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rosalind franklin |
-x-ray diffraction -DNA was a double helix with a constant diameter |
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Erwin Chargaff |
-amount of A = T -amount of C = G -base pairing rule |
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James Watson and Francis Crick |
-3D model -double helix -sugar-phosphate backbone -bases pointed inward -pyrimidine-purine pairing gives constant diameter -bases held together with hydrogen bonds |
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DNA replication |
-3D model lead to discovery of how DNA replicates -results in 2 daughter strands of DNA identical to parent strand -helical DNA molecule must first untwist |
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DNA replication continued |
-DNA strands separate -enzymes use each strand as a template -assemble new nucleotides into complementary strands -replication begins at specific sites -origins of replication -proceeds in two directions (see drawing in notes) |
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DNA |
-each strand of double helix is oriented in the opposite direction (antiparallel)
-main enzyme DNA polymerase adds nucleotides in one direction (5 --> 3) |
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leading and lagging strands
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leading- continuous replication
-lagging- replication in short pieces (okazaki fragments) (connected together by the enzyme DNA ligase) |
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biotechnology
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-manipulation of organisms or components to make useful products -ex: agriculture, domestication |
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genetic engineering
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-manipulates genes for practical purposes
-possible because of understanding of DNA structure and replication -gene cloning- produces multiple identical copies of genes/ can use bacteria and plasmids (independent loops of DNA in bacteria)/ ex: human insulin gene |
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gene cloning process
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-isolate gene of interest
-insert gene into plasmid using restriction enzyme - insert plasmid into bacterium (recombinant) -bacterium divides, copying plasmid -used to make many copies of genes or allow bacterium to express gene and make product |
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recombinant (DNA or organism)
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-has DNA from 2 different sources -ex: bacterial plasmid with human insulin gene or the bacterium it's inserted to |
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uses restriction enzymes to insert DNA |
-enzymes that cut DNA at specific sequences -cut ends are sticky, so can be joined together with complementary sticky ends |
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PCR |
-polymerase chain reaction -amplifies DNA to give millions of copies quickly -only needs a small amount of DNA -can amplify only region of interest -uses an enzyme found in hot spring bacteria (taq) |
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PCR process |
-denaturation: DNA heated --> strands separate -annealing: DNA cooled --> primers bind -extension: taq polymerase copies DNA/ heat stable DNA polymerase/ repeat result: exponential increase in number of copies |
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gene therapy |
-removal of non-functioning gene and inserting functional gene to treat genetic diseases |
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one method of gene therapy |
-clone functional gene, insert into virus -virus delivers gene to cells -cells with new gene grow in lab, returned to patient -modified cells replace original cells -works best with single-celled disorders |
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first successful gene therapy in 2000 |
-treated 10 kids with SCID -some helped by treatment -some developed cancer -one died |
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genome and genomics |
-genome: all the DNA of an organism or species - genomics: study of the genome (functions, interactions, product made, relationships) -ex: 96% similarity between humans and chimps |
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human genome project |
-sequenced all DNA of human genome -identify and locate every gene |
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results of human genome project |
-~20,000 genes in 3.2 billion nucleotide pairs -1.5% of DNA codes for proteins, tRNAs, or rRNAs -remaining 98.5% of DNA is noncoding "junk" |
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noncoding "junk" consists of: |
-telomeres- noncoding DNA at ends of chromosomes that help protect chromosomes -transposable elements- DNA segments that can move or be copied from one location to another within or between chromosomes -regulatory regions- control expression (turn genes on or off) -NOT REALLY JUNK |
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process of human genome project |
-whole genome shotgun method- restriction enzymes produce fragments (method is fast and cheap) -fragments cloned and sequenced -computer analysis pieced fragments together -HGP completed early and on budget -similar procedure used in many other organisms |
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proteome and proteomics |
proteome- all proteins produced by genome -proteomics- study of proteins (functions, interactions, etc) -human proteome- ~100,000 proteins |
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Poop |
Sloopy Poopy!!!! |
Sloooooooooop |
