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Hypothesis-Driven Science. As a formal process of inquiry, the scientific method consists of a series of steps. The key element of the scientific method is hypothesis-driven science. Revise and repeat. Observation. Question. Hypothesis. Prediction. Experiment. Figure UN1-4. - PowerPoint PPT Presentation
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Hypothesis-Driven Science– As a formal process of inquiry, the scientific method
consists of a series of steps.• The key element of the scientific method is
hypothesis-driven science.
Observation Question Hypothesis Prediction Experiment
Revise and repeat
Reporting the Results of Experiments
• Abstract• Introduction• Materials and Methods• Results• Discussion• Literature Cited
A scientific research report is a form of communication in which the investigator succinctly presents and interprets data collected in an investigation.
Introduction• General background information relevant to the topic• Information specific to your hypothesis• A short description of the hypothesis• A description of how you proposed to test the
hypothesis• Predictions of expected supportive for falsifying
results
Cellular ReproductionCell division- A process in which a cell divides into 2 or more cells.
Functions of cell division:*reproduction (at the cellular level and organismal level) *growth and development *repair
Mitosis- The process of nuclear division that results in two daughter nuclei genetically identical to the parent nucleus.
Chromosome Structure●Chromosome
unduplicated vs. duplicated● Centromere● Sister Chromatids
(a)
LM
(b)
(c)
(d)
Phases of Mitosis
A. Interphase B. ProphaseC. Metaphase D. Anaphase E. Telophase
Cellular ReproductionIn asexual reproduction:Formation of new individuals from cell(s) of a single parent resulting in offspring that are genetically identical to the parent.
Asexual ReproductionFUNCTIONS OF CELL DIVISION
Sea stars
LM
Amoeba African Violet
Sexual reproduction requires fertilization by the fusion of gametes, producing offspring that are genetically distinct from both parents.
Cellular Reproduction
MeiosisMeiosis – A type of cell division in which one diploid parent cell (2n) produces four haploid (n) daughter cells.
• Haploid – cell or organism that contains one complete set of chromosomes (n).
• Diploid - cell or organism that contains two complete sets of chromosomes (2n).
Meiosis
MEIOSIS I
Sisterchromatidsseparate.
MEIOSIS II
Homologouschromosomesseparate.
INTERPHASE BEFORE MEIOSIS
Sisterchromatids
Duplicated pair ofhomologouschromosomes
Chromosomesduplicate.
Pair of homologouschromosomes indiploid parent cell
MeiosisMEIOSIS I:
Sister chromatidsremain attached
Pair ofhomologouschromosomes
INTERPHASE
Sisterchromatids
Homologouschromosomespair up andexchangesegments.
Chromosomesduplicate.
Pairs of homologouschromosomesline up.
Pairs of homologouschromosomessplit up.
Nuclearenvelope
Chromatin
Centromere
Microtubulesattachedto chromosome
Sites of crossing over
Spindle
Centrosomes (with centriolepairs)
PROPHASE I METAPHASE I ANAPHASE I
TELOPHASE II AND
CYTOKINESIS
Sister chromatidsseparate
ANAPHASE II
Cleavagefurrow
TELOPHASE I AND
CYTOKINESIS
Two haploidcells form;chromosomesare stilldoubled.
MEIOSIS II: SISTER CHROMATIDS SEPARATEPROPHASE II METAPHASE II
During another round of cell division, the sisterchromatids finally separate; four haploiddaughter cells result, containing single
chromosomes.
Haploid daughtercells forming
Meiosis
Metaphase I
Metaphase II
Recombinant chromosomes
Gametes Recombinant chromosomescombine geneticinformation fromdifferent parents.
Homologous chromatidsexchange correspondingsegments.
Sister chromatids remain joined at theircentromeres.
Prophase Iof meiosis
Duplicated pair ofhomologouschromosomes
Chiasma, site ofcrossing over
Spindlemicrotubule
Crossing overIn crossing over:
•Homologous chromosomes exchange genetic information •Genetic recombination, the production of gene combinations different from those carried by parental chromosomes, occurs
MeiosisHow do we account for genetic variation?
*Independent assortment *Crossing over *Random fertilization
Independent Assortment:
Cross over:
Mitosis and Meiosis
Energy, Catalysis and BiosynthesisMetabolism
*catabolism
*anabolism
Complexity of metabolism
*potential energy
Enzymes–Metabolism is the total of all chemical reactions in an organism.–Most metabolic reactions require the assistance of enzymes, proteins that speed up chemical reactions.
Induced Fit
Enzymes
Enzymes
Substrate
Substrate
Substrate
Active site
Active site
Active site
Inhibitor
Inhibitor
Enzymes Physical and chemical properties affect enzyme activity:
*inhibitors
*cofactor*coenzyme
*activators