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Questions and Answers
What is the primary focus of the lab report due on Nov. 22?
What is the primary focus of the lab report due on Nov. 22?
The final draft of the lab report is due on November 8.
The final draft of the lab report is due on November 8.
False
What are the required sections of the lab report?
What are the required sections of the lab report?
Lab Report Cover, Introduction, Materials and Methods, Results, Discussion, References
The process of measuring absorbance or transmittance of a solution using a spectrophotometer is called __________.
The process of measuring absorbance or transmittance of a solution using a spectrophotometer is called __________.
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Match the following phases of mitosis with their descriptions:
Match the following phases of mitosis with their descriptions:
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During the lab skills session, students will perform which of the following tasks?
During the lab skills session, students will perform which of the following tasks?
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Crossing over is important for genetic diversity during meiosis.
Crossing over is important for genetic diversity during meiosis.
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In which kingdom do organisms undergo meiosis in specialized structures called gametangia?
In which kingdom do organisms undergo meiosis in specialized structures called gametangia?
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In animals, gametes are produced through a process that includes two rounds of DNA replication.
In animals, gametes are produced through a process that includes two rounds of DNA replication.
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What are the end products of meiosis?
What are the end products of meiosis?
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During _______ I, homologous chromosomes separate and each daughter cell receives one of the sister chromatids.
During _______ I, homologous chromosomes separate and each daughter cell receives one of the sister chromatids.
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Match the stages of meiosis with their descriptions:
Match the stages of meiosis with their descriptions:
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What is the main difference between mitosis and meiosis?
What is the main difference between mitosis and meiosis?
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Meiosis results in diploid cells.
Meiosis results in diploid cells.
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How many chromosomes are present in human somatic cells?
How many chromosomes are present in human somatic cells?
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Gametes are __________ cells that contain half the number of chromosomes as somatic cells.
Gametes are __________ cells that contain half the number of chromosomes as somatic cells.
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Match the organisms with their chromosomal numbers:
Match the organisms with their chromosomal numbers:
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Which of the following statements about homologous chromosomes is true?
Which of the following statements about homologous chromosomes is true?
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Chromatin refers to highly condensed DNA structures.
Chromatin refers to highly condensed DNA structures.
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What term describes the complete collection of all the genetic information of a cell?
What term describes the complete collection of all the genetic information of a cell?
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A pair of _________ chromosomes contains hereditary information for the same traits.
A pair of _________ chromosomes contains hereditary information for the same traits.
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What is the primary purpose of interphase?
What is the primary purpose of interphase?
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Mitosis is the phase where the cell grows in size and undergoes metabolic activities.
Mitosis is the phase where the cell grows in size and undergoes metabolic activities.
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What occurs during the S phase of interphase?
What occurs during the S phase of interphase?
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During the G1 phase, each chromosome is a ______ structure.
During the G1 phase, each chromosome is a ______ structure.
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Match the subphase of mitosis to its description:
Match the subphase of mitosis to its description:
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Which phase occupies the majority of the cell cycle?
Which phase occupies the majority of the cell cycle?
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Cytokinesis is the division of the nucleus.
Cytokinesis is the division of the nucleus.
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What are sister chromatids?
What are sister chromatids?
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Humans have _____ pairs of homologous chromosomes.
Humans have _____ pairs of homologous chromosomes.
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Which event happens first during mitosis?
Which event happens first during mitosis?
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What happens during prophase of mitosis?
What happens during prophase of mitosis?
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During metaphase, chromatid pairs are pulled apart and move to opposite poles.
During metaphase, chromatid pairs are pulled apart and move to opposite poles.
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What structure facilitates the separation of sister chromatids during anaphase?
What structure facilitates the separation of sister chromatids during anaphase?
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The _____ begins to form during prophase, made of microtubules.
The _____ begins to form during prophase, made of microtubules.
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What role do kinetochores play during prometaphase?
What role do kinetochores play during prometaphase?
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During cytokinesis, animal cells undergo cleavage furrow formation.
During cytokinesis, animal cells undergo cleavage furrow formation.
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What happens to chromosomes during telophase?
What happens to chromosomes during telophase?
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In _____, the nuclear envelope is disassembled and chromosomes are maximally condensed.
In _____, the nuclear envelope is disassembled and chromosomes are maximally condensed.
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Which two structures are involved in the orientation of chromosomes during mitosis?
Which two structures are involved in the orientation of chromosomes during mitosis?
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Study Notes
Lab 12: Mitosis and Meiosis
- Lab 12 covers mitosis and meiosis, focusing on Fall 2024 materials.
- Students have 20-minute lab slots.
- Students will be assigned a station randomly.
- The procedures for each station are similar but use slightly different materials.
- Multiple tables and stations have the same setup.
Lab Skills
- Lab skills include microscopy, pipetting and weighing, and spectrophotometry.
- Microscopy involves identifying images on slides (using a compound microscope).
- Pipetting and weighing involves transferring solution volumes, and weighing.
- Spectrophotometry includes measuring absorbance/transmittance at varying wavelengths (knowing how to blank/change mode).
Lab Report
- The lab report topic is Photosynthesis, focusing on exercises 6.3 and 6.4 from class.
- Lab 10 PowerPoints on Scientific Writing should be reviewed.
- A rubric and example reports will be provided.
- The required sections of the lab report are: cover page, introduction, materials and methods, results, discussion, and references.
Goals of this Lab
- Students need to understand differences and similarities between mitosis and meiosis.
- Students need to identify the phases of mitosis in plant and animal cells.
- Students will describe mitotic differences in plant and animal cells.
- Students should understand the crossing over process.
- Models will be used to learn mitosis and meiosis steps.
- Pictures of both animal and plant cells in all stages of mitosis will be drawn.
Mitosis vs. Meiosis
- Mitosis is part of the cell cycle.
- Mitosis generates two genetically identical cells.
- Mitosis happens when an organism grows in size or old cells need to be replaced.
- Meiosis takes place in sexually reproducing organisms.
- Meiosis reduces diploid chromosome number in half to create haploid cells.
Chromosomes
- The genome includes all genetic information (genes + non-genic regions).
- DNA can exist as chromatin or condensed chromosomes.
- The number of chromosomes varies in organisms (e.g., humans (2n=46), chimpanzee (2n=48), apples (2n=34)).
- Somatic cells have pairs of homologous chromosomes (diploid—2n).
- Gametes (sperm and ova) are haploid (n) with half the chromosomes as somatic cells.
Chromatin vs. Chromosome
- A diagram illustrates the difference between chromatin and chromosomes.
- Chromatin is a complex of DNA and histone proteins.
- A condensed chromosome is a highly packed chromatin structure.
Homologous Chromosomes
- Homologous chromosomes have similar size, shape, centromere location, and hereditary information (traits).
- One homologue is inherited from each parent.
- Homologous chromosomes carry information for the same traits but with variations.
Eukaryotic Cell Cycle
- Interphase occupies 90% of the cell cycle, including growth, metabolism, DNA duplication, and preparation for mitosis.
- Interphase has subphases: G1, S, and G2.
- Mitotic (M) phase involves nuclear division (mitosis) and division of cytoplasm (cytokinesis).
- The division of a cell is both nuclear and cytoplasmic; the main goal of mitosis is to divide the nucleus and then the cytoplasmic material to produce daughter cells that are the same as the parent cell (this includes the same number of chromosome copies).
M Phase - Two Major Events
- Mitosis involves nuclear division.
- Mitosis separates the sister chromatids.
- Mitosis is a continuous process with five subphases: prophase, prometaphase, metaphase, anaphase, and telophase.
- Cytokinesis is the division of the cytoplasm.
How the Cell Cycle Works
- A diagram illustrates the cyclical process of the cell cycle.
- Interphase includes stages G1, S, and G2.
- Mitotic (M) phase has stages mitosis and cytokinesis.
- Different events (e.g., chromosomes condensing, spindle formation, chromosome alignment) occur in each phase.
Exercise 7.1: Modeling the Cell Cycle and Mitosis in an Animal Cell
- Students will model the cell cycle and mitosis stages using pop beads and magnetic centromeres.
- Stages to model and identify these are provided in the slide.
- Definitions for a list of terms will be used and analyzed in the exercises.
Prophase
- Chromosomes condense.
- The nuclear envelope breaks down.
- Nucleolus disappears.
- Mitotic spindle begins to form.
- Microtubules form cables, extending toward centromeres.
Prometaphase
- Nuclear envelope is disassembled.
- Chromosomes are at their most condensed.
- Two kinetochores are present (which are attached to spindle fibers).
- Spindle fibers attach to kinetochores.
Metaphase
- Spindle apparatus is assembled.
- Chromosomes line up at the spindle's equator.
- This alignment is known as the metaphase plate, in between the two poles of the cell.
Anaphase
- Centromeres separate, pulling sister chromatids apart.
- Sister chromatids are pulled to the opposing spindle poles.
Telophase
- Chromosomes decondense (lose visible form).
- A new nuclear envelope forms around each set of chromosomes.
- Nucleoli are reformed.
- Spindle apparatus disassembles.
Cytokinesis
- Cytoplasm divides.
- This produces twin daughter cells with identical genetic makeup.
- Animal cells have cleavage furrows, while plant cells have cell plate formation.
Results of Mitosis
- Two daughter nuclei are produced, identical to the parent cell's chromosomes.
- Chromosomes in the daughter cells are unduplicated (to be replicated later).
Exercise 7.2: Observing Mitosis and Cytokinesis in Plant Cells
- Students observe onion root tip slides for mitosis.
- Students will diagram each phase identified in the slides to determine if it is in interphase or part of mitosis/cytokinesis.
- Stages to look for are provided.
Allium (onion) root tip, L.S.
- Images of prepared Allium (onion) root tip slides at 40X and 100X magnification are included for study purposes.
Whitefish Blastula, Section
- Images of whitefish blastula, sectioned at 40X and 100X are included for study.
Whitefish Interphase, Prophase, Metaphase, Anaphase, and Telophase
- Images of whitefish cells in the phases are included for study purposes.
- These slides provide different examples to distinguish and recognize particular stages of mitosis.
Exercise 7.3: Observing Chromosomes, Mitosis and Cytokinesis In Animal Cells
- Students locate and diagram phases of mitosis in animal cells.
- Diagrams of different animal cells in specific mitosis phases are included for study.
Meiosis and the Life Cycle of Sexually Reproducing Organisms
- Meiosis and fertilization alternate.
- Meiosis is critical for chromosome number maintenance.
- Meiosis is vital in multicellular eukaryotes (e.g., fungi, plants, animals).
- Stages of meiosis and fertilization vary across organisms.
Meiosis in Animals vs. Plants
- Differences in meiosis between animal and plant cell organization, timing, and location of events are analyzed.
Key Terms in Meiosis
- Key terms for meiosis are provided and analyzed in the study of specific slides.
The Stages of Meiosis
- Meiosis involves two successive rounds of nuclear divisions (meiosis I and meiosis II).
- Meiosis I separates homologous pairs (and sister chromatids do not separate at this stage).
- Meiosis II separates sister chromatids.
Crossing Over
- Crossing over occurs by the exchange of genetic material between non-sister chromatids.
- This exchange happens during synapsis in prophase I.
- This exchange contributes to genetic variation.
Prophase I, Metaphase I, Anaphase I, and Telophase I
- Events distinctive from mitosis happen in these phases of meiosis.
- Diploid cells undergo events to create haploid cells for sexual reproduction.
Prophase II, Metaphase II, Anaphase II, and Telophase II
- These stages function analogously to their mitosis counterparts.
- Sister chromatids are separated and diploid cells begin to have their chromosomes replicated into haploid daughter cells.
- Meiosis II results in four haploid cells.
Exercise 7.4: Modeling Meiosis
- Specific lab instructions for building models are included.
Exercise 7.5: Meiosis in Sordaria fimicola: A Study of Crossing Over
- This activity focuses on studying crossing over in the Sordaria fimicola organism.
- Students analyze images of Sordaria to determine if crossing over occurred, and draw diagrams of the cells that show that.
Parental and Crossover Phenotypes
- Images demonstrate various phenotypic outcomes in the laboratory exercise.
Exercise 7.5 (cont.) Summary of Outputs:
- Students will complete a post-lab assignment: create flashcards and submit definitions.
- Notes in the notebook include diagrams, questions, and a table.
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Related Documents
Description
Test your understanding of key concepts related to the lab report, including required sections and the process of measuring absorbance. Additionally, assess your knowledge of mitosis and meiosis, including descriptions, phases, and genetic diversity.
