Category Archives: Meiosis

Week 21

Monday, February 3, 2020 (HS-LS3-1): We took notes on the structure of genes, including a review of how chromosomes are found in the nucleus of cells, how chromosomes consist of DNA coiled around histone proteins, and how genes consist of regulatory regions, exons, and introns.

Biology 200203 Picture

Class concluded with the Crash Course video about heredity (below).  We paused strategically to capture important vocabulary terms (diploid, haploid, somatic cells, gametes) which were added to our vocabulary list from Friday.

Tuesday, February 4, 2020 (HS-LS3-2): To begin class, we watched the Amoeba Sisters video about meiosis (below) and students worked through a guided worksheet.

After the video, students had the remainder of class to read pages 52-59 of Inside the Cell to help them complete the Amoeba Sisters worksheet and to investigate the processes of independent assortment and crossing over.  Students answered the “Got It?” questions on page 59 of the book in their lab notebooks.

To demonstrate evidence of understanding, students were tasked with creating a stop-motion claymation video or Google Slides explaining the processes of independent assortment and crossing over (shared with the teacher).

Wednesday, February 5, 2020: Today is a continuation of yesterday.  Completed videos or slides depicting independent assortment and crossing over are due today.  Students who finish early should begin working on the One Trait Mouse Genetics Gizmo.

Thursday, February 6, 2020: As we enter the final week of Unit 5: Inheritance and Meiosis, we turn our attention toward the process of reproduction.  Class begins with a video which explains the process of human fertilization.  After a brief class discussion about what was learned and what questions remain, students were assigned a reading from the textbook along with the questions below:

In the BSCS textbook, read “Making More People” (p.477-481)

  1. How many ova are found in the ovaries of a newborn baby?
  2. How many ova mature into healthy ova?
  3. Where and when do ova begin maturing?
  4. Where are mature ova fertilized by sperm?
  5. Where are sperm formed?
  6. How long does it take an individual sperm to develop?
  7. How do sperm obtain the energy to swim through the female reproductive tract?
  8. How and why does the male body regulate testicle temperature?
  9. Explain the difference between a zygote, an embryo, and a fetus.
  10. What determines when a woman is ready to begin labor?

Friday, February 7, 2020: Class will begin with a short quiz focusing on:

  • Punnett Square vocabulary
  • Mitosis and meiosis: similarities and differences

After the quiz, students will have the remainder of the class period to complete and turn in any remaining work from this week.  Students who finish early should work on the single-trait Punnett Square Gizmo handed out last Friday.


Week 20

Monday, January 27, 2020: No School (Semester Break)

Tuesday, January 28, 2020: Welcome to second semester!  A new semester brings fresh start and a new unit.  Before we dive in, we will roll out a new seating chart, welcome new faces to our classroom, review the class Syllabus and Safety Contract and hold a class discussion around expectations this semester.

Next, we launched Unit 3 (Heredity: Inheritance and Variation of Traits) with the following entry task:

In your lab notebook, list at least 5 traits that best describe who you are.

After responding to the entry task, students worked with their table teams and together they debated whether a list of traits provided on a worksheet are inherited via nature, nurture, or both.  We came back together as a class so students could share their thinking and hear each others ideas.

Class concluded with the following assignment, due tomorrow:

Using your list of traits from the entry task, write an explanation about which of your traits are nature, which are nurture, and which are both.  Explain your thinking!

Notes from class:

Biology 2020128 Notes 1

Biology 2020128 Notes 2
Selected traits with student ideas captured during concluding class discussion

Wednesday, January 29, 2020: Yesterday, we debated whether a variety of traits are obtained through nature (DNA) or nurture (culture). During our class discussion at the end of class, we determined the trait of sleep pattern was likely caused by both nature and nurture.  We will begin class with the TedEd video below to provide evidence to support the claim that sleep pattern is indeed a product of both DNA and culture:

In today’s lesson, we used a case study about cystic fibrosis as the mechanism to:

  • review Central Dogma (from way back in Week 5!) and introduce the stop codon;
  • connect the concepts of protein structure and function;
  • bring a human face to a genetic disease;
  • and help students recall the mechanism of genetic inheritance.

For the entry task, students were challenged to consider how genes begin and end.  We discussed how mRNA sequences always begin with AUG (which codes for methionine, and amino acid which may also occur elsewhere in a protein).  Students were then reminded of the three “stop codons” and we reviewed how those work to release a protein from the ribosome.  We reviewed the structure of amino acids, focusing on the 20 different R groups and how those R groups each have different properties.  The interactions between R groups determine protein shape, and shape determines protein function.  When the sequence changes, the shape changes, thus changing the function of a protein.  We then moved into the cystic fibrosis case study, first watching the video below and then working through the lesson PowerPoint.

Class notes:

Week 21 Picture 1

Week 21 Picture 2

Thursday, January 30, 2020 (HS-LS3-2): For day one of our two-day lesson on the structure and function of genes, we reviewed Central Dogma via the first two slides of today’s PowerPoint.  Next, we dug into the vocabulary of proteins, revisiting words like amino acid, peptide, polypeptide, protein, and peptide bonds.  Students learned that proteins fold into specific structures (shapes) and that a protein’s structure determines its function.  Next, we reviewed the structure of amino acids, and students received a handout with the names and structures of all 20 amino acids.  We drew a model of two amino acids bonding via dehydration synthesis and forming a peptide bond.  We then defined the R group for an amino acid and discussed how each amino acid contributes to the overall shape of a protein.  Finally, we connected this review of Central Dogma back to the idea of traits by considering how DNA mutations can affect proteins, sometimes with drastic consequences.

Class Notes:

200130 Bio Pic1

200130 Bio Pic2

Friday, January 31, 2020 (HS-LS3-3): For our entry task today, students worked through the Friday Quiz (click here!) using the class Chromebooks.  After the quiz, we previewed single-trait Punnett Squares to prime students for next week.  Class notes are provided below:

200131 Biology Pic 1

200131 Biology Pic 2

200131 Biology Pic 3


Chromosome Project

Welcome to the Chromosome Project!  Today you have the opportunity to select a chromosome for further research.  The goal of this project is to help you make a clear connection between DNA, genes, chromosomes, traits, and inheritance.

Your goals for Days 1 and 2 are as follows:

  1. Select one of the human chromosomes to research (autosomal chromosomes = 1-22 and the sex chromosomes are X and Y).
  2. Research and write down what happens during human development if more than two copies of the chromosome are present.  What happens if only one copy of the chromosome is present?  Be sure to document your sources!  One resource is the Wikipedia entry on aneuploidy.
  3. Conduct a search for “genes on chromosome____” and insert your selected chromosome.
  4. Research at least 5 genes on your chromosome.  Research = write it down!  You must document your work to receive credit.  For each gene, write down the key information about each gene.  How?  Read below:

To research your gene, visit the NCBI Human Genome Resources page and enter your gene name into the “Search For Human Genes” box.  When the search completes, click on your gene name (typically the first gene on the list) and browse through the entry.  There is a ton of information provided!  For each gene, write down the following:

  • Official Symbol
  • Official Name
  • Your own one-sentence summary of about the protein the gene codes for
  • Location of the gene on the chromosome
  • Number of exons in the gene
  • Length of the gene (in DNA bases) – hover your mouse over the top green line under the “genomic regions, transcripts, and products” and looking for the number after the word “length”)  
  • Length of the protein (in amino acids) the gene codes for – the length of the amino acid sequence can be found by clicking on the word “protein” on the right hand side of the page under Related Information.  Browse the entries for the full-length protein and note the number of amino acids in the protein.  The full-length protein can be challenging to find: look for an entry that does not include words like truncated, isoform, predicted, synthetic construct, or unnamed protein product.

Day 3: Select one of the genes from your list.  Research one trait associated with that gene and explain the connection between the gene and the trait.  For your final work, create a poster with the following information:

  • Chromosome
  • Brief description of what happens with too many or too few copies of the chromosome
  • For the gene you researched the most (and have trait information for):
    • Official Symbol
    • Official Name
    • Your own one-sentence summary of about the protein the gene codes for
    • Location of the gene on the chromosome
    • Number of exons in the gene
    • Length of the gene (in DNA bases)
    • Length of the protein (in amino acids)
    • Description of trait and how that is connected with your gene


Down Syndrome Case Study

Next, we transitioned in to the lesson about Down Syndrome.  We discussed the first three slides of the Down Syndrome Case Study slide deck and then detoured to the Wikipedia entry on aneuploidy.  We focused on the Types section of the entry, examining how, of the autosomal chromosomes, only Trisomy 21 will result in a viable fetus most of the time.  Students learned that when trisomy occurs in most of the other autosomal chromosomes, the result is an embryo that is non-viable, often resulting in miscarriage.

Back to the Case Study!  To learn how Trisomy 21 occurs, students watched a short video illustrating non-disjunction.  To put a human face on Trisomy 21, or Down Syndrome, students watched another short video about two young twins with Down Sydrome.  Both videos are shown below:

The second video naturally leads to questions about twins, so slide 5 explains the difference between identical and fraternal (non-identical) twins.  After slide 5, students received an article to read and annotate with questions about the connection between Down Syndrome and Alzheimer’s Disease.

Review Comparing Mitosis and Meiosis

With our next quiz rapidly approaching (tomorrow!) we used the first half of class to compare mitosis and meiosis.  Our work is shown below:

After the review, students had the opportunity to complete the dihybrid cross Gizmo.  Those who finished received a copy of a dihybrid cross practice worksheet for further review.  A copy of the completed front side of the worksheet can be viewed by clicking here.

Diybrid Crosses (two-trait Punnett Squares)

As a review from last week’s  work on monohybrid crosses (single-trait Punnett Squares) and to extend student learning of Punnett Squares to dihybrid crosses (two- traits Punnett Squares), we began class with the following video by Mr. Anderson of Bozeman Science:

We then applied these concepts to a Two-Trait Punnett Square Gizmo in which students worked together in pairs to complete a work packet which included an additional review and application of the vocabulary learned thus far.

Notes from the white board for determining the alleles in a diybrid cross:

Modeling Meiosis

We reviewed problems 1, 2, 8, and 9 from yesterday’s Punnett Square worksheet at the start of class (work shown at the bottom of the post).  Next, we watched the Amoeba Sisters video about meiosis (below) and students worked through a guided worksheet.  After the video, students had the remainder of class to use the Inside the Cell books to help them complete the worksheet and to investigate the processes of independent assortment and crossing over.

Students then had the remainder of class to complete the worksheet, complete the meosis reading assignment from last Thursday, and to get both assignments checked off in Illuminate.

EOC Review: Unit 4 Review / Research and Explore

With several students in each of my classes absent because of the Algebra EOC, we used the class period to review a variety of concepts up through Unit 4.  Students reviewed the water, carbon, and nitrogen cycles by reviewing posters they had made earlier in the school year.  For students who were absent, an example of one poster is provided below:


We also reviewed genetics (vocabulary, single-trait Punnett Squares, and dihybrid crosses) along with mitosis, meiosis, and fertilization.


Students in attendance also received a copy of the EOC-style writing prompt called Research and Explore.  We spent a few minutes discussing the prompt and looking at the rubric, and students are welcome to practice working through the prompt as homework.  The prompt will not be collected as homework.

Variation and Inheritance: Unit 4 Exam

To conclude Unit 4, students received an April Fool’s packet consisting of a set of instructions, the 2014 Biology End of Course practice exam, and the Unit 4 Exam.  Due to some confusion on behalf of our substitute on Friday, April 1, many students needed additional clarification of the packet instructions, as well as additional time to complete the quiz.  So on Monday, April 11 (after Spring Break), students had the class period to complete the quiz and other missing work.  Quarter 3 grades will be entered into Illuminate tomorrow after school (April 12), so all student work must be in my possession by the end of the school day tomorrow to count toward the quarter grade.  A list of recent assignments was written on the white board all day today as a reminder to students and a picture of the list is shown below: