SC15.BIO.12

Science (2015) Grade(s): 09-12 - Biology

Developing and Using Models; Analyzing and Interpreting Data

Patterns; Systems and System Models

Students know:

Chromosomes appearing as an "X" shape are replicated chromosomes consisting of two sister chromatids.
The difference between mitosis and meiosis in terms of chromosome number and number of daughter cells produced.
Crossing over is where chromosomal segments are exchanged when homologous chromosomes are lined up during Prophase I.
Crossing over leads to more genetic variation within the population.
Types of errors that can occur during meiosis that can lead to genetic disorders such as nondisjunction where chromosomes fail to separate properly during Meiosis I or II and result in gametes not having the proper number of chromosomes or in disorders caused by breakage and improper rejoining of chromosome broken ends such as in deletions, insertions, inversions and translocations.

Students are able to:

Develop models of replicated and non-replicated chromosomes and identify important parts of their structure.
Compare diagrams of mitosis and meiosis and list the differences between the two.
Develop a model of chromosome movement at each stage of meiosis.
Determine whether a cell is haploid or diploid.
Evaluate meiosis models, comparing them to the biological process, and identify strengths and weaknesses of the model.
Interpret human karyotypes to identify typical chromosome patterns as well as various large-scale chromosome errors.

Students understand that:

In sexual reproduction, chromosomes can sometimes swap sections during the process of meiosis, thereby creating new genetic combinations and thus more genetic variation.
Errors can occur during meiosis which can lead to genetic disorders.