Ap Biology Discussion Notes Friday 12/04
Goals for the Day Be able to describe the stages of the cell cycle (in eukaryotes) Be able to calculate the time a cell spends in each stage. Be able to describe replication & accuracy
Question of the day 12/04 Which phase of Meiosis is more similar to Mitosis?
Meiosis 1 Meiosis II DIFFERENT than Mitosis SIMILAR to Mitosis
Is there much of a difference between sperm & egg cells?
Spermatogenesis
Oogenesis
Let’s Play the Probability Game What are the 2 ways that variation is introduced in the process of Meiosis & when do they happen?
Let’s Play the Probability Game #3. Random Fertilization is the 3 rd source of variation introduced in sexual reproduction. Any sperm could fertilize any egg.
Let’s Play the Probability Game So how many possible gametes can you produce? Crossing over Random assortment Random Fertilization
Twins? Fraternal – 2 separate fertilization events »2 egg & 2 sperm (not genetically identical) Identical - only a single fertilization event »1 egg & 1 sperm (Genetically identical) Conjoined - only a single fertilization event »1 egg & 1 sperm (Genetically identical)
Karyotype #1
Karyotype #2
Can things go wrong in Meiosis?
Karyotype #3
Non-Disjunction Failure of chromosomes (or chromatids) to separate from each other.
Non-Disjunction Can non-disjunction happen in Mitosis?
Amniocentesis
Online Lab analysis
Linked Genes Linked genes – genes close together on the same chromosome. Their relative closeness means that crossing over rarely occurs between these genes, and as a result they tend to be inherited together – traits are not mixed often. Over-representation of parental Phenotypes (physical traits) is distinguishing!
Mitosis Lab What kind of cells were we looking at?
Lab analysis
Keys to success in Mitosis Lab Enter group totals into class data Calculate Percentage of cells counted in each phase and Time in Each stage using GROUP TOTAL AND CLASS TOTAL –% of cells in the stage X 1440 minutes = number of minutes in the stage
Class Total Data