More On Cell Division Annotated for 5-E Learning Cycle Engage Explore Explain Elaborate Evaluate

Engage Capture student interest and establish the “need to know” to motivate learning using devices such as: Capture student interest and establish the “need to know” to motivate learning using devices such as: Novelty Novelty Relevance Relevance Puzzle/Challenge Puzzle/Challenge Provide question that can be answered with science Provide question that can be answered with science

What if you got paid… Just 1 sen per week. Just 1 sen per week. Every week your pay doubles. Every week your pay doubles. How much would you be paid the 4 th week? How much would you be paid the 4 th week? 1 sen, 2 sen, 4 sen, 8 sen… 1 sen, 2 sen, 4 sen, 8 sen… How much would you be paid the 10 th week? How much would you be paid the 10 th week? 1, 2, 4, 8, 16, 32, 64, RM 1.28, 2.56, , 2, 4, 8, 16, 32, 64, RM 1.28, 2.56, 5.12 How much would you be paid the 16 th week? How much would you be paid the 16 th week? RM10.24, 20.48, 40.86, 81.72, , RM10.24, 20.48, 40.86, 81.72, , Geometric Progression

Fertilization Zygote Gametes SpermOvum

In sexual reproduction, reproductive cells combine— In sexual reproduction, reproductive cells combine— female — ovum, male — sperm What would happen if the reproductive cells each had the same number of chromosomes as the parent’s body cells? What would happen if the reproductive cells each had the same number of chromosomes as the parent’s body cells? This Leads To A Question What happens so that living things avoid having too many chromosomes from sexual reproduction?

Expression Not always included—or, sometimes included as part of “Engagement” or as part of “Exploration” Not always included—or, sometimes included as part of “Engagement” or as part of “Exploration” Focus is on student prior knowledge. Focus is on student prior knowledge. Provides opportunity for students to express their own ideas—may be to self, but better if it is recorded and shared Provides opportunity for students to express their own ideas—may be to self, but better if it is recorded and shared When possible, having students generate a prediction is a good way to allow expression. When possible, having students generate a prediction is a good way to allow expression. May not always be in words. May be in pictures students draw, choices students make, or other ways of expressing what they know. May not always be in words. May be in pictures students draw, choices students make, or other ways of expressing what they know.

Explore Activates prior knowledge and “schema” Activates prior knowledge and “schema” Allows some open-ended and/or interactive exploration of ideas to be studied Allows some open-ended and/or interactive exploration of ideas to be studied Should be interactive to the extent students are prepared for Should be interactive to the extent students are prepared for Follows “ABC” rule—Activity Before Content Follows “ABC” rule—Activity Before Content Best when exploration makes use of science processes (e.g., observation, inferences, prediction, measurement) Best when exploration makes use of science processes (e.g., observation, inferences, prediction, measurement) Best if process of exploration makes use of several media (text, visuals, physical models, etc.) Best if process of exploration makes use of several media (text, visuals, physical models, etc.)

As we begin… Let’s review the stages of cell division as we already know them… Let’s review the stages of cell division as we already know them… Interphase Interphase Prophase Prophase Metaphase Metaphase Anaphase Anaphase Telophase Telophase These are the stages of… These are the stages of…

Mitosis Video 1 Video 2

A B C DE F A B C D E F

A B C DE F A B C DE F

What happens so that living things avoid having too many chromosomes from sexual reproduction? ? Somatic Cell 2n=23 pairs=diploid kary

What happens so that living things avoid having too many chromosomes from sexual reproduction? Mitosis ? Somatic Cell 2n=23 pairs=diploid Normal Somatic Cells 2n=23 pairs=diploid

A Different Kind of Cell Division Meiosis ? Somatic Cell 2n=23 pairs of chromosomes diploid Reproductive Cells n=23 chromosomes haploid (gametes)

Fertilization Zygote (diploid) Gametes SpermOvum (haploid)

Explanation Builds an explanation using ideas students have generated in Exploration Builds an explanation using ideas students have generated in Exploration Teacher can add content as needed to make the explanation coherent and clear Teacher can add content as needed to make the explanation coherent and clear Best if process of explaining makes use of several media (text, visuals, physical models, etc.) Best if process of explaining makes use of several media (text, visuals, physical models, etc.)

A Different Kind of Cell Division Meiosis 2 Cycles Meiosis I Interphase I Prophase I Metaphase I Anaphase I Telophase I Meiosis II Prophase II Metaphase II Anaphase II Telophase II

Meiosis I Interphase Mother cell Meiosis II Prophase I: Tetrad formation Prophase I: Tetrad formation Metaphase I Prophase I: Condensing Chromosomes Prophase I: Condensing Chromosomes Anaphase I Telophase I Note Centromeres Note bivalents of homologous Chromosomes

Telophase I Meiosis II Meiosis II Metaphase II Anaphase II Telophase II Prophase II Note that before Prophase II There is no replication of DNA

Prophase I: Tetrad formation/ crossing over Prophase I: Tetrad formation/ crossing over Anaphase I Metaphase I Telophase I Because of crossing over, every gamete receives a unique set of genetic information. Crossing Over Crossing Over Site of crossover is called chiasma

Elaboration Adds more examples of concepts that are being learned. Adds more examples of concepts that are being learned. Avoids adding new concepts, however. Avoids adding new concepts, however. Helps students recognize the various forms the concept can take and where it can be applied in different settings. Helps students recognize the various forms the concept can take and where it can be applied in different settings.

What is each diagram showing?

What is shown?

Extension Not a part of every 5-E lesson (this is a 6 th “E”—some people think this step can cause problems) Not a part of every 5-E lesson (this is a 6 th “E”—some people think this step can cause problems) Does not go in depth, but hints at next level of learning. Does not go in depth, but hints at next level of learning. NOT the place where student is to really learn a concept, but gets an introduction to connect it to concepts in current lesson. NOT the place where student is to really learn a concept, but gets an introduction to connect it to concepts in current lesson.

Mitosis--Interphase

Meiotic Interphase Growth 1 (G1) phase: Immediately follows cytokinesis. Immediately follows cytokinesis. Very active period, Very active period, Synthesis of proteins Synthesis of proteins each of the 46 human chromosomes consists of a single (very long) molecule of DNA. each of the 46 human chromosomes consists of a single (very long) molecule of DNA. At this point cells are 46,2N, identical to somatic cells. At this point cells are 46,2N, identical to somatic cells. Synthesis (S) phase: genetic material is replicated: genetic material is replicated: each of its chromosomes duplicates (46,2N). each of its chromosomes duplicates (46,2N). cell is still diploid, however, because it still contains the same number of centromeres. cell is still diploid, however, because it still contains the same number of centromeres. chromatids are in the chromatin form because spiralisation and condensation into denser chromosomes have not taken place yet. chromatids are in the chromatin form because spiralisation and condensation into denser chromosomes have not taken place yet. Growth 2 (G2) phase: G2 phase is absent in Meiosis

Evaluation Provides a way for the student to see what has been learned—validation of learning effort Provides a way for the student to see what has been learned—validation of learning effort Calls for some ‘transformation’ of concepts— changing form of ideas from one format to another (e.g., if learning was through visuals, students may write; if learning was through text, students may build a model; if learning was through text, students may draw a diagram.) Calls for some ‘transformation’ of concepts— changing form of ideas from one format to another (e.g., if learning was through visuals, students may write; if learning was through text, students may build a model; if learning was through text, students may draw a diagram.) Return to question in “Exploration” to be sure it is answered by new learning. Return to question in “Exploration” to be sure it is answered by new learning.

How could you explain… Remember our question: Remember our question: What happens so that living things avoid having too many chromosomes from sexual reproduction? Write a short explanation as you would for someone who does NOT know about meiosis. Write a short explanation as you would for someone who does NOT know about meiosis. Avoid science vocabulary for now. Use 5-10 sentences—try to be brief.