Growth and Development Part 1

Learning Objectives To learn about the differences between animal and plant cells. To learn about how bacterial cells are different from both animal and plant cells. To learn about how cells change as they grow. To learn about stem cells.

Success Criteria I can fully label a plant cell. I can state the main difference between bacterial cells and plant/animal cells. I can list at least 5 types of cell a stem cell can differentiate into. I can argue my viewpoint on stem cell research.

Plant Cells Animal Cells Plant Cells Bacterial Cells You need to know about the features of cells from the three main kingdoms of life: Animal Cells You should already know about the features of these. Plant Cells Plant cells have extra features that animal cells don’t. Do you know what they are? Bacterial Cells These cells are very different. They are much simpler and lack many structures.

Green = Plant cells only! Label Your Plant Cell VACUOLE CELL WALL NUCLEUS CYTOPLASM Green = Plant cells only! CELL MEMBRANE CHLOROPLAST

Plant Cells vs. Animal Cells Copy & complete the table using pages 32-33 in the new student textbook: Structure Job Animal, Plant or Both Cell Membrane Vacuole Nucleus Chloroplast Cell Wall Cytoplasm

Answers Structure Job Cell Membrane Vacuole Nucleus Chloroplast Animal, Plant or Both Cell Membrane Vacuole Nucleus Chloroplast Cell Wall Cytoplasm Controls entry and exit of substances into and out of the cell Both Contains cell sap and provides support to the cell Plant Controls the cells activities and contains the genetic material Both Absorbs light energy for photosynthesis Plant Contains cellulose to provide support and prevent bursting Plant Where chemical reactions take place Both

Stem cells

We call cells at this stage: STEM CELLS. A few days after fertilisation, an embryo is only a few cells big. The cells in an embryo are unspecialised. As the embryo grows, the cells will differentiate and become specialised. Once they do, they can’t go back to being stem cells. This embryo is a few days old and all of the cells are simple and the same. We call cells at this stage: STEM CELLS.

Don’t worry about remembering these words! Just remember that stem cells can differentiate into many types of cell.

Stem Cell Research What do you think? Stem cells taken from embryos have not yet differentiated. This means that they can be taken and used for research and medical use. Taking cells from a developing embryo will result in the destruction of that embryo. An existing life could be made better or even saved. Some people object to stem research for ethical reasons. What do you think?

Questions Name three structures found in a plant cell, but not found in an animal cell. Name three structures found in both animal and plant cells. Write down five types of cell a stem cell could differentiate into. Should scientists be allowed to use embryonic stem cells? Give reasons for your answer. Cell wall, chloroplasts, vacuole Cell membrane, cytoplasm, nucleus Brain, heart, liver, pancreas, kidney, bone etc. (any valid cell type) Both yes and no are correct, with valid reasoning

Bacterial cells

Bacterial Cells Unlike animals and plants, bacteria live as single-celled organisms. Their structure is much simpler and smaller that animal and plant cells. As you can see, bacteria don’t have a nucleus. Their DNA floats in the cytoplasm. CELL MEMBRANE CELL WALL CYTOPLASM DNA

Complete Worksheet 2 Answers: Q2a No true nucleus, chloroplasts or mitochondria Q2b Cell differentiation Q2c E.g. used to treat genetic disorders Q2d Ethical issues described

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More on Bacterial DNA DNA in animal and plant cells is coiled into chromosomes. There are several chromosomes in each nucleus. Bacteria however, have a single, circular loop of DNA. It floats around in the cytoplasm.

More on Stem Cell Research Scientists have found ways of ‘instructing’ stem cells to specialise into the same cell types of those in damaged tissues. Remember that the embryo will be destroyed. Embryonic stem cells are much more useful than adult stem cells because they can differentiate into many more types of cells.

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With your partner, discuss the ethics of stem cell research. Is improving or saving an existing life, worth the ending the potential life of an embryo? Feedback to the class…

Learning Objectives To learn about the differences between animal and plant cells. To learn about how bacterial cells are different from both animal and plant cells. To learn about how cells change as they grow. To learn about stem cells.

Success Criteria I can fully label a plant cell. I can state the main difference between bacterial cells and plant/animal cells. I can list at least 5 types of cell a stem cell can differentiate into. I can argue my viewpoint on stem cell research.