Hormonal Influences


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Hormonal Influences

  1. 1. Hormonal Influences SQA HIGHER BIOLOGY Unit 3: Control and Regulation
  2. 2. What are hormones ?
  3. 3. What role do hormones play in growth ?
  4. 4. Learning Content <ul><li>Pituitary hormones. </li></ul><ul><ul><li>The role of the pituitary gland in the control of growth and development involving human growth hormone (GH) and thyroid stimulating hormone (TSH). </li></ul></ul>
  5. 5. Animal Hormones <ul><li>What are hormones? </li></ul><ul><li>Where are they produced? </li></ul><ul><li>How are they transported? </li></ul><ul><li>Can you name some endocrine glands? </li></ul>
  6. 6. Pituitary Gland <ul><li>What is TSH? </li></ul><ul><li>How does TSH affect growth? </li></ul>
  7. 7. Pituitary Gland <ul><li>The pituitary gland also produces human growth hormone - somatotrophin. </li></ul><ul><ul><li>How does this hormone affect growth? </li></ul></ul><ul><li>What happens if the body has too much, or too little somatotrophin? </li></ul>
  8. 8. Learning Content <ul><li>Plant growth substances. </li></ul><ul><ul><li>As exemplified by indole acetic (IAA) and gibberellic acid (GA). </li></ul></ul><ul><ul><li>Sites of production of IAA. </li></ul></ul><ul><ul><li>Effects of IAA at cellular and organ levels; role in apical dominance, leaf abscission and fruit formation. </li></ul></ul><ul><ul><li>Effects of GA on dormancy and in dwarf varieties of plants. </li></ul></ul><ul><ul><li>Role of GA in α-amylase induction in barley grains. </li></ul></ul><ul><ul><li>Practical applications of plant growth substances as illustrated by herbicides and rooting powders. </li></ul></ul>
  9. 9. Plant Growth Substances <ul><li>What are plant growth substances? </li></ul><ul><li>What effects can they have on plant growth? </li></ul><ul><li>There are two types of plant growth substances which you need to know about: </li></ul><ul><ul><li>Auxins - IAA </li></ul></ul><ul><ul><li>Gibberellins - GA </li></ul></ul>
  10. 10. IAA <ul><li>Indole Acetic Acid as an Auxin. </li></ul><ul><ul><li>Describe the experiments which were carried out which suggested the presence of auxins. </li></ul></ul>
  11. 11. IAA <ul><li>Where is IAA produced in plants? </li></ul><ul><li>How does it move… </li></ul><ul><ul><li>over short distances? </li></ul></ul><ul><ul><li>over long distances? </li></ul></ul><ul><li>How does IAA effect cell… </li></ul><ul><ul><li>division? </li></ul></ul><ul><ul><li>elongation? </li></ul></ul><ul><ul><li>differentiation? </li></ul></ul>
  12. 12. Effects of IAA <ul><li>Summarise the experimental method outlined on p251. </li></ul><ul><li>How were roots & shoots measured in this experiment? </li></ul><ul><li>Why do IAA solutions need to be kept in the dark? </li></ul><ul><li>Copy figure 30.10 on p253 </li></ul><ul><li>What conclusions can you draw from these results? </li></ul><ul><li>What were the reasons for the various design features of the experiment? </li></ul><ul><ul><li>Table 30.3 p253 </li></ul></ul>
  13. 13. Effects of IAA
  14. 14. Effects of IAA
  15. 15. Effects of IAA <ul><li>What are tropisms? </li></ul><ul><li>Plant shoots are positively phototrophic, what does this mean? </li></ul><ul><li>How can this be explained? </li></ul><ul><li>What is meant by apical dominance? </li></ul><ul><ul><li>How can this be demonstrated? </li></ul></ul><ul><ul><li>How do gardeners make use of this effect? </li></ul></ul>
  16. 16. Other IAA Functions <ul><li>What role does IAA play in fruit formation? </li></ul><ul><li>What is leaf abscission? </li></ul><ul><ul><li>How is IAA involved in this? </li></ul></ul><ul><li>Summarise the following commercial applications of auxins: </li></ul><ul><ul><li>Parthenocarpy </li></ul></ul><ul><ul><li>Delayed fruit abscission </li></ul></ul><ul><ul><li>Rooting powders </li></ul></ul><ul><ul><li>Herbicides </li></ul></ul>
  17. 17. Gibberellins <ul><li>What are gibberellins? </li></ul><ul><li>What is the most common gibberellin? </li></ul><ul><li>There are three effects of gibberelic acid which you need to know about: </li></ul><ul><ul><li>Effect on dwarf pea seedlings </li></ul></ul><ul><ul><li>Effect on germinating barley grains </li></ul></ul><ul><ul><li>Effect on bud dormancy </li></ul></ul><ul><li>Work in groups to produce a handout and PowerPoint presentation to explain your effect. </li></ul>