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As 90928. Demonstrate understanding of biological ideas relating to the life cycle of flowering plants. Plant growth and photosynthesis. L.O Describe primary growth and the significance of meristematic tissue.
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As 90928 Demonstrate understanding of biological ideas relating to the life cycle of flowering plants
L.ODescribe primary growth and the significance of meristematic tissue Do Now – The following statements are incorrect. Rewrite them, making them correct and adding a reason for the change you make. • Asexual reproduction is more complex than sexual. eg. Asexual reproduction is less complex than sexual, because it does not involve flowers and gametes 2. Asexual reproduction involves the production of gametes 3. Sexual reproduction results in genetically identical offspring 4. The offspring of asexual reproduction are dispersed away from the parent plant 5. Should conditions change, the offspring of sexual reproduction may all die.
Copy Primary growth Primary growth in plants is all about growing in length. This growing occurs in two areas – the tip of the root (ROOT TIP) and the tip of the shoot (SHOOT TIP). Both these areas contain meristem tissue – this means they have unspecialised cells that will divide to make more cells and make the area grow longer. Once the new cells are produced they elongate and become bigger, and then differentiate into the specialised cells eg. Root hair cells in the roots.
L.ODefine tropismDescribe the advantages of tropisms Do Now What cells are responsible for primary growth in a plant?
TROPISM Plant growth in response to a stimulus (“tropo” – ”turn”) . • There are many types of tropisms : • Phototropism • Geotropism • Thigmotropism • Hydrotropism • Chemotropism • Thermotropism 3 main types *Can be positive or negative NEXT
GEOTROPISM (“Geo” – Earth) Geotropism is the growth of a plant in response to gravity. Negative Geotropism Positive Geotropism It is the growth of a plant towards the center of the earth-down with gravity. Ex. roots growing down Negative Geotropism It is the growth of a plant away from the center of the earth-opposite from the pull of gravity Ex. stems grow up Positive Geotropism NEXT
IMPORTANCE OF GEOTROPISM • Pulls roots down to anchor a plant • Roots can get needed water and • minerals if they stay in the soil NEXT
CORN TROPISM LAB http://www.youtube.com/watch?v=iFCdAgeMGOA&feature=related
PHOTOTROPISM (“Photo” – light) The growth response of a plant in response to light direction is called phototropism. Ex. Stems growing toward the window to get to the light NEXT
Tropism http://plantsinmotion.bio.indiana.edu/plantmotion/movements/tropism/tropisms.html
IMPORTANCE OF PHOTOTROPISM Enables leaves to be in the best position possible to receive adequate light for photosynthesis NEXT http://www.darienps.org/teachers/otterspoor/botany/tropisms/Gravitropismwlight.jpg
THIGMOTROPISM (“Thigmo” – “touch”) Thigmotropism is the growth of a plant in response to touch/contact. Photo by Christopher Meloche Tendrils on a sweet pea Vines growing on a wall or fence NEXT
THERMOTROPISM (“Therm” – “heat”) Thermotropism is the tendency of plants or other organisms to bend toward or away from heat. Ex. curling of Rhododendron leaves in response to cold temperatures. HYDROTROPISM (“hydro” – “water”) Hydrotropism is the growth in response to water. Ex. roots growing toward moisture Chemotropism (“Chemo” – chemical”) Chemotropism is movement caused by chemical stimuli. Ex. Growth of a pollen tube is always towards the ovules so that reproduction can occur NEXT
Key words Root hairs Transpiration Turgid Flaccid osmosis L.O Describe how the structure of roots is related to their function Do Now- Write down the name of the process that each of these statements are describing When the pollen and egg fuse together to form a new individual Reproduction in which offspring are formed from just one parent The transfer of pollen from the anther to the stigma The movement of seeds away from the parent plant
Copy Osmosis The movement of water from a high to a low concentration across a semi-permeable membrane
The photo on the left is a picture of the microscopic root hairs on a root. Explain how these hairs help the roots carry out their job.
Copy • All roots have the same basic functions. These are • Absorb ____________ and ______________. • To ______________ the plant firmly in the ground. • Some roots also act as a _________ space for food made by the plant.
Key words Meristem Terminal bud Xylem Phloem Cambium Vascular bundle L.O Describe the function of a plant stem Do Now Highlight any words we have covered since we last looked at the key word sheet
Transportation within Stems Phloem: Phloem carry sugar and water from upper parts of the plant to lower parts to supply nutrients to the rest of the plant. Xylem: Xylem carry water from the roots to the upper parts of the plant. The movement is powered by transpiration. Water evaporates from the top, and water below moves to replace it. Copy
L.O Describe the process of secondary thickening
Types of Stems: Dicot • Dicot stems have a pith in the center with vascular tissues in a distinct ring visible in a cross section.
Secondary Growth • In vascular plants, secondary growth or, perhaps more accurately, secondary thickening is the result of the activity of the vascular cambium. The latter is a meristem that divides off cells: the cells on the inside of the meristem (the adaxial side) will become secondary xylem, while the cells on the inside (the abaxial side) will become the secondary phloem. This growth increases the girth of the plant, rather than its length, hence the phrase "secondary thickening". As long as the vascular cambium continues to produce new cells, the plant will continue to grow more stout. If this is kept up over many years, this process produces wood. • Because this growth ruptures the epidermis of the stem, woody plants also may have a cork cambium that develops among the phloem. The cork cambium gives rise to thickened cork cells to protect the surface of the plant and reduce water loss. If this is kept up over many years, this process may produce a layer of cork. In the case of the cork oak it will yield harvestable cork.
L.OCompare and contrast primary and secondary growth in plants Do Now • Do you think this flower is pollinated by wind or insects • What features show it is wind/animal pollinated • Why do these help it get pollinated?
L.OIdentify which foods contain starch Do Now 1. Where in a plant does secondary thickening occur?
What is starch? Starch or amylum is a carbohydrate consisting of a large number of glucose units joined by glycosidic bonds. This polysaccharide is produced by all green plants as an energy store.
Starch: Plants store glucose as the polysaccharide starch. The cereal grains (wheat, rice, corn, oats, barley) as well as tubers such as potatoes are rich in starch.
L.OCarry out a Do Now 1. What do we use Iodine to test for?
L.ODescribe how to carry out a starch test Do Now 1. What do we use Iodine to test for?
Explain how the thickness of the stem increases over a number of years. In your answer, you should: • identify the tissue in the stem where secondary thickening occurs • explain how the changes to those tissues in the stem allow the stem of the plant to grow thicker.
L.ODiscuss the conditions necessary for photosynthesis Do Now Write the word equation for photosynthesis
Aim: To find out if light is needed for making starch Conclusion:Light is needed for photosynthesis to produce starch in leaves.
Aim: To find out if carbon dioxide is needed for making starch
Aim: To find out if carbon dioxide is needed for making starch
Conclusion: The green substance in leaves (chlorophyll) is needed for photosynthesis to produce starch in leaves.
L.OName the products of photosynthesis and explain why they are important to life on earth Do Now Complete the reflection time section on pg 64
Photosynthesis Sunlight The chemicals used in photosynthesis are carbon dioxide (CO2) and water (H2O). The chemicals produced are Glucose (C6H12O6) and oxygen (O2). This process happens in the chlorophyll which is in chloroplast and energy from the sun is needed
L.OExplain how the rate of photosynthesis is affected Do Now Complete the reflection time section on pg 64
Rate of photosynthesis Sunlight What affects the rate of photosynthesis? Sunlight Carbon dioxide Water temperature
L.ODescribe the adaptations a leaf has to enable photosynthesis to occur Do Now Complete the reflection time section on pg 68