1 / 35

Higher Biology

Higher Biology. Unit 3 Sustainability and Interdependence. KEY AREA 1:. Learning Intentions. KEY AREA 1 – Food supply, plant growth and productivity Food supply. Food security Photosynthesis. a) Food supply, plant growth and productivity.

rjacqueline
Download Presentation

Higher Biology

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Higher Biology Unit 3 Sustainability and Interdependence KEY AREA 1:

  2. Learning Intentions KEY AREA 1 – Food supply, plant growth and productivity • Food supply. Food security • Photosynthesis

  3. a) Food supply, plant growth and productivity • Food security is the ability of human populations to access food of sufficientquality and quantity. • The Human population is growing faster than our planet can sustain. There is an increasing demand for increased food production. • Food production must be sustainable and not degrade the natural resources on which agriculture depends. https://www.youtube.com/watch?v=8vnYwvYxO6g • https://www.youtube.com/watch?v=VCYeLuURxRM

  4. Agricultural production • Agricultural production depends on factors that affect photosynthesis and plant growth • Plant crop examples include • Cereals e.g. wheat, barley • Potato • Roots e.g. carrot, parsnip • Legumes e.g. peas, beans • Plants quiz (how many can you name?)

  5. Improving yields Land suitable for growing crops is limited so we can make best use of the available land by: • Adding minerals (fertiliser) or water (irrigation systems) to remove factors limiting plant growth. • Replacing existing crop varieties with higher-yielding cultivar (cultured variety). • Using pesticides, fungicides and herbicides to protect crops from pests (e.g. insects), diseases (e.g. fungi), and competition (from weeds). • Developing pest-resistant crop plants. These will all improve crop yields

  6. 1. Fertilisers • Use fertilisers to improve yields. Fertiliser can be organic e.g. manure or inorganic (synthetic fertiliser)

  7. 2. Increasing yields • All food production is dependent ultimately upon photosynthesis. • we need to • breed higher yielding cultivars • Breeders seek to develop crops with • higher nutritional values • physical characteristics suited to rearing and harvesting e.g. uniform height, ripening of crop • the ability to thrive in particular environmental conditions e.g. drier, hotter or more saline environments.

  8. 3. Protecting crops • Protect crops from pests, diseases • Use Fungicides, insecticides • Use herbicides to reduce competition from weeds

  9. Livestock • Livestock produce less food per unit area than crop plants • Can you explain why? • It is more inefficient due to the loss of energy at each trophic level • Any advantages to producing livestock? • Livestock production is often possible in habitats unsuitable for growing crops

  10. Productivity of arable land From National 5: In what way is energy lost from a food chain? Undigested food and waste Only 10% is incorporated into body tissues Maintaining body temperature Movement As you move a long a food chain, energy (~90%) is lost between each trophic level and the next.

  11. Shorter food chains have less loss of energy: Cereal plant Farm animal Human Cereal plant Human 90% energy lost 90% energy lost 10% energy passed on 10% energy passed on 10,000 kJ 1,000 kJ 100 kJ 90% energy lost 10% energy passed on 1,000 kJ 10,000 kJ Livestock production generates far less food per area of land than plant production. • Arable land should be planted with crops. • Land not suitable for crop production, e.g. hillsides, should be used to feed livestock.

  12. Volunteer to sing ‘The Sound of Music’

  13. Metabolism and Survival Questions KEY AREA 1 – Food supply, plant growth and productivity • Testing Your Knowledge 1 Page 230 Q 1-3 (c) • What you should know page 244 Q 1-3 • Problem Solving page 59-60 Q 1-3

  14. Photosynthesis • In small groups write down everything you know about photosynthesis on an A3 sheet of paper • Put your names on the sheet • After 5 minutes you will pass the sheet to another group (clockwise) • When you get a new sheet add new information or correct any information that you think is wrong

  15. Fate of light hitting a leaf White light hitting a leaf (or any surface) will be either: Reflected White light Absorbed Transmitted White light is only part of the electromagnetic spectrum

  16. A leaf contains several pigments which can be separated by chromatography. Chlorophyll a - main photosynthetic pigment Chlorophyll b Carotene Xanthophyll Accessory pigments. Absorb light and pass the energy to chlorophyll a. Carotene and xanthophyll belong to a group called the carotenoids.

  17. Practical Extraction of leaf pigments • Leaf pigments can be extracted by crushing leaves with fine sand in a mortar and pestle with propanone/acetone. • The debris can be removed by passing the mixture through filter paper. • The pigment can then be carefully spotted onto chromatography paper using a spotter and hair dryer to obtain a small concentrated spot.

  18. Separation of leaf pigments • The chromatography paper is placed in a boiling tube or beaker with chromatography solvent at the bottom. • The solvent has to be below the spot and as the solvent moves up the paper it dissolves the leaf pigments

  19. The different pigments travel at different rates and so chromatography separates the pigments

  20. Electromagnetic spectrum Visible light is made up of a spectrum of different colours each with a different wavelength.

  21. Comparison of Absorption and Action spectra Absorption spectrum - absorption of light of each wavelength by each pigment. Action spectrum - shows the rate of photosynthesis at each wavelength of light.

  22. There is a close match between the absorption and action spectra for the different wavelengths showing the crucial role of leaf pigments in trapping light for photosynthesis. • Chlorophyll absorbs light mainly in the blue and red regions of the spectrum • Having different pigments extends the wavelengths of light the plant can use for photosynthesis

  23. What does this SHOW?

  24. Metabolism and Survival Questions KEY AREA 1b – Food supply, plant growth and productivity • Testing Your Knowledge 2 Page 235 Q 1-3 • What you should know page 244 Q 1-3 • Problem Solving page 60-61 Q 5-9

  25. Structure of the chloroplast Contain photosynthetic pigments. Location of 1st (light-dependent) stage Contains many enzymes. Location of 2nd (light-independent/Carbon Fixation) stage

  26. Photosynthesis consists of two stages: • LIGHT REACTION • - light-dependent stage • 2. CARBON FIXATION • - temperature dependent (or light- • independent) stage • Both of these stages take place in the CHLOROPLASTS: • light reactions on the thylakoid membranes of the grana, where pigments are found; • carbon fixation in the stroma.

  27. 2. Chlorophyll a releases high energy electron Primary electron acceptor 1. Light energy is absorbed by chlorophyll a creating high-energy electrons H+ H+ H+ 4. Energy also used to split water Oxygen Water 3. Electron passed along transport chain, pumping H+ into grana. Hydrogen H+ H+ H+ NADP H+ H+ H+ NADPH 5. Hydrogen bound to NADP to form NADPH - used in carbon fixation (Calvin cycle). 6. Hydrogen ions used by ATP synthase to make ATP (ADP is phosphorylated to ATP) - used in carbon fixation (Calvin cycle). H+ H+ ATP synthase enzyme ADP + Pi ATP LIGHT-DEPENDENT STAGE http://highered.mheducation.com/sites/9834092339/student_view0/chapter8/photosynthetic_electron_transport_and_atp_synthesis.html

  28. CARBON FIXATION (Calvin cycle) • This takes place in the stroma of the chloroplast. • The enzyme RuBisCO attaches carbon dioxide to RuBP. RuBP acts as a carbon dioxide acceptor. • The carbon dioxide and RuBP combine to make 3-phosphoglycerate (3PG). 3PG

  29. CARBON FIXATION (Calvin Cycle) The 3-Phosphoglyerate is phosphorylated by ATP and combined with hydrogen from NADPH to Glyceraldehyde-3-phosphate (G3P). • 3PG enzyme • https://highered.mheducation.com/sites/9834092339/student_view0/chapter39/calvin_cycle.html

  30. CARBON FIXATION (Calvin Cycle) • Some G3P is used to regenerate RuBP and some is used to make glucose. • 3PG

  31. Uses of GLUCOSE The glucose formed during photosynthesis can be used in a variety of ways. Glucose Biosynthesis pathways Respiration Starch Nucleic acids Fats and oils Cellulose (Storage carbohydrate) (Structural carbohydrate e.g. cell wall) Proteins

  32. Factors affecting Photosynthesis (plant productivity) The rate of photosynthesis is affected by several environmental factors known as limiting factors. These include: temperature, light intensity and carbon dioxide concentration.

  33. Limiting factors • What the limiting factor will be at points X, Y and Z? Z Y X

  34. KEY AREA 1b – Food supply, plant growth and productivity • Testing Your Knowledge 1 Page 239 Q1-3 • Testing Your Knowledge 2 Page 244 Q2-3 • What you should know page 245 Q 7-11 • Problem Solving page 62 Q 1-3

More Related