Bioenergetics revision Photosynthesis and respiratioin

Don’t forget that plants also carry out Respiration to make energy. Photosynthesis Water + Carbon Dioxide Glucose + Oxygen Sunlight chlorophyll From roots/soil From air through stoma Stored as starch Released into air 6 H2O + 6 CO2 C6H12O6 + 6 O2 Don’t forget that plants also carry out Respiration to make energy. Chlorophyll Green pigment Found in chloroplasts Absorbs light energy

Plant Tissues Know the features of each layer and how they help photosynthesis

Factors Affecting Photosynthesis As factor rises, so does the rate of photosynthesis Temperature - Above 45oC, enzymes denature Carbon dioxide Light intensity Nutrients Water Space to grow All of these, at a particular time, may be the limiting factor. Temperature

Light Intensity Without enough light, a plant cannot photosynthesise very quickly, even if there is plenty of water and carbon dioxide. Increasing the light intensity will boost the speed of photosynthesis. Can you explain what is happening here?

CO2 Something other than CO2 concentration is acting as a limiting factor Sometimes photosynthesis is limited by the concentration of carbon dioxide in the air. Even if there is plenty of light, a plant cannot photosynthesise if there is insufficient carbon dioxide.

Temperature If it gets too cold, the rate of photosynthesis will decrease. Plants cannot photosynthesise if it gets too hot. Why?

Greenhouses and Poly-tunnels Controls the environment Light Temperature Nutrient levels Water levels Predators Weeds Reduces the chance of Limiting factors Hydroponics Growing in plants in nutrient rich water, not soil.

Respiration Site of respiration- mitochondria

Anaerobic Respiration produces less energy than Aerobic Respiration! Takes place in all cells (apart from RBCs). Carried out by the mitochondria. Needed for energy to: Build new molecules and cells Movement- needed to make muscle cells contract Keep birds and mammals (warm blooded) at a constant temperature Glucose + Oxygen Carbon dioxide + Water C6H12O6 + 6 O2 6 CO2 + 6 H2O Anaerobic Respiration Takes place where no oxygen is present. Muscle cells Yeast Cells Anaerobic Respiration produces less energy than Aerobic Respiration! Glucose Lactic Acid Glucose Ethanol (alcohol)

Stored glucose found in muscles The Effects of Exercise Heart rate  Breathing rate  more Oxygen and Glucose supplied to muscles Increase in Respiration rate More Energy for muscle contraction. Glycogen Stored glucose found in muscles Oxygen Debt Amount of oxygen needed to breakdown Lactic acid, formed during anaerobic respiration. Lactic acid + Oxygen Carbon dioxide + water

B2 REVISION – CHAPTER 2 – ORGANISMS IN THE ENVIRONMENT What is the equation for photosynthesis Where in the plant does it occur? How are leaves adapted to perform photosynthesis? Explain how plants use glucose for the following: Respiration Transport Storage How doe the follow factors affect organisms in their environment? Temperature: Light: Water: CO2 and O2: Explain how light, CO2 and temperature are limiting factors of photosynthesis How do we measure the distribution of organisms? How do we know this data is accurate? KEY WORDS: Photosynthesis Median Glucose Mode Limiting factors Transect Quadrat Reproducible Sample size Valid Range Variables Mean ASSESSMENT: