P1: Bioenergetics Flashcards
State the word equation for Photosynthesis.
Carbon Dioxide + Water –(Light + Chlorophyll)–> Glucose + Oxygen
State the balanced symbol equation for Photosynthesis.
6CO2 + 6H20 –> C6H12O6 + 6O2
Is photosynthesis endothermic or exothermic?
Endothermic
How is the light energy required for photosynthesis absorbed?
By a green pigment called Chlorophyll located in the chloroplasts in the leaves.
Where does the Carbon Dioxide and Water required for photosynthesis come from?
Carbon Dioxide comes from the air, entering through the stomata. Water enters the plant through the roots, and it transported to the leaves in the xylem.
How is the Glucose not used for respiration in plants otherwise used?
-Many glucose molecules join to form starch
-Many glucose molecules join to form cellulose to build cell walls
-Glucose produces fat or oil used for storage.
-Glucose and nitrates absorbed from the soil form amino acids, these amino acid molecules join to form proteins.
What factors affect the rate of photosynthesis?
Light intensity, Carbon Dioxide concentration, temperature, concentration of Chlorophyll.
How does chlorophyll affect the rate of photosynthesis? Explain.
Higher concentration of chlorophyll = higher rate of photosynthesis, because it allows the plant to absorb more light.
How does light intensity affect the rate of photosynthesis?
Higher light intensity = higher rate of photosynthesis.
How does Carbon Dioxide concentration affect the rate of photosynthesis?
Higher concentration of CO2 = Higher rate of photosynthesis, because it is one of the reactants in photosynthesis.
How does temperature affect the rate of photosynthesis?
Higher temperature = higher rate of photosynthesis. However, at particularly high temperatures, the enzymes are denatured.
How do you test to see if a leaf contained chlorophyll? (Long answer).
-Drop a leaf in boiling water to kill and preserve it
-Leave the left for 10 minutes in a hot ethanol boiling tube to remove the chlorophyll
-Dip the leaf in boiling water to soften it
-Spread the leaf out in a Petri dish and cover with iodine solution
-The areas that had the chlorophyll stain blue-black, areas that didn’t remain pale.
How can plant growers increase the light intensity?
-Use greenhouses constructed from glass that enable maximum transmission of light.
-Position plants for maximum light absorption
-Introduce artificial lighting systems
How can plant growers increase the carbon dioxide concentration?
-Use paraffin heaters on a small scale
-Use Carbon Dioxide wastes from industrial processes
-Use liquid Carbon Dioxide applied through pipes
-Place fungi that respire in bags around the greenhouse
How can plant growers increase water concentration?
-Introduce irrigation systems in greenhouses
-Spray plants with water
-Use hydroponics
What type of process is respiration - exothermic or endothermic?
Exothermic
What is the word equation for respiration?
Glucose + Oxygen –> Water + Carbon Dioxide
What is the balanced symbol equation for respiration?
C6H12O6 + 602 –> 6H20 + 6CO2
What do organisms use energy for?
-To drive the chemical reactions needed to keep them alive
-Movement (to make muscles contract, and for transport of substances)
-Cell division
-Maintaining constant conditions in cells and the body
-To move molecules against concentration gradients in active transport
-For the transmission of nerve impulses
What is the equation for anaerobic respiration in humans?
Glucose –> Lactic Acid + Energy
What is the word equation for yeast respiring anaerobically?
Glucose –> ethanol + carbon dioxide + energy released.
How much energy does anaerobic respiration release?
A small amount quickly.
What is yeast used for?
Making alcoholic drinks, producing bread.
What does the body do to give the muscles additional energy during exercise? 2 points.
The breathing rate and volume of each breath increases to bring more oxygen and remove carbon dioxide
The heart rate increases to supply the muscles with extra oxygen and remove the carbon dioxide produced.
What happens during long periods of vigorous activity?
Lactic acid levels build up
Glycogen reserves in the muscles become low as more glucose is used for respiration, and additional glucose is transported from the liver.
Muscles continue to contract, but less efficiently
What does the build-up of lactic acid produce?
Oxygen debt.
What happens as body stores of glycogen become low?
The person suffers from muscle fatigue.
What happens to lactic acid after it is taken to the liver by the blood?
Either oxidised to carbon dioxide and water, or converted to glucose, then glycogen.
What is oxygen debt?
The amount of oxygen required to remove the lactic acid and replace the body’s reserves of oxygen.
What is the metabolism?
The term used for all of the chemical reactions that go on inside an organism’s body.
What is broken down to meet short-term demands for energy?
Glycogen
What is broken down to meet longer-term demands for energy?
Lipids
What is broken down to meet energy demands during starvation?
Proteins
How does the rate of your metabolism affect your body temperature?
If your metabolism is slow, there will be a slower rate of respiration. Respiration is an exothermic reaction, so less heat will be released, meaning the body temperature will be lower.
What is the word equation for plants respiring anaerobically?
Glucose —> Carbon Dioxide + Ethanol
