4 Bioenergetics Flashcards
Is photosynthesis endothermic or exothermic?
Endothermic
State the equation of photosynthesis.
6CO2 + 6H2O –> C6H12O6 + 6O2
Where does photosynthesis occur in the cell?
Chloroplast
What is photosynthesis?
Building glucose from carbon dioxide and water using light
Name the pigment in chloroplasts that absorbs light.
Chlorophyll
State an adaptation of the leaf for efficient photosynthesis.
Broad leaves/Thin/Have chlorophyll/Air spaces/Guard cells to regulate stomata opening
How does higher light intensity affect the rate of photosynthesis?
Increase
Apart from light and carbon dioxide concentration, name one other limiting factor of photosynthetic rate.
Temperature/Chlorophyll levels
Why would photosynthetic rate decrease at higher temperatures?
Enzymes become denatured
Name one use of glucose in plants.
Respiration/Make and strenghten cellulose cell wall/Make starch for storage/Make lipids as energy store
Why do plants need nitrates for good growth?
Make proteins
State one factor to maintain in a greenhouse for optimal plant growth.
High CO2 levels/Constant light/Appropriate temperatures/Regulate watering
Define ‘aerobic respiration’.
Exothermic reaction that breaks down glucose to release energy using oxygen
State the equation of aerobic respiration.
Glucose + Oxygen –> Carbon dioxide + Water
Is respiration endothermic or exothermic?
Exothermic
Where does aerobic respiration occur in the cell?
Mitochondria
Give one importance of respiration.
Metabolic reactions (eg. Build)/Muscle contraction/Mainting body temp/Active transport
State one response of the body to exercise.
Increase heart rate/breathing rate/Glycogen coverted to glucose/Increase blood flow to muscles
What happens to the glycogen stored in muscles when you exercise?
Converted into glucose for respiration
What is anaerobic respiration?
Breakdown of glucose to release small amount of energy without the use of oxygen
Name the toxic substance produced by anaerobic respiration.
Lactic acid
State an effect on your body after anaerobic respiration.
Muscle fatigue
Define ‘oxygen debt’.
Amount of oxygen needed to break down lactic acid
What do plants make in anaerobic respiration?
Ethanol and carbon dioxide
Give one use of yeast doing anaerobic respiration.
Making bread/alcohol
Give one example of a metabolic reaction in cells.
Convert glucose to glycogen,starch,cellulose/Make lipids/proteins/Respiration/Photosynthesis/Breakdown of proteins
State a function of liver.
Detoxification/Breakdown of old blood cells/Remove lactic acid (convert to glucose)
Pollen grains grow down into female flowers on their way to fertilising an egg. In the flower tissue, oxygen concentrations are low. Suggest which molecules are produced as a pollen grain respires
Ethanol and carbon dioxide. Pollen grains can respire anaerobically as the pollen tube moves towards an egg.
Describe how anaerobic respiration is important in bread making
The anaerobic respiration of) yeast is involved. Bubbles of carbon dioxide make the bread rise
Define the inverse square law.
For a type of electromagnetic radiation such as light, as the distance from the light source increases, light intensity is inversely proportional to the square of the distance.
Explain how some plants are adapted to growing in the shade
Shade-adapted plants produce more chlorophyll (so that they are more efficient at absorbing light. This allows them to photosynthesise at lower light intensities.
Describe an experiment to investigate the effect of the presence of chlorophyll on photosynthesis
1) use a plant with variegated leaves
2) kill and preserve a leaf by dipping it in boiling water
3) decolorize/remove chlorophyll from the leaf by immersing it in hot alcohol
3) dip it in water to soften it
4) place in a Petri dish and flood with iodine solution
5) a blue-black colour indicates the presence of starch
6) the parts of the leaf that contained chlorophyll will stain blue-black, indicating that chlorophyll is required for photosynthesis
A student investigated the effect of different parts of the spectrum on photosynthesis. She covered three test tubes containing pond weed with plastic filters. She counted the bubbles produced over one minute intervals. Suggest how the student could check the repeatability of her results.
by carrying out the experiment/repeating it several times
the student can see how close they are together, ie repeatable
