Bioenergetics Flashcards
What do plants use photosynthesis for?
To trap light energy
What type of reaction is photosynthesis?
Endothermic
What chemical within a leave allows it to absorb light?
Chlorophyll
Where does photosynthesis take place?
In the chloroplasts in the leaves of a plant
What is the word equation for photosynthesis?
carbon dioxide + water → glucose + oxygen
What is the symbol equation for photosynthesis?
6CO2 + 6H2O → C6H12O6 + 6O2
How would we know if light intensity was the limiting factor of photosynthesis?
If increasing the light intensity also increased the rate of reaction
How does the amount of light and carbon dioxide affect the rate of photosynthesis?
The more light and carbon dioxide, the faster the reaction
How would we know when light intensity was no longer the limiting factor?
When the rate of photosynthesis stops increasing in correlation with the added light intensity.
Other than light intensity, what are the possible limiting factors of photosynthesis?
Carbon dioxide, temperature, chlorophyll
What affects the amount of chlorophyll in a plant
Disease like tobacco mosaic virus and environmental stress like lack of nutrients
What do plants use glucose for
Respiration, making cellulose, making proteins by making amino acids, storing it as fats and starch
At what temperature do the enzymes needed for photosynthesis denature
About 45 degrees celsius
What does the inverse square law state?
Light intensity decreases in the proportion to the square of the distance
What is the equation of the inverse square law?
Light intensity is proportional to 1/distance^2
How do greenhouses work?
They trap the sun’s heat meaning the temperature is not the limiting factor. Heaters can be added in the winter and blinds and ventilators in the summer (so the enzymes aren’t denatured)
How do farmers increase light?
Using artificial lights after the sun goes down
How do farmers increase carbon dioxide?
Using paraffin heaters - paraffin makes carbon dioxide as it burns
What is respiration?
The process of transferring energy from the breakdown of sugar
Where and when does respiration take place?
In every cell in the body all of the time
What type of reaction is respiration?
Exothermic
How do organisms use the energy they get from respiration?
To build large molecules from small ones (e.g. amino acids -> proteins), for muscle contractions, in mammals and birds to keep the body temperature steady
What are some examples of smaller molecules forming large ones?
Glucose turning into: starch (stored in plant cells), glycogen (stored in animal cells) and cellulose (strengthens plant cell walls)
How are proteins formed?
Glucose reacts with nitrate ions to make amino acids which join together to make proteins
What is metabolism?
The sum total of all the chemical reactions in a cell or the body
What are some examples of larger molecules being broken down into smaller ones?
Glucose is broken down in respiration
What is aerobic respiration?
respiration using oxygen - most efficient way to release energy from glucose
Where does aerobic respiration take place?
In the mitochondria
What is the word equation for aerobic respiration?
glucose + oxygen -> carbon dioxide + water
What is the word equation for anaerobic respiration in animals?
Glucose -> Lactic Acid
What is the symbol equation for aerobic respiration?
C6H12O6 + 6O2 -> 6CO2 + 6H2O
When does anaerobic respiration take place?
When the body can’t supply enough oxygen to the muscles during vigorous exercise
What is anaerobic respiration?
Respiration without oxygen. The incomplete breakdown of glucose, making lactic acid
What is anaerobic respiration in yeast cells called?
Fermentation - It’s used in bread and alcoholic drinks like beer and wine
What is the equation for anaerobic respiration in plants?
Glucose -> Ethanol + Carbon Dioxide
Why does breathing rate increase during exercise?
To get more oxygen in the blood.
Why does the heart rate increase when exercising?
To get the oxygenated blood around the body faster and remove carbon dioxide quicker
What is oxygen debt?
The amount of extra oxygen the body needs to react with the lactic acid from anaerobic respiration to remove it, forming carbon dioxide and water
How does the liver help remove lactic acid?
The blood that enters the muscles transports the lactic acid to the liver which converts it to glucose
