Bioenergetics Flashcards
(38 cards)
What is photosynthesis?
An endothermic reaction where light energy is transferred by chloroplasts to produce glucose.
What is the word equation for photosynthesis?
Carbon dioxide + water → glucose + oxygen
What is the symbol equation for photosynthesis?
CO₂ + H₂O → C₆H₁₂O₆ + O₂
Where in a plant does photosynthesis take place?
Inside chloroplasts in plant cells.
Do all plant cells have chloroplasts?
No, only the ones that receive light.
Which plant cells have the most chloroplasts?
The cells that receive the most light…the palisade mesophyll cells in leaves.
What factors affect the rate of photosynthesis?
Light intensity, carbon dioxide concentration, temperature, amount of chlorophyll.
Why does temperature affect photosynthesis?
If the enzymes get warmer, photosynthesis happens at a faster rate, but if the enzymes get too hot, they will denature and photosynthesis will stop.
What other organisms photosynthesise?
Algae (pondweed and seaweed), as well as some bacteria.
What is the inverse square law?
The light energy reaching a certain point is equal to the inverse square of the distance to that point.
Why does anyone care about the rate of photosynthesis?
Anyone producing food crops will want to maximise profit.
What is the glucose produced in photosynthesis used for?
Respiration by all living cells. Also some is converted into starch, fats/oils, cellulose and amino acids.
Why do plants store glucose as starch?
Starch is insoluble, so doesn’t affect osmosis. Also it is more compact, so easier to store large amounts. The starch is used by cells as a source of glucose for respiration when it is dark.
Why do plants convert some glucose to oils?
Seeds have oils stored in them as the energy supply for the new plant to start to grow (germinate).
Why do plants convert some glucose to cellulose?
Cell walls are made of cellulose. It is strong and helps to support the plant. All plant cells have cell walls.
Why do plants convert some glucose to amino acids?
Amino acids are the building blocks of protein (for growth and repair). Plants need amino acids for protein synthesis.
What else do plants need to turn glucose into amino acids?
Glucose just contains the elements CHO. Amino acids contain CHON. Plants need to get nitrate ions from the soil to make amino acids.
What is respiration?
An exothermic reaction where energy is released from glucose molecules. It happens continuously in all living cells.
Why do living cells need to respire?
Living cells need an energy supply for all the processes they carry out (eg, chemical reactions, keeping warm and movement). Without this energy supply, cells would die.
What are the two types of respiration?
Aerobic (with oxygen) and anaerobic (without oxygen).
What is the word equation for aerobic respiration?
Glucose + oxygen → carbon dioxide + water (plus energy is transferred, but it is not a chemical so can’t go in a chemical equation).
What is the word equation for anaerobic respiration?
Glucose → lactic acid (plus energy is transferred…not as much as in aerobic respiration as it is not as efficient due to the oxidation of glucose being incomplete).
Is all anaerobic respiration the same?
No, the equation above is for respiration in muscles. In plant and yeast cells it is different.
What’s the anaerobic respiration equation in plants/yeast?
Glucose → ethanol + carbon dioxide.
