B8 Flashcards
(38 cards)
Where does photosynthesis take place in plants ?
Takes place in the green parts of the plant , especially the leaves .
Do algae carry out photosynthesis ?
Yes
How does photosynthesis work ?
The cells in algae and plant leaves are full of small green parts called chloroplasts , which contain a green substance called chlorophyll. During photosynthesis , energy is transferred from the environment to the chloroplast by light . This energy is then transferred to convert carbon dioxide from the air , plus water from the soil into a simple sugar called glucose and produces oxygen also .
What type of reaction is photosynthesis ?
Endothermic reaction
What is the equation of photosynthesis ?
Carbon dioxide + water = glucose + oxygen
The leaves of plants are perfectly adapted as organs of photosynthesis because ?
- Most leaves are broad , giving them a big surface area for light to fall on
- Most leaves are thin so diffusion distances for the gas are short
- They have air spaces that allow carbon dioxide to get to the cells and oxygen to leave by diffusion
- They have guard cells that open and close the stomata to regulate gas exchange
How can you show that a plant is photosynthesising ?
By the oxygen gas it gives off as a by product
In water plants like Cambomba and Elodea , how can we see how much oxygen is given off ?
The bubbles produced
Plants need what three things to photosynthesise and grow as fast as they can ?
Light , warmth and carbon dioxide
What is a limiting factor ?
Sometimes any one or more of light, warmth and carbon dioxide can be in short supply and limit the amount of photosynthesis a plant can manage .
What is the most obvious factor affecting photosynthesis ?
Light intensity
If there is plenty of light , does a lot of photosynthesis take place ?
Yes
As the temperature rises , the rate of photosynthesis increases . But when the temperature rises too much , what happens ?
The enzymes that photosynthesis is controlled by , will denature . The rate of photosynthesis will fall .
The enzymes in photosynthesis will denature at what temperature ?
40 - 50 degrees
Will increasing the carbon dioxide concentration increase the rate of photosynthesis ?
Yes
On a sunny day , what is the most limiting factor ?
Carbon dioxide
What time of day does the carbon dioxide concentration increase ?
Night time
Explain what the light intensity and rate of photosynthesis practical is .
At the beginning of the investigation , the rate of photosynthesis in the water plant increases as the light is moved closer to the plant , which increases the light intensity . When the light is moved further away from the water plant , the rate of photosynthesis falls , shown by a slowing down in the stream of bubbles produced . If the light is moved closer again the stream of bubbles becomes faster , showing an increase rate of photosynthesis .
What is the light intensity and the inverse square law ?
As the distance of the light from the plant increases , the light intensity decreases . That is an inverse relationship - as one goes up , the other goes down .
How do you work out light intensity ?
1 / distance and 1/2 squared = 1/4
Plants cells and algal cells like any other living cells respire all the time . What do they use from photosynthesis when they respire ?
Glucose
During respiration what happens to the glucose taken from photosynthesis ?
The glucose is broken down using oxygen to provide energy for the cells . Carbon dioxide and water are the waste products of the reaction
What is the equation for aerobic respiration ?
Glucose + oxygen - carbon dioxide + water
Energy transferred in respiration can be used for what ?
Used to build up glucose into complex carbohydrates such as cellulose
