Questions tagged [photosynthesis]

The process by which light energy is harnessed to assemble organic compounds (esp. glucose) from inorganic carbon dioxide.

Filter by
Sorted by
Tagged with
0
votes
0answers
5 views

absorption spectrum & photosystems

i've a doubt in biology on photosynthesis and it's super confusing to attempt to solve solo. can someone help me out please? my biology textbook states that photosystem 1 and photosystem 2 has ...
1
vote
1answer
22 views

Photosynthesis immature fruits [duplicate]

Do immature fruits perform photosynthesis? Yes they have chlorophyll bodies. But do they have stomata through which they can absorb carbondioxide like the green leaves? Sincerely Ulrik
5
votes
1answer
77 views

Why have plants evolved to photosynthesize glucose instead of another molecular compound?

I think this question can be broken down into two sub-questions: Why do plants produce $C_6H_{12}O_6$ as opposed to another molecule following the formula of $C_nH_{2n}O_n$? Why not $C_8H_{16}O_8$, $...
13
votes
1answer
1k views

Chorophyll and photosynthesis in plants with coloured leaves

Do plants that have only coloured leaves (e.g. ‘ornamental’ plants) contain chlorophyll and perform photosynthesis? If they don’t, how do they obtain energy and metabolic intermediates?
1
vote
0answers
11 views

How many electrons does the b6-f complex need to pump one proton into the thylakoid lumen?

In photosynthesis, photons are used through photolysis to split water molecules and retrieve their hydrogen ions and electrons in the water-splitting complex. For each four photons, two water ...
0
votes
0answers
14 views

what is the integral of PAR radiation over total solar radiation

This paper say 48%: What is the maximum efficiency with which photosynthesis can convert solar energy into biomass? -Zhu 2008 Also why does Zhu use 740 nm at high end of PAR wavelength! My ...
4
votes
1answer
66 views

Which complexes physically pump protons in photosynthesis?

The cytochrome b6f complex is often drawn as pumping protons, but then someone told me that actually there is no pumping, rather the Q cycle. According to this view, what actually moves the protons ...
1
vote
0answers
65 views

How does the emerson effect produce a higher rate of photosynthesis?

Can anyone explain how the emerson effect works to increase the rate of photosynthesis, and as the original studies were done over 50 years ago, how much research is still done into this area? Or is ...
4
votes
2answers
137 views

Is coral photosynthesis dependant on the wavelength or frequency of light?

When buying a light fixture for a marine fish tank, it is often sold with some technical data reguarding the spectral output of the light, with a peak in the blue region of visible light, somewhere ...
34
votes
2answers
9k views

Why “Having chlorophyll without photosynthesis is actually very dangerous” and “like living with a bomb”?

The Phys.org article Scientists discover first organism with chlorophyll genes that doesn't photosynthesize says "For the first time scientists have found an organism that can produce chlorophyll ...
2
votes
0answers
18 views

Photosynthesis: Can light directly excite the reaction center instead of going through the antenna complex?

The reaction centers that I am interested in are P680(photosystem II) and P700 (photosystem I) Here is what I think: If pigments such as chlorophyll a and b capture light in the antenna complex, and ...
1
vote
1answer
32 views

Fuel from photosynthesis

I was reading how plants make use of sunlight, CO2 and some other stuff to make energy. So why can't we create artificially engineered bio solar panels which will take sunlight, C02, water and other ...
2
votes
0answers
35 views

Winter is getting shorter and warmer. Does this mean deciduous trees can photosynthesise for longer and thus absorb more carbon dioxide?

As springtime is starting earlier this year, I wondered if that would mean deciduous trees had more time to photosynthesise and, therefore, they could absorb more CO2 or have longer periods to grow, ...
1
vote
0answers
35 views

Calculation of Respiration Fluxes in Terrestrial Ecosystems Based on Total Respiration (RT)

Overview Researchers have been studying a temperate grassland ecosystem with the view to understand it's current status with regard to carbon inputs and outputs and to identify whether the grassland ...
0
votes
1answer
127 views

What does the difference between GPP - NPP represent?

Overview Researchers have been studying a temperate grassland ecosystem with the view to understand it's current status with regard to carbon inputs and outputs and to identify whether the grassland ...
3
votes
1answer
52 views

How much energy takes C4 photosyntesis to make glucose?

Wikipedia has a kind of contradiction that I would like to understand: According to this link The C3 pathway requires 18 ATP for the synthesis of one molecule of glucose while the C4 pathway ...
-2
votes
2answers
128 views

Why is photosynthesis described as a “physico-chemical” process? [closed]

In my textbook it is given that photosynthesis is a physico-chemical process. How can it be a physical process?
2
votes
1answer
136 views

In plant photosynthesis, in the light dependent reactions, why is 3 ATP produced per 2 H2O?

I've been looking at the light-dependent reactions on Wikipedia and Khan Academy. This is the net reaction: $$2H_2O + 2NADP^+ + 3ADP + 3P_i \to O_2 + 2NADPH + 3ATP$$ So for every $2H_2O$ I expect $...
3
votes
2answers
115 views

What is the evolutionary relationship between heme, chlorophyll and other tetrapyrroles?

As a non-biologist, I have searched the Internet and found dozens of papers discussing the similarity between the structures of heme and chlorophyll molecules, but I could not find any discussion of ...
2
votes
1answer
73 views

What does the spectrum of Chlorophyll fluorescence look like?

I've just posted the question Which spacecraft can see plants "glow" during photosynthesis during the day, and what wavelength does it use? in a different SE site. I can't remember the details of ...
1
vote
0answers
166 views

What is difference between light harvesting complex , reaction centre and photosystem

my book says light harvesting Complex are made up of hundred of pigment molecule bound to protein. Is photosystem has all the pigment (except one molecule of chlorophyll A )forming light harvesting ...
1
vote
2answers
64 views

How to add oxygen to indoor air without opening windows?

I'm not a biologist. I have read that low oxygen levels in the home can have a negative effect on health. I am interested in increasing the amount of oxygen in the air in my home. To open the windows ...
5
votes
1answer
258 views

Why aren't leaves black?

I s'pose this is a variant of the age-old question, "Why are leaves green?" It's fairly easy to ask teh internets and find plenty of answers for that one. I have a different but related question: ...
1
vote
0answers
25 views

How much plant grow is required for a human's oxygen consumption?

I think Plants do: 6CO2 + 6H2O -> C6H12O + 6O2 I'm thinking that plants take 12 + 6 moles of oxygen and give back 12 mols of breathable oxygen and 1 mol of Cellulose. I've read that a person needs ...
0
votes
1answer
55 views

Are the bacteria doing the same photosynthesis as plants do?

I mean Plants during photosynthesis produce oxygen but Do bacteria also produce oxygen during photosynthesis or produce other gases? If yes , how do these bacteria process photosynthesis by ...
0
votes
1answer
63 views

How does temperature affect photosynthesis?

I am doing a lab for biology and my teacher required me to do this virtual lab. However, it does not make sense when seeing the results of the lab. In 30 second trials, it shows that there are 16 ...
0
votes
1answer
441 views

How do plants take in only carbon dioxide?

There are only 400 molecules of CO2 in 1 million molecules of air. How do plants only take in CO2 but not the other gases? My teacher told me that's because there is less concentration of CO2 in ...
0
votes
2answers
89 views

Could cyanobacteria thrive with very high CO2 concentrations and almost no oxygen to start with?

Has there been research to see if cyanobacteria could live in high levels of CO2, like in the atmosphere of Venus ? Because cyanobacteria caused the Great Oxygenation Event one might expect that they ...
-1
votes
1answer
35 views

Can humans eat green leaves to get necessary daily energy intake? [closed]

Green leaves make carbohydrates by photosynthesis. This means that green leaves are abundant source of energy. Can humans eat enough green leaves off the trees and get necessary daily energy intake?
6
votes
2answers
739 views

Are bananas C3, C4, or CAM plants?

Are bananas C3, C4, or CAM plants? I have been researching for some time and cannot find the answer.
2
votes
0answers
47 views

What happens when pure chlorophyll A absorbs blue light?

When pure chlorophyll A is put in the presence of only blue light, what happens? My guess is that the extra energy is released as heat/kinetic energy, and then the electron has dropped to the lowest ...
0
votes
1answer
226 views

Where does NADP+ come from?

Trying to understand Photosynthesis better. I understand the NADP+ is reduced to NADPH in light dependent reactions and NADPH is then recycled back into NADP+ in the Calvin cycle. What I don't ...
6
votes
1answer
214 views

Does an old growth forest ecosystem produce more oxygen than it consumes?

I would like to consider an old growth forest ecosystem such as a large part of the Amazonian forest. It is common to refer to such beautiful forests as a source of oxygen for the world. For example, ...
1
vote
1answer
58 views

What values to be taken for x-axis and y-axis?

I did a lab on form and function in photosynthesis and I recorded the values of absorption spectrum in spinach chlorophyll extract. I have the following data and I need to draw a graph. I didn't ...
1
vote
0answers
59 views

Could higher carbon dioxide levels be beneficial to plants?

C4 plants take ATP-expensive routes to ensure photorespiration does not occur. They minimise oxygen concentration in cells where the Krebs cycle occurs and cart carbon dioxide into these same cells. ...
0
votes
1answer
55 views

Does the sun light have to have *direct access* to fruits to make them sweet?

I understand that sun light is needed for fruits to ripen. In the years with less sun light, the fruits are usually not so sweet. So the sun light is needed to make the fruits sweet. Where and how ...
1
vote
1answer
1k views

Is the rate of photosynthesis higher than the rate of respiration?

In photosynthesis carbon dioxide is used up and oxygen is produced and at the same time plants respire too. So oxygen is used up and carbon dioxide is produced. Then the net exchange of gases should ...
3
votes
1answer
525 views

From where does the oxygen in glucose come in photosynthesis?

Is it carbon dioxide or water? I'm talking about the oxygen present in glucose and not the oxygen that is released after photolysis of water.
11
votes
1answer
247 views

Do fallen leaves produce oxygen?

After a leaf has fallen from a tree, if it is still green and hasn't dried out, is it still converting CO2 into O2 if not put in water? Can anyone find any data showing how long any different ...
0
votes
1answer
28 views

Can plants yield two more molecules of ATP from glycolysis?

Since 2 ATP are used to convert glucose to glyceraldehyde 3-phosphate in glycolysis, can plants bypass this step of ATP investment since they produce glyceraldehyde 3-phosphate directly from the ...
6
votes
1answer
551 views

Why are C4 plants mainly tropical plants?

Why is it that most C4 plants are tropical plants? As far as I am aware the C4 cycle does not prevent water loss; so having it exist in tropical areas does not serve these plants any good other than ...
4
votes
1answer
68 views

If all animals were to die, would all plants die too?

Humans and many other animals are able to breathe because plants produce more oxygen than they need. I was thinking if all animals died all of a sudden, then wouldn't plants die too. Eventually they ...
1
vote
0answers
148 views

The effect of Atrazine on the LDR in Photosynthesis

The herbicide Atrazine causes inhibition within the Qb site in the D1 protein of photosystem 2. Given this information, would Atrazine’s inhibitory effect halt the production of oxygen or ATP first? ...
3
votes
0answers
93 views

Recent research in bioluminescence powering photosynthesis?

In 2013 there was a Chinese study published on "Bioluminescence as a light source for photosynthesis," which is briefly summarized in this Chemistry World article. There was a question on Biology.SE ...
2
votes
0answers
540 views

How many photons are used to make one glucose?

This was a question in a test. The options were (1) 8 (2) 16 (3) 24 (4) 48 My answer is 30 which was not in options. Given answer was 48. 12 NADPH 18 ATP for one glucose 12 NADPH and ATP ...
1
vote
0answers
147 views

Could alternatives to Photosynthesis be possible? [closed]

I'm working on a world for stories and games, and I'm trying to figure out some more diverse plantlife. There are areas of the world that won't get enough sunlight for Photosynthesis, so I'm thinking ...
2
votes
0answers
119 views

Does blue light cause stomata to open or close?

In my biology lecture notes, it says that blue light causes stomata to close. But thinking about it logically, since plants absorb a high percentage of blue light compared to light at other ...
0
votes
1answer
527 views

c4 cycle in photosynthesis occurs in monocots or dicots

the biosynthetic portion of the c4 cycle occurs in the bundle sheath cells and i have studies that bundle sheath cells are present only in dicots and not monocots. according to this, the c4 cycle ...
32
votes
3answers
6k views

Can plants suffer from CO2 poisoning?

Is there a point where too much CO2 is bad for a plant? Basically when there is too much CO2 in the air can a plant get sick? Since plants photosynthesize and need CO2 to generate glucose and store ...
0
votes
1answer
37 views

Oxygen balence from growing plants for food

I had thought photosynthesis and respiration where pretty much Oxygen and Carbon neutral per calorie. http://news.mit.edu/2014/technical-feasibility-mars-one-1014 If, as the project plans, crops ...