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Questions tagged [chloroplasts]

The organelle in which photosynthesis occurs

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Chloroplast arrangement in high and low intensity of light

I have read that there are different alignments of chloroplast according to the intensity of light. I read that in high intensity the chloroplast align themselves parallel to the incident light (...
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How many photosystems in a chloroplast?

I haven't been able to find any good order-of-magnitude estimates for how many photosystems (e.g. how many PSII complexes, how many PSI complexes) are in an average chloroplast (or perhaps per area of ...
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Explanation behind the observed chloroplasts in Elodea during Hypotonic vs Isotonic Solution

Me and my colleagues put the elodea leaf in distilled (hypotonic) and tap water (isotonic). We observed under the microscope that the elodea under the hypotonic solution became elongated and turgid, ...
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Absorption bands of chlorophyll

I am currently reading this article, which discusses the functional impact of the $Q_x$ and $Q_y$ absorption bands of chlorophyll in photosynthesis. However, the article didn't say where on the ...
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Is Chemiosmosis a hypothesis or a theory?

I was trying to find out whether chemiosmosis is a hypothesis or a theory. Naturally, I first searched on Wikipedia, but the article on chemiosmosis uses both the words, which is confusing. The ...
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Sources of chlorophyll fluorescence

I have been reading this article recently, which claims that photoinhibition of photosystem II can have measurable impacts of chlorophyll fluorescence. This confused me, however, because ...
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Is Thylakoid membrane continuous with the Inner membrane of Choloroplast?

This article mentions that thylakoid membrane is continuous with the inner membrane of cholorplast Thylakoid membrane encloses the innermost compartment or thylakoid lumen. The inner membrane of ...
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In the Kok cycle occurring in Photosystem II's Oxygen-evolving Complex, what exactly does P680 do?

I've been reading up on the oxygen-evolving complex using a few sources, but am a non-biology major so my understanding might be somewhat/very flawed. I've been using this source mainly: https://...
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Is circular DNA the same as plasmids?

Chloroplasts have circular DNA, but would it be right to say that they have plasmids? Are plasmids and circular DNA even the same thing? Thank you in advance.
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Do some vascular tissue cells have chloroplast? [closed]

Vascular tissue includes xylem, phloem, parenchyma, and cambium cells. Does photosynthesis occur in some vascular tissue cells? Do some of them have chloroplast? Vascular tissues are made up of xylem ...
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Calvin cycle- combining three "turns"

In the common Calvin cycle diagram, it is commonly stated that "three cycles are combined to show the production of 1 molecule of G3P". How does the G3P molecule escape from this cycle in ...
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Is there a known efficiency rate for CO2 capture from ambient air in photosynthesising plants?

When humans take in air to their lungs, we capture about 5% of the total quantity of the air as oxygen (which in turn equals about 24% of the available oxygen in the air) Is there an equivalent rate ...
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Can we produce sugar using chlorophyll dissolved in ethanol?

I can't find anything about this on the net. I read in my (high-school) textbook that if plants get sunlight, water and carbon dioxide, and the catalyst called chlorophyll, they can make sugar. I'm ...
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Are stroma lamellum and grannum lamellum the same?

I have a picture in my textbook that is confusing me as to how they are different.I tried looking for some info on the internet, but could'nt get it clear.Please help me.
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What happens to the absorbed blue and red light in the chlorophyll molecule?

If the chlorophyll molecule (its chromophore) absorbs red and blue light and reflects green light, shouldn't the absorbed blue and red light be emitted back when its excited electrons relax?
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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?
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Do all cells of a plant contain chloroplasts? [closed]

If the answer is no, then how do plant cells tell whether they need to keep chloroplasts or not? What kind of signals are used, and how are chloroplasts eliminated?
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Why do proteins targeted for chloroplasts require two signal peptides?

Question #11 of the GRE Biology Practice Test says that proteins targeted for chloroplasts require two signal peptides: Targeting of a newly synthesized protein is most likely to require two ...
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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 ...
Rithwik Sudharsan's user avatar
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What plants use the green spectrum? [closed]

What if the only light provided to a plant was from the green spectrum would plants adapt or starve?
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Chloroplasts in an animal cell

What would happen if we inject a chloroplast organelle into an animal cell? Will the animal cell destroy it? Or is it possible that the chloroplast will somehow survive, and even replicate? Could ...
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Mobile carriers of Light reaction in higher plants

The hydrogen carrier PQ and the electron carrier PC are the mobile carriers in light reaction facilitating electron transfer from PS II to PS I during non-cyclic process. My question is - How do ...
anamika Singh's user avatar
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Reaction centre in Photosystems of higher plants

In photosystems of higher plants, there are about 250-400 pigments (number wise) in a particular photosystem. Out of which,approx 170-180 pigments are of chlorophyll a molecules. And any one of them ...
anamika Singh's user avatar
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Which cell organelle is more important in giving colour to petals? [closed]

It was a question in our school test and given answer was vacuole. But I think it should be chromoplast as they are the organelles specialised to provide colour. But options were given, so which is ...
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How long can algae survive with no air recycling (closed bottle)

In a small bottle nearly filled of Chlorella in water and grow medium, how long would it take for them to die (with or without light). Thanks in advance ;)
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What is this green micro-organism found living in water?

I study biology in France and experiment on water filtration with plants. I found that some chlorophyll-containing micro-organisms (about 10 micrometers in length) were raised in my basin. I can't ...
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Photosystem 1 and 2; P680/P700; Chlorophyll a/b

I am getting slightly confused about how the above relate to each other. My current understanding is that P680 and P700 refer to the primary pigment reaction centres in Photosystems 2 and 1 ...
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Enhanced Spectrum Chloroplasts

As far as I'm aware, chloroplasts produce energy through the use of photosynthesis which essentiall converts CO2 and Water into Glucose (I'm an engineer by trade so really wracking my brains to the ...
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Difference in ATP synthesis in mitochondria and chloroplast

The mechanism of ATP synthesis in mitochondria and chloroplasts are almost the same, but there is a big difference: the f1 particle in mitochondria uses 2 H+ ions to synthesize one ATP, whereas in ...
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Mg in bacteriochlorophyll

In the figure 1A of http://photobiology.info/Jones.html the Mg is not belong to other structure. Is that because something is omitted or is it indeed like a pearl in a mussel's mouth? In the later ...
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Do Gametes contain mitochondria/chloroplasts from their parent cell?

It has now been established (according to the Cambridge A level text book) that organisms form a symbiotic partnership, typically by one engulfing the other – a process known as endosymbiosis. ...
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Evolution of plants and chloroplasts?

I am considering the evolution of plants, specifically considering the chloroplast. I am getting slightly confused and cannot seem to find the information I need to build a coherent picture in my head....
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Is lumen space of a thylakoid completely separate from the intermembrane chloroplast space?

The question I have is whether thylakoids form actually completely independent "vacuoles" (i.e. independent membrane enclosed spaces) or whether the lumen space is connected to the intermembrane space ...
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Plant cell question in age 12 science test

Can anyone help me answer the questions in the attachment about plant cells. It was a question in my 12 year olds science exam. I'm baffled as I think he has given a good knowledgable answer but it ...
MasterSQL's user avatar
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How does an increase in CO2 concentration affect Photosynthesis and Transpiration

I noticed a strange thing in my book. At one place it says that an increase in CO$_2$ concentration in the outside air decreases the rate of transpiration but at the other place it says that an ...
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Why is chlorophyll green? Isn't there a more energetically favorable color? [duplicate]

Chlorophyll being green means it absorbs light in the red and blue area of the spectrum. Isn't this the high and low energy light? Wouldn't plants get more energy if they absorbed light in the green ...
Sarah Toufiq's user avatar
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Origin of the double membrane of mitochondria and chloroplasts

Most websites and textbooks say that the double membrane of mitochondria and chloroplasts are a result of the endocytosis of ancient prokaryotes (the outer membrane is from the vesicle containing the ...
Jason Yang's user avatar
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Trouble understanding how uncouplers in the thylakoid membrane increase the rates of the Electron transport chain?

I am a undergrad in a cell physiology class and just did a learning exercise involving testing rates of the electron transport chain via the reduction of DCPIP, analyzed by spectrophotometry. ( I ...
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Why do chlorotic leaves have green veins?

If chlorotic leaves are chlorophyll deficient, why should the veins be green? shouldn't all the available chlorophyll be directed to the leaf lamina?
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What do the numbers in Photosystem I P700 and Photosystem II P680 stand for? Is it the optimum wavelenght? The maximum wavelenght?

I am a bit confused about this because my teacher and english Wikipedia say it's the wavelenght the Photosystem is most reactive to; my textbook and the german Wikipedia say that it is the maximum ...
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Do plants with non-green leaves have chlorophyll and photosynthesis?

Is it even possible that plants with non-green leaves have chlorophyll, and do such non-green leaved plants carry out photosynthesis?
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Which biosynthetic pathways take place in the plastid and were are they located?

I know that the isoprenoid, jasmonate, glucosinolate, fatty acids, chlorophyll, starch, and aromatic amino acid syntheses are located in the plastid. But I don't know if they are located in the ...
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Is chloroplasts per cell indicative of the photosynthetic power of a plant?

Plant-A has on average N chloroplasts per cell. Plant-B has on average M chloroplasts per cell. If N > M, is plant-A more efficient in turning carbon dioxide into oxygen? Also, is it possible to see ...
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Difference between thylakoids and lamellae in a chloroplast?

I'm slightly confused as to the difference between thylakoids and lamellae. My understanding was that thylakoids are 'discs' that are stacked into grana and there is a membrane between the grana ...
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Was the mitochondrion or chloroplast first?

I still don't know if the mitochondrion or chloroplast was first? I've looked for it on the internet and in various books but haven't found anything. Does anyone have the answer and a theory which ...
user114141's user avatar
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1 answer
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Plastid and mitochondria

I am not a biologist, so please bear with me for this basic question. Although I tried googling, I am confused. What is the difference between plastids, chloroplasts and mitochondria? Are there any ...
user6188's user avatar
4 votes
1 answer
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Common Ancestry of ETCs and ATP Synthase complexes

Rickettsiales are widely regarded as the ancestor of eukaryotic mitochondria through endosymbiosis. Cyanobacteria are widely regarded as the ancestor of eukaryotic chloroplasts through endosymbiosis. ...
single_digit's user avatar
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2 answers
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How fast does the rotor in ATP synthase spin?

I'm sure the exact frequency varies, but does anyone know roughly how many revolutions per minute / second the rotating center part makes?
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Why do plants have green leaves and not red?

I know plants are green due to chlorophyll. Surely it would be more beneficial for plants to be red than green as by being green they reflect green light and do not absorb it even though green light ...
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How many times did endosymbiosis occur?

According to the endosymbiont theory, mitochondria and chloroplasts originated as bacteria which were engulfed by larger cells. How many times is it estimated that this occurred in the past? Are there ...
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