Cellular energy _ photosynthesis
C3 plants' photosynthesis is reduced by hot, dry weather. Why? What are examples of C3 plants?
The bright light in the hot climate and dryness in the air reduces the photosynthetic efficiency of C3 plants because the dryness in the weather reduces the concentration of carbon dioxide in the chloroplasts which enables the Rubisco to engage oxygen instead of carbon di oxide.
How many turns of the Calvin cycle are needed to make one molecule of glucose? Each turn of the cycle yields one G3P that can be "skimmed off" to make glucose - What happens to the other 5 molecules of G3P?
. In each turn of the calvin cycle one carbon is fixed. Glucose is a six carbon molecule, hence six turns are needed to construct a single glucose molecule. The glyceraldehyde 3 phosphate is synthesized by the Rubisco which is further used to build ribulose phosphate. One out of six carbon molecules are removed to synthesize sucrose to supply through out the plant and stored in the form of starch granules.
Diagram a thylakoid membrane showing how the Chemiosmotic Model accounts for ATP generation by electron flow and proton pumping. What is the role of ATP synthase? What provides the energy for ATP synthesis by the ATP synthase?
ATP synthease also referred as F1F0 ATPase is a mitochondrial enzyme located in the inner membrane that plays a predominant role in the synthesis of Adenosine triphosphate from adenosine diphosphate and inorganic phosphate. The chemiosmotic potential has two components such as the elelectrochemical gradient of the protons created across the inner mitochondrial membrane denoted by the term ΔpH and the other component ΔΨ is the difference in electrical potential, These two components plays a major role in providing enough energy for ATP synthese to produce ATP.
Where would you place the following organisms on a food pyramid - wolves, rabbits, humans, trees, algae, elephants.
Algae: Primary producers Wolves: Tertiary consumer Rabbits: Primary consumers Humans: Tertiary consumers Elephants: Primary consumers Trees: Primary producers
Why is the production of complex organic molecules such as sugars by autotrophic organisms (green plants) important to heterotrophs?
Autotrophs are the producers can synthesize their own food but the heterotrophs cannot synthesize their own food but depend on another organism such as plant or animal as their living source.
The Calvin cycle uses energy trapped during the light reactions to make sugar. What are the raw materials used by the Calvin cycle? Where does the plant get these raw materials? Why do we call the Calvin cycle a "cycle?"
Carbon di oxide, water, ATP and NADPH are the raw materials involved in calvin cycle. Carbon in the Carbon di oxide and water is derived from the atmosphere, ATP and NADPH are derived from the light reactions.
What is the "carbon fixation" step in the Calvin cycle? What supplies the energy for the Calvin cycle reactions?
Carbon fixation is the primary step in the Calvin cycle in which, carbon dioxide is fixed to synthesize organic compounds through a set of reactions in which RuBisCO serve as a catalyst.
Describe the structure of a chloroplast. What are the names of the important parts of this organelle?
Chloroplasts in green plants derive solar energy from the light, undergoes photosynthesis process and convert to chemical energy in the form of glucose and release oxygen gas. It is a biconvex shaped organelle, that has a inner and outer membrane. Stroma is protein rich aqueous fluid that and that DNA and ribosomes of chloroplast, thylakoid system and starch granules. The thylakoid system is the stack of membranous sacks known as thylakoids that contains the chlorophyll pigments.
What is the food pyramid?
Food pyramid is a graphical representation of interaction between the organisms at different trophic levels in the food chain.
Describe the electron flow through Photosystem II and Photosystem I
In photosystem II, energy from sunlight is captured to use water molecules as the electron donor and liberate a molecule of diatomic oxygen gas. Photosystem I is an integral membrane protein complex that absorbs photons of the wavelength of 700 nm to produce the high energy carriers such as ATP and reduce NADP+ to produce NADPH.
. Describe some ways that human activities negatively impact photosynthesis in plants on land and algae in the ocean. What are some natural events that can strongly reduce photosynthesis?
Over exploitation of the resources, Air pollution and some of the natural ways such as the changes in the temperatures, concentration and accumulation of carbon di oxide in the plant leaves, stress factors such as salt level in the soil, drought, and deficiency in the nutrient salt and air pollution impact on photosynthetic activity of the crop.
. C4 plants have developed a way of escaping from the influence of hot, dry weather to some extent. How have they done this? CAM plants have developed a similar method of keeping photosynthesis going. What do CAM plants do that C3 plants can't?
The C4 plants have developed an adaptation in which the photorespiration is limited by restricting the stomata to be opened. The narrow opening of stomata prevents the major water loss. The adapted special anatomy of the leaf with bundle sheath cells around the leaf veins play a predominant role in concentrating the carbon di oxide in C4 plants than C3 plants which is essential for Calvin cycle.
. The Calvin cycle could work in the dark as long as it is supplied with what? What happens to the ADP + Pi and the NADP that are produced in the Calvin cycle after using ATP and NADPH? Would the light reactions continue to work if they didn't have ADP + Pi and NADP?
The calvin cycle is not expected to be carried out in the dark since it needs NADP for the reaction which is derived from the light dependant reactions.
Describe how chlorophyll traps the energy in photons of light. Where in a plant cell would you find chlorophyll?
The chlorophyll-containing green plants absorb the light energy to convert water, carbon dioxide, and minerals into oxygen and energy-rich organic compounds through a process called photosynthesis. When a chlorophyll absorbs light energy from the sun, the photons from the light excites an electron from its ground energy level to an excited energy level. The electron acceptor receives the electron and creates photo induced charge separation in the reaction center. Chlorophyll is the photosynthetic pigment located on the leaf portion of the plant and gives its green color to the leaf.
What basic facts about energy relationships are implied by the shape of the food pyramid?
The different energy levels in the pyramids refers the energy flow in which the energy is transformed or transferred from one trophic level to next trophic level.
What is the "greenhouse effect?" Is the greenhouse effect good or bad for plant growth? What are the global effects of the greenhouse effect? What happens to the environment as a result of global warming? How will this affect species diversity on the Earth? Can climate change lead to an "extinction crisis" on Earth?
The greenhouse effect is the warming of the Earth's surface due to human activity, boosted with an elevated concentration of carbon dioxide in the atmosphere which are detrimental to plant growth. Climate change due to accumulation of heat, extreme weather conditions, wild fires, rise of sea level, challenges in crop cultivation and food supply, disruption of ozone layer. The extinction crisis eventually results in loss of habitat for the crops and degradation, hyper exploitation of bioresources results in environmental and extreme climatic changes which serve as the main drivers of sixth mass extinction crisis.
What happens to chlorophyll when light strikes it in a leaf? What is the importance of the "reaction center chlorophyll a molecule?" What happens to electrons that are excited to higher energy levels when light photons are absorbed by the chlorophyll molecules?
The photons from the light energy hits the photosystem I and excite the electrons of the cholorophyll located in the reaction center, moves to the iron containing protein, ferrodxoin which are further moved through cytochrome b complex to plastocyanin complex and returns to the chlorophyll molecule. A photosynthetic reaction centre is a protein that is the site of the light reactions of photosynthesis. The reaction centre contains pigments such as chlorophyll and phaeophytin. They absorb light, and promotes an electron to a higher energy level within the pigment.
