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Mila [183]
3 years ago
14

Which of the following is an example of an ABAB design? Half of the subjects receive one treatment and the other half are not tr

eated. All subjects received one of two treatments. A subject is observed and treated. A subject is observed both before and after two exposures to the treatment.
Biology
1 answer:
Karolina [17]3 years ago
4 0

Answer:

Option D, A subject is observed both before and after two exposures to the treatment.

Explanation:

In A-B-A-B design the alphabets have following meaning

a) First A – It is the baseline value or the value measured before treatment

b) First B – It is the treatment measurement

c) Second A  - It is the withdrawal of treatment  

d) Second B – It is the reintroduction of treatment  

The second A is known as the reversal phase in which the intervention is withdrawn to see if the target behavior returns to the baseline behaviour

Thus , there are two measurements involved one before the intervention and second after the intervention

Option D is correct

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fiasKO [112]

Explanation:

-Pheophytin

P680 the primary donor of Photosystem II becomes excited and transfers an electron to pheophytin. Pheophytin is the initial intermediate electron acceptor and carrier in Photosystem II; it is a chlorophyll-like molecule that lacks a central magnesium ion.

Further Explanation:

Photosynthesis is a chemical pathway that’s integral to producing energy in plants and other primary producers. Energy in the form of molecules of glucose is produced from light, water and carbon dioxide while oxygen is released. This occurs in several complex steps, photosynthesis is a rate limited reaction, depends on several factors including carbon dioxide concentration, ambient temperature and light intensity; the energy is retrieved from photons, I.e. particles of light, and water is used as a reducing agent. This occurs in the thykaloids, where pigment molecules like chlorophyll reside.

The chloroplast is a membrane bound organelle found in plants. It contains several invaginations of a plasma membrane called the thylakoid membrane. This contains chlorophyll pigments, in stacks called granum, while the internal spaces of the organelle are called the lumen. Liquid surrounds the granum, forming the stroma.

During the light reaction:

  • Light is absorbed by pigments in phosystem II (PSII). This energy is transferred among pigments til it gets to the reaction center, and is transferred to P680; this promotes an electron to a higher energy level where it then goes to an acceptor molecule, like Pheophytin .
  • Water supplies the chlorophyll in plant cell with replacement electrons for the ones removed from photosystem II. Additionally, water (H2O) split by light during photolysis into H+ and OH- acts as a source of oxygen along with functioning as a reducing agent.
  • the electron moves down an electron transport chain (to PS I)where it experiences continuous energy loss. This energy fuels the pumping of H+ from the stroma to thykaloid, leading to the formation of a gradient. The H+ move along their gradient and cross through ATP synthase, into the the stroma.
  • ATP synthase converts ADP and Pi to the energy storage molecule ATP.
  • The electron gets to photosystem I where it goes to pigments at P700. It absorbs light energy, the electron is promoted to a higher energy level, and passed to an electron acceptor. This leaves a space for another electron which is then replaced by one from photosystem II.
  • in the ETC, the molecule NADP is reduced to NADPH by providing H+ ions. NADP and NADPH are integral to the Calvin cycle where monosaccharides or sugars like glucose are produced after the modification of several molecules.

Learn more about Photosynthesis at brainly.com/question/4216541

Learn more about cellular life at brainly.com/question/11259903

#LearnWithBrainly

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Which neurotransmitter prepares the body for "fight or flight" and is seen in increased levels in patients with anxiety-related
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The neurotransmitter in the body which prepares it for "fight or flight" reaction is EPINEPHRINE. The level of Epinephrine is remarkably high in patients who have anxiety-related disorders. Also known as adrenalin or adrenaline, epinephrine is a hormone and at the same time a neurotransmitter; it is also used as medication.

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3 0
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Which of the following is necessary for the light-independent reactions to proceed?
Yanka [14]

Answer;

C) ATP

Explanation;

-Photosynthesis can be divided into two parts: the light-dependent reactions and the light-independent reactions (also referred to as the "dark" reactions).

-The two products of the light-dependent reactions of photosystem are ATP and NADPH.  The movement of high energy electrons releases the free energy that is needed to produce these molecules.  The ATP and NADPH are used in the light-independent reactions to make sugar.

-The light-independent reactions, or dark reactions, of photosynthesis are chemical reactions that convert carbon dioxide and other compounds into glucose. These reactions occur in the stroma, the fluid-filled area of a chloroplast outside the thylakoid membranes.

8 0
3 years ago
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