Tag: simple nutrients into cells
Questions Related to simple nutrients into cells
Which is the control point in roots where a plant adjust the quantity and quality of solute that reach the xylem:
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At root hair cell
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At endodermal cell
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At pericycle
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At cortical cell
Much of starch is deposited in fruits as it matures. Which of the following explains that how the starch gets there?
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Starch solution passes through cells from xylem to fruit.
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Starch solution passes through companion cells to fruit.
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Starch grains passes through cells from xylem to fruit.
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A sugar solution passes through phloem cells to the fruit, where it is changed to starch.
According to the most widely accepted theory of translocation of organic solutes - 'Mass flow hypothesis' or 'Pressure flow hypothesis', organic substances move in the sieve tubes from the region of higher osmotic concentration to the region of lower osmotic concentration in a mass flow, due to occurrence of a pressure gradient.
A scientist associated with work on translocation is
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Arnon
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Calvin
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Dixon
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Munch
'Mass flow hypothesis' or 'Pressure flow hypothesis' to explain translocation was given by Munch, 1930.
Translocation of food in higher plants is related to the idea of
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Source and sink
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Ascent of sap
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Diffusion
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Cyclosis
Translocation of organic solutes in phloem is bidirectional. The transport of prepared food is from source to sink. The source is the area, where sugars are present in larger amount either because they are synthesized there, example leaves or are stored there, example storage organs.
Which of the following act as sink?
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Root cells
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Fruit
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Seeds
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All of the above
Translocation of organic solutes in phloem is bidirectional. The transport of prepared food is from source to sink.
Pacemaker is situated in the
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Wall of right atrium
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Interauricular septum
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Interventricular septum
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Wall of left atrium
The pacemaker of heart is
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Foramen ovale
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Sinoatrial node
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Ductus arteriosus
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Bundle of His
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Vagus nerve
Electrical impulses from the heart muscle cause your heart to beat (contract). This electrical signal begins in the sinoatrial (SA) node, located at the top of the heart's upper-right chamber (the right atrium). The SA node is sometimes called the heart's“natural pacemaker.”
Rate of heart beat is determined by
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Purkinje fibres
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Papillary muscles
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AV-node
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SA-node
The heart beat is initiated and regulated by nodal tissue made of specialised cardiac muscles called
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Spongy tissue
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Purkinje tissue
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Alveolar tissue
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None of these
Purkinje tissue is influenced by electrical discharge from the sinoatrial node. During the ventricular contraction portion of the cardiac cycle, the Purkinje fibres carry the contraction impulse from both the left and right bundle branch to the myocardium of the ventricles. In this way these fibres control and initiate heart beat.
The action potential is conducted from the atria to ventricles by:
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Purkinje fibre
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SA node and AVN
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Bundle of his and SAN
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All of the above
- Sino-atrial node (SA node) is located the right upper corner of the right atrium and AVN(AV node) is located in the lower-left corner of the right atrium close to the atrioventricular septum.
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The SAN can generate the maximum number of action potentials, i.e., $70-75 min^{–1}$, and is responsible for initiating and maintaining the rhythmic contractile activity of the heart. Therefore, it is called the pacemaker. From the SA node, the action potential is conducted from the atria to ventricles by AVN.
- Hence the action potential is conducted from the atria to ventricles via SA node and AVN.
- So, the correct answer is 'SA node and AVN'.