Lucy Garland
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AS - Level (Mass Transport in Plants) Biology Test sobre How does water get to the top of a tree?, creado por Lucy Garland el 09/04/2016.

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Lucy Garland
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How does water get to the top of a tree?

Pregunta 1 de 6

1

What do xylem vessels transport?

Selecciona una de las siguientes respuestas posibles:

  • Minerals

  • Water

  • The products of photosynthesis

Explicación

Pregunta 2 de 6

9

Rellena los espacios en blanco para completar el texto.

Leaves have , which open to let in for photosynthesis. This, unavoidably, lets water diffuse out of the leaf due to the surrounding air usually having a than inside the leaf. This process is called which defines as the evaporation of water vapour, mainly through the stomata in the surface of a leaf. It is a process, using energy from the sun, which evaporates water from the cells.
As water vapour diffuses from the air spaces in the mesophyll and through the stomata, it is replaced by water from the cells. This in turn is replaced by water from the in the veins of the leaf.

Explicación

Pregunta 3 de 6

10

Selecciona la opción correcta de los menús desplegables para completar el texto.

Water cannot be pulled up more than ( 10, 5, 20 )m, which is a problem tall trees must be overcome. Xylem vessels are very narrow, and water molecules tend to stick together because of the ( hydrogen, covalent, strong ) bonds between them - this property of water is called ( cohesion, tension ). As water moves out of the ( xylem, phloem ) in a leaf, it drags other molecules of water behind it. Because the vessels are so ( narrow, wide ), the column of water behind does not break, and water is pulled up all the way from the roots.
The pulling force is so great that the column of water is actually being ( stretched, pulled ) - it is under ( tension, cohesion ). The tension in the column of water tends to pull the walls of the vessels ( inwards, outwards ) slightly. However, the ( lignin, cellulose ) in the walls is strong enough to stop the vessels ( collapsing, bursting, breaking ).

Explicación

Pregunta 4 de 6

5

Water enters the roots by and passes up the stem to the leaves, where it evaporates into the inside the leaf and then passes out to the atmosphere through the . The air has a low because it normally has a low percentage of .

Arrastra y suelta para completar el texto.

    osmosis
    diffusion
    transpiration
    air spaces
    cells
    stomata
    mesophyll
    water potential
    concentration
    water vapour
    water molecules

Explicación

Pregunta 5 de 6

2

Which of these are advantages of transpiration

Selecciona una o más de las siguientes respuestas posibles:

  • The stream of water transports mineral ions around the plant

  • The flow of water helps to cool down the plant.

  • The evaporation of water from the leaves has a cooling effect which prevents enzymes denaturing.

  • The evaporation of water has a cooling effect which gives the plant energy.

Explicación

Pregunta 6 de 6

1

The two ideas, of cohesion and tension, used to explain how water is pulled up in a plant, are brought together by what theory?

Selecciona una de las siguientes respuestas posibles:

  • Cohesion-tension theory

  • Tension-cohesion theory

  • Cohesion theory

Explicación

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