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Topic 4: Biodiversity and natural resources > How plants are adapted to survive > Flashcards

How plants are adapted to survive Flashcards

1
Q

What does adhesion (of water molecules) refer to?

A
  • adhesion is the binding of a cell to another cell or a cell to a surface through cell adhesion molecules
  • water is able to form hydrogen bonds with other molecules which is known as adhesion
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2
Q

What does capillary action refer to? How does it occur?

A
  • capillary action refers to liquid flowing through a narrow tube without the assistance of any force
  • it occurs when the force of adhesion is greater than the force of cohesion
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3
Q

What does cohesion (of water molecules) refer to?

A
  • cohesion refers to the state of cohering or sticking together of the same substance
  • the sticking together is by intermolecular forces that hold molecules together
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4
Q

How does cohesion occur in plants?

A
  • in plants cohesion occurs when water molecules stick together via hydrogen bonds in transpiration
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5
Q

What is the difference between cohesion and adhesion?

A
  • cohesion is the attraction between molecules of the same substance while adhesion is the attraction between molecules of different substances
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6
Q

Define diffusion

A

diffusion is the net movement of molecules from a region of their higher concentration to a region of their lower concentration by relatively slow random movement of molecules

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7
Q

Define mass flow

A
  • mass flow is the movement of water and solutes from high to low concentration across a selectively permeable membrane
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8
Q

Define osmosis

A
  • osmosis is the net movement of water molecules from a region of higher water potential to a region of lower water potential through a partially permeable membrane
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9
Q

Define evaporation?

A
  • the process of a liquid turning into a gas
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10
Q

Where are cell walls formed and what do they offer?

A
  • cell walls are formed outside of the cell membrane and offer structural support to the cell by providing the polysaccharide cellulose
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11
Q

What does the middle lamella form? And what does it do?

A
  • the middle lamella forms the outermost layer of the plant cell and acts like glue to stick adjacent plant cells together
  • it provides stability to the plant
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12
Q

What are plasmodesmata? What does it allow?

A
  • plasmodesmata are narrow threads of cytoplasm (surrounded by a cell membrane) which connect the cytoplasm of neighbouring plant cells
  • this allows substances to be transported between plant cells and facilitates (enables) cell to cell communication
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13
Q

What are pits? How are they lined up? What does this do?

A
  • these are very thin regions or the cell wall
  • the pits in adjacent plant cells are lined up in pairs
  • this facilitates (enables) transport of substances between cells
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14
Q

What are chloroplasts? What are chloroplasts the site of? What do they contain?

A
  • chloroplasts are larger than mitochondria
  • surrounded by a double membrane
  • chloroplasts are the site of photosynthesis
  • chloroplasts contain thylakoids
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15
Q

What else do chloroplasts contain? Why do they need this?

A
  • chloroplasts contain small circular pieces of DNA and ribosomes
  • this is used to synthesise proteins needed in chloroplast replication and photosynthesis
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16
Q

Where are thylakoids found? What are they? What do they form? What are lamellae?

A
  • found in chloroplasts
  • they are membrane-bound compartments which contain chlorophyll stack to form structures called grana
  • grana are joined together by lamellae
  • lamellae are thin and flat thylakoid membranes
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17
Q

Where is chlorophyll found? What does it absorb?

A
  • chlorophyll is found inside thylakoids (which is inside chloroplasts)
  • chlorophyll absorbs light (with wavelengths)
18
Q

What are amyloplasts? What do they contain? What are they responsible for storing?

A
  • amyloplasts are small membrane bound organelles
  • they contain starch granules
  • they are responsible for storing starch in plants and converting it back to glucose when the plant needs it (starch is converted back to glucose in plants during photosynthesis)
19
Q

What is the vacuole? What is it surrounded by? What does it contain?

A
  • the vacuole is a sac in plant cells surrounded by tonoplast (selectively permeable membrane/ vacuolar membrane)
  • it contains cell sap
20
Q

What are the functions of the vacuole and tonoplast?

A

functions of the vacuole and tonoplast:
- they keep cells turgid, which stops the plant wilting (drooping)
- they can break down and isolate unwanted chemicals in plant cells
- the tonoplast controls what can enter and leave (the vacuole)

21
Q

What is turgor pressure? What does turgid mean?

A
  • turgor pressure is the force exerted by stored water against a cell wall
  • a cell with high turgor pressure is said to be turgid
  • plant cells which have higher turgor pressure due to the intake of water by osmosis making the cell rigid
22
Q

What is cell sap a mixture of?

A
  • cell sap is a mixture of different substances such as water, minerals, waste and enzymes
23
Q

Why is water important for plants?

A
  • important component required for photosynthesis
  • provides a transport medium for minerals
  • maintains turgidity in plant cells through pressure in cell vacuoles
  • regulates temperature - to ensure that enzymes can function at their optimum rate
24
Q

Why are magnesium ions important for plants?

A
  • important requirement for the production of chlorophyll
  • this provides the green colour of stems and leaves and is essential for photosynthesis
25
Q

Why are nitrate ions important for plants?

A
  • without nitrate ions, the plant would be unable to synthesis DNA, proteins and chlorophyll
  • enzymes are important proteins for which nitrate ions are needed
  • these molecules are essential for plant growth, as well as the production of fruit and seeds
26
Q

Why are calcium ions important for plants?

A
  • these form important cell wall components
  • plants require calcium ions for proper growth
27
Q

What is the basic function of xylem tissues?

A

function of xylem tissues:
- vascular tissue that transports dissolved minerals and water around the plant
- structural support

28
Q

What do the cell walls of xylem vessels contain?

A
  • xylem vessel cell walls contain lignin
29
Q

What do xylem vessels form? What are they formed by? What does the xylem vessel not contain because of this?

A
  • xylem vessels form long, hollow straw-like structures that are formed by dead cells
  • this means that they do not contain any cytoplasm or organelles that could slow down the flow of water
30
Q

Why are xylem vessels made up of dead cells? How is this an advantage?

A
  • xylem vessels are formed by dead cells due to lignification of cell walls
  • the adaptation helps in efficient transportation of water because if these cells were living then they would have absorbed water for its survival and so the (green) areas of the plants that require water for photosynthesis might not have received adequate amounts of water.
31
Q

What regions in the walls of xylem vessels are not lignified? What does this allow?

A
  • pits are small regions in the walls which are not lignified
  • this allows for lateral movement of water and minerals between xylem vessels
32
Q

What are the structures of xylem vessels?

A
  • lignified cell walls (aka mature cells)
  • no end plates (mature)
  • no protoplasm (cells are dead when mature)
  • pits in wall (non-lignified regions)
  • small diameter of vessels
33
Q

Structure and function = lignified cell walls

A
  • lignified cells walls = adds strength to withstand the hydrostatic pressure so vessels don’t collapse, impermeable to water (water cannot penetrate)
34
Q

Structure and function = no end plates

A
  • no end plates = allows the mass flow of water and dissolved solutes as cohesive and adhesive forces are not impeded
35
Q

Structure and function = no protoplasm (cells are dead when mature)

A
  • doesn’t impede the mass flow of water and dissolved solutes (transpiration stream)
36
Q

Structure and function = pits in wall

A
  • lateral movement of water, allows continual flow in case of air bubbles forming in the vessels
37
Q

Structure and function = small diameter of vessels

A
  • helps prevent the water column from breaking and assists with capillary action
38
Q

What is capillary action in plants?

A
  • is a process where water is able to ascent from the root upward through the xylem tissues of a plant
39
Q

What are slcerenchyma fibres?

A

-

40
Q

Where do plants take in water and inorganic ions?

A
  • they are absorbed through the root hairs on the root and travel up the stem in xylem vessels

Topic 4: Biodiversity and natural resources (8 decks)

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