Unit 1 Quizzes

Question 1

List the characteristics that are unique to plants

Answer 1

large central vacuole, cellulose cell wall, specialized plastids, unique sterols, and non-living substances

Question 2

what is the difference between apoplast and symplast?

Answer 2

the symplast refers to the continuous cytoplasm and controls what comes in and out of the cell, while apoplast is the continuous connection between cell walls

Question 3

between apoplasts and symplasts, which is a better system to conduct water? which is better to conduct large biomolecules?

Answer 3

apoplast because you do not have to go through a small pore; symplast

Question 4

why do plants need water? why do they need so much?

Answer 4

plants are made of water and needs it for physiological changes, photosynthesis, evaporative cooling, transpiration, and structural integrity

transpiration causes most of the water loss in a plant and it makes up 95% of the plant

Question 5

why is transpirational cooling effective?

Answer 5

due to the high specific heat of water, it takes a lot of heat to make the temperature of water in a plant to be raised, therefore keeping the plant cool. The water in the plant absorbs the energy from the sun so the plant does not get heated up. In addition, the water can be evaporated from the plant as well as keeping it cool

Question 6

explain water as a super solvent and its dependence on hydrogen bonds

Answer 6

water is a super solvent due to its polarity. It is able to bind to substances that have a positive or negative charge. This is due to the two hydrogen atoms that are opposite to the oxygen making the atom unbalanced and polar

Question 7

explain the thermal properties of water and its dependence on hydrogen bonds

Answer 7

water has a high specific heat and a high heat of vaporization. It takes a lot of heat to raise one degree of water or to make water phase change respectively. This is because it takes a lot of energy to separate the hydrogens from the oxygen

Question 8

explain capillarity and its dependence on hydrogen bonds

Answer 8

due to adhesion, cohesion, and surface tension, water molecules are highly attracted to each other. With cohesion, the water molecules bind to each other and follow one another, but with adhesion, the water molecules bind to the surface it is rising up in. Surface tension brings all of these components together as capillarity

Question 9

explain high tensile strength and its dependence on hydrogen bonds

Answer 9

if you pull on the water molecules they will not break apart. This is because the water molecules are strongly attracted to each other and what they are bound to

Question 10

explain diffusion

Answer 10

diffusion is water trying to achieve equilibrium, For water to achieve equilibrium, there must be a concentration gradient to diffuse into and achieve equilibrium. It is dependent on the driving force - concentration gradient - and the diffusion coefficient - the transport coefficient

Question 11

explain bulk flow

Answer 11

bulk flow is the pressure gradient that is required to move water in a plant. It is dependent on hydraulic conductance, the transport coefficient, and a pressure gradient, which is the driving force

Question 12

how does a larger leaf influence bulk flow?

Answer 12

there is an increase in the boundary layer because bigger things have bigger boundary layers. This leads to a decrease in transpiration because there is more surface area on the leaf for water to exit out of the plant

Question 13

how does a slower windspeed influence transpiration rate?

Answer 13

the transpiration rate decreases because the wind is taking the water away from the leaf and moving it into the boundary layer. The boundary later is reduced because you are disrupting the still air that is around the leaf

Question 14

how does a higher relative humidity influence the transpiration rate?

Answer 14

the transpiration rate decreases and VPD decreases because the ambient vapor pressure is going up while saturation vapor pressure is going up, there is less concentration gradient and less water is in the plant than in the air

Question 15

how does a higher temperature influence the transpiration rate?

Answer 15

it increases the transpiration rate an increases the VPD because a higher temperature can hold more water. Saturation vapor pressure increases in the leaf, leading to more transpiration to occur since the leaf is wetter than the air

Question 16

suppose that a pine tree has tracheids of 10 micrometers in diameter, and a sunflower has vessels of 50 micrometers in diameter, Kh is higher for the sunflower by up to how many times?

Answer 16

600

Question 17

how does a larger stomatal aperture influence transpiration?

Answer 17

increases the transpiration rate because there is a decrease stomatal resistance. There is a decrease in stomatal resistance because more water is entering the plant because it has larger pores and a larger radius increases the flow rate. If more water is entering the plant, then more water can be release, this increasing the transpiration rate

Question 18

what can the mobility of nutrients tell us about deficiencies?

Answer 18

when a mineral is mobile, a plant is able to move it around where it is needed, however, when its immobile, it stays where was originally placed. For example, in nitrogen deficiency, there will be yellowing leaves neat the bottom of the plant where the older leaves are. Nitrogen in mobile so the plant allocates its resources towards newer leaves to prevent nitrogen deficiency in other parts of the plant

Question 19

what differentiates active from passive transport? how does this relate to the three types of transporters?

Answer 19

the differences between active and passive transport is that passive transport does not use energy to transport ions while active transport does
- the three types of transport proteins are channels, carriers, and pumps. Both channels and carriers are involved with passive transport, while pumps are associated with active transport. channels are essentially tubes that allow molecules to diffuse into the cell, and it can turn on and off when needed and be selectable. Carriers move across the membrane, but can be selective to ion sizes. carriers move across the membrane but are more selective than channels and have a conformation change. Pumps can either have ATPase attached to the pump to actively move ions in or have ATPase act away from the pump to also bring ions in (proton motive force)