Theme 4

Question 1

what is homeostasis?

Answer 1

dynamic process compensating/ adjusting for changes in the internal and external environment

Question 2

what are the components of the environment/metabolism?

Answer 2

temperature
pH
solutes
water
pressure

Question 3

what are the essential elements for plants?

Answer 3

essential element
macronutrients
micronutrients

Question 4

what are essential elements for plants comprised of?

Answer 4

-components of nucleic acids and amino acids
-function as enzyme cofactors
-have a role in photosynthesis or regulation of osmotic potential

Question 5

what are the traits of macronutrients for plants?

Answer 5

-account for 96% of dry mass
-essential in large quantities
-C, H, O from air and water not considered minerals
-N, P, K, S, Ca, Mg are mineral nutrients, available to plants through the soil as dissolved ions in water

Question 6

what are traits of micronutrients?

Answer 6

-essential in trace quantities
-Cu, Cl, Ni

Question 7

what are the traits of nitrogen?

Answer 7

-abundant element in air
-limiting to plant
-triple bond requires specific enzyme
-nitrogen cycle provides soil nitrogen

Question 8

what is nitrogen fixation?

Answer 8

incorporates atmospheric N2 into plant- available compounds NH4

Question 9

what is bacterial ammonification?

Answer 9

breaks decaying organic N compounds into NH4

Question 10

what happens to NH4 in plants?

Answer 10

its taken up by plants but they prefer NO3

Question 11

what does bacterial nitrification do?

Answer 11

oxidizes NH4 to NO3

Question 12

why do plants convert NO3 to NH4?

Answer 12

to assimilate N into organic compounds

Question 13

what is eutrophication?

Answer 13

enrichment of an ecosystem with chemical nutrients such as compounds containing nitrogen and phosphorous

Question 14

what is soil as a body part?

Answer 14

the living skin of the earth

Question 15

what does soil contain?

Answer 15

soil-mineral particles
compounds
ions
decomposing organics
water
air
organisms

Question 16

what determines soil properties?

Answer 16

relative amount of soil particles

Question 17

when is soil solution avalaible for plant uptake?

Answer 17

after gravity drainage

Question 18

what does soil solution do?

Answer 18

coats soil particles
partially fills pore spaces

Question 19

what type of soil holds more water?

Answer 19

clay soils holds more water than sandy, loose soil

Question 20

what type of soil composition increases water availability?

Answer 20

humus

Question 21

what is soil solution?

Answer 21

a combination of water and dissolved substances

Question 22

how does soil solution uptake work?

Answer 22

water molecules are attracted by negatively charged clay and humus particles

Question 23

what types of ions are present in soil solution?

Answer 23

both cations and anions but not equally available to plants

Question 24

how do minerals enter plants?

Answer 24

passively enters the roots with the water

Question 25

how do roots select for mineral uptake?

Answer 25

selectivley absorbed vio ion-specific transport proteins

Question 26

what is cation exchange?

Answer 26

replaces minerals with H+ produced by roots as excreted H+ or carbonic acid

Question 27

where are mineral cations absorbed to?

Answer 27

negative soil particles

Question 28

where are protons pumped from?

Answer 28

root hairs

Question 29

what are the traits of anions?

Answer 29

weakly bound to soil move freely into root hairs leach easily by excess water

Question 30

why is soil usually alkaline?

Answer 30

due to negatively charged clay particles bound to cations

Question 31

what happens when soil turns acidic?

Answer 31

the negative charged on the clay are occupied by H+ and the cations are leached out easily and become unavailable to the plant

Question 32

what is passive transport?

Answer 32

requires no metabolic energy

Question 33

what is active transport?

Answer 33

requires metabolic energy (ATP)

Question 34

in passive transport, how do substances move?

Answer 34

down a concentration or electrochemical gradient

Question 35

what are examples of forms of passive transport?

Answer 35

simple diffusion transport proteins ion channels carrier proteins

Question 36

in active transport how do substances move?

Answer 36

substances move against the gradient

Question 37

what are examples of active transport?

Answer 37

transport proteins using energy H+ pump

Question 38

what are the two mechanisms to increase uptake?

Answer 38

root hairs mycorrhizae

Question 39

how do root hairs increase uptake?

Answer 39

increase root surface area absorb water and minerals

Question 40

what is mycorrhizae?

Answer 40

symbiotic association between fungus and plant roots

Question 41

how does mycorrhizae benefit both partners?

Answer 41

by two way exchange of nutrients

Question 42

what does the plant provide the fungus in mycorrhizae?

Answer 42

carbon

Question 43

what does fungus supply the plant in mycorrhizae?

Answer 43

increases plants supply of soil nutrients

Question 44

what do charged particles require?

Answer 44

a channel or transporter

Question 45

what is the most important soil layer?

Answer 45

the top layer with humus

Question 46

what does nitrogen fixation do for plants?

Answer 46

incorporates atmospheric N2 into plant available compounds

Question 47

in what ways do plant mechanisms allow solutes to move?

Answer 47

into and out of cells laterally from cell to cell over long distances between root and shoot

Question 48

what are the 3 types of water movement in plants?

Answer 48

osmosis aquaporin water potential

Question 49

what is osmosis?

Answer 49

passive movement of water across a selectively permeable membrane

Question 50

what is aquaporin?

Answer 50

proteins that allow rapid movement of water through hydrophobic membrane core

Question 51

what is water potential?

Answer 51

the potential energy of water driving force

Question 52

what is the water potential of pure water?

Answer 52

0 megapascals

Question 53

where does water move on the water potential gradient?

Answer 53

from high to low water potential

Question 54

what does the presence of solutes do to water potential?

Answer 54

lowers it (value is always negative)

Question 55

what is pressure potential?

Answer 55

the force required to stop water movement

Question 56

what does positive pressure do to water potential?

Answer 56

increases water potential

Question 57

what does osmosis create?

Answer 57

turgor pressure

Question 58

when does wilting occur?

Answer 58

when plants lose more water than they gain

Question 59

what does an increase of solutes inside the cell result in?

Answer 59

more negative solute potential and more positive turgor pressure inside the system

Question 60

why does a plant cell adjust solutes?

Answer 60

to keep itself turgid and allow water to come in until equilibrium is reached

Question 61

what are the three pathways of water into roots?

Answer 61

apoplastic pathway symplastic pathway cell to cell movement

Question 62

what is the apoplastic pathway?

Answer 62

water moves across cortex to endodermis via cell walls and intercellular spaces

Question 63

what is the symplastic pathway?

Answer 63

water flows from cytoplasm of one cell to the next via plasmodesmata

Question 64

which pathway is the fastest?

Answer 64

apoplastic

Question 65

where do apoplastic pathways end?

Answer 65

the casparian stripe

Question 66

what is the casparian strip?

Answer 66

a selective barrier for ions

Question 67

where is the casparian strips?

Answer 67

in the endoderm of roots

Question 68

what does the casparian strip do?

Answer 68

-forces apoplastic water and nutrients into symplast -ensures all water and solutes pass through a plasma membrane -restricts solutes from flowing back

Question 69

why do water and solutes have to pass through a plamsa membrane?

Answer 69

in order to regulate the ions that pass into vascular tissue

Question 70

what type of anatomy contributes to cohesion-tension forces?

Answer 70

leaf anatomy

Question 71

where may cohesion-tension mechanism reach its physical limit?

Answer 71

in the tallest trees

Question 72

what is transpiration?

Answer 72

evaporation of water out of plants

Question 73

what are traits of cohesion-tension mechanisms of water transport?

Answer 73

-evaporation from mesophyll walls -replacement by cohesion (H-bonded) water in xylem -tension, negative pressure gradient, adhesion of water to xylem walls adds to tension

Question 74

what is cohesion-tension mechanism of water transport driven by?

Answer 74

transpiration