lecture 19

Question 1

available forms of Hydrogen

Answer 1

H2O

Question 2

available forms of Carbon

Answer 2

CO2

Question 3

available forms of Oxygen

Answer 3

• O2, CO2, H2O
• carbohydrates and other organic compounds

Question 4

available forms of Nitrogen

Answer 4

• NO3-, NH4+, N2
• amino acids (proteins), chlorophyll, nucleic acids

Question 5

available forms of Phosphorous

Answer 5

• H2PO4-, HPO4^2-
• nucleic acids, energy transfer (ATP), phospholipids

Question 6

available forms of Sulfur

Answer 6

• SO4^2-
• amino acids and proteins

Question 7

available forms of Potassium

Answer 7

• K+
• osmoregulation, movement

Question 8

available forms of Calcium

Answer 8

• Ca^2+
• root hair growth, cell division, signaling

Question 9

available forms of Magnesium

Answer 9

• Mg^2+
• chlorophyll

Question 10

which elements make up the structural components of a plant (~98% of the dry weight)?

Answer 10

hydrogen, carbon, oxygen, nitrogen, phosphorous, sulfur

Question 11

which elements are involved in fundamental processes in the plant (~1.5% dry weight)?

Answer 11

potassium, calcium, magnesium

Question 12

which elements are considered micronutrients?

Answer 12

Cl, B, Fe, Mn, Zn, Cu, Mo, Ni

Question 13

what is the role of iron?

Answer 13

chlorophyll synthesis and respiration

Question 14

what is the role of Boron?

Answer 14

component of plant cell walls

Question 15

what is the role of manganese?

Answer 15

enzyme cofactor and photosynthesis

Question 16

what is the role of nickel?

Answer 16

only known role is to activate urease, an enzyme involved in nitrogen metabolism

Question 17

what are the two important factors in plant nutrient status?

Answer 17

availability in the soil and uptake into the plant

Question 18

what factors influence the availability of nutrients in the soil?

Answer 18

• soil structure
• moisture
• temperature
• pH

Question 19

how can soil pH be altered?

Answer 19

secreting H+ or organic acids to lower soil pH and increase nutrient uptake through cation exchange, co-transport (anions), and solubility

Question 20

what methods have plants adapted to increase their ability to explore the soil and absorb nutrients?

Answer 20

• lateral roots and root hairs
• development of symbiotic associations with fungi called mycorhizzae (fungus-roots)

Question 21

how is nitrogen absorbed in the plant?

Answer 21

• organic matter in the soil breaks down, releasing nitrogen into the soil as ammonia
• nitrifying bacteria convert soil ammonia to nitrate

Question 22

what is biological nitrogen fixation?

Answer 22

process where free-living bacteria convert atmospheric nitrogen to ammonia

Question 23

how do seeds store carbon?

Answer 23

as starch or as oil, which is broken down and used as an energy source in respiration

Question 24

what are amyloplasts?

Answer 24

specialized plastids densely packed with starch; play a role in gravitropism

Question 25

what is phytate?

Answer 25

a hexose sugar with a PO4 at each carbon; gives it a highly negative charge and associated with cations