BFG Ch 8

Question 1

Demands of autotrophs

Answer 1

water
minerals from soil
carbon dioxide
sun

=photosynthesis

Question 2

How do plants get their water

Answer 2

osmosis

water crosses epidermal cells in the roots via osmotic pressure (trying to dilute the cells compared to environment)

Question 3

Difference between turgid and flaccid

Answer 3

Turgid cells are fully inflated and exerting pressures against the cell walls. Flaccid cells dont’ have enough water to be pushing strongly against the cell walls

Question 4

Does water continue to diffuse into turgid cells?

Answer 4

Yes; it simply displaces the comparable volume of water.

This turgor pressure “safety valve” keeps cells from bursting

Question 5

Why are saline soils bad

Answer 5

they cause roots to lose water because they have a lower water content than the roots.

Osmotic flow is reversed.

Question 6

Plasmolysis

Answer 6

when the plasma membrane shrinks away from the cell wall. Prolonged plasmolysis results in cell death.

Question 7

Why can some sp. survive in saline soils?

Answer 7

beacuse they can store salts and thus keep osmotic pressures going the right direction

Question 8

Development of root pressure:

Answer 8

Root pressure occurs when the epidermal and endodermal pumps push water across the root and up the xylem with a slight pressure.

Question 9

Describe the flow of water from soil to the xylem

Answer 9

Water contacts root hairs
osmotic pressure pulls water in to epidermis

from the epidermis, water flows into the cortex (first osmotic pump)

Cortex–> endodermis (2nd osmotic pump)

endodermis–> xylem

Question 10

what is water of guttation

Answer 10

the water droplets that appear early morning on leaves. They emerge from special pores and are used to rid the plant of extra salts.

Question 11

What are the two ways that water is pumped through the plant?

Answer 11

Root pressure

transpirational pull

This not only moves water, but also minerals and has a significant cooling effect on the plant and causes shady humid under-stories

Question 12

What is transpirational pull?

Answer 12

The pull of water through the plants due to it evaporating off the leaves.

Question 13

How does water enter the leaves from the xylem?

Answer 13

mesophyll cells with high concentrations of photosynthesized sugars use osmosis to draw water from the xylem

Water is later discharged from turgid mesophyll cells; sun heat turns it to vapor= transpiration

Question 14

Major source of water loss for plants

Answer 14

stomata

hot environments cause high transpiration rates. Some species only open their stomata at night and store CO2 inside for the next day’s use.

Question 15

What is cold hardening?

Answer 15

The process in which an accumulation in the protoplasm of sugars functions as antifreeze. The permeability of cell membranes is changed in another phase of cold hardening, which allows water to leak into intercellular spaces and thereby averting ice crystams forming inside living protoplasm.

Question 16

Mineral nutrient needs of plants (class acronym)

Answer 16

In Class:
Macro: CHOPKINS
micro: CaFe Mg

Question 17

Elements used in greatest quantities by growing plants

Answer 17

Carbon
Hydrogen
Oxygen

Question 18

Macronutrients

Answer 18

used in large quantities

Question 19

micronutrients

Answer 19

used in lesser amounts, sometimes are simply introduced as impurities in fertilizer mixes or dissovled in tap water.

Question 20

Unique elements that some plants need in trace amounts include..

Answer 20

Chlorine
Aluminum
Sodium
Silivon
Colbalt

Question 21

What is chlorosis?

Answer 21

the yellowing of leaves due to deficiencies in magnesium and iron (and sometimes nitrogen)

Question 22

What element is an integral part of chlorophyll and can result in chlorosis if there’s a deficiency?

Answer 22

magnesium or nitrogen

Question 23

Nitrogen

Answer 23

incorporated into the structure of chlorophyll and amino acids.

Deficiencies result in stunted growth and chlorosis

Question 24

Phosphorus

Answer 24

deficiency causes reduced growth and poor cell development.

Used in fatty membrane components; involved in DNA synth

Question 25

Calcium

Answer 25

involved in synthesis of pectin (glue bonding cell walls)

vital to tissue formation in meristems.

deficiency: rapid death (necrosis) of stem and root tips and leaf margins

Question 26

Things that can kill plants

Answer 26

overwatering
salty soils
high air pollution
invasion of pathogen
nutrients can be unavailable to plant

Question 27

Why should we wait to pluck yellow leaves off plants?

Answer 27

because the plant is undergoing nutrient relocation from the leaf and it’s best to just let it resoak it up.

Question 28

Do plant nutrient requirements stay the same over its life?

Answer 28

no. they change with the course of grwoth

namely, when ripeness to flower is achieved, they need more phosphorous and potassium

N-P-K ratios change (common fertilizer language)

Question 29

3 classes of inorganic soil particles

Answer 29

sand (largest)
silt (middle)
clay (smallest)

Question 30

What are loams?

Answer 30

mixtures of sand, silt, and clay.

ex. sandy-loams contain more sand than other parts; humus-loams contain various proportions of organic matter mixed in.

Question 31

Soil

Answer 31

mixture of inorganic materials derived from rock erosion and organic matter called humus (decomposed remains of plants and animals)

Question 32

Water-holding capacity of soil

Answer 32

defined by water content of a thoroughly wetted soil after surplus water has drained

sandy soil retains little water

humus increases water holding capacity

Question 33

capillary water

Answer 33

water held between spaces of soil particles

principle source of moisture to roots

Question 34

Why is clay bad

Answer 34

has electrical charges that attract water

really bad water availability

also lacks porosity

Question 35

soil pH

Answer 35

relative acidity/alkalinity

most things grow well in neutral soil

minerals in water can alter soil pH

air pollution in acid rain can alter pH

• causes aluminum, manganese, and iron to be more available and poison the cells
• can interfere with uptake of calcium by roots

Molybdenum can be relased in alkaline soils; also makes phosphates and calcium unavailable to roots

ESSENTIALLY alter nutrient availability in a bad way.

Question 36

Chelates

Answer 36

soluble organic compounds to which iron is bound

make element available to plants without toxic effects

often used in alkaline soils that don’t have high iron availability

Question 37

Describe chloroplasts

Answer 37

membrane enclosed

stacks of membranes, called grana- exact location of chlorophyll and other pigments.

either have chlorophyll a or b
have carotene (orange-yellow) and xanthophylls (yellow to colorless)

Question 38

yellow leaves are showing what pigments?

Answer 38

xanthophylls and carotenes (because chlorophyll has been removed)

Anthocyanin may also be present; not active in photosynthesis because it’s in its own storage.

Question 39

Variegated leaves

Answer 39

have inherited color patterns

formed by tissues in which pigments occur separately or in unusual combos

Question 40

What colors of light should artificial illumination include?

Answer 40

blue and red wavelengths

Question 41

Cellular respiration

Answer 41

the way that cells make energy from glucose.

requires oxygen obviously (for aerobic respiration)

Question 42

Describe photosynthesis: light reaction and carbon dioxide fixation

Answer 42

chlorophyll b, carotene, and xanthophylls channel light energy to chlorophyll a.

electrons from c. a. are diverted into a system that extracts and stores their energy for later use in the synthesis of substances such as sugar

chlorophyll a electrons are replenished from breakdown of WATER (releases oxygen as byproduct)

second phase: carbon dioxide fixation
Co2 unites with sugar ribose diphosphate
forms PGAL

PGAL is used to make more elaborate storage forms. This is slower than the light reaction

Question 43

Products of photosynthesis

Answer 43

first: several types of sugars (ribulose diphosphates, glucose, fructose, sucrose)
then: starch and cellulose

Question 44

starch

Answer 44

principle food storage in plant cells

Question 45

cellulose

Answer 45

not normally decompsed for other purposes.

structural in cell walls

Question 46

anaerobic respiration

Answer 46

yeast fermentation to form alcohols

Question 47

Oxygen uses

Answer 47

cellular respiration

replenish atmospheric oxygen lost to burning and rusting processes

Question 48

Issues with burning fossil fuels

Answer 48

we’re liberating lots of CO2 that the earth trapped in dead plant bodies underground long ago.

it raises atmospheric CO2 above the 0.03% we like.

Photosynthesis could reset CO2 levels if we stopped burning fossil fuels

but.. yeah. we don’t. so there’s that.