Botany Exam 2

Front 1

What is parasitism in plants?

Back 1

Parasitism: A relationship in which one species benefits at the expense of another​

Parasitic plants have a haustorium​

invasive, vascular organ​

secretes digestive enzymes​

may attach to host stems or roots.​

anatomically diverse structures​

movement of nutrients from​

host to parasite is passive​

Front 2

What is hemiparasitism?

Back 2

Hemiparasite: under-goes photosynthesis at some stage in life.

Front 3

What is holoparasitsm and what kinds of evolutionary change accompany it?

Back 3

Holoparasite: obtains all photosynthates, water and minerals from the host.

Front 4

How many times has parasitism arisen in the evolution of plants?

Back 4

Many times (ask nick about #) (maybe 12)

Front 5

How is Hydnora triceps pollinated?

Back 5

Pollinator drawn by the rotten smell.

Pollinator enters through through androecial ring,

Spends time in gynoecium chamber (where pollen from any other flower is shed on receptive surface). Androecial ring closes for @24 hours.

Androecial ring opens, and sheds pollen which the pollinator carries on her way out.

Front 6

How does Rhizanthes infanticide use blowflies in reproduction?

Back 6

Flies lay eggs in potent smelling, warm flower, thinking it is excrement, larva die in plant once born.

Front 7

What is the lifecycle of mistletoe like? How do seeds find their way to host plants?

Back 7

The fruits of mistletoe contain a substance that is very sweet and yet very sticky. Birds love the white berries, and when they empty their little cloacas the seeds stick to branches rather than fall to the forest floor. Its here that the seeds germinate to produce the next generation of mistletoe

Front 8

What is mycorrhizal heterotrophy?

Back 8

-Not haustorial parasites, but parasites just the same​

-Acquire nutrients from other plants indirectly through a fungus​

-Convergent morphological evolution with parasites​

Front 9

What are the functions of stems?

Back 9

-Nutrient transport

-support leaves

Front 10

How has the protostele present in roots and early plant lineages been modified in other major lineages of plants?

Back 10

A variation on this is the siphonostele in which the xylem is surrounded by two layers of phloem, and this is what most of the seedless vascular plants (ferns and fern allies) have. In some of the more derived groups of plants we see a modification of the protostele into a eustele (meaning true stele) in which the vascular cylinder surrounds a region of parenchyma and has begun to break into bundles. This is something that occurs in both the dicots and the gymnosperms.

Front 11

Describe the transition in the stele from the roots to the shoots of plants with eusteles in their stems.

Back 11

ask

Front 12

Describe the various ways that leaves are arranged on stems.

Back 12

1. Alternate​

-may be spiraled​

2. Opposite​

-may be decussate​

3. Whorled​

-more than 2 leaves per node​

Front 13

What is the importance of the Fibonacci series in leaf presentation?

Back 13

the stem must present leaves in a way that they can present the maximum surface area to the sun…the way that stems do this is by presenting their leaves in the form of a fibonacci series (swirl pattern). Remember the newest leaves will always be at the tip of a shoot.

Front 14

How may stems be modified to aid in survival in disparate ecological conditions?

Back 14

*Stolons grow horizontally (aboveground): asexual reproduction​

*Rhizomes grow horizontally (below ground): asexual reproduction​

*Tubers are underground stems that store food

*Bulb:-stems reduced in length ​

-internodes shortened ​

-leaves overlap and store both starch and sugar

*Corm:

-stems store starch underground​

-one internode with papery leaf tissue

Front 15

What clues indicate that a potato is a modified stem and that a sweet potato is a modified root?

Back 15

Potato = tuber​

-nightshade family​

-axillary buds = eyes​

-vascular bundles​

- eustele

Sweet Potato = root​

-morning glory family​

-internal branching​

-endodermis, pericycle, protostele

Front 16

What are the functions of leaves?

Back 16

-Photosynthesis

-Transpiration

Front 17

How do guard cells of stomates minimize water loss while maximizing the potential for gas exchange?

Back 17

When the plant is full of water, the guard cells’ vacuoles become turgid causing the guard cells to flex which opens up stomates, allowing gas exchange. However, when water is scarce the vacuole empties causing the guard cells to relax and close the stomates (to avoid water loss).

Front 18

How do palisade and spongy mesophyll work together to optimize photosynthesis?

Back 18

Palisade cells are columnar and although they look tightly packed in this picture there is plenty of room in the intracellular space (or apoplast) for gases to permeate. The columnar arrangement of these plants allows the maximum amount of light to permeate each cell…these have very thin cell walls to allow light in. Note that these cells have the greatest concentration of chloroplasts in the plant, as their primary role is in photosynthesis.

The bottom layer is called spongy parenchyma…while these cells are also capable of photosynthesis they also have very large intracellular spaces to allow the gases from the stomates to permeate the leaf. The sponginess also causes light to be reflected back through the leaf.

Front 19

Explain the arrangement of vascular tissue in the vascular bundles of a leaf (xylem on top, phloem on bottom).

Back 19

Bundle sheath cells load sugars into the phloem for transport to other parts of the cell and receive no small amount of water from the xylem.

Front 20

Describe the process by which leaves change color and fall off in autumn.

Back 20

Abscission triggered by hormones​

In abscission zone, a layer of cells close to the leaf petiole undergoes degradation of the cell wall, while the layer close to the stem undergoes cell wall thickening.​

Leaf falls off.​

Leaf scar remains.

Front 21

To what ecological conditions are the needle leaves of conifers especially adapted?

Back 21

Needle leaves are thought to be an adaptation to the cool dry Permian period (300-250 mya)

Front 22

How may leaves be modified to aid in survival in disparate ecological conditions?

Back 22

Spines – sharp modified leaves or modified stipules that discourage animals from eating the plant.

Thorns are modified stems.

Tendrils: leaf modified for attachment to vertical surface.

Window leaves: leaf modified to allow in light while remaining underground

Bracts are modified leaves often at the base of flowers but are not flower parts themselves.

Front 23

What are secondary tissues and how do they arise from secondary meristems?

Back 23

There are two secondary meristems…one is called the vascular cambium and this gives rise to secondary vascular tissue. The other is called the cork cambium and this gives rise to secondary dermal tissue.

Front 24

Why does the wood of temperate trees exhibit growth rings?

Back 24

Growth rings: large cells of early wood in the spring and small cells of late wood in the fall.​

Variation in ring width is due to environmental factors such as water, temperature, or nutrients.

Front 25

What can wood tell us about climate and history?

Back 25

Years in which little rain falls are categorized by thinner rings than years in which lots of rain falls.

Front 26

Are monocots capable of producing wood? Why or why not?

Back 26

Not really! ​

-No 2° Xylem​

-Tall “woody” monocots produce more vascular bundles than herbaceous monocots with thick, lignified, fibrous sheaths.​

Front 27

How does secondary growth in roots differ from that in stems?

Back 27

Secondary growth​ of roots

-similar to stems​

-vascular cambium forms between xylem and phloem​

-cork cambium forms from enlarged pericycle, and pushes off the endodermis, cortex and epidermis​

-loss of water absorbing abilit

Front 28

Is it more harmful to peel a ring of bark from the circumference of a woody stem or to drill a hole through the middle of a woody stem?

Back 28

Hole through the middle because it would damage the living tissue inside.

(ask Nick)

Front 29

Besides providing construction material, paper, and fuel, how do forests, serve other human interests?

Back 29

Forests are made of trees.​
50% of all known plant and animal species live in forests.​
Plants and animals are awesome.​
Tall plants provide better shade than short ones.​
Trees are better to climb than cacti.

Front 30

Who was Jean Baptista van Helmont and what did he discover?

Back 30

An early Flemish scientist​

Used empirical or inductive reasoning to discover things

Spontaneous Generation​

The idea that living matter arises from inanimate matter​

Specifically that mice may arise from wheat and fabric

plants made out of water

Front 31

What are the laws of thermodynamics? How are they related to the flow of energy through biological systems?

Back 31

*Energy cannot be created or destroyed, but its form can be changed.

*The transfer of energy is not perfect but results in the transformation of some of that energy into entropy, or disorder in the system, often in the form of heat.

*

Front 32

How are photosynthesis and respiration related?

Back 32

Photosynthesis produces oxygen and sugar which are used in respiration which produces carbon dioxide and water which are used in photosynthesis which produces oxygen and sugar which are used in respiration which produces carbon dioxide and water which are used in photosynthesis which........

Front 33

What does a plant require to undergo photosynthesis? What are the primary products of photosynthesis?

Back 33

-light

-water

-carbon dioxide

Front 34

What is light?

Back 34

Light is the visible form of radiation​

-Radiation is composed of packets of energy or photons​

-Photons have particle-like AND wave-like properties​

-The photons of light occupy the visible portion of the electromagnetic spectrum 380-750 nm​

Front 35

Describe the photoelectric effect.

Back 35

light shown on gold foil created a measurable current. That is to say that the energy from the photons of light was transferred to electrons in gold atoms, and these energized electrons were made to “jump” out of their atoms. This effect is what allows solar panels to convert the energy of sunlight into electrical current. Frequency (color) is important.

Front 36

How do discoveries of Einstein and Engelann explain the light reactions of photosynthesis?

Back 36

Light from the sun reacts with the photosystem. The antenna pigments reflect the suns energy toward the middle of the photosystem, to a spot called the reaction center, where chlorophyll a is produced. This causes chlorophyll a to give up an electron from the center of this structure here in the middle.

Front 37

What portion of the spectrum of visible light is most useful for photosynthesis?What portion of the spectrum is least useful?

Back 37

Violet blue and red sections most useful, green least useful.

Front 38

Explain how energy moves through the light reactions of photosynthesis. What are the products of light reactions?

Back 38

ask

Front 39

What is the source of electrons used in the light reactions?

Back 39

ask

Front 40

What products of the light reactions are required for the dark reactions to take place?

Back 40

Energy from the light reactions in the form of ATP and NADPH

Front 41

Describe the dark (light-independent) reactions of photosynthesis.

Back 41

Stroma​

Do not require light​

Energy from the light reactions in the form of ATP and NADPH used to convert CO2 into sugar in a process called the Calvin cycle.​

Waste products ADP and NADP+ sent back to light reactions to be “recharged”.​

CO2 is said to be “fixed” in the dark reactions.​

Front 42

Why are the dark reactions sometimes known as C3 reactions, the Calvin Cycle, or the Calvin-Benson Cycle?

Back 42

They were discovered by a man named Melvin Calvin and his graduate student, Benson.

Front 43

Why does it take three turns of the Calvin Cycle to produce one molecule of G3P?

Back 43

Three molecules of carbon dioxide are added to three molecules of the five carbon RuBP for a total of 18 carbon molecules included)…to make this cyclical, three carbons have to be lost (so you can get back to fifteen) and to do that one three carbon molecule is released (rather than three one carbon molecules).

Front 44

How efficient is the Calvin Cycle at producing glucose?

Back 44

The output is just double the Keep in mind first that glucose has different and more varied uses than does ATP…for instance just speaking of energetics, it can be stored for long periods of time. Also it can be converted to all of the other macromolecule building blocks.

Front 45

Describe the experiment that Melvin Calvin used to elucidate the dark reactions of photosynthesis.

Back 45

Algae were grown in a lollipop like device with constant light. The flask was pulsed with carbon dioxide that included a radioactive carbon (or carbon 14). After a specific time interval the algae were boiled in alcohol to stop the rest of the reaction. Because the carbon was radioactive , Calvin and Benson could trace which molecules it had been incorporated into. They deciphered the whole cycle by performing this with ever increasing amounts of time. Sort of like still pictures in a cartoon.

Front 46

How do C4 plants avoid photorespiration? In what environmental conditions are C4 plants more efficient photosynthesizers than C3 plants?

Back 46

PEP carboxylase in the mesophyll traps carbon in 4-carbon molecules called malate​

Malate pumped into bundle sheath cells; metabolized to release CO2​

Light reactions and Calvin cycle occur in chloroplasts of the bundle sheath cells only.

C4 photosynthesis is less efficient in certain environmental conditions than C3 photosynthesis​

-Low light levels​

-Moderate temperatures​

-High CO2 concentrations​

Front 47

How do CAM plants maximize photosynthesis while minimizing water loss?

Back 47

1. CAM plants only open their stomates at night, and fix carbon dioxide with PEP carboxylase.

2. Malate is stored over night in vacuole as malic acid.

3. During the day, stomates are closed. Malic acid metabolized to releases CO2 to the Calvin Cycle

Front 48

What does a plant require to undergo aerobic respiration? What are the principle products?

Back 48

AK

Front 49

What are the three sets of reactions involved in aerobic respiration? Where do they occur in a cell?

Back 49

There are three steps, glycolysis which takes place in the cytosol, the Krebs or Citric Acid Cycle and an Electron Transport Chain both of which take place in the mitochondrion.

Front 50

What materials do they require and what do they reproduce?

Back 50

ASK

Front 51

How is the electron transport chain of aerobic respiration similar to that of Photsystem II?

Back 51

ASK

Front 52

What is the final electron acceptor of respiration? How does this mirror the electron donor in Photosystem II?

Back 52

ASK

Front 53

What is fermentation? What does fermentation produce?

Back 53

Without O2, pyruvate is used to regenerate NAD+, resulting in either lactic acid or ethanol. ​

Front 54

How does the current atmosphere differ from that of the early earth?

Back 54

-initially “atmosophere” was Hydrogen and Helium only​

-upon cooling, gases released from volcanoes added much to the atmosphere

Front 55

How is the majority of carbon in the early atmosphere currently distributed?

Back 55

Oceans absorb ~50% of initial CO2.​

​

Carbon is sequestered in photosynthetic organisms and fossil fuels.​

​

Coral building animals deposit carbon dioxide into CaCO3 which takes a long time to degrade into Ca+ and CO2.

Front 56

How do we know that carbon levels fluctuate cyclically?

Back 56

Ice Coring: Long cylinders of ice are removed from the Antarctic. ​

Bubbles in cores represent historical record of atmosphere when ice was formed​

Deeper the ice, the older the ice.

Front 57

What historic event altered the carbon balance in the atmosphere?

Back 57

The industrial revolution

Front 58

What is the green house effect? Global Climate Change?

Back 58

ASK