Question

33)    The expression “one bad apple ruins the bunch” can be applied figuratively to one violent person at an otherwise peaceful Donald Trump protest (or rally!), but in literal, botanical terms, this expression refers to

34)    Ethylene        B) Auxin        C) Cytokinin        D) Gibberellic acid       E) Abscisic acid

31)Which hormone is directly responsible the precise programmed cell death in the abscission zone of a senescing leaf when it is shed in the autumn?

A)   Cytokinin         B) Abscisic acid         C) Gibberellins         D) Ethylene         E) Auxins

32)Pollen tubes are some of the fastest growing cells known. In corn for example, the pollen tube can grow twelve inches or more down the style (the corn silk) and into the husk to fertilize the egg on the inflorescence (the immature corncob) in a few hours. To do this

A)   The pollen tube receives an abundance of nutrients and photoassimilate from the style to sustain this growth

B)   The pollen tube concentrates it cytoplasm at the growing tip and seals off the older empty tube

C)   Asymmetric cell divisions keep the cytoplasm at the growing tip with numerous highly vacuolated cells behind

D)   The sperm cells secrete RNases ahead of them, creating a tube of dead cells through which they swim

E)    The pollen tube differentiates from style tissue to provide a path for the sperm to swim through

21)    The graft transmissible, phloem mobile signal called ‘florigen’ is thought to be

A)A hormone B)A molecule of RNA C)A protein

D)A specific ratio of carbon to nitrogen in the phloem E)A virus

15)When a new leaf grows on a stem, the vascular system

A)   is present in the primordia and expands with the new leaf

B)   grows up from the pre-existing vascular system and into the new leaf

C)   starts within the new leaf and cells differentiate down toward the pre-existing vascular system

D)   Dividing cells in the new leaf push down through the stem toward the preexisting vascular system

E)    Hormone gradients trigger a line of apoptosis/programmed cell death to from the new vascular strand

12)In the tissue surrounding the apical meristem, a local accumulation of __________________ will determine where the next new leaf will form.

11)Formation of a distinct organ, tissue or cell type requires a boundary between the material that will form the organ tissue, or cell, and that which will not. Explain how such a boundary may arise (2 points) and give an example of such a boundary in plants (1 point).

10)his is a mesquite leaf that I plucked from a mesquite tree outside the EESAT building. Note that it has a distinctive bifurcation and compound pinnate structure. Also note that the leaflets I separated from the leaf show aberrant morphology and developed additional leaflets on the leaflets. If this development resulted from aberrant hormone distribution, the new leaflets likely correspond to localized increases in

A)   Gibberellic acid            B) Auxin             C) Cytokinin
             D) Strigolactone         E) Abscisic acid

1)In the shade avoidance response, PIF transcription factors promote the expression of cell elongation genes because the low ratio of red:far red light converts P_fr to P_r such that P_fr is not present to target PIF for ubiquitination and degradation, AND gibberellic acid promotes ubiquitination and degradation of DELLA repressors, which otherwise bind to and inhibit PIF transcription factors.

A)   TRUE                 B) FALSE                  C) WHAAAAAT?

2)In a classic experiment, Ian Sussex carefully separated a leaf primordia from the adjacent apical meristem. What was observed?

A)   The leaf developed normally

B)   The leaf primordia transitioned into a second apical meristem

C)   The leaf primordia grew out as branch

D)   The leaf grew out as needle-like structure instead of a flat blade

E)    The leaf primordia transitioned to a flower primordia

Answer 1

Please find the answers below:

Answer 33: Choice A (Ethylene is a gaseous hormone found in plants which is responsible for ripening of fruits. Ripened fruits release this gaseous hormone and tend to ripe the other fruits as well)

Answer 34: Choice B (Abscisic acid remains the hormone necessarily required to control programmed cell death in plants)

Answer 31: Choice A (The pollen tube not only receives stimulatory signal from the style, it also receives necessary water for hydration along with nutrient supply from the style for its growth)

Answer 21: Choice A (Florigen is a phytohormone released by leaves which prompts the plant to bear flowers)