BIO 116 Exam 3 Questions with
Complete Answers
4 Phytochrome responses - ANSWER-De-etiolation, seed germination, shade
avoidance, & control of biological clock
Phytochromes exist in 2 photo-reversible states with a conversation of _____ to
____ triggering many developmental responses - ANSWER-P(r) to P(fr)
A naturally occurring organic molecule that is synthesized in one part of the
organism and has an effect on another part of the organism - ANSWER-Hormone
In a plant cell, most hormones can also have significant effects in _______ where
they are synthesized - ANSWER-the same cells
Plant hormones are ______ that modify or control one or more specific physiological
processes within a plant - ANSWER-chemical signals
Plant hormones help coordinate: (3 things) - ANSWER-growth, development,&
responses to stimuli
Are plant hormones produced in low or high concentrations? - ANSWER-Low
concentrations
Each hormone has multiple effects, but _______ - ANSWER-multiple hormones can
influence a single process
What do plant responses depend on? - ANSWER-The amount & concentration of
specific hormones and often the combination of hormones present
Any chemical that promotes elongation of shoot tip - ANSWER-Auxin
One of the common naturally occurring auxins in plants - ANSWER-Indoleacetic acid
Transport of auxin is ____; it is produced in _______ and is transported ______. -
ANSWER-polar; shoot tips, down the stem
Where do aux transporter proteins move the hormone? - ANSWER-From the basal
end of one cell into the apical end of the neighboring cell
Where in the cell can transport occur? - ANSWER-From shoot to root (polar auxin
transport) and across the stem (lateral transport)
What does auxin mediate in plants? - ANSWER-Phototropism
,According to the acid growth hypothesis, what does auxin stimulate and where? -
ANSWER-Proton pumps in the plasma membrane
What do proton pumps do? - ANSWER-Move H+ into the cell that in turn lowers the
pH in the cell wall and increases membrane potential
What does reduced pH activate? - ANSWER-Expansins: enzymes that loosen the
fabric of the cell wall
What enables the cell to elongate? - ANSWER-Increased cell wall plasticity
combined with increased turgor pressure
How is auxin involved in cell elongation? - ANSWER-By loosening the microfibrils of
the cell wall
What does reduced aux flow from the shoot of a branch stimulate? - ANSWER-
Growth in lower branches
The arrangement of leaves on the stem (pattern of veins) - ANSWER-Phyllotaxy
What does polar transport of auxin from leaf margins direct? - ANSWER-Leaf
venation pattern
The activity of the vascular cambium is under control of _____ - ANSWER-auxin
transport
Expression of diverse genes - ANSWER-Auxin-response genes
Cytokines stimulate _____ - ANSWER-Cytokinesis (cell division)
Where are cytokinins produced? - ANSWER-actively growing tissues such as roots,
embryos, and fruits
What do cytokinins control? - ANSWER-Cell division and differentiation
A terminal bud's ability to suppress the development of axillary buds. Under the
control of sugar, cytokinins, auxin, and strigolactone - ANSWER-Apical dominance
What does removal of the apical bud increase & decrease? - ANSWER-Increases
sugar availability and decreases auxin and cytokinin levels, initiating axillary bud
growth
How do cytokinins slow aging of plant organs? - ANSWER-By inhibiting protein
breakdown, stimulating RNA and protein synthesis, and mobilizing nutrients from
surrounding tissues
What effects do gibberellins have? - ANSWER-Stem elongation, fruit growth, and
seed germination
, Where are gibberellins produced? - ANSWER-young roots and leaves
How do gibberellins stimulate growth of leaves and stems? - ANSWER-By
enhancing cell elongation and cell division
Rapid growth of the floral stalk and induced by gibberellins - ANSWER-Bolting
Why do plants produce ethylene? - ANSWER-In response to stresses such as
drought, flooding, pressure, injury, and infection
The effects of ethylene include - ANSWER-response to mechanical stress,
senescence, leaf abscission, and fruit ripening
What is the only hormone that is a gas? - ANSWER-Ethylene (C2H4)
The programmed death of certain cells or organs or entire plants - ANSWER-
Senescence
What is a burst of ethylene associated with? - ANSWER-The onset of apoptosis
(programmed cell death)
The process that accours in fall when a leaf falls controlled by a change in the
balance of auxin and ethylene - ANSWER-Leaf abscission
What does ripening trigger from a burst of ethylene? - ANSWER-The release of
more ethylene
Stimulates cell elongation; regulates branching and organ bending - ANSWER-Auxin
Stimulate plant cell division; promote later bud growth; slow organ death - ANSWER-
Cytokinins
Promote stem elongation; help seeds break dormancy and use stored reserves -
ANSWER-gibberellins
Mediates fruit ripening and the triple response - ANSWER-ethylene
Endosymbiosis is an evolutionary theory that explains the origin of eukaryotes and
suggests a specific order in which this might have occurred. Ancestral cells engulfed
and then began to use the metabolic processes of the smaller cells. Based on
shared-core processes and features, which statement most accurately describes the
evidence for endosymbiosis theory for all organisms within domain Eukarya? -
ANSWER-Inner membranes of both organelles (mitochondria and chloroplasts) are
similar to plasma membranes of living bacteria. DNA structure and cell division in
these two eukaryotic organelles are similar to bacteria. Both eukaryotic mitochondria
and chloroplasts transcribe and translate their own DNA.
Which of the following are examples of cell attachment that helps animal cells to
form a multicellular organism? - ANSWER-Tight junctions, gap junctions and
desmosomes
Complete Answers
4 Phytochrome responses - ANSWER-De-etiolation, seed germination, shade
avoidance, & control of biological clock
Phytochromes exist in 2 photo-reversible states with a conversation of _____ to
____ triggering many developmental responses - ANSWER-P(r) to P(fr)
A naturally occurring organic molecule that is synthesized in one part of the
organism and has an effect on another part of the organism - ANSWER-Hormone
In a plant cell, most hormones can also have significant effects in _______ where
they are synthesized - ANSWER-the same cells
Plant hormones are ______ that modify or control one or more specific physiological
processes within a plant - ANSWER-chemical signals
Plant hormones help coordinate: (3 things) - ANSWER-growth, development,&
responses to stimuli
Are plant hormones produced in low or high concentrations? - ANSWER-Low
concentrations
Each hormone has multiple effects, but _______ - ANSWER-multiple hormones can
influence a single process
What do plant responses depend on? - ANSWER-The amount & concentration of
specific hormones and often the combination of hormones present
Any chemical that promotes elongation of shoot tip - ANSWER-Auxin
One of the common naturally occurring auxins in plants - ANSWER-Indoleacetic acid
Transport of auxin is ____; it is produced in _______ and is transported ______. -
ANSWER-polar; shoot tips, down the stem
Where do aux transporter proteins move the hormone? - ANSWER-From the basal
end of one cell into the apical end of the neighboring cell
Where in the cell can transport occur? - ANSWER-From shoot to root (polar auxin
transport) and across the stem (lateral transport)
What does auxin mediate in plants? - ANSWER-Phototropism
,According to the acid growth hypothesis, what does auxin stimulate and where? -
ANSWER-Proton pumps in the plasma membrane
What do proton pumps do? - ANSWER-Move H+ into the cell that in turn lowers the
pH in the cell wall and increases membrane potential
What does reduced pH activate? - ANSWER-Expansins: enzymes that loosen the
fabric of the cell wall
What enables the cell to elongate? - ANSWER-Increased cell wall plasticity
combined with increased turgor pressure
How is auxin involved in cell elongation? - ANSWER-By loosening the microfibrils of
the cell wall
What does reduced aux flow from the shoot of a branch stimulate? - ANSWER-
Growth in lower branches
The arrangement of leaves on the stem (pattern of veins) - ANSWER-Phyllotaxy
What does polar transport of auxin from leaf margins direct? - ANSWER-Leaf
venation pattern
The activity of the vascular cambium is under control of _____ - ANSWER-auxin
transport
Expression of diverse genes - ANSWER-Auxin-response genes
Cytokines stimulate _____ - ANSWER-Cytokinesis (cell division)
Where are cytokinins produced? - ANSWER-actively growing tissues such as roots,
embryos, and fruits
What do cytokinins control? - ANSWER-Cell division and differentiation
A terminal bud's ability to suppress the development of axillary buds. Under the
control of sugar, cytokinins, auxin, and strigolactone - ANSWER-Apical dominance
What does removal of the apical bud increase & decrease? - ANSWER-Increases
sugar availability and decreases auxin and cytokinin levels, initiating axillary bud
growth
How do cytokinins slow aging of plant organs? - ANSWER-By inhibiting protein
breakdown, stimulating RNA and protein synthesis, and mobilizing nutrients from
surrounding tissues
What effects do gibberellins have? - ANSWER-Stem elongation, fruit growth, and
seed germination
, Where are gibberellins produced? - ANSWER-young roots and leaves
How do gibberellins stimulate growth of leaves and stems? - ANSWER-By
enhancing cell elongation and cell division
Rapid growth of the floral stalk and induced by gibberellins - ANSWER-Bolting
Why do plants produce ethylene? - ANSWER-In response to stresses such as
drought, flooding, pressure, injury, and infection
The effects of ethylene include - ANSWER-response to mechanical stress,
senescence, leaf abscission, and fruit ripening
What is the only hormone that is a gas? - ANSWER-Ethylene (C2H4)
The programmed death of certain cells or organs or entire plants - ANSWER-
Senescence
What is a burst of ethylene associated with? - ANSWER-The onset of apoptosis
(programmed cell death)
The process that accours in fall when a leaf falls controlled by a change in the
balance of auxin and ethylene - ANSWER-Leaf abscission
What does ripening trigger from a burst of ethylene? - ANSWER-The release of
more ethylene
Stimulates cell elongation; regulates branching and organ bending - ANSWER-Auxin
Stimulate plant cell division; promote later bud growth; slow organ death - ANSWER-
Cytokinins
Promote stem elongation; help seeds break dormancy and use stored reserves -
ANSWER-gibberellins
Mediates fruit ripening and the triple response - ANSWER-ethylene
Endosymbiosis is an evolutionary theory that explains the origin of eukaryotes and
suggests a specific order in which this might have occurred. Ancestral cells engulfed
and then began to use the metabolic processes of the smaller cells. Based on
shared-core processes and features, which statement most accurately describes the
evidence for endosymbiosis theory for all organisms within domain Eukarya? -
ANSWER-Inner membranes of both organelles (mitochondria and chloroplasts) are
similar to plasma membranes of living bacteria. DNA structure and cell division in
these two eukaryotic organelles are similar to bacteria. Both eukaryotic mitochondria
and chloroplasts transcribe and translate their own DNA.
Which of the following are examples of cell attachment that helps animal cells to
form a multicellular organism? - ANSWER-Tight junctions, gap junctions and
desmosomes
