Question 1

Which of the following processes in plants is influenced by a phytochrome reaction?

Accepted Answer

A)  Seed germination 
B)  Internode elongation 
C)  Initiation of flowering 
D)  Chlorophyll synthesis 
E)  All of the answers are correct 
A)  Seed germination 
B)  Internode elongation 
C)  Initiation of flowering 
D)  Chlorophyll synthesis 
E)  All of the answers are correct

Question 2

In germinating cereal seeds, the gibberellan GA1 activates genes that

Accepted Answer

A)  induce stem elongation. 
B)  control the synthesis of enzymes that convert sucrose to starch. 
C)  control the synthesis of enzymes that convert starch to sugar. 
D)  repress the stem development of the embryo. 
E)  induce root development. 
A)  induce stem elongation. 
B)  control the synthesis of enzymes that convert sucrose to starch. 
C)  control the synthesis of enzymes that convert starch to sugar. 
D)  repress the stem development of the embryo. 
E)  induce root development.

Question 3

Which of the following plant hormones are used in tissue culture to promote cell enlargement and division?

Accepted Answer

A)  Abscisic acid and auxin 
B)  Gibberellins and auxin 
C)  Cytokinin and ethylene 
D)  Cytokinin and auxin 
E)  Auxin and ethylene 
A)  Abscisic acid and auxin 
B)  Gibberellins and auxin 
C)  Cytokinin and ethylene 
D)  Cytokinin and auxin 
E)  Auxin and ethylene

Question 4

Phototropism in plants is the

Accepted Answer

A)  bending of the coleoptile away from a light source. 
B)  bending of the coleoptile towards a light source. 
C)  bending of the rhizoid in the direction of the force of gravity. 
D)  straight growth of the stem. 
E)  growth of roots towards a light source. 
A)  bending of the coleoptile away from a light source. 
B)  bending of the coleoptile towards a light source. 
C)  bending of the rhizoid in the direction of the force of gravity. 
D)  straight growth of the stem. 
E)  growth of roots towards a light source.

Question 5

Which plant hormone is known to be necessary for the development of seed dormancy?

Accepted Answer

A)  Gibberellic acid. 
B)  Auxin. 
C)  Ethylene. 
D)  Abscisic acid. 
E)  Cytokinin. 
A)  Gibberellic acid. 
B)  Auxin. 
C)  Ethylene. 
D)  Abscisic acid. 
E)  Cytokinin.

Question 6

In barley, gibberellin is produced in the embryo and

Accepted Answer

A)  directly breaks down endosperm starch into smaller molecules. 
B)  regulates the production of amylase there. 
C)  regulates production of abscisic acid in the endosperm. 
D)  moves to the aleurone layer where it suppresses gene transcription. 
E)  regulates production of amylase in the endosperm via GAMYB. 
A)  directly breaks down endosperm starch into smaller molecules. 
B)  regulates the production of amylase there. 
C)  regulates production of abscisic acid in the endosperm. 
D)  moves to the aleurone layer where it suppresses gene transcription. 
E)  regulates production of amylase in the endosperm via GAMYB.

Question 7

The plant hormone, indole-3-acetic acid (IAA) is synthesised from

Accepted Answer

A)  an amino acid. 
B)  gibberellin. 
C)  a polysaccharide. 
D)  meualonic acid. 
E)  acetic acid. 
A)  an amino acid. 
B)  gibberellin. 
C)  a polysaccharide. 
D)  meualonic acid. 
E)  acetic acid.

Question 8

The plant hormones known as cytokinins are synthesised in the

Accepted Answer

A)  shoots. 
B)  stems. 
C)  coleoptiles. 
D)  roots. 
E)  apical buds. 
A)  shoots. 
B)  stems. 
C)  coleoptiles. 
D)  roots. 
E)  apical buds.

Question 9

Which of the following affects plant growth and development?

Accepted Answer

A)  Day length 
B)  Gravity 
C)  Temperature 
D)  Soil nutrients 
E)  All of the answers are correct 
A)  Day length 
B)  Gravity 
C)  Temperature 
D)  Soil nutrients 
E)  All of the answers are correct

Question 10

You have a bowl full of slightly under-ripe bananas that you decide to leave for a few days until they are ready to eat. After returning a few days later to eat a banana, you discover they are now black and over-ripe. Upon further investigation you also discover a very over-ripe banana at the bottom of the bowl that you had not previously noticed. How would you explain this observation?

Accepted Answer

A)  The over-ripe banana released methylene which triggered rapid ripening in the other bananas. 
B)  The over-ripe banana released ethanol which triggered rapid ripening in the other bananas. 
C)  The over-ripe banana released cytokinins which triggered rapid ripening in the other bananas. 
D)  The over-ripe banana released auxins which triggered rapid ripening in the other bananas. 
E)  The over-ripe banana released ethylene which triggered rapid ripening in the other bananas. 
A)  The over-ripe banana released methylene which triggered rapid ripening in the other bananas. 
B)  The over-ripe banana released ethanol which triggered rapid ripening in the other bananas. 
C)  The over-ripe banana released cytokinins which triggered rapid ripening in the other bananas. 
D)  The over-ripe banana released auxins which triggered rapid ripening in the other bananas. 
E)  The over-ripe banana released ethylene which triggered rapid ripening in the other bananas.

Question 11

In the 1920s Friedrich Went, a plant physiologist from the Netherlands, proposed the existence of

Accepted Answer

A)  acetic acid. 
B)  indole-3-acetic acid. 
C)  auxin. 
D)  amyloplasts. 
E)  cytokinins. 
A)  acetic acid. 
B)  indole-3-acetic acid. 
C)  auxin. 
D)  amyloplasts. 
E)  cytokinins.

Question 12

Stratification is

Accepted Answer

A)  the prevention of seed germination after only light rain in some plants. 
B)  germination of seeds after exposure to red light. 
C)  genes switched on in response to environmental stress. 
D)  the period of cold which breaks dormancy and causes seed germination. 
E)  dehydration of the seed after development of the embryo. 
A)  the prevention of seed germination after only light rain in some plants. 
B)  germination of seeds after exposure to red light. 
C)  genes switched on in response to environmental stress. 
D)  the period of cold which breaks dormancy and causes seed germination. 
E)  dehydration of the seed after development of the embryo.

Question 13

The photoperiod response in plants is detected by

Accepted Answer

A)  the leaves. 
B)  the stems. 
C)  the apical buds. 
D)  chlorophyll molecules. 
E)  leaf stomata. 
A)  the leaves. 
B)  the stems. 
C)  the apical buds. 
D)  chlorophyll molecules. 
E)  leaf stomata.

Question 14

The ability of plants to produce flowers seasonally is due to the phenomenon known as

Accepted Answer

A)  signal transduction. 
B)  photoperiodism. 
C)  florigen. 
D)  vernalisation. 
E)  hormonal response. 
A)  signal transduction. 
B)  photoperiodism. 
C)  florigen. 
D)  vernalisation. 
E)  hormonal response.

Question 15

The compound known as 2,4-D

Accepted Answer

A)  is a synthetic gibberellin. 
B)  is a synthetic auxin. 
C)  promotes roots in tissue culture. 
D)  is responsible for dwarfism. 
E)  is an essential plant hormone. 
A)  is a synthetic gibberellin. 
B)  is a synthetic auxin. 
C)  promotes roots in tissue culture. 
D)  is responsible for dwarfism. 
E)  is an essential plant hormone.

Question 16

Brassinosteroids are

Accepted Answer

A)  hormones involved in the differentiation of xylem. 
B)  plant steroid hormones that promote cell elongation. 
C)  control cell growth through a signal transduction pathway and protein phosphorylation. 
D)  active transcription factors which induce mRNA synthesis. 
E)  All of the answers are correct. 
A)  hormones involved in the differentiation of xylem. 
B)  plant steroid hormones that promote cell elongation. 
C)  control cell growth through a signal transduction pathway and protein phosphorylation. 
D)  active transcription factors which induce mRNA synthesis. 
E)  All of the answers are correct.

Question 17

Synthetic growth retardants

Accepted Answer

A)  reduce vegetative plant growth. 
B)  reduce overall plant growth. 
C)  increase plant growth. 
D)  reduce bud growth. 
E)  reduce root growth. 
A)  reduce vegetative plant growth. 
B)  reduce overall plant growth. 
C)  increase plant growth. 
D)  reduce bud growth. 
E)  reduce root growth.

Question 18

A florist comes to you asking for advice on how he might be able to extend the shelf life of his stock. Using your knowledge of plant hormones, what would you suggest as a potential treatment?

Accepted Answer

A)  Spraying them with cytokinin 
B)  Spraying them with auxin 
C)  Spraying them with gibberellic acid 
D)  Spraying them with abscisic acid 
E)  Spraying them with ethylene 
A)  Spraying them with cytokinin 
B)  Spraying them with auxin 
C)  Spraying them with gibberellic acid 
D)  Spraying them with abscisic acid 
E)  Spraying them with ethylene

Question 19

In a frost resistant plant, it was found that when exposed to cold, abscisic acid (ABA) levels were elevated. For this to occur, what must be the state of the phosphatase involved in ABA regulation?

Accepted Answer

A)  Free (unbound) 
B)  Bound to the SnRK2 protein kinase 
C)  Bound to the ABA receptor 
D)  Activating (phosphorylating) downstream proteins in the ABA signalling pathway 
E)  Bound directly to gene sequences regulated by ABA 
A)  Free (unbound) 
B)  Bound to the SnRK2 protein kinase 
C)  Bound to the ABA receptor 
D)  Activating (phosphorylating) downstream proteins in the ABA signalling pathway 
E)  Bound directly to gene sequences regulated by ABA

Question 20

In gravitropism, the plant root bends. This bending

Accepted Answer

A)  occurs in the root cap. 
B)  occurs in the zone of elongation. 
C)  is mediated by gibberellins. 
D)  is a response to darkness. 
E)  involves the uptake of Ca2+ from the soil. 
A)  occurs in the root cap. 
B)  occurs in the zone of elongation. 
C)  is mediated by gibberellins. 
D)  is a response to darkness. 
E)  involves the uptake of Ca2+ from the soil.

Exam 19: Plant Hormones and Growth Responses

Which of the following processes in plants is influenced by a phytochrome reaction?

In germinating cereal seeds, the gibberellan GA1 activates genes that

Which of the following plant hormones are used in tissue culture to promote cell enlargement and division?

Phototropism in plants is the

Which plant hormone is known to be necessary for the development of seed dormancy?

In barley, gibberellin is produced in the embryo and

The plant hormone, indole-3-acetic acid (IAA) is synthesised from

The plant hormones known as cytokinins are synthesised in the

Which of the following affects plant growth and development?

In the 1920s Friedrich Went, a plant physiologist from the Netherlands, proposed the existence of

Stratification is

The photoperiod response in plants is detected by

The ability of plants to produce flowers seasonally is due to the phenomenon known as

The compound known as 2,4-D

Brassinosteroids are

Synthetic growth retardants

A florist comes to you asking for advice on how he might be able to extend the shelf life of his stock. Using your knowledge of plant hormones, what would you suggest as a potential treatment?

In a frost resistant plant, it was found that when exposed to cold, abscisic acid (ABA) levels were elevated. For this to occur, what must be the state of the phosphatase involved in ABA regulation?

In gravitropism, the plant root bends. This bending

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In germinating cereal seeds, the gibberellan GA₁ activates genes that