Praxis (5236) - Biology > 4C3 Plant Growth, Development, and Survival > Flashcards

4C3 Plant Growth, Development, and Survival Flashcards

Describe plant responses to environmental changes for resource acquisition and protection. (76 cards)

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1
Q

What is the alternation of generations in plants?

A

It is a reproductive cycle in plants that alternates between a multicellular diploid sporophyte and a multicellular haploid gametophyte.

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2
Q

What are the two main stages in the alternation of generations in plants?

A
  • Sporophyte (diploid stage)
  • Gametophyte (haploid stage)
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3
Q

What is a sporophyte in the alternation of generations?

A

This is the diploid stage that grows from the fusion of male and female sex cells.

First stage of the life cycle.

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4
Q

What is the main function of the sporophyte stage?

A

To make spores.

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5
Q

Where are spores produced in the sporophyte stage through meiosis?

A

In a structure called the sporangium.

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6
Q

Where is the sporangium located in ferns?

A

Numerous sporangia are located on the undersides of fern fronds, often grouped in clusters called sori.

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7
Q

What is a gametophyte in the alternation of generations?

A

This is the haploid stage.

Second stage of the life cycle.

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8
Q

What is the role of gametophytes in plant reproduction?

A

They produce gametes or sex cells in plants, which are essential for sexual reproduction and genetic diversity.

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9
Q

What is pollination and why is it important?

A

The process in which pollen from the male part of a plant is transferred to the female part of a plant. Pollination is required for plants to reproduce more of the same type of plant.

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10
Q

What are the two types of pollination?

A
  • Cross-pollination
  • Self-pollination
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11
Q

How does cross-pollination occur?

A

When pollen from one plant is transferred to another plant, often with the assistance of insects, wind, or animals.

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12
Q

How does self-pollination occur?

A

When a plant has both male and female parts and completes the pollination process within the same plant.

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13
Q

What is artificial pollination?

A

Any pollination completed with intervention by humans, rather than through natural methods such as insects or the wind.

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14
Q

What happens when bees pollinate?

A

As bees travel from plant to plant collecting pollen and nectar, they inadvertently transfer the pollen that sticks to them to other plants.

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15
Q

What is fertilization in plants?

A

The process of fusion of the female gamete (ovum or egg) with the male gamete (sperm).

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16
Q

What is the main difference between the ovules of gymnosperms and angiosperms?

A
  • The ovule in gymnosperms is not completely enclosed by sporophyte tissue at the time of pollination.
  • In Angiosperms, the ovules are completely enclosed within sporophyte tissue at the time of pollination.

Gymnosperms: Plants that produce cones.

Angiosperms: Plants that produce flowers.

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17
Q

What are the four primary steps of fertilization in plants?

A
  1. Pollination
  2. Germination
  3. Penetration of the ovule
  4. Fertilization
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18
Q

What is the purpose of the pollen tube formed during germination?

A

To pass through the cells of the stigma and style to reach the ovary, acting as a pathway for the sperm cells to travel down to the ovule.

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19
Q

What occurs during the penetration of the ovule?

A

The pollen tube reaches the ovary and penetrates through the ovule, creating a path for the sperm to travel from the tip of the stigma to the egg in the ovule.

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20
Q

What is produced when the egg and sperm merge in plant fertilization?

A

Zygote

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21
Q

What is the function of the endosperm in plants?

A

Develops after fertilization as a source of energy and nutrition for the growing embryo.

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22
Q

What structure develops into the seed in gymnosperms and into both the seed and fruit in angiosperms?

A

Ovule

The ovule develops into the seed, and in angiosperms, the ovary surrounding the ovule becomes the fruit.

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23
Q

What is the definition of spores?

A

Reproductive units or cells that germinate or develop into new individuals without fusion with other reproductive cells.

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24
Q

What is the purpose of bacteria producing spores?

A

Mainly for survival as opposed to reproduction.

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25
What is **sporogenesis**?
The process by which the diploid sporophyte generation produces spores in plants. ## Footnote These spores are initially haploid and are formed through meiosis. Subsequently, the formed spores undergo mitosis to give rise to a haploid gametophyte generation responsible for producing gametes.
26
What is **vegetative propagation**?
The process of making new plants from a part of the parent plant.
27
What is **grafting** in vegetative propagation?
Attaching a scion, bud, stem, or branch from one plant to the stem and roots of a different plant. ## Footnote Plants typically grown through grafting are apples, pears, and plums.
28
What is **layering** in vegetative propagation?
When a part of the plant, usually the stem, is covered with soil to develop its own root system. ## Footnote Examples of plants that are reproduced through layering include forsythia, rhododendron, and climbing vines.
29
What is **stolon propagation**?
Propagation that occurs above ground through stems that grow horizontally and develop into individual plants. ## Footnote Plants commonly produced through stolons are strawberries, spider plants and some grasses.
30
What is a **stolon**?
A horizontally growing stem above ground that can become individual offspring.
31
How can a plant that reproduces through stolons be propagated?
By cutting and planting the stolon to produce many individual plants.
32
What is a **sucker**?
A shoot that arises from the existing root structure of an established plant. ## Footnote Plants that commonly reproduce through suckering include lilacs, roses, fruit trees.
33
How can suckers be propagated?
By separating them from the parent root system once they have their own root system.
34
What are **tubers**?
Special thickened underground stem sections that grow horizontally to the surface of the soil. ## Footnote Examples: Potatoes, yams.
35
What is **tissue culture**?
An efficient method for vegetatively propagating large numbers of plants using **tissue in a growth hormone solution under sterile conditions**. ## Footnote It can produce large numbers of plant clones using very little material from the parent plant.
36
What is **cutting** in the context of plant propagation?
A plant segment separated from the parent plant and placed in a growing medium to develop roots and grow into an individual offspring. ## Footnote Plants commonly propagated using cuttings include softwood trees, various shrubs.
37
What is **seed germination**?
The process that a seed or a spore goes through in order to sprout.
38
What external factors could **initiate seed germination**?
* Water absorption * Time passage * Exposure to light * Oxygen * Changes in temperature
39
What is a **seed**?
A **fertilized and ripe ovule** that contains the young, embryonic plant.
40
What are the essential **components** of a seed?
* Embryo * Seed coat
41
What are the **three essential steps** in the process of seed germination?
1. Imbibition 2. Respiration 3. Cell-division of the embryo cells
42
What is **imbibition** in seed germination?
The **absorption of water by the seed**, leading to rehydration and the rupturing of the protective coat surrounding the embryo.
43
What is **respiration** in seed germination?
The metabolic activity of the plant that transitions from anaerobic to aerobic after the **absorption of oxygen**.
44
What is the **final stage** of germination?
The **division of cells within the seed**, leading to the growth of the seedling.
45
What is the **major trigger** for most seeds to grow?
Water uptake | (imbibition) ## Footnote Sunlight influences seedling development post-germination.
46
What temperature do most seeds require for **germination**?
25-30°C | (77-86°F)
47
What are the **internal factors** that may affect seed germination?
* Seed dormancy * Resistance of seed coat to water * Immature seeds * Requirement of more time
48
What does **tropism** refer to in plants?
A **directional growth response in plants** to an external stimulus such as light, gravity, or touch. ## Footnote 'Tropism' comes from the Greek word tropos which means turning.
49
What are the **two types** of tropism based on the movement response of an organism?
* **Positive tropism**: movement or growth response **toward** the stimulus. * **Negative tropism**: movement or growth response **away** from the stimulus.
50
What determines the **direction of tropism** in plants?
The direction of the stimulus influencing the plant.
51
What is the **significance** of the interaction between intracellular turgor pressure and the plant cell wall in plant movements?
Turgor pressure changes inside cells push against the plant cell wall, enabling movements such as opening/closing stomata and fast leaf movements.
52
How are **fast movements** in plants regulated?
Usually driven by **quick changes in water transport** supported by mechanical instabilities in the structure of the plants.
53
What regulates the relatively **slower movements** in plants?
These are created by the differential growth of the live tissues.
54
What is **chemotaxis**?
The **movement in the direction of a chemical stimulus** in the environment by an organism or a living motile cell.
55
What is **chemokinesis**?
A **non-directional movement** of cells or organisms in response to a chemical stimulus, where the **rate of movement changes but not the direction**.
56
What is **phototropism**?
The growth or movement of a cell or an organism or part of an organism **toward the light**.
57
What is **gravitropism**?
The growth response of a plant towards the gravitational field, with roots growing towards the ground and stems growing away from it. ## Footnote Also known as geotropism.
58
What does **positive gravitropism** represent?
The **growth of roots** toward the ground.
59
What is **thigmotropism**?
A type of tropism where an organism **responds to touch stimuli**. ## Footnote Positive thigmotropism moving towards the stimulus and negative moving away.
60
What is **hydrotropism**?
A form of tropism where an organism shows growth or movement **in response to water or moisture**.
61
What is **heliotropism**?
A type of tropism where the response of the organism is directed **towards sunlight**.
62
What is **thermotropism**?
A type of tropism where a part of an organism shows movement response to **temperature changes**.
63
What is **electrotropism**?
A type of tropism exhibited by an organism as a **response to the electric field**, with different cell types showing electrotropism.
64
What are some plant defenses against **herbivores**?
* Physical defenses - trichomes and thorns. * Chemical compounds - substances that make the plant distasteful to herbivores.
65
What is the **hypersensitive response** in plants?
A defense mechanism that causes cells and tissues around the infection site to die off to prevent the spread of a pathogen.
66
What is **systemic acquired resistance?**
Before the hypersensitive response cells die, they release methylsalicylic acid, which activates signaling pathways that force distant cells to produce molecules that protect the plant against pathogens.
67
Explain the **relationship** between the hypersensitive response and systemic acquired resistance.
The hypersensitive response causes cells to die off, releasing a signal that triggers distant cells to produce protective molecules in systemic acquired resistance.
68
What are **plant hormones**?
Chemicals produced in many parts of the plant that promote and regulate functions in other parts of the plant.
69
**Where** are hormones synthesized in plants?
In **all parts of the plant**, including in the roots, stems, and leaves, then transported to the part that needs them through vascular tissues.
70
What are the **five types** of hormones in plants?
* Auxins * Cytokinins * Gibberellins (GAs) * Ethylene * Abscisic acid (ABA)
71
What are the **two categories** of plant hormones based on their primary function?
* Growth promoters * Growth inhibitors
72
What role does **auxin** play in growth-mediated plant movements?
Auxin promotes cell elongation, root and shoot differentiation, and directional growth in response to light and gravity. It is produced in the apical meristems.
73
What is the main function of **cytokinins** in plants?
* Promotes cell division * Differentiates between root and shoot cells * Delays senescence of leaf tissue ## Footnote Cytokinins are growth-promoting hormones located in the root and shoot tips of plants. They can inhibit plant aging.
74
What is the main role of **gibberellins** in plants?
* Stimulates stem growth * Promotes fruit growth * Aids in seed growth * Encourages shoot elongation * Facilitates flower and fruit maturation * Delays senescence ## Footnote Gibberellins are growth-promoting hormones.
75
What is the primary function of **ethylene** in plants?
* Promotes aging in plants * Ripens fruit * Causes mature leaves and flowers to age, fade, and drop ## Footnote Ethylene is a growth inhibitor.
76
What is the main responsibility of **abscisic acid** (ABA) in plants?
* Induces dormancy in different plant organs * Causes leaf drop * Promotes seed dormancy * Closes stomata during drought conditions | Growth inhibitor.
Praxis (5236) - Biology
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