Bio112 exam 2

What makes a plant a plant?

Plants are multicellular organisms with chlorophyll, cell walls made of cellulose, and a life cycle including alternation of generations.

What are the main structures in a plant cell?

Cell wall, chloroplasts, central vacuole, nucleus, mitochondria, plasmodesmata.

What is the function of chloroplasts?

Chloroplasts contain chlorophyll and are responsible for photosynthesis.

What is the role of the central vacuole in plants?

The central vacuole stores water, nutrients, and waste products, helping maintain turgor pressure.

What does the term 'alternation of generations' refer to in plants?

It refers to the life cycle that includes the sporophyte (diploid) and gametophyte (haploid) generations.

What are the main functions of roots in a plant?

Roots anchor the plant and absorb water and nutrients.

Define 'taproot'.

A taproot is the main root that grows downward.

What are lateral roots?

Lateral roots branch off the primary root to increase surface area for absorption.

What does the shoot system include?

The shoot system includes stems, leaves, and reproductive structures such as flowers.

What are the functions of stems in plants?

Stems support leaves and flowers and transport water, nutrients, and sugars.

What is the function of leaves?

Leaves perform photosynthesis.

What is an adventitious root?

Adventitious roots grow from unusual places, like stems or leaves.

What is a rhizome?

A rhizome is an underground stem found in plants like ginger.

Give an example of a modified stem. How does it function?

Tubers, like potatoes, are modified stems that store nutrients.

What are tendrils in plants?

Tendrils are modified leaves that serve as support structures.

What distinguishes monocots from eudicots regarding cotyledons?

Monocots have 1 cotyledon, while eudicots have 2 cotyledons.

How do monocots and eudicots differ in leaf venation?

Monocots have parallel veins; eudicots have reticulate (branching) veins.

What is the difference in vascular bundles between monocots and eudicots?

Monocots have scattered vascular bundles; eudicots have vascular bundles in a ring.

What is parenchyma tissue?

Parenchyma consists of thin-walled, flexible cells responsible for photosynthesis, storage, and wound healing.

Describe collenchyma tissue.

Collenchyma consists of cells with unevenly thickened walls that support growing parts of the plant.

What is sclerenchyma tissue?

Sclerenchyma has thick, lignified cell walls providing rigid support.

What is ground tissue?

Ground tissue includes parenchyma, collenchyma, and sclerenchyma, functioning in photosynthesis, storage, and support.

What is vascular tissue responsible for?

Vascular tissue includes xylem (water and minerals transport) and phloem (sugars transport).

What is the function of dermal tissue?

Dermal tissue serves as the outer protective layer of the plant.

What is the purpose of the epidermis in a leaf?

The epidermis acts as a protective outer layer.

What is mesophyll?

Mesophyll includes palisade parenchyma (for photosynthesis) and spongy parenchyma (for gas exchange).

What are vascular bundles in a leaf?

Vascular bundles contain xylem and phloem for transport.

What is the role of apical meristems?

Apical meristems are responsible for growth at the tips of roots and shoots.

What does indeterminate growth in plants mean?

Indeterminate growth means plants can grow continuously throughout their life.

What is a root cap?

A root cap protects the growing tip of the root.

What is gravitropism?

Gravitropism is the plant's response to gravity, directing roots to grow downward.

What drives the downward movement of roots?

Gravity (gravitropism) and root pressure (osmotic pressure) push roots downward.

What are tracheids?

Tracheids are water-conducting cells in the xylem.

What are sieve tube members?

Sieve tube members are cells in the phloem that conduct sugars.

Describe secondary growth in plants.

Secondary growth occurs in lateral meristems, increasing the thickness of stems and roots.

What are annual growth rings?

Annual growth rings indicate varying growth rates in different seasons.

What is bark made of?

Bark consists of periderm (cork cambium and cork) and secondary phloem.

What does girdling a tree do?

Girdling removes the phloem layer, disrupting nutrient transport.

What are the key macronutrients required by plants?

Carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium, magnesium.

How do plants get nitrogen?

Plants obtain nitrogen primarily from soil as nitrate (NO₃⁻) or ammonium (NH₄⁺).

What is the role of phosphorus in plants?

Phosphorus is important for ATP production and nucleic acids.

How do carnivorous plants adapt to nutrient-poor conditions?

They consume insects to obtain required nitrogen.

What do soil bacteria do in the nitrogen cycle?

They convert atmospheric nitrogen into usable forms for plants.

Which plants have mutualistic nitrogen-fixing bacteria?

Legumes have mutualistic relationships with nitrogen-fixing bacteria in root nodules.

What do mycorrhizae gain from their relationship with plants?

Mycorrhizae gain carbohydrates from plants.

How do plants respond to herbivory?

Plants may produce volatile organic compounds to attract predators of herbivores.

What is phototropism?

Phototropism is the growth of a plant toward light.

What is the role of auxin in plant growth?

Auxin promotes cell elongation and is involved in phototropism and gravitropism.

How does auxin affect phototropism?

Auxin concentrates on the shaded side of the stem, causing that side to elongate and bend toward the light.

What is the function of ethylene in plants?

Ethylene promotes fruit ripening and responses to stress.

What causes herbaceous plants to grow thicker in windy conditions?

Thigmomorphogenesis leads to the development of shorter, thicker stems for resistance.

How do gibberellins affect seed dormancy?

Gibberellins promote seed germination and break dormancy.

What hormone is involved in root gravitropism?

Auxin is involved in the gravitropic response of roots.

What is a gametophyte?

A gametophyte is the haploid phase of the plant life cycle that produces gametes.

What is a sporophyte?

A sporophyte is the diploid phase of a plant's life cycle that produces spores.

What is double fertilization in angiosperms?

Double fertilization involves the fertilization of an egg and the fusion of a sperm with polar nuclei to form endosperm.

What is the embryo sac?

The embryo sac is the female gametophyte within the ovule of a flower.

How do angiosperms prevent self-fertilization?

Mechanisms like self-incompatibility and separate male and female organs help prevent self-fertilization.

What is the role of pollination?

Pollination transfers pollen from the anther to the stigma.

Where do sperm and eggs occur in angiosperms?

Sperm are in pollen produced in the anther; eggs are in the ovule in the ovary.

What forms the seed?

The seed forms from the zygote, endosperm, and seed coat.

What is the purpose of the fruit?

The fruit protects seeds and aids in their dispersal.

Define apical dominance.

Apical dominance is the phenomenon where the apical bud inhibits the growth of lateral buds.

What adaptations do plants exhibit for wind resistance?

Plants grow shorter and thicker stems with increased lignin in windy conditions.

How do cytokinins interact with auxin in apical dominance?

Cytokinins promote lateral bud growth when auxin levels decrease.

What is the function of root hairs?

Root hairs increase surface area for water and nutrient absorption.

What is the Casparian strip?

A waxy barrier in the endodermis that controls the flow of water into the vascular tissue.

Define osmosis.

Osmosis is the movement of water across a semipermeable membrane from lower to higher solute concentration.

What role does turgor pressure play in plants?

Turgor pressure maintains cell shape and helps support the plant structure.

What do guard cells do?

Guard cells regulate the opening and closing of stomata for gas exchange.

What is root pressure?

Root pressure is the pressure generated in roots as water is absorbed, pushing it upward.

What is the purpose of the periderm?

Periderm protects the plant and reduces water loss.

How do plants use potassium ions (K+)?

K+ ions regulate stomatal opening and water balance in plants.

What is thigmotropism?

Thigmotropism is the directional growth of plants in response to touch.

What is dry soil's effect on a plant's water potential?

Dry soil results in low water potential, leading to reduced turgor pressure and potential wilting.

What plants require high levels of phosphorus?

Plants in poorly drained soils or those that grow rapidly need higher phosphorus levels.

What hormone regulates growth during seed dormancy?

Abscisic acid (ABA) maintains seed dormancy.

What is the role of nitrogen-fixing bacteria?

They convert atmospheric nitrogen into forms usable by plants.

What happens during the process of transpiration?

Water evaporates from leaves, creating negative pressure that pulls water and minerals upward.

Name the two forms of nitrogen plants can absorb.

Ammonium (NH₄⁺) and nitrate (NO₃⁻).

Define thigmomorphogenesis.

The process by which plants adjust their growth in response to mechanical stress.

How are grafting and budding used in plant cultivation?

They are methods of asexual reproduction that maintain desired plant characteristics.

What is the benefit of crop rotation?

It helps maintain soil fertility and reduces dependency on fertilizers.

What do legumes contribute to soil fertility?

Legumes add nitrogen to the soil via their relationship with nitrogen-fixing bacteria.

What effect does deforestation have on soil quality?

Deforestation decreases soil fertility and increases erosion.

What is the role of mycorrhizae?

Mycorrhizae help plants absorb water and nutrients through fungal hyphae.

What is the importance of fruit in the angiosperm lifecycle?

Fruit protects seeds and aids in their dispersal.

How do flowering plants ensure genetic diversity?

They employ mechanisms to prevent self-fertilization and promote cross-pollination.

What defines a micronutrient?

Essential elements required by plants in small quantities.

What do tracheids and vessel elements do?

They conduct water and minerals in the xylem.

What adaptation inhibits grazing in some plants?

Spines and thorns can deter herbivores.

What is the consequence of removing a plant's apical bud?

It encourages the growth of lateral buds, increasing branching.

How do temperature changes affect plant metabolism?

Temperature changes can influence enzyme activity and growth rates.

What cellular structure do plants use for gas exchange?

Stomata are the small openings on leaves that facilitate gas exchange.

What cellular component is crucial for photosynthesis?

Chlorophyll, found in chloroplasts, is essential for photosynthesis.

How does the structure of xylem facilitate water transport?

Xylem vessels are hollow, allowing water to flow through them efficiently.

What is the term for mature xylem in trees?

Heartwood is the inner, non-functioning portion of xylem.

What environmental conditions lead to seed dormancy?

Unfavorable conditions, such as lack of water or nutrients, can induce dormancy.

Define translocation in plants.

Translocation is the movement of sugars through the phloem from source to sink.

What is the difference between a source and a sink?

A source produces sugars; a sink consumes or stores them.