Botany for Finale Flashcards
Q: What are the main functions of stems in plants?
A: Stems provide support for vertical growth and transport water, nutrients, and sugars between roots and leaves.
Q: What is primary growth, and why is it important?
A: Primary growth is the elongation of stems, allowing plants to grow taller and maximize sunlight exposure for photosynthesis.
Q: What are meristems, and what role do they play in primary growth?
A: Meristems are zones of actively dividing cells located at the tips of roots and shoots. The apical meristem, found at shoot tips, drives primary growth by producing new cells for elongation and tissue formation.
Q: What is differentiation in plants?
A: Differentiation is the process where new cells develop into specialized tissues like dermal, vascular, and ground tissues, enabling the formation of the plant’s structure.
Q: What are the three basic types of plant cells, and their functions?
A:
1. Parenchyma: Photosynthesis, storage, and healing; thin-walled and flexible.
2. Collenchyma: Provides support in growing areas; thicker walls.
3. Sclerenchyma: Provides rigid support for mature areas; thick, lignified walls, often dead at maturity.
Q: What are the two types of sclerenchyma cells, and their functions?
A:
1. Conducting Sclerenchyma: Helps move water and nutrients (e.g., xylem).
2. Mechanical Sclerenchyma: Provides structural strength.
Q: What are the key external structures of a stem?
A:
1.Nodes: Points on the stem where leaves or branches grow.
2.Internodes: Sections of the stem between nodes.
3.Leaf Axil: The angle just above where a leaf joins the stem.
Q: What is phyllotaxy, and why is it important?
A: Phyllotaxy refers to the arrangement of leaves on a stem, ensuring efficient sunlight access without shading other leaves.
Q: What are the types of leaf arrangements in phyllotaxy?
A:
1.Alternate: One leaf per node.
2.Opposite: Two leaves per node.
3.Whorled: More than two leaves per node.
4.Distichous: Two-rowed arrangement.
5.Decussate: Opposite pairs rotated 90 degrees between nodes.
6.Spiral: Arranged in a spiral pattern along the stem.
Q: How do monocot and dicot stems differ in vascular bundle arrangement?
A:
1.Monocots: Scattered vascular bundles; no secondary growth (no wood).
2.Dicots: Vascular bundles arranged in a ring; secondary growth allows wood formation.
Q: What are the main functions of xylem and phloem?
A:
1.Xylem: Transports water and minerals from roots to leaves.
2.Phloem: Transports sugars from leaves to other parts of the plant.
Q: What are the two types of tracheary elements in xylem, and their functions?
A:
1.Tracheids: Long and narrow cells for water transport.
2.Vessel Elements: Short and wide cells for efficient water movement.
Q: How do vines and stolons adapt for growth and exploration?
A:
1.Vines: Use elongated internodes to climb and explore.
2.Stolons: Horizontal stems that form new shoots after finding suitable spots.
Q: How does artificial selection influence plant structure?
A: Genetic selection, such as in cabbage, can modify leaf clustering and adaptation traits for specific purposes.
Q: What are the steps of primary growth in stems?
A:
1.Cell Division: At the apical meristem, cells divide and elongate, pushing the stem upward.
2.Differentiation: Newly formed cells specialize into tissues like xylem and phloem.
Q: What is the role of the apical meristem in primary growth?
A: It drives stem elongation and forms leaves, branches, and flowers.
Q: What adaptations do tracheary elements have for water transport?
A:
1.Annular and Helical Thickenings: Flexible, allowing rapid water movement.
2.Scalariform and Reticulate Thickenings: Stronger, suited for dry conditions.
Q: How do guard cells regulate stomatal opening and closing?
A:
1.Opening: Guard cells absorb water, swell, and curve, opening the stomata.
2.Closing: Guard cells lose water, shrink, and straighten, closing the stomata.
What are the primary functions of roots?
Roots perform three main functions:
Anchoring: Secure plants to the ground, providing stability.
Absorption: Absorb water and minerals for plant growth, acting like “drinking straws.”
Hormone Production: Produce hormones that regulate plant growth and development.
Why are roots essential for plant survival and stability?
Roots provide a strong foundation, enabling plants to resist wind and other disturbances. This ensures proper orientation of stems, leaves, flowers, and fruits for:
Photosynthesis (leaves).
Pollination (flowers).
Seed dispersal (fruits).
What are storage roots, and how are they adapted?
Storage roots, like those in carrots, beets, and radishes, store carbohydrates to help plants survive adverse conditions. They have modified tissues for large sugar and starch reserves.
How do roots aid in vegetative reproduction?
Horizontal roots in plants like willows produce shoot buds that grow into new plants. This adaptation allows rapid spread and colonization, especially when seed dispersal is limited.
What is the role of spines in root systems?
In some palms, roots grow into spines that deter herbivores and protect the plant from damage.
How do holdfast roots function?
Found in vines like ivy, holdfast roots cling to surfaces, enabling climbing and access to sunlight in competitive environments.
What are parasitic roots, and how do they work?
Parasitic plants like mistletoe use haustorial roots to penetrate host tissues, extracting water and nutrients for survival. They connect to the host’s xylem and/or phloem.
What are the differences between fibrous and tap root systems?
-Fibrous Root System: Dense, grass-like roots near the soil surface (e.g., grasses, wheat). Prevent soil erosion.
-Tap Root System: One main root with lateral branches (e.g., carrots, dandelions). Penetrates deep into the soil.
What is the role of the root cap?
The root cap protects meristematic tissue, helps the root push through the soil, and aids in soil perception and growth direction.
What are the zones of root growth?
1.Root Apical Meristem: Produces new cells for root growth.
2.Zone of Elongation: Cells elongate, contributing to root length.
3.Zone of Maturation: Cells differentiate into specialized types like root hairs and vascular cells.
How do lateral roots develop?
Lateral roots originate from the pericycle. A lateral root primordium forms, pushing through the cortex and epidermis to emerge as a new root.
What are aerial roots, and how are they adapted?
Found in epiphytes like orchids, aerial roots have a spongy outer layer (velamen radicum) to absorb moisture from the air. This adaptation helps them survive in humid environments without soil contact.
What are contractile roots, and what is their purpose?
Contractile roots pull plants like bulbs or corms deeper into the soil for optimal growth, anchorage, and protection against environmental hazards.
What are mycorrhizae, and how do they benefit plants?
Mycorrhizae are symbiotic relationships between fungi and plant roots. Fungi help plants absorb water and nutrients, while plants provide carbohydrates to fungi.
What are root nodules, and how do they fix nitrogen?
Found in legumes, root nodules house nitrogen-fixing bacteria (e.g., Rhizobium) that convert atmospheric nitrogen into ammonia for plant use. The plant provides carbohydrates in return, forming a mutualistic relationship.
What are prop roots, and what do they do?
Prop roots provide additional support for plants with heavy foliage or those in unstable environments (e.g., mangroves).
What are haustorial roots, and where are they found?
Haustorial roots are parasitic roots in plants like dodder and Rafflesia. They penetrate host plants to extract water, nutrients, and sometimes carbohydrates.
Q: What are vascular plants also known as?
A: Tracheophytes, plants with specialized vascular tissues (xylem and phloem).
Q: Name the four types of vascular plants.
A: Lycophytes (Clubmosses, Quillworts), Pteridophytes (Ferns), Gymnosperms (Seed-producing plants with exposed seeds), Angiosperms (Flowering plants with seeds enclosed in fruits).
Q: What does “gymnosperm” mean in Greek?
A: “Gymnos” (naked) + “sperma” (seeds).
Q: What distinguishes gymnosperms from angiosperms?
A: Gymnosperms produce exposed seeds in cones, while angiosperms enclose seeds in fruits.
Q: List key characteristics of gymnosperms.
A: Naked seeds, heterosporous reproduction, cones as reproductive structures, mostly woody plants, wind-pollinated, evergreen leaves, slow reproductive cycle, vascular cambium for secondary growth, three generations in seeds.
Q: How do gymnosperms protect megagametophytes?
A: The megagametophyte develops within the sporangium, remaining protected inside the maternal sporophyte.
Q: What evolutionary modification in gymnosperms aids pollination?
A: Megasporophylls evolved into upright cones, facilitating wind pollination.
Q: What is the significance of progymnosperms?
A: They are ancestors to modern gymnosperms and represent the transition from spore-producing to seed-producing plants.
Q: What two major orders did progymnosperms include?
A: Aneurophytales and Archaeopteridales.
Q: What are seed ferns (Pteridospermatophyta)?
A: Extinct woody plants with fern-like foliage that produced seeds instead of spores.
Q: Why did seed ferns go extinct?
A: Competition with advanced plant groups like angiosperms and changing climatic conditions.
Q: Name three uses of conifers.
A: Timber production, paper production, and erosion control.
Q: What is unique about conifer wood?
A: It lacks vessels and sieve tubes, consisting mainly of tracheids.
Q: Which tree is among the largest conifers?
A: The giant redwood, reaching heights of 90 m.
Q: How do cycads reproduce sexually?
A: They produce male and female cones, with pollination often carried out by beetles or small bees.
Q: What makes cycads ecologically significant?
A: They serve as habitats and food sources for various wildlife species.
Q: How do cycads reproduce asexually?
A: By growing shoots from their main stem, which take root to form separate cycads.
Q: What makes Ginkgo biloba unique among gymnosperms?
A: It is the only living species of its division, known for its resilience and fan-shaped leaves.
Q: Name two uses of Ginkgo biloba.
A: Medicinal extracts to improve cognitive function and air quality improvement by absorbing pollutants.
Q: What percentage of gymnosperm species are at risk of extinction in some regions?
A: Nearly 41%.
Q: List three proposed solutions for gymnosperm conservation.
A: Biotechnological interventions, seed banks, and enhanced forest management.
What are nonvascular plants?
Answer: Nonvascular plants are plants that do not have a vascular system consisting of xylem and phloem. Instead, they possess simpler tissues that perform specialized functions for the internal transport of water.
How do nonvascular plants adapt to dry conditions?
Answer: Nonvascular plants can adapt to dry conditions through two strategies:
Desiccation Tolerance: They can survive significant water loss, though they grow slowly in moist conditions.
Desiccation Avoidance: They retain water or access a stable water source, allowing continued growth and reproduction during dry periods.
What is the role of spores in nonvascular plants?
Answer: Many nonvascular plants produce spores that help them survive during stressful conditions. These spores are stress-tolerant cells that can endure desiccation and allow the plant to reproduce or regenerate once favorable conditions return.
What are the main classifications of nonvascular plants?
Answer: Nonvascular plants are classified into:
Kingdom Plantae, Division Bryophyta: Includes mosses.
Kingdom Plantae, Division Hepatophyta: Includes liverworts.
Kingdom Plantae, Division Anthocerophyta: Includes hornworts.
What are the characteristics of bryophytes?
Answer: Bryophytes are small plants typically found in moist environments. They lack true stems, roots, or leaves but have cells that perform similar functions. They absorb water and nutrients from the air through their surface and have rhizoids that help anchor them.
What is the dominant generation in mosses?
Answer: The dominant generation in mosses is the gametophyte generation, which is photosynthetic and produces gametes for reproduction. The sporophyte generation is smaller and depends on the gametophyte for nutrition.
How do mosses reproduce?
Answer: Mosses reproduce sexually via gametes produced in specialized structures called gametangia. The male gametangium, antheridia, produces sperm that fertilize eggs in the female gametangium, archegonia, resulting in the formation of a zygote that develops into the sporophyte.
What is the role of mosses in ecosystems?
Answer: Mosses play a crucial role in ecosystems by aiding in soil formation, water retention, and nutrient cycling. They contribute to the ecosystem’s structure, especially in forests, wetlands, and deserts.
How do liverworts differ from mosses?
Answer: Liverworts are small plants that can be leafy or thallose (flat and ribbon-like). They have an alternation of generations, and some species can reproduce asexually through gemmae, fragmentation, or budding, in addition to sexual reproduction involving free-swimming sperm.
How do liverworts reproduce asexually?
Answer: Liverworts reproduce asexually by producing gemmae, which are buds that develop in gemma cups on the plant’s surface. They can also reproduce through fragmentation (when parts of the plant break apart) or budding (where new parts develop into separate plants).
What is the life cycle of hornworts?
Answer: Hornworts have an alternation of generations:
The gametophyte generation is flat and photosynthetic, producing male and female sex organs (antheridia and archegonia).
The sporophyte generation grows from fertilized embryos and produces spores, completing the cycle.
What are the characteristics of hornworts?
Answer: Hornworts are small, flowerless plants that have an elongated horn-like structure. They lack true roots but have rhizoids to anchor them. They reproduce by alternating between a gametophyte and sporophyte generation.
What are the differences between the three divisions of nonvascular plants (Bryophyta, Hepatophyta, Anthocerophyta)?
Answer:
Bryophyta (Mosses): Characterized by small, leaf-like appendages and a dominant gametophyte generation.
Hepatophyta (Liverworts): Can be leafy or thallose, reproducing both sexually and asexually through gemmae and fragmentation.
Anthocerophyta (Hornworts): Have horn-like structures and rhizoids, with a dominant gametophyte generation and a smaller sporophyte generation.
Why are mosses sensitive to environmental disturbances?
Answer: Mosses are sensitive to environmental disturbances, especially air pollution, because they absorb water and nutrients through their entire surface. This makes them vulnerable to changes in air quality, which can affect their ability to perform photosynthesis and grow.
How do liverworts reproduce sexually?
Answer: Liverworts reproduce sexually when free-swimming sperm fertilize eggs produced in the archegonia. This results in the formation of a zygote, which develops into a sporophyte that releases spores.
What is the study of ecology about?
Answer: Ecology is the study of how living organisms interact with their surroundings. It focuses on how plants and animals change over time to survive in their environments.
Q. How do plants change over time?
Answer: Plants change over time due to mutations, which are small changes in their genes. Beneficial mutations help plants survive and are passed down to their offspring.
Q. What is a population in the context of plants?
Answer: A population refers to a group of plants of the same species living in a specific area. Plants rarely live alone and often form populations that interact with each other.
Q. How does a population behave differently from individual plants?
Answer: A population behaves differently because the whole group can demonstrate characteristics or responses that are greater than the sum of individual plants’ behaviors.
Q. What is a community in plant ecology?
Answer: A community consists of different species, including plants, animals, fungi, and microorganisms, interacting with each other in a specific environment.
Q. What is an ecosystem?
Answer: An ecosystem refers to a community of living organisms (plants, animals, fungi, and microorganisms) and their physical environment. It is the entire system in which plants thrive, considering both the community and the environment.
Q. What is a habitat?
Answer: A habitat is the set of conditions where an organism completes its life cycle. It provides the necessary resources like food, water, shelter, and suitable living conditions for survival.
Q. How do Redwoods affect their habitat?
Answer: Redwoods dominate their habitat by providing filtered light and protection from wind for understory plants. Their large size and structure create an environment that supports other species that cannot tolerate full sunlight.
Q. Why are pollinators important to plants?
Answer: Pollinators are critical for plants because they help with fertilization. The plants depend on pollinators to reproduce, and any disease or predator affecting these pollinators can directly impact plant survival.
Q. What is the difference between operational habitat and habitat?
Answer: The operational habitat consists of the specific aspects of the environment that directly affect a plant’s survival. The habitat, on the other hand, includes all components, both known and unknown, that might affect the plant.
Q. What are abiotic components in an ecosystem?
Answer: Abiotic components are the non-living parts of an ecosystem that affect living organisms. These include factors like climate, soil, and disturbances like fire and floods.
Q. How do abiotic factors affect plant life?
Answer: Abiotic factors, such as climate change and soil composition, influence where plants can live and how well they thrive. For example, plants are often restricted to certain regions due to climate conditions they can tolerate.
Q. What are biotic components in an ecosystem?
Answer: Biotic components are the living organisms in an ecosystem, including plants, animals, fungi, and microorganisms. They interact with each other and with their non-living environment.
Q. What happens when two plant species interact?
Answer: When two plant species interact, they can form different types of relationships. If one species benefits and the other is unaffected, it is a commensal relationship. If one species benefits at the expense of the other, it is predation.
Q. What is competition in plant ecology?
Answer: Competition occurs when two populations of plants or different species interact in a way that hinders their growth. This typically happens when resources like light, water, or nutrients are limited.
Q. What factors influence the geographic distribution of plants?
Answer: The geographic range of plants is influenced by both abiotic factors (like climate and soil) and biotic factors (like interactions with other species).
Q. What is the difference between large-scale and local geographic distribution?
Answer: Large-scale geographic distribution refers to the overall range of a species, while local geographic distribution refers to the specific arrangement of individuals within a smaller area or habitat.
Q. What are the three types of local distribution in plants?
Answer: The three types of local distribution are:
Random distribution: Individuals are scattered without any particular pattern.
Clumped distribution: Individuals are grouped together in specific areas.
Uniform distribution: Individuals are spaced evenly across the habitat.
Q. What is demography in plant populations?
Answer: Demography is the study of the age structure of plant populations. It looks at the proportion of young, middle-aged, and old individuals in a population, which influences the growth rate.
Q. What factors influence plant population growth?
Answer: Factors that influence growth include:
Generation time: How quickly plants reach reproductive maturity.
Biotic potential: The maximum reproductive capacity of a plant under ideal conditions.
Q. What are the different structures of ecosystems?
Answer: Ecosystems can be described in terms of their physiognomic structure, temporal structure, species diversity, and trophic levels. These factors help define the ecosystem’s characteristics and how it functions.
Q. What is physiognomic structure?
Answer: Physiognomic structure refers to the general appearance of an ecosystem, particularly the size and shape of the vegetation. It includes how plants are distributed and their life forms, such as trees, shrubs, and herbs.
Q. How do different climatic conditions affect the physiognomic structure?
Answer: Similar climatic conditions often lead to similar physiognomic structures in different regions, although soil types can create variations. For example, regions with similar climates may have similar distributions of trees, shrubs, and other plants.
Q. Why are there only a few basic types of ecosystems?
Answer: Despite the vast number of possible combinations of life forms and structures, there are only a few basic types of ecosystems because environmental factors like climate and soil type impose limits on how ecosystems can form. These basic types are easily recognized, such as forests, grasslands, and marshes.
Q. What are angiosperms?
Answer: Angiosperms, also known as tracheophytes, are plants with specialized tissues for transporting water, minerals, and food. They are characterized by having flowers, fruits with seeds, and are found everywhere, dominating plant life globally.
Key Factors:
Flowers: The reproductive structures that often have colorful petals to attract pollinators.
Fruit: Develops from the ovary after fertilization, serving to protect the seeds and aid in their dispersal.
Seeds: Enclosed within the fruit, providing protection and facilitating dispersal.
Q. What is pollination?
Answer: Pollination is the process that angiosperms undergo before they can reproduce, involving the transfer of pollen to fertilize the ovule.
Q. What are flower structures?
Answer: Flowers are the reproductive organs of angiosperms, designed for efficient sexual reproduction. They consist of various parts:
Sepals: Green structures at the base of the flower that protect it before it opens.
Petals: Often brightly colored to attract pollinators.
Stamens: The male reproductive structures, consisting of the filament (stalk) and the anther (where pollen develops).
Carpels: The female reproductive structures, including the stigma (sticky tip), style (connecting stalk), and ovary (protective chamber containing ovules).
Q. What are the functions of roots?
Answer: Roots anchor the plant in the soil, absorb water and minerals, transport materials to the shoots, and sometimes store food (e.g., carrots).
Types of Roots:
Tap Root: A deep-growing primary root with smaller lateral roots.
Fibrous Root: A dense network of equally sized roots.
Adventitious Roots: Roots growing from unusual parts like stems or leaves.
Q. What are the functions of stems?
Answer: Stems support aerial parts of the plant, transport water and minerals from roots to leaves/flowers, carry food made in leaves to roots, and may store food. Some green stems also carry out photosynthesis.
Q. What are leaf structures?
Answer: Leaves are composed of several parts:
Petiole: The stalk that attaches the leaf to the stem.
Lamina: The flat part of the leaf.
Midrib: The central vein running through the lamina.
Xylem and Phloem: Found in petiole, midrib, and lamina for transport.
Q. What are the functions of leaves?
Answer: Leaves are responsible for making food through photosynthesis, exchanging gases (CO₂ and O₂), losing water through transpiration, and sometimes storing food (e.g., lettuce, cabbage).
Q. What is the classification of flowering plants?
Answer: Flowering plants are classified into two major groups based on seed structure:
Dicots (Two cotyledons)
Monocots (One cotyledon)
Q. What are monocots?
Answer: Monocots are flowering plants with one seed leaf or cotyledon. Their flowers typically have parts in multiples of three, and they have fibrous roots and scattered vascular bundles.
Q. What are eudicots?
Answer: Eudicots are flowering plants with two cotyledons. They have a central vein in their leaves and a taproot system. Their flowers typically have four or five parts, and their stems have a ring of vascular bundles.
Q. How are plants classified based on longevity?
Answer:
Ephemeral: Live for a few weeks.
Annuals: Complete their life cycle in one season.
Biennials: Complete their life cycle in two seasons.
Perennials: Live for multiple years.
Q. How are plants classified based on habit?
Answer:
Herbs: Small, non-woody plants.
Shrubs: Woody plants with no main trunk.
Trees: Perennial plants with a main trunk.
Q. How are plants classified based on habitat?
Answer: Plants can be categorized based on their habitat:
Hydrophytes: Aquatic plants.
Xerophytes: Plants in dry environments.
Mesophytes: Plants in moderate conditions.
Halophytes: Plants in saline conditions.
Epiphytes: Plants that grow on other plants.
Q. What is the structure of fruits?
Answer: Fruits are the “ripened ovary” of a flower. They typically consist of three regions:
Exocarp: The skin.
Endocarp: The inner boundary around seeds.
Mesocarp: The tissue between the exocarp and endocarp.
Q. What are the different types of fruits?
Answer: Fruits can be classified into three categories:
Simple Fruits: Develop from a single ovary.
Aggregate Fruits: Develop from many small ovaries of one flower (e.g., strawberries).
Multiple Fruits: Develop from several flowers clustered together (e.g., pineapples).
Q. What are bryophytes and how do they differ from angiosperms?
Answer:
Bryophytes are non-vascular plants that rely on diffusion for nutrient transport and reproduce via spores. They require water for fertilization.
Angiosperms are vascular plants with complex structures, reproducing via seeds enclosed within fruits. They can grow larger and can survive in various habitats.
