Biology 4 Flashcards
If the phloem of a healthy plant is killed by heat treatment, it would disrupt the plant’s ability to transport organic nutrients, such as sugars and amino acids, from the leaves (where they are produced) to other parts of the plant, including the roots and developing tissues.
Here are some potential consequences of killing the phloem:
Nutrient Transport Disruption: The primary function of phloem is to transport organic nutrients produced during photosynthesis from sources (like leaves) to sinks (such as roots, fruits, and growing tissues). If the phloem is killed, this transport system is disrupted, and nutrients cannot be distributed efficiently throughout the plant.
Reduced Growth: Without the ability to transport essential nutrients, the growth and development of the plant would be severely affected. The roots may not receive an adequate supply of sugars and other nutrients, which could lead to stunted growth or even death of the plant.
Wilting and Yellowing: The lack of nutrient transport may result in wilting of leaves and other symptoms of nutrient deficiency, such as yellowing or browning of leaves due to the inability to transport sugars and other compounds effectively.
Decreased Yield: In fruit-bearing plants, the inability to transport nutrients to developing fruits may result in reduced fruit yield or poor fruit quality.
Overall, killing the phloem of a healthy plant would have detrimental effects on its growth, development, and overall health.
The main waste products formed in plants include:
Oxygen: During photosynthesis, plants produce oxygen as a byproduct when they use carbon dioxide and water to create glucose and oxygen using light energy.
Respiratory Carbon Dioxide: Just like animals, plants undergo cellular respiration to generate energy. As a result, they release carbon dioxide as a waste product during respiration.
Ethylene: Ethylene is a plant hormone that regulates various physiological processes, including fruit ripening, flowering, and senescence. It is also produced as a waste product during certain metabolic processes in plants.
Plant Metabolites: Plants produce a variety of secondary metabolites, such as alkaloids, terpenoids, and phenolic compounds, as part of their normal metabolic processes. Some of these metabolites may not be actively used by the plant and can be considered waste products.
Unused or Excess Metabolites: Plants produce a wide range of organic compounds through various metabolic pathways. Some of these compounds may not be utilized by the plant and can accumulate as waste products.
Overall, plants generate waste products as a result of their metabolic activities, just like any other living organism. However, these waste products often serve important roles in plant physiology and ecology.
In the kidney, the Malpighian corpuscle is located in the
In the kidney, the Malpighian corpuscle is located in the renal cortex. It is part of the structure known as the renal corpuscle, which is the initial filtering component of the nephron, the functional unit of the kidney. The Malpighian corpuscle consists of the glomerulus and the Bowman’s capsule. The glomerulus is a tuft of capillaries where blood filtration occurs, while the Bowman’s capsule surrounds the glomerulus and collects the filtrate that will eventually be processed into urine.
Parenchyma cells primarily function as the
Parenchyma cells primarily function as the fundamental tissue in plants, playing roles in photosynthesis, storage, and secretion. While they are not typically classified as supporting tissue in the same way as collenchyma or sclerenchyma cells, parenchyma cells do contribute to the overall structural integrity of the plant. They are often found in the cortex and pith of stems, leaves, and roots, providing structural support and helping to maintain the shape of plant organs. However, their main functions are related to metabolic activities rather than mechanical support.
Taxism
Taxism:
Taxism refers to the directed movement of an organism in response to an external stimulus.
Examples of taxism include:
Phototaxis: Movement of organisms in response to light. For example, plants bending toward light (positive phototaxis) or away from light (negative phototaxis).
Chemotaxis: Movement of organisms in response to chemical stimuli. For instance, bacteria moving toward nutrients or away from toxins.
Taxism can be positive (movement toward the stimulus) or negative (movement away from the stimulus).
Tropism
Tropism:
Tropism refers to the growth or movement of an organism or part of an organism in response to a stimulus, typically involving the bending of the organism toward or away from the stimulus.
Examples of tropisms include:
Phototropism: Growth or movement of organisms in response to light. For instance, plants bending toward light for photosynthesis.
Gravitropism (also known as geotropism): Growth or movement of organisms in response to gravity. For example, roots growing downward (positive gravitropism) and stems growing upward (negative gravitropism).
Thigmotropism: Growth or movement of organisms in response to touch or contact. One example is vines wrapping around a support structure.
Tropisms typically involve the growth or bending of plant parts in response to stimuli, whereas taxisms involve the entire organism moving in response to stimuli.
In summary, taxism involves directed movement of an entire organism in response to stimuli, while tropism refers to the growth or movement of specific parts of an organism in response to stimuli. Tropisms are often observed in plants and are essential for their survival and adaptation to their environment.
Alkaloids
Alkaloids:
Alkaloids are nitrogen-containing organic compounds that often have pharmacological effects on humans and animals.
They are typically bitter-tasting and can have a variety of physiological effects, including analgesic, stimulant, or toxic properties.
Examples of alkaloids include caffeine, nicotine, morphine, quinine, and cocaine.
Alkaloids are often produced by plants as a defense mechanism against herbivores or to attract pollinators.
Tannins
Tannins:
Tannins are polyphenolic compounds that are found in various parts of plants, including leaves, bark, roots, and fruits.
They have astringent properties, which give them the ability to precipitate proteins and form complexes with other organic compounds.
Tannins are often involved in plant defense mechanisms against herbivores, pathogens, and UV radiation.
They are also used in tanning leather, dyeing fabrics, and as antioxidants in food and beverages.
Examples of tannin-rich plants include oak trees, tea leaves, grape skins, and pomegranates.
Resins
Resins:
Resins are a heterogeneous mixture of organic compounds produced by many plants, particularly trees and shrubs.
They are typically viscous, sticky substances that harden upon exposure to air.
Resins often serve protective functions in plants, sealing wounds and protecting against pathogens and herbivores.
They can also act as a barrier against water loss and UV radiation.
Examples of resin-producing plants include pine trees (which produce pine resin), frankincense trees, and various species of conifers and angiosperms.
Scion
Scion:
A scion is a detached shoot or bud from a desired plant variety that is grafted onto the rootstock of another plant.
In grafting, the scion provides the desired characteristics of the plant, such as fruit quality or flower color, while the rootstock provides the root system and may contribute disease resistance or tolerance to specific environmental conditions.
Bulb
A bulb is a specialized underground storage organ consisting of a short stem with fleshy, scale-like leaves (or leaf bases) surrounding a central bud or growing point.
Bulbs contain stored reserves of energy and nutrients that enable the plant to survive adverse conditions and to produce new shoots and roots.
Examples of plants that propagate through bulbs include tulips, daffodils, onions, and garlic.
Rhizome
A rhizome is a horizontal underground stem that grows horizontally below the soil surface and sends out roots and shoots from its nodes.
Rhizomes allow plants to spread horizontally and produce new individuals at the nodes along the rhizome.
Examples of plants that propagate through rhizomes include ginger, bamboo, iris, and some grasses.
Sucker
A sucker is a shoot that arises from the roots or lower part of the stem of a plant.
Suckers often grow from underground parts of the plant and can emerge some distance away from the main plant.
Suckers allow plants to reproduce vegetatively by forming new plants from the parent plant’s root system.
Examples of plants that produce suckers include raspberries, blackberries, roses, and some trees like poplars.
Seeds Dispersed by Birds:
Characteristics:
Often have fleshy and attractive fruits to entice birds.
Seeds are usually small and hard.
Some seeds have specialized adaptations, such as hooks or barbs, that attach to a bird’s feathers for transportation.
Birds consume the fruit, and the seeds pass through their digestive system, aiding in dispersal.
Seeds Dispersed by Water:
Characteristics:
Seeds are often buoyant to float on water.
Fruits may have a fibrous or lightweight structure.
Some seeds have air-filled structures to enhance floating.
Examples include coconuts, which can float on water and are dispersed by ocean currents.
Seeds Dispersed by Wind:
Characteristics:
Seeds are lightweight to be carried by the wind.
Often have structures like wings, hairs, or parachutes to increase airborne time.
Examples include dandelion seeds with a parachute-like structure.
Some seeds have a hard outer coat that protects them during wind dispersal.
Explosive Mechanism:
Characteristics:
Typically, seeds are housed in pods or capsules that split open forcefully.
The dispersal mechanism is triggered by environmental factors like dryness, heat, or physical disturbance.
Seeds are often ejected over a distance, increasing the chance of colonization.
Examples include the seed pods of the touch-me-not plant (Impatiens), which burst open when touched.
A dry dehiscent fruit that breaks up into one-seeded parts is called
A dry dehiscent fruit that breaks up into one-seeded parts is called a schizocarp. Schizocarps typically develop from compound ovaries with two or more carpels. As the fruit matures, it splits into separate one-seeded segments, each derived from an individual carpel. Examples of plants with schizocarp fruits include members of the Apiaceae (parsley or carrot family), such as anise, caraway, and fennel.
A capsule
A capsule is a type of dry dehiscent fruit that typically develops from a compound ovary with two or more carpels. It is characterized by being several-seeded and splitting open at maturity to release the seeds. Capsules can dehisce along various lines, including both longitudinal and transverse lines, depending on the plant species. Examples of plants that produce capsules include poppies, lilies, and irises.
Phylum Cnidaria, formerly known as Coelenterata,
Phylum Cnidaria, formerly known as Coelenterata, includes organisms like jellyfish, corals, hydras, and sea anemones. Here are some key characteristics of organisms in the phylum Cnidaria:
Radial Symmetry: Cnidarians exhibit radial symmetry, meaning their body parts are arranged symmetrically around a central axis.
Diploblastic Organization: Their body is composed of two layers of cells: an outer ectoderm and an inner endoderm, with a gelatinous layer called the mesoglea in between.
Cnidocytes: Specialized cells called cnidocytes contain nematocysts, which are stinging structures used for defense and capturing prey.
Gastrovascular Cavity: Cnidarians have a central digestive cavity with a single opening, serving as both a mouth and anus. This cavity is lined with gastrodermis, which helps in digestion.
Tentacles: Most cnidarians have tentacles armed with cnidocytes, which they use to capture prey and defend themselves.
Polyp and Medusa Forms: Cnidarians may exist in two main body forms: the polyp, which is typically sessile and cylindrical with tentacles around the mouth, and the medusa, which is free-swimming and umbrella-shaped.
Nerve Net: Cnidarians have a simple nerve net that helps in coordinating movements and responses to stimuli, but they lack a centralized nervous system.
Reproduction: Cnidarians can reproduce both sexually and asexually. Sexual reproduction often involves the release of gametes into the water, where fertilization occurs. Asexual reproduction can occur through budding or fragmentation.
Fungi comprise a diverse group of organisms with various characteristics, but there are several key features that are common among them:
Eukaryotic Cells: Fungi are made up of eukaryotic cells, which means their cells have a defined nucleus enclosed within a membrane.
Heterotrophic Nutrition: Fungi are heterotrophs, which means they obtain their nutrients by absorbing organic matter from their environment. They secrete enzymes that break down complex organic molecules into simpler compounds, which are then absorbed by the fungal cells.
Chitin Cell Walls: Unlike plants, which have cell walls made of cellulose, fungi have cell walls primarily composed of chitin. Chitin provides structural support to fungal cells.
Absorptive Mode of Nutrition: Fungi absorb nutrients from their surroundings through their hyphae, which are thread-like structures that make up the body of the fungus. The hyphae secrete enzymes that break down organic matter into smaller molecules, which are then absorbed by the hyphae.
Reproduction: Fungi reproduce through the production of spores. Spores are tiny reproductive structures that can be produced sexually or asexually. They are dispersed by various means, including wind, water, and animals, allowing fungi to colonize new habitats.
Diverse Lifestyles: Fungi exhibit a wide range of lifestyles, including saprotrophic (feeding on dead organic matter), parasitic (feeding on living organisms), and mutualistic (forming symbiotic relationships with other organisms, such as mycorrhizal fungi associating with plant roots).
Mycelium: The body of a fungus is typically made up of a network of hyphae called mycelium. The mycelium grows through the substrate, facilitating nutrient absorption and the colonization of new areas.
Ecological Importance: Fungi play crucial roles in ecosystems as decomposers, nutrient recyclers, and symbiotic partners with plants and other organisms. They contribute to the breakdown of organic matter, the formation of soil, and the cycling of nutrients.
These are some of the key characteristics of fungi, which make them a diverse and ecologically important group of organisms in nature.
syncytium
A syncytium is a multinucleated cell or organism in which the cell boundaries are absent, allowing the nuclei to be dispersed throughout the cytoplasm without being separated by cell membranes. This arrangement of nuclei within a single cytoplasmic mass is a characteristic feature of certain types of cells and organisms.
Syncytia can be found in various organisms and tissues, including certain types of muscle cells, fungal hyphae, and some developmental stages of embryos. In the context of fungi, syncytial structures can be observed in the mycelium, which is the vegetative body of the fungus composed of branching hyphae.
The absence of internal cell boundaries in syncytia allows for efficient transport of materials and signals throughout the cell, facilitating coordinated functions across the entire cytoplasmic mass. This structural adaptation is particularly advantageous in processes such as nutrient uptake, growth, and response to environmental stimuli.
Overall, syncytia represent an interesting adaptation in cellular organization that allows for specialized functions and behaviors in diverse organisms.
Bryophytes are a group of non-vascular plants that typically include mosses, liverworts, and hornworts. Here are some key characteristics of bryophytes:
Non-Vascular: Bryophytes lack specialized vascular tissues like xylem and phloem found in higher plants. As a result, they do not have true roots, stems, or leaves.
Small Size: Most bryophytes are small and low-growing plants, often forming dense mats or cushions in damp habitats.
Dominant Gametophyte Stage: The gametophyte generation (haploid) is the dominant and photosynthetically active stage in the life cycle of bryophytes. The sporophyte generation (diploid) is dependent on the gametophyte for nutrition and is usually short-lived.
Water-Dependent Reproduction: Bryophytes require water for sexual reproduction because the sperm cells must swim to reach the egg cells. They produce specialized reproductive structures, such as archegonia (female reproductive structures) and antheridia (male reproductive structures).
Spore Dispersal: Bryophytes reproduce through spores, which are produced in sporangia located on the sporophyte. Spores are dispersed by wind or water and germinate to produce new gametophytes.
Moisture-Dependent Habitat: Bryophytes are commonly found in moist environments, such as forests, bogs, wetlands, and stream banks, where water availability is high.
Ecological Importance: Bryophytes play essential roles in ecosystems by stabilizing soil, retaining moisture, and providing habitats for various microorganisms and small invertebrates. They also contribute to nutrient cycling and help regulate water flow in terrestrial ecosystems.
Angiosperms and gymnosperms are two major groups of seed-producing plants. While they share some similarities, they also exhibit several key differences:
Angiosperms and gymnosperms are two major groups of seed-producing plants. While they share some similarities, they also exhibit several key differences:
Reproductive Structures:
Angiosperms: Angiosperms produce seeds enclosed within a protective structure called a fruit. The flower is the reproductive structure of angiosperms, where seeds are enclosed within ovaries.
Gymnosperms: Gymnosperms produce seeds that are not enclosed within a fruit. Instead, seeds are typically borne naked on the surface of specialized structures called cones or strobili.
Seeds:
Angiosperms: Seeds of angiosperms are enclosed within a fruit, which provides protection and aids in seed dispersal by animals or wind.
Gymnosperms: Gymnosperm seeds are not enclosed within a fruit but are exposed on the surface of cones. They lack the protective covering provided by fruits.
Flowers:
Angiosperms: Angiosperms produce flowers, which are often brightly colored and attract pollinators such as insects, birds, and mammals.
Gymnosperms: Gymnosperms do not produce flowers. Instead, they produce cones or strobili, which contain reproductive structures called microsporangia (male) and megasporangia (female).
Leaf Type:
Angiosperms: Angiosperms typically have broad leaves with a network of veins.
Gymnosperms: Gymnosperms often have needle-like or scale-like leaves, which help reduce water loss in arid environments.
Vascular Tissue:
Angiosperms: Angiosperms have vessels in their vascular tissue, which aids in the efficient transport of water, minerals, and nutrients throughout the plant.
Gymnosperms: Gymnosperms lack vessels in their vascular tissue. Instead, they have tracheids, which are elongated cells that transport water and nutrients.
Diversity:
Angiosperms: Angiosperms are the most diverse group of plants, with over 300,000 species. They include flowering plants found in a wide range of habitats worldwide.
Gymnosperms: Gymnosperms are less diverse than angiosperms, with approximately 1,000 species. They are often found in colder climates and include conifers, cycads, ginkgoes, and gnetophytes.
Algae are a diverse group of photosynthetic organisms that can be found in various aquatic environments. Here are some key characteristics of algae:
Algae are a diverse group of photosynthetic organisms that can be found in various aquatic environments. Here are some key characteristics of algae:
Photosynthesis:
Algae are photosynthetic organisms, capable of producing their own food through photosynthesis. They contain chlorophyll and other pigments that capture light energy to convert carbon dioxide and water into sugars.
Habitats:
Algae can be found in a wide range of habitats, including freshwater, marine environments, and moist terrestrial areas. Some algae are also capable of surviving in extreme environments.
Cell Types:
Algae can exist as single-celled organisms, colonies of cells, or multicellular structures. The complexity of their structure varies among different types of algae.
Cell Wall:
Algal cells are surrounded by a cell wall that provides structural support. The composition of the cell wall can vary between different groups of algae.
Pigments:
In addition to chlorophyll, algae may contain other pigments such as carotenoids, phycobilins, and xanthophylls. These pigments contribute to the diverse colors observed in different types of algae.
Reproduction:
Algae reproduce through various mechanisms, including asexual and sexual reproduction. Asexual reproduction often involves cell division, while sexual reproduction may involve the formation of specialized reproductive structures.
Classification:
Algae are classified into several major groups based on their characteristics. Common groups include green algae (Chlorophyta), red algae (Rhodophyta), brown algae (Ochrophyta), and diatoms (Bacillariophyta).
Nutrient Absorption:
Algae absorb nutrients from their surrounding environment, and some species are capable of fixing nitrogen. They play a crucial role in nutrient cycling in aquatic ecosystems.
Economic Importance:
Some species of algae have economic importance. For example, certain types of algae are used as food (e.g., seaweed), and others are used in the production of agar, carrageenan, and biofuels.
Ecological Role:
Algae play a vital role in aquatic ecosystems by contributing to primary production and serving as a food source for various organisms. They are also important in the global carbon cycle.
Symbiotic Relationships:
Some algae form symbiotic relationships with other organisms. For instance, lichens are a mutualistic association between algae or cyanobacteria and fungi.
Pteridophytes are a group of vascular plants that reproduce via spores and do not produce seeds or flowers. They are commonly known as ferns and their relatives. Here are some key characteristics of pteridophytes:
Pteridophytes are a group of vascular plants that reproduce via spores and do not produce seeds or flowers. They are commonly known as ferns and their relatives. Here are some key characteristics of pteridophytes:
Vascular Tissue:
Pteridophytes possess well-developed vascular tissue, which allows for the transport of water, minerals, and nutrients throughout the plant. The vascular tissue consists of xylem and phloem.
Alternation of Generations:
Pteridophytes exhibit a life cycle characterized by alternation of generations. This involves the alternation between a gametophyte (haploid) generation and a sporophyte (diploid) generation.
Sporophyte Dominance:
In the life cycle of pteridophytes, the sporophyte generation is the dominant phase. It is the conspicuous, photosynthetic plant body that produces spores through meiosis.
Spore Production:
Spores are produced in structures called sporangia, which are typically found on the underside of fern fronds or in specialized structures such as sori. Spores are released and dispersed by wind or water.
Gametophyte Stage:
Spores germinate to form the gametophyte stage, which is usually a small, heart-shaped structure known as a prothallus. The gametophyte produces male (antheridia) and female (archegonia) sex organs that produce gametes.
Fertilization:
Fertilization occurs when sperm from the antheridia swim through water to reach the archegonia and fertilize the eggs. This process results in the formation of a zygote, which develops into a new sporophyte plant.
Habitats:
Pteridophytes are found in a variety of habitats, including moist forests, swamps, grasslands, and rocky crevices. They often thrive in shaded and humid environments.
Reproduction Without Seeds:
Unlike seed plants, pteridophytes do not produce seeds. Instead, they reproduce through spores, which are dispersed to new areas where they germinate and grow into new plants.
Diversity:
Pteridophytes exhibit a diverse range of forms and sizes, from small, delicate ferns to large tree ferns. Some common examples of pteridophytes include ferns, horsetails, and club mosses.
Ecological Significance:
Pteridophytes play important ecological roles in various ecosystems. They help stabilize soil, provide habitat for wildlife, and contribute to nutrient cycling.
Pteridophytes represent an ancient group of plants that have existed for millions of years and continue to thrive in diverse habitats around the world.
