Plant Biology & Diversity of Life Structure of Plants PDF

8/27/24, 8:23 PM Platform | Study Fetch Plant Biology and Diversity of Life Structure of Plants (00:00:38 - 00:01:47) Anatomy of a Seed Seed coat - Protects the seed from the environment Stores nutrients to feed the e...

8/27/24, 8:23 PM Platform | Study Fetch Plant Biology and Diversity of Life Structure of Plants (00:00:38 - 00:01:47) Anatomy of a Seed Seed coat - Protects the seed from the environment Stores nutrients to feed the embryo as it grows Radicle - Young root that will grow into the full root system Hypocotyl - Young shoot Epicotyl - Shoot tip Plumule - Young leaves Primary vs. Secondary Growth Primary growth - Vertical growth at apical meristem (shoot tip and root tips) Secondary growth - Horizontal growth by the vascular cambium Plant Structures Meristems - Areas of plant growth Apical meristems - Vertical growth at shoot tip and root tips Lateral meristems - Horizontal growth Root Zones: Zone of maturation - Cells differentiate Zone of elongation - New cells lengthen and elongate the root Zone of cell division - Actively dividing undifferentiated cells Characteristics of Plants (00:00:26 - 00:00:38) Plants are photosynthetic eukaryotes of the kingdom Plantae Plant biology is a unique topic for the dental exam Homosporous vs. Heterosporous Plants (00:00:38 - 00:00:48) Homosporous plants - Produce only one type of spore Heterosporous plants - Produce two different types of spores (male and female) Germination and Embryonic Leaves https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce6bd48ab287f54e41f2a8/document?go=note 1/6 8/27/24, 8:23 PM Platform | Study Fetch (00:01:36 - 00:01:47) Germination - The growth of a seed Monocots - Flowering plants with one embryonic leaf Dicots - Flowering plants with two embryonic leaves Secondary Growth in Plants (00:02:54 - 00:03:08) Secondary growth occurs in plants, leading to increased development and external growth. This is more developed than the initial primary growth. Plant Structures: Ground Tissues (00:03:08 - 00:03:33) Ground tissue provides structural support to the plant. There are three main types of ground tissue: Parenchyma: The filler tissue and bulk of the plant. Remember this by "parents buy groceries in bulk to support their kids." Collenchyma: Provides extra support, especially in areas where the plant is growing or has a regular set of walls. Remember this by "Colin is a growing teen and has irregular moods." Sclerenchyma: The main support tissue with the thickest walls. Remember this by "S" for structural support. Vascular Tissues (00:03:55 - 00:04:23) The vascular tissues in plants include: Phloem: Transports sugars through the plant. Xylem: Transports water. The pith is the center of any root or stem. Dermal tissue (also called the epidermis) protects the plant and regulates responses to the environment, such as water permeability and gas exchange. The epidermis has a cuticle that limits water evaporation, similar to the function of human skin. Root Structures (00:04:48 - 00:05:20) Root hairs increase the surface area of the root, allowing for improved water and nutrient uptake. This is similar to how the villi of the intestines and alveoli of the lungs increase surface area for absorption. https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce6bd48ab287f54e41f2a8/document?go=note 2/6 8/27/24, 8:23 PM Platform | Study Fetch Detoxification and Plant Protection Mechanisms (00:05:20 - 00:05:30) The liver (hepatocytes) helps detoxify substances that enter the body. The Casparian strip in plant roots regulates the flow of substances that can travel from the soil into the plant. Plant Root Structure and Function (00:05:30 - 00:05:44) The root structure consists of several layers: Epidermis Cortex Endodermis Pericycle These layers protect and regulate what enters the root and reaches the xylem. The plant uses this structure to filter and protect itself from what is absorbed from the environment. Leaf Structure and Gas Exchange (00:05:44 - 00:05:57) Leaves have openings called stomata located on the lower epidermis. Stomata are responsible for gas exchange. Stomata are surrounded by guard cells that can regulate their opening and closing. Photosynthesis and Vascular Transport (00:05:57 - 00:06:18) The palisade mesophyll is where photosynthesis occurs. The spongy mesophyll is where gas exchange takes place. Bundle sheath cells protect the vascular bundles (xylem and phloem) from air exposure to prevent desiccation during transport. Water Movement in Plants (00:06:18 - 00:06:51) Transpiration: Water evaporation from stems and leaves through the stomata, which creates a negative pressure that pulls water upwards. Capillary action: Surface tension of water causes it to climb and move upwards in the plant. Root pressure: Osmotic flow of water into the roots due to a high concentration of solutes, which also forces water upwards. Nutrient Transport in Plants (00:07:02 - 00:07:28) https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce6bd48ab287f54e41f2a8/document?go=note 3/6 8/27/24, 8:23 PM Platform | Study Fetch Pressure flow hypothesis: High concentration of sugars in the phloem creates an osmotic gradient. Water moves from the xylem into the phloem cells, creating a pressure that drives the bulk flow of sugars from source (leaves) to sink (other parts of the plant). Pressure Flow Hypothesis and Plant Hormones (00:07:44 - 00:08:09) Pressure Flow Hypothesis: Add pressure to the flow in the leaves and the sugar or water will flow to the roots. Plant Hormones: Ethylene: Helps to ripen fruit Auxin: Promotes cell growth and causes tropism Cytokinins: Induce cell differentiation and cell division Gibberellins: Induce flowering, fruit production, stem elongation, and leaf and fruit death Abscisic Acid: Promotes dormancy and inhibits growth, particularly during times of stress Alternation of Generations (00:08:31 - 00:09:00) Alternation of generation is when plants can alternate between sexual and asexual phases. The cycle: 1. Two gametes can create one zygote via fertilization. 2. The zygote can become a sporophyte via mitosis. 3. The sporophyte can create spores via meiosis. 4. One spore can become a gametophyte via mitosis. 5. The gametophyte can create gametes. Homosporous vs. Heterosporous Plants (00:09:00 - 00:09:19) Homosporous Plants: Create one type of spore Heterosporous Plants: Create two types of spores: Microspores (male gametophyte) Megaspores (female gametophyte) Bryophytes (Nonvascular Plants) (00:09:19 - 00:09:46) Bryophytes include mosses, hornworts, and liverworts. They have no true roots, but rhizoids help absorb water. The main part of the stem serves the function that roots would have. https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce6bd48ab287f54e41f2a8/document?go=note 4/6 8/27/24, 8:23 PM Platform | Study Fetch They are short and grow horizontally to exchange water and nutrients with their environment. Tracheophytes (Vascular Plants) (00:09:46 - 00:10:09) Tracheophytes have a xylem and a phloem, as well as true roots. They are tall and grow horizontally. The sporophyte stage is the dominant life cycle stage. Tracheophytes include seedless plants (lycophytes and ferns) and seed-bearing plants. Gymnosperms and Angiosperms (00:10:09 - 00:10:27) Tracheophytes are divided into two main groups: Gymnosperms: Seed plants with exposed seeds (e.g., conifers) Angiosperms: Seed plants with enclosed seeds (flowering plants) Plant Anatomy and Reproduction (00:10:27 - 00:10:40) The reproductive parts of a flower are important to know The petals are the colorful parts of the flower The stamen is the male sex organ of the flower The pistil is the female sex organ of the flower The pistil contains the stigma, style, and ovule The ovules will be fertilized and develop into the ovary (00:10:40 - 00:10:54) The reproductive parts of the flower are arranged in a specific way The stamen is the male part of the flower (00:10:54 - 00:11:07) Monocots and dicots are two main groups of angiosperms (flowering plants) Monocots have: Only one cotyledon (seed leaf) Parallel veins in the leaves Vascular bundles arranged in a complex pattern Dicots have: Two cotyledons Netlike veins in the leaves Vascular bundles arranged in rings (00:11:07 - 00:11:21) Monocots usually have: A fibrous root system https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce6bd48ab287f54e41f2a8/document?go=note 5/6 8/27/24, 8:23 PM Platform | Study Fetch Flower parts in multiples of three Dicots usually have: A taproot system Flower parts in multiples of four or five (00:11:21 - 00:11:32) Nitrogen-fixing bacteria convert nitrogen to ammonia and nitrate Nitrifying bacteria convert ammonia to nitrite and then to nitrate This nitrogen cycle is important for plants to access nitrogen (00:11:32 - 00:11:49) Animal waste produces ammonia Nitrogen-fixing bacteria convert the ammonia to nitrate, which can then be taken up by plants (00:11:49 - 00:12:08) The nitrogen cycle is crucial for converting ammonia to nitrate, which plants can use Nitrogen-fixing bacteria convert ammonia to nitrite, and nitrifying bacteria convert nitrite to nitrate (00:12:08 - 00:12:23) Animal waste produces ammonia Nitrogen-fixing bacteria convert the ammonia to nitrate, which can then be taken up by plants (00:12:23 - 00:12:35) You have now mastered the basics of plant biology! This section covered a lot of important information about plant anatomy, reproduction, and the nitrogen cycle https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce6bd48ab287f54e41f2a8/document?go=note 6/6