G11 Biology Summative Study PDF

Unit 1 - Plants Forms and Functions: Angiosperms - Plants that produce flowers and bear their seeds in fruit Ex. Flowering plants. Divided into two separate groups - Monocots and Dicots. Monocots/Monocotyledon: Monocot seeds are one solid seed. Dicots/dicotyledon: Seed split into two parts. FEATURE...

Unit 1 - Plants Forms and Functions: Angiosperms - Plants that produce flowers and bear their seeds in fruit Ex. Flowering plants. Divided into two separate groups - Monocots and Dicots. Monocots/Monocotyledon: Monocot seeds are one solid seed. Dicots/dicotyledon: Seed split into two parts. FEATURE MONOCOTS DICOTS Number of Cotyledons 1 2 Root system Fibrous Tap Vascular Tissues in Arranged in a ring Arranged in a star-like Root shape Vascular Tissues in Scattered Arranged in a circle Stem Randomly Types of Stems Herbaceous Herbaceous or Woody Leaf Venation Parallel Net-like Groups of Floral Parts In 3’s In 4’s or 5’s The function of leaves is to maximize exposure to the sun for photosynthesis. Photosynthesis Equation: 6 CO2 + 6 H2O --light energy→ C6H12O6 + 6 O2 Key Similarities and Differences Between Dicot and Monocot Leaves  Leaves have several key structures that help them carry out photosynthesis efficiently: 1.​Chloroplasts: These are tiny organelles inside leaf cells that contain chlorophyll, which absorbs sunlight and helps convert it into energy. Chlorophylls. The chlorophylls, a and b, are the pigments of photosynthesis. They are produced in chloroplasts in the photosynthetic tissues of the leaf. 2.​Stomata: These are small openings on the underside of the leaf that allow carbon dioxide (needed for photosynthesis) to enter and oxygen (a by-product) to exit. 3.​Mesophyll cells: These cells are found in the middle layer of the leaf and are packed with chloroplasts. The arrangement of these cells helps capture sunlight and carry out the chemical processes of photosynthesis. Chlorophylls. The chlorophylls, a and b, are the pigments of photosynthesis. They are produced in chloroplasts in the photosynthetic tissues of the leaf. Leaf Type Similarities Differences Both leaves attach at a node Dicot leaves attach with a petiole Dicot Leaves Both types of leaves have veins Dicot leaves have net-like veins Both types of leaves perform Monocot leaves attach to stems with a Monocot Leaves photosynthesis sheath Monocot veins run parallel A) VASCULAR PLANT STRUCTURE & FUNCTION Definitions: 1)​ Meristem – a region of the plant where some cells retain the ability to divide repeatedly by mitosis 2)​ Primary Growth – plant growth originating at the apical meristems which results in an increase in length; occurs during the plant’s entire life (ie. tips of stems and roots, Fig. 16.21 on p. 543) 3)​ Secondary Growth – plant growth originating at the lateral meristems which results in an increase in diameter of the roots and stems; occurs during the second and subsequent years of a plant’s life (ex. Tree rings, p. 544 Fig. 16.23) B) PLANT TISSUES (p. 541-544) Name of Tissue Structural Location in the Plant Functions System Characteristics MERISTEMATIC: (1)​ apical meristems Small, thin-walled, Growing tip of stems Divide frequently no vacuoles and roots to produce cells that will become various tissues (2)​vascular as above A layer in the stems Divides to produce cambium and roots of woody more vascular plants tissue (xylem and phloem) DERMAL: (1) epidermis One layer of tightly Outermost layer of Produces cuticle packed cells. main plant body Protects against Includes specialized H20 loss and cells such as root infection hair cells and guard cells. (2) periderm Many layers of Same Waterproofs special cells that Protects inner are dead tissues from structural damage (ex. cork, bark) GROUND: (1) parenchyma Living cells Plant body Photosynthesis Thin- walled Storage of carbs (Ex. apple flesh)  Large spaces for Wound healing and H2O storage regeneration (2) collenchyma Living cells Same Strength (ex. Thickened cell walls celery) Flexible support (3) sclerenchyma Mature cells are Continuous mass or Supports mature dead scattered plants Thick walls throughout the plant Strength Made of cellulose (ex. pear granules) and lignin VASCULAR: (1) xylem Dead at maturity, Found in vascular Conducting H2O hollow cells plants, throughout and dissolved the plant nutrients (2) phloem Mature phloem is Throughout the plant ​ living 2 types of cells: -sieve tubes Long, thin tubes Passage of H2O and formed by many dissolved sugars sieve elements -companion cells Small narrow cells Direct activities of beside sieve tubes sieve tubes Name Functions How Structure Suits its Function Cuticle Provides a waterproof layer The cuticle is made of a waxy substance which repels water Epidermis Protects the inner cells Epidermal cells are tightly packed together to stop bacteria from entering Stomata Allow gases to pass through the The stoma is a hole in the surface of the (singular = epidermis of the leaf leaf stoma) Guard Cell Controls the opening of the Sausage shaped cells that open the stomata to control when gas stoma when swollen full of water exchange occurs (turgid) and close the stoma when lacking water and shrunken (flaccid) Mesophyll -Palisade Location of most of the Close to the surface of the leaf to obtain photosynthesis the most sunlight. Palisade mesophyll cells have a lot of chloroplasts (the site of photosynthesis). Air gaps to store gases and for gas -Spongy Location of some photosynthesis exchange. Spongy mesophyll cells have fewer chloroplasts. Vein Transport materials throughout Tube-like cells the plant and provide strength -​ xylem: H2O + minerals Made of tough materials to provide -​ phloem: H2O + sugars strength to the plant  Four main Functions of roots: 1.​ Storing nutrients 2.​ Absorbing water, nutrients, and minerals. 3.​ Support/anchor plant 4.​ Reproduction: Root cuttings are taken and can grow new plants from them. Definitions: Root Cap: protective cells found at the tip of the root that protect the root tip tissues as it grows through the soil Root Hairs: extensions of epidermal cells for absorption of water and minerals Endodermis: wax coated inner layer of the cortex of a plant root Vascular Cylinder: the center of a root that contains the plant’s conductive tissues known as xylem and phloem Stem Functions: 1.)​Transport materials (ie. sugars from leaves to plant and water from roots to plant) 2.)​Hold up leaves to sunlight  3.)​Photosynthesis (herbaceous/green stems photosynthesize) 4.)​Storage of carbohydrates (ex. potatoes) Movement of Materials in Plants (pp. 545-550) Definitions: Active transport—the transport of substances against their concentration gradient, with the use of energy (ATP). Materials move from an area of low concentration to an area of high concentration. Passive transport—the transport of substances with their concentration gradient (no energy required) Materials move from an area of high concentration to an area of low concentration. Osmosis—the diffusion of water (passively) Water moves from an area of high concentration to an area of low concentration. adhesion—water clings to non-oily (hydrophilic) surfaces cohesion—ability of water to stick to itself (H-bonds) Root Pressure: How Water Moves into the Root ​ Nutrients and minerals move into the root endodermis by active transport. Water then moves by osmosis into the root from the soil. ​ The accumulation of water and dissolved nutrients creates root pressure. Root pressure can only move water a maximum of a few metres in most plants. So root pressure can’t account for all water movement in the xylem.  ​ Cohesion Theory: How xylem transports minerals and water to leaves Water sticks to itself due to cohesion. In this process, adjacent water molecules’ hydrogen atoms create hydrogen bonds (see image). The cohesion of water molecules in the xylem of plants results in the water column holding together continuously from the ground to the top of the highest leaves. ​ “Leaf pull” is created by transpiration (evaporation of water from the leaves): when a water molecule evaporates from the leaf (transpiration) at the top of the xylem column, there is enough cohesive strength to draw water all the way up from the roots. Pressure-Flow Theory: How sugars move through phloem cells to roots ​ In this process, leaf cells are ‘source’ and root cells are ‘sink’ for sugars. ​ in leaves, sugars are pumped into sieve-tubes (phloem) by active transport, water follows passively by osmosis ​ this creates water pressure, pushing sugars away from leaves to roots ​ once in root, sugars are moved to parenchyma cells, water follows, therefore keeping reduced pressure in root sieve tube cells Four Common Plant Hormones 1)​ Auxins: Auxins are plant hormones that promote cell growth or elongation. Auxins move away from a light source to cause growth toward light. 2. Cytokinins: Cytokinins are plant hormones that promote cell division and differentiation. They can help a plant to branch out rather than growing straight up. They also can be sprayed on cut flowers to make them last longer. 3. Gibberellins: Gibberellins are plant hormones that interact with auxins to control plant growth and fruit development. They are also involved in seed germination. 4. Ethylene: Ethylene is a gas that ripening fruits like apples give off. It promotes the ripening of other fruits. It can also be used to make tropical plants flower. If you put a ripe apple in a bag with a pineapple plant, it will encourage flowering and fruit production. Tropism: A tropism is a plant growth movement in response to a stimulus. -​ A positive tropism is a growth movement toward a stimulus. -​ A negative tropism is a growth movement away from the stimulus. 1)​ Phototropism: a growth movement in response to light ​ e.g. plant stems grow toward the light = + phototropism plant roots grow away from light = - phototropism 2)​ Gravitropism/Geotropism: a growth movement in response to gravity e.g. stems grow against the force of gravity = - geotropism 3)​ Thigmotropism: a growth movement in response to touch ​ e.g. vines have tendrils that curl around things they touch = + thigmotropism 4)Hydrotropism: a growth movement in response to water  e.g. roots grow toward water = + hydrotropism 5) Chemotropism: a growth movement in response to chemical substances ex. roots grow towards nutrients= + chemotropism Turgor Responses: A turgor response is a rapid movement due to the movement of water out of the plant’s cells. Two Examples: (check out the video links!) 1)​ Sensitive Plant - leaves close when touched 2)​ Venus Fly Trap - leaves close quickly to trap flies Flowering plant: Life Cycle: - Male pollen grains contain sperm cells. They are released from the anther of a male stamen - Via birds/bees/animals/wind, pollen reaches the female carpel, enters through the stigma, and then travels down the pollen tube. - The pollen fertilizes the female ovum (egg cell) to produce a zygote (which develops into an embryo) contained in a seed. - The ovary in which the seed develops becomes the fruit Summary: Pollination of flowers leads to the formation of seeds, contained within a fruit. Fruit: A fruit is a fertilized ovary of an angiosperm ​ Usually contain seeds, BUT AREN’T ALWAYS SWEET (ex. Tomato, zucchini, corn, peas, cucumbers, peppers, squash) ​ Help to disperse seeds away from parent plant. For example, when a seed passes through the digestive tract of an animal that has consumed it, then it is eliminated as waste elsewhere. Some seeds must go through the digestive tract of an animal in order to germinate. Other examples are specialized fruit structures, like maple keys and dandelion “parachutes”. ​ Pollination is usually required for fruit production. The honeybee pollinates 85% of apple trees. ​ Seedless fruits are produced from unpollinated flowers ​ Cannot be stored for long periods (DISADV.) as ethylene gas is released at final stage of fruit ripening, when starches convert to sugars. Ethylene needs to be minimized when storing fruits. Seeds ​ High in protein, carbs or fats, and fibre→ very nutritious! ​ Can be stored for long periods of time (ADV.) Germination of Seeds: ​ When exposed to enough heat, water and oxygen, a seed germinates (starts to grow) ​ Before a seed grows, it is dormant (in a “resting state”)  Gibberellin: a hormone released by the embryo of a seed which begins germination by starting breakdown of carbohydrates for energy. → Water is absorbed by the seed, the seed coat cracks and oxygen is let in → Radicle emerges and develops into the root → In plants like the bean, the cotyledons are pulled out of the soil by the hypocotyl → The cotyledons stay on the plant to photosynthesize until true leaves form from the apical meristem