2 13.1.1 Outline the wide diversity in the plant kingdom as exemplified by the structural differencesbetween bryophytes, filicinophytes,coniferophytes and angiospermophytes.Bryophytes are mosses, liverwortsand hornworts. Filicinophytes are ....
3 13.1.2 Draw a diagram to show the external parts of a named dicotyledonous plant.Drawing will be inserted at a later date.
4 13.1.3 Draw plan diagrams to show the distribution of tissues in the stem,root and leaf of a generalizeddicotyledonous plant.Drawing will be inserted at a later date.
5 13.1.4 Explain the relationship between the distribution of tissues in theleaf and the functions of these tissues.The leaves of plants are very thin,so they have a lots of surface area.this surface area allows them toabsorb light energy to performphotosynthesis (photosynthesisoccurs only iin the leaves).
6 It also has specially designed cells that allow for the exchange of gases(carbon dioxide out and oxygen in).Leaves also have spongy layer ofcells. The air spaces in the leaf tissueso that cells can absorb carbondioxide to perform photosynthesis.
7 13.1.5 Outline four adaptations of xerophytes.Some xerophytes have small,thick leaves to limit water loss bylimiting surface area. They also havea thick cuticles to limit water loss.CAM plants absorb carbon dioxideduring the night, during the nighttemperature is lower so lesswater vapor escapes.
8 They convert the carbon dioxide into organic acids and use them in photosynthesis during the daytimewhen sunlight is available. C4 plantsdo the same thing, but use differentacids to store carbon dioxide.Xerophytes also have less leaves(some even lose thier leaves duringdry months), Some have leaves thatare rolled to prevent water loss.
9 They have extensive and deep roots systems to obtain maximum amounts of water. Stomata are in pits or aresurrounded by hairs to prevent waterloss. They store water in specializedtissues. They often have short lifecycles to coordinate withthe rain season.
10 13.1.6 Outline two structural adaptations of hydrophytes.Hydrophytes live in watery habitats.They have a lot of air spaces inthe tissues to help them float.Leaves and stems are flexiblebecause water gives them support.Leaves are divided into small partsto provide a big surface area forabsorption of substances.
11 is simple and sometimes functions as Root systemis simple and sometimes functions asan anchoring device since absorptionis carried out by all otherparts of the plant.
12 Topic 13.2 - Transport in Angiospermophytes Explain how the root system provides a large surface area for mineral ion and water uptake by means of branching, root hairs and cortex cell walls.Roots have tiny root hairs on them, which increase the surface area and allow maximum uptake of water.
13 Mineral ions are taken in the root hairs by active transport. Branching allowsthe roots to cover a large amount ofarea to get a variety of nutrients andmore water. The cortex cell wallsallow for osmosis to occurbecause they are permeable
14 13.2.2 Describe the process of mineral ion uptake into roots by active transport.Roots excrete ions ....
15 13.2.3 Explain the process of water uptake by root epidermis cells and its movement by the symplasticand apoplastic pathways acrossthe root to the xylem.Minerals are absorbed with thesoil solution by the root surface,especially by root hairs.
16 The water and minerals then move across the root cortex to the vascularcylinder by a combination of theapoplastic and symplastic routes.The uptake of soil solution by thehydrophilic walls of the epidermisprovides access to the apoplast,and water and minerals can soakinto the cortex along thismatrix of walls.
17 Minerals and water that cross the plasma membranes of root hairs enter the symplast. As soil solutionmoves along the apoplast,some water and minerals aretransported into cells of the epidermisand cortex and then move inward viathe symplast. Water and minerals thatmove all the way to the endodermisalong cell walls cannot continue intothe stele via the apoplastic route.
18 Within the wall of each endodermal cell is a belt of waxy material (black band)that blocks the passage of water anddissolved nutrients. This barrier toapoplastic transport is called theCasparian strip. Only materialsthat are already in the symplastor enter that pathway by crossingthe plasma membrane of an endodermalcell can detour around the Casparianstrip and pass into the stele.
19 Thus, the transport of minerals that are admitted into the cells within thestele, discharge water and mineralsinto their walls, which, as part ofthe apoplast, are continuous withinthe xylem vessels. Water and mineralsabsorbed from soil are now ready forupwards transport into theshoot system.
20 13.2.4 State that terrestrial plants support themselves by means of thickenedcellulose, cell turgor and xylem.Terrestrial plants support themselvesby means of thickened cellulose,cell turgor and xylem.
21 Transpiration is the loss of water vapour Define transpiration.Transpiration is the loss of water vapourfrom the leaves and stems of plants.
22 13.2.6 Explain how water is carried by the transpiration stream, includingthe structure of xylem vessels,transpiration pull, cohesionand evaporation.Xylem tubes are made of deadcells that have sieve-like ends toallow water flow. Water moves throughxylem because it is pulled. Water is apolar molecule so it bonds toother water molecules.
23 Therefore, when water molecules in the leaves are pulled into the air by evaporation, all the waterthat is in the xylem tubes movesup the stems towards the leaves.
24 This is called the tranpiration pull. Cohesion is the attraction of waterto the sides of the xylem tubes, whichare very thin. This helps the watertravel a little. Evaporation powersthe transpirational pull.
25 13.2.7 State that guard cells can open and close stomata to regulate transpiration.Guard cells can open andclose stomata to regulate transpiration.
26 13.2.8 Explain how the abiotic factors, light, temperature, wind and humidity,affect the rate transpiration in atypical terrestrial mesophyticenvironment.If stomata open, transpirationincreases, and vice versa. Lighteffects blue-light receptors in theleaves that open stomata by creatinga potassium gradient and causing theguard cells to absorb water. Hottemperatures cause stomates to close.
27 Wind causes the water vapor that is emitted from the stomates to travelvery quickly, causing the air near theleaves to be dryer than it would bewithout wind. This causes a greaterdifference between water concentrationbetween the stomatal air and theoutside air, causing more transpiration.
28 Humidity does the opposite. Because there is less difference betweeninner and outer air, the water doesnot travel out of the leaf as much,causing tranpiration to decrease
29 13.2.9 Outline the role of phloem in active translocation of biochemicals.Phloem is a living tissue withfood-conductingcells arrangedinto tubes that distribute sugar,amino acids, and other organicnutrients throughout the plant.
30 This tissue transports food made in the leaves to the roots and to nonphotosynthetic partsof the shoot system, from sourceto sink. Proton pumps do thework that enables the cellsto accumulate sucrose.
31 The ATP-driven pumps move H+ concentration across the plasma membrane. Another membrane proteinuses this energy source toco transport sucrose in the cellalong wih returning hydrogen ions.
32 In some plants, the sucrose may be unloaded from phloem by active transport. In other species, diffusionis sufficient to move sucrose fromphloem to the surrounding cellsof the sink organ.
33 Sugars are stored in the form of starch in plants. Some examples Describe an example offood storage in a plant.Sugars are stored in the form ofstarch in plants. Some examplesare thick roots (like carrots),or tubers (potatoes).
34 Topic 13.3 - Reproduction in Flowering Plants Draw the structure of a dicotyledonous animal-pollinated flower, as seen wit the naked eye and hand eyes.Drawing will be inserted later.
35 Pollination - The placement of pollen Define pollinationPollination - The placement of pollenonto the stigma of a carpel by windor animal carriers, a prerequisiteto fertilization.
36 13.3.3 Distinguish between pollination, fertilization, and seed dispersal.Pollination is the first event tooccur. It is the movement of pollenonto the stigma of a carpel by acarrier. Following this event isfertilization which is the unionof haploid gametes to producea diploid gamete.
37 Fertilization happens within the ovary of the plant. This gamete is nowthe seed produced by the plant. Seeddispersal describes the action of theseed moving from its place of originto another site where it will grow.
38 13.3.4 Draw the external and internal structure of a named dicotyledonous seed.Drawing will be inserted at a later date.
39 13.3.5 Describe the metabolic events of germination in a typical starchy seed.Absorption of water precedes theformation of gibberellin in thecotyledon. This stimulates theproduction of amylase which catalyzesthe breakdown of starch to maltose.This subsequently diffuses tothe embryo for energy productionand growth.
40 13.3.6 Explain the conditions needed for the germination of a typical seed.Seeds are dormant which help thesurvival and conservation ofplant species because seedscan wait for their optimal environmentto grow. They are resistant to variousfactors and can stay dormant formany years until all factors aroundthem are suitable to thier individual needs.
41 They are resistant to various factors and can stay dormant for many years until all factors aroundthem are suitable to thier individual needs.
42 When they are provided with the right conditions their dormancy breaks and they start germinating and growingwater is provided, however eachseed requires different conditions.