14846113
Descripción
Fichas por Olivia Gniadek, actualizado hace más de 1 año
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Creado por Olivia Gniadek
hace alrededor de 6 años
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| Pregunta | Respuesta |
| what are the benefits of seeds | protection of embryo food for nourishment promotes dispersal development can be delayed |
| what is the formation from ovule to seed | image |
| what is the microgametophyte development process | image |
| how do we identify sporophyte and gametophyte in this diagram | image |
| what is the formation of an ovule | megasporangium produces a megaspore by meiosis megaspore develops into megagametophyte megagametophyte remains attached to sporophyte megagametophyte forms egg after fertilisation, ovule becomes seed |
| what is the formation of pollen | microsporangium with many microspores microspores form microgametophyte pollen transported into female gametophyte sperm is delivered via pollen tube |
| what are gymnosperms | ovules not totally enclosed by sporophyte at fertilisation largest and oldest living organisms 4 phyla |
| what are the names of the 4 gymnosperm phyla | coniferophyta cycadophyta ginkophyta gnetophyta |
| what is an angiosperm | largest phylem of photosynthetic organisms very diverse in size and structure economic and ecological importance |
| what is the difference between monocots and eudicots | monocot = parallel veins eudicot = netted veins |
| how is an embryo protected in an angiosperm | ovule completely enclosed by sporophyte tissue at fertilization enclosing tissue = carpel ovary develops into fruit fruit helps seed dispersal |
| what are the different fruit types of different plants | image |
| what is the floral structure | image |
| what is pollination | transfer of pollen to stigma and the growth of the pollen tube pollen is spread by birds, insects, wind and mammals |
| what are the reproductive features of plants | 1. gametophytes form within flowers 2. mature microgametophyte has 3 cells inside pollen grain 3. mature megagametophyte has 7 cells in ovule 4. no antheridia or archegonia 5. megagametophyte retained in sporophyte 6. sperm transferred by pollen tube 7. ovary develops into fruit |
| what is the angiosperm life cycle | image |
| how is pollen formed | microsporangia in anthers microsporocytes (2n) divide by meiosis to produce 4 mictospores microspores develop into microgametophytes (n) inside pollen grains |
| what is the formation of microgametophytes | 1st division = tube cell + generative cells 2nd division = 2 sperm cells |
| what is the formation of the megagametophyte | megasporangium forms in ovule megasporocyte (2n) divides by meiosis single megaspore (n) retained, develops into megagametophyte (embryo sac) ovule = the integuments (2n) + megagametophyte |
| what is the concept of double fertilisation in plants | 1st fertilisation = forms zygote (sperm fuses with egg) 2nd fertilisation = forms endosperm (food reserve) sperm fuses with 2 polar nuclei (cental cell) zygote develops into embryo, central (3n) cell develops into endosperm |
| how does the ovary in the female stigma attract the pollen tube | chemical signal sent by female ovary directs pollen tube to fertilise |
| how does the endosperm form | from 'fertilised' central cell (3n) nucleus divides many times multinucleate central cell membranes and cell walls develop later |
| in gymnosperms does the food reserve develop regardless whether the egg is fertilised or not? what happens in angiosperms? why is this an advantage | yes angiosperms = food reserve forms only when fertilisation occurs advantage = don't waste energy making a food reserve is the egg is not fertilised |
| what is a plant organ and what are the three main organs of plants | arrangement of tissues with a particular function leaves, stems and roots |
| what is the purpose of the shoots and roots | access above ground resources (light and CO2) roots access nutrients from underground (water and nutrients) |
| w | petiole |
| what is the purpose of roots | absorb water and nutrients hold plants in place can store food |
| what is the difference between monocot and eudicot roots | monocot = fibrous root systems eudicot = tap root systems |
| where do root hairs occur and what is their purpose? | occur near root tips most absorption occurs here increases surface area elongated epidermal cells |
| what are some examples of root modifications | prop roots for support root tubers for storage mangrove roots for aeration |
| what are stems | alternating nodes/internodes leaves are attached at nodes auxilliary buds form in the angle between each leaf and stem terminal buds at shoot tips |
| what is an example of a stem modification | thorns are stem extensions for protection |
| what are leaves | major photosynthetic organs consist of a blade and petiole many monocots lack a petiole |
| how can you determine if a leaf is compound or simple | position of auxiliary bud |
| what are some examples of leaf modifications | insect trap spikes water storage |
| what are plant cells | have plastids central vacuole cell walls |
| plant cell diagram | image |
| what are plant cell walls made up of | cellulose fibres |
| what is the second wall in plants made up of | lignin to increase strength |
| what is cellulose | linear chain of ß (1->4) linked D-glucose units (hydrophilic), can be increased or decreased when needed |
| what is lignin | cross linked (very complex) polysaccharide (hydrophobic) once deposited, lignin cannot be removed |
| what are the three types of plant tissue | dermal ground vascular |
| what is the function of the dermal tissues | primary stems, roots and leaf dermal tissues are called the epidermis (epidermal cells, guard cells, tricomes) secondary stems and roots, dermal tissue is called periderm (cork cells, cork cambium) |
| what is the function of the epidermal cells | outer cuticle, mechanical protection which prevents water loss, deters pathogen attack |
| what is the guard cell function | control stomatal aperture regulate CO2 and H2O fluxes |
| what is the function of the trichomes | reduce water loss nutrient uptake defence reflectance |
| what is ground tissue | matrix in which other tissues are embedded (Pith (ground tissue internal to vascular tissue) and cortex (ground tissue external to vascular tissue)) |
| what are vascular tissues | Xylem tissues (water and nutrient conducting tissue + structual support) (made up of tracheids, vessel elements and fibres) Phloem tissue: food (soluable sugar) conducting (made up of sieve-tube members and companion cells) |
| what is the difference between a vessel member and tracheid | bigger diameter therefore more productive |
| What are the three main cell types | Parenchyma cells Collenchyma cells Sclerenchyma cells |
| what are parenchyma cells | simple structure large vacuole no secondary wall photosynthesis, storage and space filling |
| what are collenchyma cells | elongated cells unevenly thickened cell walls use cellulose form discreet strands or cylinders provide support for young growing and non-woody tissues gives strength but allows growth |
| what are sclerenchyma cells | thick lignified secondary cell walls continuous masses, small groups or single cells provide extra support and strength or used in transport of water and nutrients |
| what is the purpose of a meristem | plant growth = indeterminate plants often replace lost tissue meristems found in young plant shoots and roots in mature plants found all over |
| what how long can plants live for | varies Annuals complete life cycle in one year Biennials complete life cycle in 2 years Perennials live for many years |
| how can membranes move across membranes | plasma membrane is selectively permeable controls movement of solutes hydrophobic phospholipid bilayer transport proteins span membrane |
| what role does diffusion have in plants | can be directional detemined by concentration gradients low to high concentration |
| what is passive transport | movement down concentration a gradient (no energy input reuired) |
| what is active transport | movement against a gradient (requires energy input) |
| what role do proton pumps have in plants | important for membrane transport move H+ out of cells against gradient uses ATP |
| what role does water balance have in plants | vital in water movement water movement across membranes is passive - osmosis direction of movement is determined by a gradient in water potential |
| what is water potential | function of solute concentration and resistence of cell wall water moves from low to high water potential |
| what is the impact of solutes and cell walls on water potential | if water concentration is high, the cell won't burst due to cell wall |
| what are the two components of water potential | solute concentration pressure exerted by cell wall |
| why can't cell walls expand if water enters the cell resulting in the increase in cell pressure | cellulose wall prevents expansion |
| what is transmembrane transport | fluid from one cell foes through membrane-cell wall-membrane-cell |
| what is symplastic transport | solutes go from cell to cell but not membrane |
| what is apoplastic transport | water flows through cell membrane fibres membranes which allow water flow without resistance |
| how are nutrients transported from soil to roots | water and dissolved minerals = soil solution solution moves through the epidermis to cortex and into xylem from xylem the whole plant is supplied |
| how are water and nutrients transported in the epidermis and cortex | soil solution is taken up by apoplast moves into symplast exchange between apoplast and symplast occurs |
| how are nutrients delivered into the xylem | long distance transport of water and dissolved minerals moves from roots to xylem to the shoot eventually water is lost through the stomata on leaves |
| what is transpiration | water that is evaporated through the open stomata ~99% of water is lost in transpiration plants must maintain continual flow of water to survive |
| what is root pressure | no transpiration at night some plants continue to take up minerals :. water potential decreases water moves in and creates upward flow in xylem cannot move water more than few meters |
| what is guttation | water forced out by root at night |
| what is the transpiration-cohesion-tension principle | transpiration from leaf provides driving force cohesive properties of water maintain water column places water under tension in xylem water is pulled up plant |
| how do plants regulate transpiration | stomata respond to light, temperature, tissue, CO2 and water potential of air |
| How does the stomata open and close | Active transport of K+ into guard cells water potential decreases and water flows in guard cells swell and bow outwards closing occurs when K+ moves out followed by water cells lose turgor |
| how are nutrients transported in the phloem | long distance transport of sugars and other organic molecules from sources to sinks |
| what is a source | sites of photosynthesis or starch breakdown (photosynthetic tissue) |
| what is a sink | sites where sugars are consumed or stored (non-photosynthetic) |
| what are plants composed of | 96% Carbon, Hydrogen and Oxygen 4% inorganic nutrients |
| where do the nutrients come from | sunlight CO2 and O2 Water and minerals |
| What are the essential elements of plants | Macronutrients - required in large amounts micronutrients - required in trace amounts |
| What are the most vital macronutrients for plants | Carbon Oxygen Hydrogen Nitrogen Phosphorous Sulfur |
| where does nitrogen deficiency first show up in plants | older leaves |
| where will iron deficiency first show up | younger leaves |
| what is nitrogen used for | nucleic acids proteins hormones chlorophylls coenzymes can be reabsorbed and transported to growing tip of plant |
| what is the function of nitrogen and plant symbioses | nitrogen is required in large amounts rubisco ~ 40% of all total plant protein 70% of atmosphere is N2 Plants require NO3- or NH4+ (bacteria is vital) cannot use N2 |
| Where does N2 fixing bacteria reside | in soil and plant roots convert N2 to nitrate NO3- and ammonia NH4+ energenetically expensive |
| how do legumes aid in crop rotation | ploughed into soil to improve N content for subsequent crops |
| what do carnivorous plants do | trap invertebrates e.g. insects |
| what do parasitic plants do | steal from other plants e.g. mistletoes |
| where do carnivorous plants grow | in soils with low N availability trap and digest small animals augments N supply |
| what does the amount of light reaching the plant vary with | latitude season time of day position of plant within environment |
| what is greening | seedlings raised in darkness are tall and pale when exposed to light, greening occurs when exposed to light, stems shorten, leaves expand and chlorophyll is synthesised |
| what is etiolation | morphological adaptation for growing in darkness |
| what is de-etiolation | greening is a morphological change in response to light |
| how do plants respond to environmental signals | sensing the light = reception amplifying signal = transduction response at cellular level growth response at whole plant level |
| what is the signal transduction pathway | receptor molecule senses signal signal is relayed and amplified within cell response initiated plant has growth response |
| how do plant hormones influence growth | cell division elongation differentiation effects depend on concentration, site of action and developmental stage |
| what is tropism | growth response or bending of the stem in response to stimuli |
| what is phototropism | growth in response to light |
| what is the purpose of auxin | auxin is synthesised in the shoot apical meristem on the shaded side moves downwards through the cortex stimulates growth in region below apical meristem through cell elongation |
| What is gravitropism | growth in response to gravity |
| what is thigmotropism | growth with respect to touch |
| what are the major plant hormones | Auxins Cytokinins Gibberellins Brassinosteroids Abscisic acid Ethylene |
| what do auxins and cytokines promote | Auxins inhibit lateral shoots Cytokines promote lateral shoots |
| what is senescence | programmed changes leading to the death of a leaf |
| What do gibberellins do | synthesised in shoot and root apical regions stimulate stem elongation, fruit growth and seed germination |
| what are brassinosteroids | chemically similar to steroids in animals similar effects to those of auxin cell elongation, division and differentiation |
| what is abscisic acid (ABA) | inhibits growth antagonises action of growth promoting hormones produced in root - travels via xylem |
| What is ethylene | simple gaseous hydrocarbon promotes fruit development involved in stress response |
| what is a phytochrome | protein dimer with chromosphere |
| what is heat stress | when the threshold temperature is exceeded and tissue damage results |
| what happens to a plant when it becomes heat stressed | - changes in plant metabolism - increasing temperature inhibits photosynthesis before respiration - high temp reduces membrane stability - plants that become water stressed become heat stressed - low transpiration can result in heat stress |
| what is the temperature compensation point | the point where CO2 fixed by photosynthesis = Co2 lost by respiration more carbon is lost resulting in: carbohydrate reserves decline plants grow slowly productivity decreases fruit is less sweet |
| what causes photorespiration | when rubisco fixes on O2 instead of fixing CO2 occurs in hot climate or in heat stressed plants |
| what is reradiating | reflecting the light |
| what is conduction | heat moving from leaf to the air |
| what is convection | moving the air away from leaf |
| what is evaporative cooling | heat is required to turn water to gas which leave the surface cooler |
| what are the plant adaptations to avoid heat stress | - leaves can decrease heat absorption by morphological adaptations - molecules have their own response to heat stress - metabolism has a response to heat stress - isoprene synthesis increased in response to heat stress |
| What is HSP | assist heat damaged proteins and help maintain protein configuration under hight temperature increased heat triggers the synthesis of HSP |
| why are the blue mountains of NSW blue | due to isoprene plants emmitt hydrocarbons plants that don't emitt isoprene at 20º start to emitt it at 30º leaf damage occurs at 37.5º in the absence of isoprene isoprene is made and lost rapidly :. correlates to leaf temperature during day |
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