A turgid plant cell is one that has excess water in its cytosol Active transport requires energy and occurs against the concentration gradient across a cell membrane Organic products of photosynthesis are directly loaded from sugar producing cells into xylem vessel elements for rapid transport to sink tissues False The cohesion tension theory explains the role of transpiration in long distance water transport In early spring when leaves are not yet developed and photosynthetic processes don t take place starch storage can be converted into sugars which are then transported through xylem sap to be used for bud morphogenesis True The hormone receptor present on the plasma membrane of guard cells responsible for stomatal pore closing under conditions of water stress is the Abscisic Acid Receptor Unlike animals plant are autotrophic and use sunlight CO2 water macronutrients eg Nitrogen phosphorous and potassium and micronutrients eg Zinc copper calcium to synthesize vitamins as well as their own source of energy True Knowledge of halophyte plant physiology gives scientists clues for developing agricultural plants that might survive in environments that are desertic acid Cellulose present in the plant cell wall is highly hydrophobic and slows down apoplastic transport False Characteristics of most animals o They havehox genes o They are heterotrophic o They have an extracellular matrix rich in scaffolding molecules such o THEY DON T HAVE CELL WALLS COMPOSED OF LARGE LINEAR as collagen SUGAR POLYMERS o They have a nervous system The following are major morphological criterions on which traditional classification of animals is based All of the below o Presence absence of a true body cavity o Type of symmetry o Pattern of embryonic development Coelomates are bilaterians that have a true fluid filled body cavity that derived from the mesoderm layer during development True In vertebrates the developmental expression pattern of a specific isoform of the hoxC gene complex hoxc 6 controls neck length and forelimb morphogenesis Mammals that can control their internal body temperature regardless of changes in the surrounding environmental temperature as long as critical values are not reaches are considered to be regulators endotherms The following is true of a tissue specialized for absorption of solutes from one compartment to another eg Small intestine o Has a relatively large surface area volume ratio o Is organized as a tight epithelium layer with one side in direct contact with dissolved solutes Sensory nerve free endings present in the skin contain cold detecting thermo sensitive receptors that can stimulate shivering via the central nervous system to generate heat in muscles Homoeostasis refers to the property of maintaining particular physiological variables such as body temperature and solute concentration absolutely constant False Organization of a mammalian body from least to most complex is cell tissue organ organ system The resting potential of a neuron corresponds to a voltage across the axon membrane that does not conduct nerve impulses The movement f an ion across an axon membrane depends on the all of the following direction of the nerve impulse net elastic charges on both sides of the membrane presence of channel and or pumps specific for this ion in the membrane concentration of this specific ion on both sides of the membrane The schematic drawing of ungated K passive open voltage gated Na channel closed voltage gated K channel open and the 2K entering and 3Na exiting through Na K pump is active hyperpolarization Signal transmission from one neuron to the next requires the presense of a synapse Inputs received by a post synaptic neuronal membrane can be both excitatory and inhibitory AND need to be integrated in both time and space A nerve impulse spreads along a myelinated motor neuron that belongs to a neuronal network in the following order dendrites axon hillock axon axon terminal Acetylcholine is a neurotransmitter All inhibiting cardiac muscle contraction inducing skeletal muscle contraction stimulating neurons in the brain and released in the synaptic cleft Skeletal muscles are also called striated muscles Casperian strip Plamodesmata Cortex Stomata Impermeable layer of suberin located in the root endodermal cells wall preventing compounds from entering the xylem via apoplastic transport Membrane channels connecting two plant cell cytoplasms and involved in symplastic transport in plant roots Root tissue made of parenchyma cells surrounded on the outside by the epidermis and on the inside by the endodermis Structure through which transpiration water loss occurs Cell wall Structure made from cellulose present on the outside of plant cell membrane that provides structural support and restricts the extent to which plant cells can swell Physiological reaction of an organism to the length of day or night Light mediated changes in plant growth and development Directional growth response to an environmental stimulus Non directional response of a plant stimuli Photoperiodism Photomorphogenesis Tropism Nastic Movement Nutation of plant organ Swaying or rotating motion resulting from uneven growth of different side Resting potential 70 threshold potential 50 depolarization 25 repolarization 10 hyperpolarization 80 hyperpolarization 90 resting potential 70 x axis time msec y axis membrane potential mV Myelin substance that wraps around the outside portion of axons in intermode regions Function myelin sheath increases the speed in which a signal travels the axon and acts as a protective layer around the axon of a neuron Multiple Sclerosis MS autoimmune disease with no cure is associated with progressive deterioration of this substance
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