생명과학2 기말(28~38) PDF

Willem de Kooning Copland Sibellius Karajan Bernstein Strabinsky Yousuf Karsh Dior Rembrandt Chapter 28 Nervous Systems Anatomy of Dr. Deyman 28.1 Nervous systems receive sensory input, interpret it, and send...

Willem de Kooning Copland Sibellius Karajan Bernstein Strabinsky Yousuf Karsh Dior Rembrandt Chapter 28 Nervous Systems Anatomy of Dr. Deyman 28.1 Nervous systems receive sensory input, interpret it, and send out appropriate commands Ø The nervous system ** A sight of a cat on the road à Press the brake 1. Sensory input: the flow of signal from sensory receptor to the CNS 2. Processes sensory information (analysis and interpretation of sensory signals and formulation of appropriate responses) 3. Motor output: the flow of signal from the CNS to effector cells 정보 분석 감각 수용 및 처리방안 결정 운동출력 *Autonomic = can not be controlled by the mind Components of the general neural 3 functional types of neurons impulse transmission pathway Ø Sensory neurons Conduct signals from sensory receptors to the CNS Ø Interneurons in the CNS Integrate information Send it to motor neurons Ø Motor neurons Convey signals to effector cells knee-jerk reflex 현상은 3가지 종류의 신경세포를 포함하는 신경전달과정을 잘 나타냄… 이렇듯 정보를 전달하고 처리 하는 Neuron들을 살펴보면.. 28.2 Neurons are the functional units of nervous systems Ø Neurons The functional units of the nervous system Cells specialized for carrying signals Ø A neuron consists of 1. Cell body 2. Two types of extensions (fibers) that conduct signals Dendrites 수상돌기 ü Transmit signal to cell body Axon 축삭 ü Transmit signal to other cells Nerves: our bodies' ELECTRICAL CABLES Neuron이 정상적으로 기능하기 위해선 supporting cells들의 도움이 있어야… Ø glial cells (Myelin sheaths) 수초 Enclose axons ü Form a cellular insulation Composed of ü Nerves (bundles of fibers of ü Speed up signal transmission sensory and motor neurons) Nourish neuron  NERVE SIGNALS AND THEIR TRANSMISSION 28.3 Nerve function depends on charge differences across neuron membranes Just inside the cell à slightly negative Ø Plasma memb. 안과 밖으로 전기적 성질을 띈 물질들 (ions, etc)의 농도 차이가 형성 Ø 이로 인해 membrane 을 사이에 두고 분리된 공간에는 구별되는 전기적 환경 (전기적 위치에너지 = 전위)이 조성 Ø 막을 사이에 두고 형성되는 전위차 = Membrane potential (막전위) Nerve signal à electrical signal 로서 신경세포 membrane potential 의 변화에 의해 진행… Action potential  세포막을 사이에 둔 공간에 구별되는 전기적 환경 조성.. ØThe nerve cell inside is slightly negative... à Due to the differences in ion concentration inside and outside a cell Outside a cell K+ not so low Na+ high Na+-K+ pump (Na+ Out / K+ In) More K+ channels à open More Na+ channelsà closed Inside a cell K+ not so high Na+ low K+ leak channel § Resting potential - voltage across the plasma membrane at rest § Action potential - voltage across the PM upon excited  세포막 사이의 전위차의 정도는 전기적 장비를 통해 측정 가능해.. Voltage is the potential energy that makes the electrical charges flow ü Insert a microelectrode into the cell and compare that reading outside the cell. ü By convention, extracellular fluid is assigned a voltage of zero, and the polarity (positive or negative) of the membrane potential is stated in terms of the sign of the excess charge on the inside of the cell. ü For example, if the intracellular fluid has an excess of negative charge (e.g. phosphate ions and negatively charged proteins, organic anions) and the potential difference across the membrane has a magnitude of 70 mV, we say that the membrane potential is -70 mV (inside relative to outside). 28.4 A nerve signal begins as a change in the membrane potential A stimulus à To alter the permeability of a section of membrane 즉 To allow ions to pass through à changes the membrane’s potential à 이러한 변화에 의해 유도되어진 memb. potential = an action potential à a nerve signal Opening of some of Na+ channels Opening of majority of Na+ channels Closing of Na+ channels Opening of K+ channels Closing of K+ channels Stimuli Opening of some of Na+ channels Opening of majority of Na+ channels Closing of Na+ channels Opening of K+ channels Closing of K+ channels  Characteristics of Action potentials 1. Polarity Ø are self-propagated in a one-way chain reaction along a neuron X Why ? 28.5 The action potential propagates itself along the neuron Sodium pump has Refractory period  자극의 크기 > threshold? 여부에 따라 Action potential 의 Characteristics of Action potentials 발생 여부가결정 (all-or-none events) 자극의 크기정도에 따라 2. All-or-none events 큰 Action potential 또는 작은 action potential 발생여부 X Action potential 의 발생 빈도를 결정 Ø The strength of the stimulus changes Threshold Potential Uniform Response Not expressed as the strength of action (No Partial Action Potentials) potentials Frequency of action potential But, as the frequency of action potentials Characteristics of Action potentials Action potential 은 axon 상에서 jumping mode로 전파돼.. 3. Jump of action potential à neuron의 구조적 특징때문.. Ø The nervous system comprised of two primary cell types: neurons and glial cells. Ø The interface between two neurons is called a synapse. Just inside the synapse, the axon contains synaptic vesicles that store neurotransmitters. Ø Synaptic vesicles cluster near synapses.. Arrival of Action potential at the end of axon The depolarization opens voltage-gated Ca2+ channels located near the synapse Synaptic vesicles fuse with membrane and release the neurotransmitter. à Binding of neurotransmitter to receptor triggers change in potential in postsynaptic cell 28.6 Neurons communicate at synapses Ø Synapses are junctions where signals are transmitted between two neurons or between neurons and effector cells 1. Chemical synapses Sending (presynaptic) cell secretes a chemical signal, a neurotransmitter The neurotransmitter crosses the synaptic cleft The neurotransmitter binds to a receptor on the surface of the receiving (postsynaptic) cell 2. Electrical synapses Electrical signals pass between cells A direct flow of current from pre- to postsynaptic cell initiating (or in some instances inhibiting) the generation of postsynaptic action potentials. 28.7 Chemical synapses enable complex information to be processed 하나의 neuron은 수백 개의 neuron들에게서 정보를 받을 수 있음 Ø A neuron may receive information From hundreds of other neurons via thousands of synaptic terminals 각 neuron으로 부터의 neurotransmitter의 종류 나 양은 각기 다양 Ø Some neurotransmitters Excite the receiving cell Inhibit the receiving cell’s activity by decreasing its ability to develop action potentials Ø The summation of excitation and inhibition à Determines if a neuron will transmit a nerve signal Ø Excitatory postsynaptic potentials (EPSPs) Ø Inhibitory postsynaptic potentials (IPSPs) 28.8 A variety of small molecules function as neurotransmitters Many small, nitrogen-containing molecule serve as neurotransmitters Ø Biogenic amines (neurotransmitter derived from amino acids) - important in the CNS (eg: Serotonin and dopamine affect sleep, mood, attention) Ø Acetylcholine – important in the brain and between neurons and muscle cells Clostridium boltulinum Clostridium tetani Botulinum toxin Botox® Ø Some amino acids (aspartate, glutamate, glycine and g-aminobutyric acid) - important in the CNS (Some are excitatory and Some are inhibitory) Ø Neuropeptides -Substance P (mediates perceptions of pain) & Endorphins (decrease perception of pain) Ø Nitric oxide (triggers erections; Viagra)  Some neurotransmitters produce EPSP or IPSP. Some serve either of EPSP or IPSP depending on the case. 28.9 CONNECTION: Many drugs act at chemical synapses Ø Many psychoactive drugs ü Act at synapses ü Affect neurotransmitter action Ø Caffeine counteracts inhibitory neurotransmitters Ø Nicotine acts as a stimulant Ø Alcohol is a depressant 28.10 EVOLUTION CONNECTION: The evolution of animal nervous systems reflects changes in body symmetry Ø Invertebrate nervous system Radially symmetrical animals ü Nervous system arranged in a weblike system of neurons ü Nerve net Ø Most bilaterally symmetrical animals exhibit Centralization—presence of a central nervous system Cephalization—concentration of the nervous system in the head region 28.11 Vertebrate nervous systems are highly centralized and cephalized Vertebrate nervous systems Vertebrate nervous systems are – Highly centralized 뇌신경 – Cephalized § Central nervous system (CNS) Ø The brain and spinal cord Ø Contains fluid-filled spaces ü In ventricles of the brain 뇌척수액 ü In the central canal of 뇌척수막 회색질 the spinal cord 백색질 ü Surrounding the brain § Peripheral nervous system (PNS) Ø Nerves—cranial nerves 뇌실 중심관 and spinal nerves Ø Ganglia 28.12 The peripheral nervous system of vertebrates is a functional hierarchy 말초신경계는 기능적으로 구분될수 있는 여러 § Two functional components of the PNS 단계로 구성… 1. Somatic nervous system—mostly voluntary 체성신경계 2. Autonomic nervous system (ANS)—mostly involuntary 자율신경계 § Somatic nervous system Ø Carries signals to and from skeletal muscles Ø Mainly in response to external stimuli Ø All volutary actions via nerve impluses from PNS to the muscle of body. § Autonomic nervous system Ø Regulates the internal environment Ø Controls ü Smooth muscle ü Cardiac muscle ü Organs of various body systems 28.13 Opposing actions of sympathetic and parasympathetic neurons regulate the internal environment § Parasympathetic division of ANS Primes the body for activities that gain and conserve energy for the body (Rest /Relaxation/ Recovery) § Sympathetic division of ANS Prepares the body for intense, energy-consuming activities (Fright / Flight / Fight) 28.14 The vertebrate brain develops from three anterior bulges of the neural tube 신경관의 3 부위가 부풀어 형성… Ø The vertebrate brain develops from 3 bulges of neural tube Forebrain Midbrain Hindbrain Ø evolved to be subdivided structurally and functionally into several regions of specific responsibilities § In birds and mammals – Size and complexity of the cerebrum correlates with their sophisticated behavior  THE HUMAN BRAIN 28.15 The structure of a living supercomputer: The human brain Ø The human brain More powerful than the most sophisticated computer Composed of three main parts ü Forebrain ü Midbrain ü Hindbrain 대뇌 시상 시상하부 뇌하수체 뇌교 연수 소뇌 뇌량 기저핵 28.15 The structure of a living supercomputer: The human brain Ø Brainstem Conduct information to and from higher brain centers Regulate homeostatic functions Keep track of body position Ø Thalamus Input and output sensory information Ø Hypothalamus Homeostatic control center Ø Cerebellum Coordination of body movement Ø Cerebrum Most integrative power is in the cerebral cortex 28.16 The cerebral cortex is a mosaic of specialized, interactive regions Cerebral cortex Ø About 5 mm thick Ø Accounts for 80% of brain mass Ø Specialized integrative regions 1) Somatosensory cortex ü Centers for vision, hearing, taste, and smell 2) Motor cortex—directs responses 3) Association cortex ü Make up most of the cerebrum ü Higher mental activities – Reasoning – Language Ø Right and left cerebral hemispheres Specialize in different mental tasks 28.17 CONNECTION: Injuries and brain operations provide insight into brain function Ø Brain injuries and surgeries reveal brain functions The case of Phineas Gage at 1848 ü Survived from the accident during railroad construction ü Intellectually intact, but ü Drastic change in his personality (mean, vulgar, irresponsible, etc) à The modern analysis of his injury offered an explanation for his bizarre behavior. ü The damages on both of his frontal lobes, which are part of the limbic system (a group of brain structure involved with emotions) Ø Various surgical alterations of the brains offered the information about various brain functions the remarkable plasticity of the brain 원래 조절기능을 하던 한쪽 뇌부위가 상실된 경우 어린 아이의 경우엔 다른 부위가 control 하기도 (plasticity) Ø Electrical stimulation of the cerebral cortex during surgery The conscious patient during surgery (‘.’ neuronsurgeon is operable with the patient awake) ü Questioning to and answering from the patient awake allowed functional analyses the areas of cerebral cortex 28.18 CONNECTION: fMRI scans can provide insight into brain structure and function Ø fMRI (Functional magnetic resonance imaging) A scanning and imaging technology used to study brain functions Used on conscious patients Monitors changes in blood oxygen usage in the brain by tracking blood flow Tracking blood flow and comparing that activity to what you were doing at the time à Mapping the specific areas of the brain and the function of the brain 28.19 Several parts of the brain regulate sleep and arousal Ø The brainstem has several centers for controlling arousal and sleep 뇌간 뇌줄기 the reticular망상 formation (a diffuse 전파 network of neurons extending through the core 망양체 or of the brainstem) is a region that is involved in 확장하다 그물형성체 ü Multiple tasks such as regulation the sleep-wake cycle and filtering incoming stimuli Medulla oblongata and Pons 뇌교 연수 ü have centers that promote sleep when stimulated Midbrain ü has a center that promotes arousal 흥분 Ø Sleep Is essential for survival Is an active state at least for the brain (high electrical activity) Brain progresses through several distinct stages of sleep ü REM sleep à high brain activity which is more like those of aware state à dreaming during REM sleep (~6 X for 5 to 50 minutes each per night) Sleep and dream may be involved in consolidating 통합하다 learning and memory 28.20 The limbic system is involved in emotions, memory, and learning 대뇌변연계 “limbus” = border 변두리, 뇌의 변두리 A border between the cerebral cortex and the subcortical structures of the diencephalon 간뇌 간뇌 Ø The limbic system (대뇌변연계) Is a functional unit that includes the parts of thalamus, hypothalamus, 시상하부 amygdala, hippocampus, cingulate gyrus etc…시상 편도 해마 대상회, 띠이랑 Cingulate gyrus Responsible for controlling emotional drives and memory formation. It is the part of the brain involved when it comes to behaviors we need for survival: feeding, reproduction and caring for our young, and fight or flight responses -play a central role in our emotional -transfer of short- responses, including feelings like term memory to fear, anxiety and anger. long-term memory 28.21 CONNECTION: Changes in brain physiology can produce neurological disorders Ø Many neurological disorders can be linked to changes in brain physiology Schizophrenia 정신분열증 ü A severe mental disturbance ü Characterized by psychotic episodes in which patients lose the ability to distinguish reality Depression 우울증 Pet scans showing ü Two broad forms of depressive illness have been identified brain activity § Major depression § Bipolar disorder—manic-depressive 양극성 장애, 조울증 disorder ü Treatments may include selective serotonin reuptake inhibitors (SSRIs) Depressed person Alzheimer’s disease ü is characterized by Confusion and Memory loss ü A firm diagnosis is difficult to make Parkinson’s disease Healthy person ü Motor disorder ü Characterized by difficulty in initiating movements, slowness of movement and rigidity 강직 Chapter 29. The Senses M. Night Shyamalan touch sight smell hearing taste  SENSORY RECEPTION 29.1 Sensory organs share a common cellular basis All senses à detected by sensory receptor cells Sensory receptors that detect stimuli Sensory receptors are grouped into several types Mechano- Chemo- pain and electromagnetic receoptors receoptors thermoreceptors receptors involved in involved in many types found in sensitive to Electricity, touch, hearing, taste and human skin magnetism, balance smell light many are most common are Hair cells photoreceoptors 29.2 Sensory receptors convert stimulus energy to action potentials Ø Sensory transduction Conversion of stimulus energy to electrical signal (receptor potential) à Trigger action potentials in sensory neurons Receptor potentials à graded, non-propagated potentials whose amplitude is proportional to the intensity of the stimulus being transduced. à converted into the frequency of action potentials All different kinds of stimuli à The same electrical signal to brain à How distinguish the stimuli … à By the particular interneurons that are stimulated. A repeated stimulus –May lead to decrease sensitivity = Sensory adaptation 29.3 Specialized sensory receptors detect five categories of stimuli 1. Pain receptors detect dangerous stimuli like excess heat, pressure or to chemicals Highest density Aspirin or Ibuprofenà inhibits the synthesis of prostaglandin which increase pain by increasing the sensitivity of the pain receptors 2. Thermoreceptors detect heat or cold Hypothalamus serve as a body’s thermostat 3. Mechanoreceptors respond to mechanical energy like touch, pressure, sound etc § Human skin has many types of sensory receptors 4. Chemoreceptors respond to chemicals 5. Electromagnetic receptors respond to Electricity Magnetism Light (sensed by photoreceptors)  HEARING AND BALANCE 29.4 The ear converts air pressure waves to action potentials that are perceived as sound Ø The human ear channels sound waves From the outer ear To the eardrum To a chain of bones in the middle ear To the fluid in the coiled cochlea in the inner ear § Vibrations from the sound waves are amplified as they are transferred through the ear 소리 파동은 Cochlea upper canal fluid로 전달된 후 lower canal로 전달.. Amplified vibrations from the sound waves à cause a pressure wave in the fluid of upper canal of cochlea à fade away by travelling to lower canal via the tip of cochlea (와우) upper canal fluid로 전달된 소리파동은 organ of Corti에서 감지 Amplified vibrations from the sound waves à cause a pressure wave in the fluid of upper canal of cochlea à fade away by travelling to lower canal via the tip of cochlea (와우) Pressure wave in the fluid of upper canal à Basilar memb. vibration à Bend hair cells in the organ of Corti against a tectorial membrane à Ion channel opening of PM à Triggering nerve signals to the brain Volume and pitch Ø Louder sounds generate more action potentials Ø Pitches stimulate different regions of the organ of Corti (‘.’ Basal memb. is not uniform in its width or stiffness) 29.5 The inner ear houses our organs of balance 균형의 문제.. Ø Organs of balance are part of the inner ear 반고리관 (반규관) Semicircular canals Ø They include Utricle 반형낭 와우 Saccule 구형낭 Ø These organs sense body position and movement 29.6 CONNECTION: What causes motion sickness? Ø Motion sickness May be caused by conflicting signals between Inner ear & Eyes  VISION 29.7 EVOLUTION CONNECTION: Several types of eyes have evolved among animals Ø Invertebrate eyes include Simple eye cups that sense No lens Light intensity Direction Ø Compound eyes of insects 공막 (鞏膜) sclera 맥락막 (脈絡膜) choroid Many lenses 망막 (網膜) retina 각막 (角膜) cornea Acute motion detectors Most see in color 모양체 인대 중심와 각막 Ø Single-lens eyes are found in 홍채 황반 동공 Squids Humans 방수 수정체 유리체 Eye Trace : 시야 따라잡기 易地思之 29.8 Humans have single-lens eyes that focus by changing position or shape Ø Vertebrate eyes Single-lens eyes Light is focused by the curved cornea and lens Changing the shape of the lens focuses near and far Photoreceptor cells in the retina detect light 29.9 CONNECTION: Artificial lenses or surgery can correct focusing problems Ø Nearsightedness and farsightedness Result when the focal point is not on the retina Corrective lenses bend the light rays to compensate 20/10 à 2.0 à 정상인이 10 feet에서 볼 수 있는 것을 20 feet 떨어진 곳에서도 볼수 있는것 20/40 à 0.5 à 정상인이 40 feet 떨어진 곳에서도 볼 수 있는 것을 20 feet 떨어져야 볼 수 있는 것 Presbyopia Astigmatism ü Decreased flexibility of lens due to age ü Blurred vision ü Decreased ability to focus closely ü Misshapen lens or cornea 수정체의 탄력이 감소되어 근거리 시력이 떨어지는 눈의 변화 각막이나 수정체의 모양이 불규칙하여 굴절률이 고르지 않아 선명한 상 x 29.10 The human retina contains two types of photoreceptors: rods and cones Ø Rods and cones send action potentials to the brain Ø Rods 간상세포 Rhodopsin More sensitive to light Responsible for vision in dim light Cones 원추세포 Photopsin Less sensitive to light Allow us to see color in bright light 황반, 망막  Rhodopsin (transmembrane complex) = Opsin (transmembrane protein) + Retinal (pigment) Retinal à light absorption à conformation change à Rhodopsin activation à à action potential generation  빛을 받게 된 망막은 시세포에서 생화학적 신호를 생성, 이 신호는 결국 전기적 신호로 변경되어 뇌로 전달 1. Rhodopsin is activated when light causes retinal to change shape. 2. Rhodopsin activates the membrane protein transducin, which in turn activates the enzyme phosphodiesterase (PDE). 3. PDE breaks down cyclic guanosine monophosphate (cGMP) to guanosine monophosphate (GMP). 4. As cGMP levels decline, cGMP-gated sodium channels in the plasma membrane of the rod cell close. 5. When sodium channels close, Na+ entry decreases and the membrane hyperpolarizes, decreasing neurotransmitter release à Telling bipolar cells that rod cell absorbs light à neuron No light Photoreceptor cells in the dark à depolarized à Release of inhibitory neurotransmitter to bipolar cells à Hyperpolarized bipolar cells à No release of neurotransmitter.’. No activation of neuron Photoreceptor cells Bipolar cells X Sensory neurons in the dark Via release of Inhibitory neurotransmitters Light Photoreceptor cells in the light à Hyperpolarized à No release of inhibitory neurotransmitter to bipolar cells à Depolarized bipolar cells à Release of neurotransmitter.’. Activation of neuron Photoreceptor cells X Bipolar cells Sensory neurons in the light Via no release of Inhibitory neurotransmitters  TASTE AND SMELL 29.11 Taste and odor receptors detect chemicals present in solution or air Ø Taste à Depend on chemoreceptors that bind specific molecules Ø Taste receptors Located in taste buds on the tongue Produce five taste sensations 1. Sweet 2. Salty 3. Sour 4. Bitter 5. Umami 29.11 Taste and odor receptors detect chemicals present in solution or air Ø Smell à Depend on chemoreceptors that bind specific molecules Ø Olfactory (smell) sensory neurons Line the nasal cavity Ø Much of tastes result from taste and smell … 29.12 CONNECTION: “Supertasters” have a heightened sense of taste Ø Supertaster = A person whose sense of taste is of far greater intensity than the average person, having an elevated taste response. Up to three times the sensitivity to bitter Up to 25% of humans More likely to avoid ü Spinach, broccoli, cabbage ü Coffee ü Alcoholic beverages Ø Supertasters May be less likely to eat vegetables May result in a higher risk of obesity and related disease Chapter 30 How Animals Move Skeleton Muscle  MOVEMENT AND LOCOMOTION Locomotion à Active travel from place to place 30.1 Animals have evolved diverse means of locomotion Ø Swimming Supported by water But slowed by friction Ø Walking, hopping, or running Less affected by friction But must resist gravity Ø Burrowing or crawling Must overcome great friction Or may move by a form of peristalsis May move by side-to-side undulations Ø Flying Wings are airfoils that generate lift Flying is seen in birds, bats, and most insects 30.2 Skeletons function in support, movement, and protection Ø Body support Ø Movement by working with muscles Ø Protection of internal organs 1. Hydrostatic skeletons Fluid held under pressure in a closed body compartment (gastrovacular cavity of the cells of body wall Found in worms and cnidarians 2. Exoskeletons Hard external cases of protein and chitin of arthropods Calcium carbonate shells of molluscs 3. Endoskeletons Internal skeleton May be made of ü Cartilage or bone—vertebrates ü Hard plates—echinoderms 30.3 EVOLUTION CONNECTION: Vertebrate skeletons are variations on an ancient theme Ø Vertebrate bodies reveal variations of the basic skeletal arrangement Human skeleton 1. Axial skeleton 경추 (체간 골격) ü Skull ü Vertebrae 흉추 ü Ribs 2. Appendicular 요추 skeleton (체지 골격) 천추 미추 ü Shoulder and pelvic girdles ü Arms & legs 체간 골격(axial skeleton) 체지 골격( appendicular skeleton) 견갑대(shoulder girdle) 골반대 (骨盤帶, pelvic girdle )  골격형성은 homeotic genes의 조절을 받아 진행.. 30.3 EVOLUTION CONNECTION: Vertebrate skeletons are variations on an ancient theme Ø Master control (homeotic) genes are active during early development and direct the arrangement of the skeleton Ø Vertebrates have evolved by changes in these master control genes Cervical vertebrae ends at the point where Hox6 expression begins. Lumbar vertebrae starts at the point where Hox8 expression ends. Limbs originate at the boundary b/w them. Hox gene 발현조절부위의 돌연변이에 의해 Hox genes이 모든 부위에서 발현됨으로써 no cervical verebrae ….’. Limb 발생X During the evolution of snakes, mutation in the DNA segments that control the expression of Hox6 and Hox8 changed the cervical vertebrae to thoracic..’. Snake has no limbs. 30.4 Bones are complex living organs The bones that make up your skeleton are all very much alive, growing and changing all § Bone cells the time like other parts of your body. Ø Secrete a matrix consisting of Flexible fibers of the protein collagens à flexibility Mineral crystals of calcium and phosphate salts à hardness Ø Are kept alive by Blood vessels /Hormones /Nerves Ø Cartilage at the ends of bones Cushions joints Reduces friction of movements 해면골 Ø Spongy bone Located at the ends of bones Contains red bone marrow, the site of blood cell production Ø Compact bone Long bones have a fat-storing central cavity (yellow bone marrow) Connective tissue 30.5 CONNECTION: Healthy bones resist stress and heal from injuries Ø Bone cells Repair bones Reshape bones throughout life Ø Broken bones Are realigned and immobilized Bone cells build new bone, healing the break Ø Osteoporosis is a bone disease characterized by Weak, porous bones Less likely if ü High levels of calcium in diet ü Regular exercise ü No smoking 30.6 Joints permit different types of movement Joints allow limited movement of bones Different joints permit various movements  MUSCLE CONTRACTION AND MOVEMENT 30.7 The skeleton and muscles interact in movement 골격과 근육이 함께 작용하여… Ø Muscles and bones interact to produce movement Ø Muscles are connected to bones by tendons (Wha diff. with ligament ?) Tendon – muscle to bone Ligament – bone to bone Ø Antagonistic pairs of muscles Reverse actions (antagonistic actions) Relengthen muscles by contraction and relaxation of antagonistic pairs 30.8 Each muscle cell has its own contractile apparatus Ø Muscle fibers Are cells. 즉, single muscle fiber = single muscle cell Consist of bundles of myofibrils Myofibrils contain overlapping ü Thick (myosin) filaments ü Thin (actin) filaments Ø Sarcomeres are The contractile unit à the fundamental unit of muscle action Repeating groups of thick and thin filaments 30.9 A muscle contracts when thin filaments slide across thick filaments Ø The sliding-filament model explains muscle contraction Thin filament : ü A polymer of two actin chains and tightly bound regulatory proteins, toponin and tropomyosin Thick filament : ü Myosin: 총 6개의 polypeptide chains로 구성 (2개의 heavy chains à 2 heads & 2 tails) ü myosin는 긴 단백질이 여러 개의 다발을 이루어 형성 ü Myosin heads는 모두 thin filament와 상호작용 2 heavy chains 4 light chains  ATP binds to myosin head, causing the cross-bridge to break. Myosin head binds a molecule of ATP ü Myosin head à in low-energy position Myosin head hydrolyzes the ATP to ADP and Pi ü Released energy extended myosin head in high-energy position Extended myosin head latches on to the binding site of an actin, forming a cross- bridge. ADP and pi are released, and the myosin head pivots back to its low-energy position (power stroke). 30.9 A muscle contracts when thin filaments slide across thick filaments ØThe sliding-filament model explains muscle contraction ATP binding to myosin (myosin head release from thin filament) ATP가 hydrolyzed 되며 high-energy state인 myosin– ADP-Pi complex 형성 (myosin head pivots and binds to actin) ADP, pi release (myosin head가 power stroke) Ø A motor unit consists of A neuron The set of muscle fibers it controls 30.10 Motor neurons stimulate muscle contraction Ø Motor neurons Carry action potentials that initiate muscle contractions Ø The axon of a motor neuron Forms synapses with a muscle at a neuromuscular junction Ø Acetylcholine Is released from the synaptic terminal of a motor neuron and triggering action potentials that diffuse to the plasma membrane of the muscle fiber Ø An action potential in a muscle fiber Passes along T tubules into the center of muscle fiber Opens Ca2+ channels on ER Ø Calcium ions Are released from the endoplasmic reticulum Initiate muscle contraction by moving regulatory proteins away from the actin binding sites Muscle contraction à Mediated via ATP hydrolysis by myosin head (ATPase activity: ADP + pi) Low ATPase activity à Slow (slow twitch fibres) * Twitch = a single stimulus-contraction-relax High ATPase activity à Fast (Fast twitch fibres) action sequence in a muscle fiber Skeletal muscle fibers I. Slow-twitch muscle fibre à Contracts slowly and for longer durations I. Surface area/volume à High II. High capillary density à High III. Myoglobin à High IV. Mitochondria density à High High O2 supply à oxidative phosphorylation à ATPs II. Fast-twitch muscle fibre à Contracts faster and for shorter durations I. Surface area/volume à Low II. High capillary density à Low III. Myoglobin à Low IV. Mitochondria density à Low Low O2 supplyà Glycolysis à ATPs “Quick production” 30.11 CONNECTION: Aerobic respiration supplies most of the energy for exercise Ø Muscle – contain only small amount of ATP & phosphocreatine (PCr) storedà allow for only 10~15 sec contraction.’. Bulk of ATP for aerobic exercise à from aerobic respiration… Ø Aerobic exercise – effective method of maintaining or losing weight Ø The demand for ATP à beyond supply of ATP from aerobic respiration à lactic acid fermentation 30.12 CONNECTION: Muscle fiber characteristics affect athletic performance Ø Muscle fibers can be classified as Slow fibers Intermediate fibers Fast fibers Ø Different muscle fibers à different forms of myosins of thick filament (hydrolyzing the ATP at different speeds) hydrolysis of ATP by myosin in fast fibers à fast hydrolysis of ATP by myosin in slow fibers à slow Ø Aerobic exercise – uses ATPs that were generated from the pathway of efficient ATP production (aerobic respiration) Ø Anaerobic exercise – uses ATPs that were generated from the pathway of anaerobic respiration. Generates ATP faster Is much less efficient at producing ATP Ø Most muscles have a combination of fiber types Ø The proportion of fiber types can be affected by exercise Ø Muscles adapt to exercise by increasing Levels of myoglobin Number of mitochondria Number of capillaries going to muscles Plants are multicellular Advantages: Bigger means better able to compete for light, nutrients Cells can specialize Disadvantages: Need to move resources and information, coordinate actions v Three Tissue Systems: Dermal, Vascular, and Ground Ø Three plant tissue systems make up the plant body… 1. dermal tissue system à protective coverings 2. vascular tissue system à primary conductivity 3. ground tissue system à fundamental Ø 식물체의 겉부분을 차지하는 Dermal tissue Ø 물과 양분을 식물 각 부위로 손실없이 수송하 는 Vascular tissue 그리고 Ø 그 나머지 부위를 채우는 Ground tissue Ø Topographic (continuity) sense à Each plant organ 1. dermal tissues 2. vascular tissues Dermal tissue 3. ground tissues Ground tissue Vascular tissue  epidermis Usually outermost single layer Dermal tissues periderm àDuring 2nd growth, epidermis is replaced by periderm à consists of cork cambium and its derivatives 1. Parenchyma (유조직) Ground 2. Collenchyma (후각조직) tissues 3. Sclerenchyma (후벽조직) 4. Xylem : Water-conducting cells Vascular tissues 5. phloem : Food-conducting cells  Epidermal Tissue Epidermis covers primary plant body epidermal cell - Waxy cuticle layer restricts water loss epidermis à protection and water loss prevention 즉 external cell wall of epidermis cell à coated with cuticle Epidermal cells – 1) pavement cells 2) trichomes 3) guard cells 4) root hairs Epidermal specializations Pairs of guard cells in leaf epidermis create stomata (openings) for gas exchange Trichomes (hairs) 사상체 Trichome – protection Absorbent root hairs Glandular trichome – imparting aroma Plants are assembled from ground cells... 2. Ground tissue 1) Parenchyma tissue à Prarenchyma cells 2) Collenchyma tissue à Collenchyma cells 3) Sclerenchyma tissue à Sclerenchyma cells A typical plant cell v Plant cell wall Fibrils embedded in a glue-like materials called matrix Fibril (Cellulose Microfibril) Cellulose microfibril (CMF) Pectins – polymers of galacturonic acids Matrix polysaccharides Xyloglucans Hemicelluloses Mixed–linkage glucans Matrix Arabinogalactans HRGP Arabinoxylans…… Matrix PRP proteins GRP  Expansion of the cell is affected by the orientation of cellulose deposition Ø The orientation of the cytoskeleton Affects the direction of cell elongation by controlling the orientation of cellulose microfibrils within the cell wall  Expansion Cellulose Lignin GRP synthesis precursors 1° cell wall added intensifies added Lignin polymers made 1° cell wall 2° cell wall Lignin – Highly branched polymer of phenylpropanoids Formed from three different phenylprpane alcohols p-coumaryl alcohol coniferyl alcohol sinapyl alcohol 1. Parenchyma: soft primary tissues - perform most of the plant's metabolic functions Metabolic functions No secondary cell wall Totipotent (total + able) 잎의 구조... Epidermis Vascular tissues 나머지à ground tissues à parenchyma cells 책상모양 스폰지 * mesophyll 중간을 차지하는 세포 ‘.’ parenchyma cell의 특징을 보임. Cell Differentiation Totipotency 동물발생에서의 분화 … totipotent 수정란à배반포à낭배 (외/중/내배엽) pluripotent unipotent v Totipotency The cells of a single plant can be placed in a growing medium to produce clones (Have the ability to develop into a whole new organism) Root of carrot plant Plantlet Cell division in culture Single cell Root cells in Adult plant growth medium  Eg: Leaf vein area, Tissues under Elongated epidermis in stem, Celery strings... Thick primary cell wall ‘.’ cellulose and pectin.’. Collenchyma cells이 분포하는 식물 부위 à strengthened 하지만 No secondary cell wall  Eg: The main component of the wood. Thick secondary cell walls (lignin 존재) No growing Mature sclerenchyma cells are dead. Fiber : long & slender cells 섬유 à making rope and clothings the lignified sclerenchyma of flax plants à paper Sclereids : short à hardness to nutshells and seed coats 보강세포 pear à gritty texture Sclerenchyma cells -1) fibers 캔버스, 로프등을 만드는 마 … 2) sclereids 씨 껍질 3. Vascular tissue 1) Xylem : transporting water and minerals 2) Phloem 2가지 종류의 세포 -1) vessel element –tube-like short cell 물관 요소 2) tracheids –long tapered cell 헛물관 Phloem : transporting sugars and other solutes Phloem – 1) sieve tube member à sieve tube (s.t. member : no nucleus).’. To survive, it depends on c.c 2) companion cell à plasmodesmata를 통해 sieve tube member에 연결.’. Metabolic maintenace of s.t.member * sieve tube member로 sugar loading 또는 unloading을 도움 The strategy of plant development Ø Higher animal strategy Vertebrates treat “development” as a necessary evil – A process that must be accomplished as fast as possible to reach a mature form. – Development occupies only a small fraction of the life span. à determinate growth Ø Flowering plant strategy Early development – The same strategy as animals late development – Instead of reaching mature form that is maintained through most of the plant’s life, most plants continue to develop as long as they live. “ Indeterminate growth” The plant does not have a definite adult form…. Organogenesis à continued throughout the life cycle à plant organ primordia를 통해 지속적으로 modular structure를 만들어 냄 Apical meristems Most plants continue to develop as long as they live. à “Indeterminate growth” The plant does not have a definite adult form…. Only a small parts of the plant remain immature and continueto develop à “ Meristems “ Ø Apart from the meristems, other parts of the plant body have determinate development : they reach a mature form that is maintained for the life of the plant – leaf, internode Ø Why the plants should have many meristems and keep developing ? The discard-and-replace strategy Rely on development to reach new territory * reproduction is another way to reach new territory… * Plants make their development sensitive to the environment. they have sensors that detect environmental factors and call for changes in the path of development. “Plasticity” … Only a small parts of the plant remain immature and continue to develop à “ Meristems “ Ø Meristems - regions where the cells continue to divide and grow, giving rise to new tissues. Apical meristems – meristem at the tip of each shoot and root 1) Shoot Apical Meristem (SAM) 2) Root Apical Meristem (RAM) à Primary growth lengthens roots and shoots Lateral meristems – meristems beneath the surface of the organ (stems and roots) 1) Vascular cambium 2) Cork Cambium à Secondary growth increases the girth of woody plants Ø The meristematic cells à maintain population of undifferentiated cells of the potential to differentiate into various organs Ø Other parts à determinate growth (eg: leaf, internode) 1. Primary growth Primary growth덕분에 root는 땅을 계속 뚫고 퍼져 갈수 있고 shoot는 위로 성장을 계속해 더 풍부한 light를 얻을수 있게 됨 “ Modular structure “ Terminal bud Apical meristem Lateral bud Node Internode Node  a. Stages in primary growth Early Leaf primordium stage Shoot apical meristem: Meristemic cell이 분열 Procambium àDaughter cells중 하나는 Dome에 남고 (initial) 다른 하나는 Procambium Derivative (분화되는 세포) Protoderm Ground meristem 3 primary meristems 1) Protoderm à epidermis 2) procambium Primary phloem Primary xylem 3) Ground Cortex à cork cambium meristem pith Epidermis Later Cortex Pith Primary phloem stage Procambium Primary xylem Ø Primary growth occurs behind the root tip in three zones Zone of cell division Zone of elongation Zone of maturation 2. Secondary growth à Secondary growth increases the girth of woody plants Ø Secondary growth is produced by lateral meristems, two cylinders of dividing cells 1) Vascular cambium Lies between primary xylem and primary phloem Thickens a stem by adding secondary xylem and phloem on both sides 2) Cork cambium Makes cork, a new outer layer of epidermis * Wood is made of secondary xylem 변재 periderm 주피 심재 Plant Reproduction Making more plants … Alternation of Generation Multicellular complex Multicellular complex  Generative cell is inside the Microgametogenesis tube cell of the pollen = male gametogenesis Male Gametophyte Pollen = 1.tube cell 2. generative cell generative cell àsperm à Multicellular complex composed of haploid cells Development of embyro & seed production Pollination Female Gametophyte Megagametogenesis Embryo sac à Multicellular complex composed of haploid cells = female gametogenesis 1.Egg apparatus (Egg cell + synergids) 2. Central cell 3. Antipodal cells Triploid cell Ovule Zygote Cotyledons Endosperm Seed coat Two cells Shoot Embryo Root Seed Tomato is fruit or vegetable ? Lycopersicon esculentum In 1893, the Nix vs. Hedden Tomato importer Tax collector Tariff on shipment of tomatoes (10% duty placed on vegetables) A fruit is a specialized vessel that houses and protects seeds and helps them disperse Ø Fruits are classified into several types Depending on their developmental origin 1) simple fruit : one carpel à one fruit 2) aggregate fruit : many carpels of one flowerà one fruit 3) multiple fruit: many carpels of many flowers à a multiple fruit Ø Asexual reproduction produces plant clones v Asexual reproduction is a mainstay of modern agriculture è 좋은 형질의 동일한 개체들을 대량으로 증폭 가능 Asexual reproduction à usual cell à adult … Ø Tissue Culture Methods “ totipotency “ Ø Plant genetic engineering Ø A plant of desired trait à Massive cultivation è Most crops today are grown in monocultures Ø 하지만 이는 원하는 형질의 개체만을 대량 경작 à 유전적 다양성을 위축시키는 결과... (reduced genetic diversity) Great Famine Multicellular organisms need to transmit materials and information Information has to be Metabolic products transmitted to have to be distributed integrate activities throughout the body Raw materials have to be distributed – diffusion is inadequate for larger organisms Chapter 32 Plant Nutrition and Transport Increase of the surface area of root cells by root hairs The plasma membranes of root cells control solute uptake Transport routes between cells A cell must exchange materials with its surroundings, a process controlled by the plasma membrane The plasma membrane - Is the boundary that separates the living cell from its nonliving surroundings Membrane is selectively permeable Cytoplasm Casparian Strips in Roots -All substances in solution enter the root and are transported through vascular system. - To enter the vascular system, all substances have to virtually pass through the plasma membranes..’. selectivity of PM regulate the mineral caomposition of a plant. - Apoplastic movement – no way to control the solute movement : But waxy barrier = Casparian strip Vascular plants have long-distance transport systems XYLEM PHLOEM Water moves from Photosynthetically- the soil to the produced sugars (and atmosphere other molecules) move through the hollow from their source to dead cells of the sinks (non- xylem photosynthetic tissues) through the phloem ? Pushing down the Pulling up the plunger causes plunger causes the pressure the pressure inside the barrel inside the barrel to be higher than to be lower than atmospheric. atmospheric. Water from the Water from the barrel moves out, beaker moves towards the towards the region of lower region of lower pressure. pressure, into the barrel. Xylem transport (Transpiration) cohesion-adhesion theory Xylem sap up against the gravity : Pushing and pulling? Root pressure ? : root cells pump the inorganic ions into root cells à osmosisà water uptake à xylem.’. pushing forces ? Transpiration ? : a loss of water from leaves à the tendency cohesion & adhesion of water à pulling foreces molecules to stick to other molecules the tendency of water molecules to stick together - Hydrogen bonds make liquid water cohesive and adhesive v Nonwoody plant species like lawn... Ø A positive pressure can develop in roots and force xylem sap upward = root pressure ‘.’ evaporation is low at night ‘.’ high humidity guttation Ø Root pressure can only provide a modest push in the overall process of water transport. Ø Its greatest contribution maybe to reestablish the continuous chains of water molecules in the xylem which often break under the enormous tensions created by transpiration... v Waxy cuticles prevent water loss; regulated pores allow it OPEN Guard cells change their volume to open and close the pore. Guard cells are sensitive to the CLOSED atmospheric conditions and the Most plant aerial surfaces are plant’s needs for covered by a waxy cuticle. Pores gas exchange and called stomata, usually covered by water conservation pairs of guard cells, permit transpiration v Guard cells control transpiration Stoma Guard cells K+ Vacuole Stoma opening Stoma closing Ø Stomata regulate transpiration depending on changing environmental conditions. Potassium ions pumped into guard cells à water inà open ü Light à stomata opening ü CO2 à drop under light ‘.’ photosynthesis used up CO2 à opening ü Water stress à ABA 증가 à close v The phloem transport Phloem transports sugars, a main product of photosynthesis Ø Xylem sap : upward movement Ø Phloem sap : various directions Sugar source ßà sugar sink (changeable depending on condition) Source and Sink Source: where the sugar starts its journey (either where it is produced or stored):net exporters of assimilate Sink: where sugar ends up (either where it is needed or will be stored). The coordination of source & sink àAvoid large fluctuations and imbalances b/w supply and demand (avoid feast and famine) v The pressure flow hypothesis In source, 1. Active transport of sugar into phloem 2. Water into phloem by osmosis from xylem 3. Hydrostatic pressure increase In sink, 1. Sugar leave the phloem 2. Water out of phloem by osmosis 3. Hydrostatic pressure decrease à A gradient of hydrostatic pressure v Xylem sap & phloem sap transport를 Long distance transport throughout the plant 전체적으로 살펴보면… Cells load and unload organic molecules (including CO2) into and b. Transport in out of phloem (purple vascular tissues arrows to/from phloem). Sugar from photosynthesis Phloem: transport of sugars Vascular tissue distributes substances throughout the plant, sometimes over Xylem: great distances. transport of H2O and O2 Water and mineral ions travel from root hairs into xylem a. Short distance vessels by passing through transport across cell or between cells (black arrow membranes into roots into/out of xylem). Water and solutes from soil enter plant roots by passive or active transport through the plasma membrane of root hairs. Sugar from photosynthesis Minerals Mineral ions v Vascular tissues are essential conduits for information flow Some signals move in the In animals, signals xylem. Signals moving through the nervous and from drought- circulatory systems stressed roots convey information cause guard cells to close Other xylem-borne signals convey information about nutrient availability and soil-microbes v Plant health depends on a complete diet of essential inorganic nutrients Heterotrophs : need a complex diet of organic foods… Although Plants are autotrophs, they still need inorganic ions Hydroponic Culture v Mineral Deficiencies 영양에 관련된 물질을 찾기위해 특정 물질 하나씩 빼보며 변화를 관찰함. Ø Essential elements are those 17 a plant must obtain to complete its life cycle – 9 macronutrients needed in large amounts Mostly build organic molecules – 8 micronutrients needed in small amounts Act mainly as enzyme cofactors Ø Average % dry weight à > 0.1 Complete solution containing all minerals (control) Solution lacking potassium (experimental) à macroelements à < 0.01 à microelements` Ø Macronutrients Ø Micronutrients v Nitrogen sources Atmospheric N2 Organic compounds Ø 대기의 80%가 N2이지만 plants cannot absorb N2 gas Transamination Nitrogen fixation from glutamate Dissolved in water Ammonification nitrication Ø Most plants depend on bacteria to supply nitrogen à Soil bacteria convert nitrogen to forms plants can use Atmospheric N2 ü Nitrogen-fixing bacteria convert atmospheric N2 to ammonia (NH3) Organic compounds ü Ammonifying bacteria decompose organic matter, producing ammonium (NH4+) ü Nitrifying bacteria convert NH4+ to nitrate NO3- Ø Legumes and certain other plants house nitrogen-fixing bacteria Legume-family plants have a symbiotic relationship with nitrogen-fixing bacteria ü Rhizobium live in vesicles in root nodules ü Plant provides bacteria with carbohydrates and other organic compounds ü Bacteria have enzymes that catalyze conversion of N2 to NH4+ ü Can increase fertility of soil as well as nourish plant Bacteria within a root nodule cell  v Mycorrhiza = a symbiotic association between a fungus and a plant 곰팡이와 뿌리간의 상관관계로 인해 만들어진 것 Ø Fungi help most plants absorb nutrients from the soil MYCORRHIZA의 복수형. 균사 Most plants form mycorrhizae, mutually beneficial associations with fungi ü Fungus obtains sugar from host plant ü Plant benefits from increased surface area for nutrient and water absorption Mycorrhizae are an early adaptation that may have helped plants colonize land.’. Farmers can combat plant malnutrition by inoculating seeds with fungal spores Chapter 33 Control system in plants : Plant Responses to Internal & External Signals So splendidly adapted to their environment … 너무 환경에 멋지게 적응해서 움직이지 않고도 살아가는 방법을 고안해냄. Ø Because of their immobility, Plants must adjust to a wide range of environmental circumstances through developmental and physiological mechanisms (1) Light (빛) (2) Gravity (중력) (3) Mechanical Stimuli (물리적 자극) (4) Environmental stresses (환경요인): Abiotic stresses Drought(가뭄) Flooding(홍수) Salt Stress(염류 스트레스) Heat Stress(고온 스트레스) Cold stress (저온 스트레스), etc Biotic stresses pathogens Herbivores, etc (움직일 수 없기 때문에 다양한 환경요인에 대해 적절한 반응기작을 구축하는 방향으로 진화함) 식물은 한곳에 고정되어 있어 다양한 자극에 대해 식물성장/발달과정의 패턴을 조정하는 v Plants, being rooted to the ground 방식으로 대처함 (sedentary) 따라서 같은 종일지라도 개체 별로 몸체의 모양이나 가지 수 등에서 다양성을 보임 The life cycle of Arabidopsis “Plasticity” 성장과 발달이 일방향적으로 진행되는 것이 아닌 주변환경에 따라 FLEXIABILITY 유연함을 가지고 다르게 진행되는 것을 PLASTICITY라고 함. Signal transduction pathway “Plasticity” Reception Transduction Response  Signal input : Hormones, Light, Abiotic stresses, Biotic stresses Receptors Sensors SIGNAL CASCADE 하는 데 중요한 역할을 수행함. 2nd messengers (Ca2+, PA, cNucleotides etc) Gene expressions protein modifications Signal전체에 cascade 신호 전파 Phosphorylation Dephosphorylation Ubiquitination etc 조절 DIVERSIFICATION. 하나의 정보가 다양한 갈래로 나뉘어짐. Protein amount Physiological condition Ion channels Protein activity transporters Physiological and cellular responses Altered growth & develpoment v Second messenger system… 2nd messengers (Ca2+, PA, cNucleotides etc) Ø The first/second messenger concept Sutherland et al (1968) “Secondary messenger” Earl Wilbur Sutherland, Jr. (1915–1974) Nobel prize 1971 physiology nervous stimulation Adrenal gland Adrenaline (1st messenger) Remote target tissues cAMP (2nd messenger) v Amplification of signal intensity and Divergence of signal 1 1 1개가 100개를 활성화 1. One molecule of adrenalin/receptor 시킴. complex can activate many G-proteins 100 100 100개가 1개씩 활성화 2. One molecule of active G protein can 총 100개 activate one molecule of inactive 1 100 adenyl cyclase. 1개 분자당 10개씩 활성화 시킴 3. One molecule of adenyl cyclase can 1000 produce many molecules of cyclic AMP 10 1개씩 활성화 시킴 4. One molecule of active cyclic AMP- dependent protein kinase can 1 1000 phosphorylate 10개씩 활성화 시킴 5. One molecule of active protein kinase 10000 activate many molecules of inactive 10 phosphorylase kinase 5. One molecule of active phosphorylase 100000 kinase can phosphorylate and activate 10 many molecules of inactive glycogen phosphorylase Thus, the original weak signal can be amplified v 4 Classes of second messengers * phospoholipids 1. Ca2+ IP3 DAG 2. Lipid messengers (membrane lipid derivatives) PA PIP2 PIP3 etc * Membrane lipids 3. Cyclic nucleotides (cAMP, cGMP) 4. NO  The selective breakdown of proteins is another control mechanism operating after translation UBIQUITIN- PROTEASIME MEDIATED PROTEIN DEGRIATION 선택적으로 특정한 단백질을 없앰 -> 신호 전달 Aaron Avram Irwin Ciechanover Hershko Rose The Nobel Prize in Chemistry 2004 Plant hormones help coordinate growth, development, and responses to stimuli In general, plant hormones control plant growth and development by affecting the division, elongation, and differentiation of cells THE POWER OF MOVEMENTS IN PLANTS. BY CHARLES DARWIN ASSISTED BY FRANCIS DARWIN. The Discovery of Plant Hormones Tropism의 발견 – Any growth response that results in curvatures of whole plant organs toward or away from a stimulus is called a tropism (모든 성장반응은 자극에 반응하여 전체 식물의 기관을 굽어지게 하는 현상을 굴성이라고 함) – Is caused by hormones (굴성은 호르몬에 의해 유도됨) 굴광성 (phototropism)의 발견 Charles Darwin and his son Francis – Conducted some of the earliest experiments on phototropism, a plant’s response to light, in the late 19th century (2) 굴광성을 유도하는 신호는 빛에 의해 활성화되어 이동 가능한 화학 물질임 Boysen-Jensen (1913) Light Control Tip Tip Tip Base Tip Tip separated removed covered by covered covered by separated by mica opaque by trans- opaque by gelatin cap parent shield block cap Darwin and Darwin (1880) (1) 정단부위에서만 빛 인지함 Frits Went (1926) isolated a plant growth substance by placing agar blocks under coleoptile tips for a period of time then removing them and placing them on decapitated Avena stems A coleoptile curved toward light because its dark side had a higher concentration of the growth-promoting chemical, which he named auxin. 20년후 chemical identy확인 Brassinosteroids 식물의 성장과 발달에 중요한 것들임 Polyamines Jasmonic acids … What is in common in followings... Charles Darwin, Cone shape of tree, Weed killer, Vietnam war... 1. Auxin “Auxin” = Greek “auxein , meaning “ to increase” or “grow” Indole acetic acid and related molecules 으로 부터 auxin이 유도되(만들)어진다. I Influence A Almost A Anything  Gravitropism = Coleoptile growth Phototropism Geotropism Thigmotropism - IAA + IAA Ø Auxin stimulates the elongation of cells : Acid growth hypothesis Loosening of cell wall b. Rays from the sun c. Auxin (red) diffuses d. The auxin-stimulated strike one side of a shoot down from the shoot tip cells elongate more tip. to cells on its shaded side. quickly, causing the seedling to bend. The shoot hormone, made in the shoot apex Travels down the stem Polar Auxin Transport Basipetal transport 1 1 2 2 IAAH IAA- H+ Ø Polar Auxin Transport The pH environment of cell wall Polar distribution of auxin efflux carrier Apical dominance rooting Agent Orange - 1:1 ratio of 2,4-D and 2,4,5-T used to defoliate trees in Vietnam War. Dioxin usually contaminates 2,4,5-T, which is linked to miscarriages, birth defects, leukemia, and other types of cancer.  Youth hormone... Plant tissue culture.. 2. Cytokinin Ø In the 1940s, Johannes van Overbeek, noted that plant embryos grew faster when they were supplied with coconut milk (liquid endosperm), which is rich in nucleic acids. Ø Based on Overbeek’s work, Miller and his associates added old herring sperm DNA to culture medium, which made tobacco cells divide. This compound was named kinetin because of its ability to promote cytokinesis. Ø Hall and deRopp reported that kinetin could be formed from DNA degradation products in 1955. Ø cell division을 촉진시킨다 해서 cytokinin Ø The first naturally occurring cytokinin was isolated from corn in 1961 by Miller. It was later called zeatin. 1) Control of Cell Division and Differentiation (세포분열과 분화조절) 2) Control of Apical Dominance (정단우성 조절) 3) Anti-Aging Effects (노화억제작용) Auxin Cytokinin (1) 끝눈의 auxin이 곁눈 의 생장을 억제하며 줄기의 주축성장을 촉진함 “Stump” after (2) 뿌리에서 이동되어 removal of 온 cytokinin은 옥신 apical bud 과는 반대로 곁눈생장 Axillary buds 을 촉진함 Lateral branches What do a fungal disease of rice, green revolution, flowering, and beer have in common? 3. Gibberellins (Gibberellic acid) 136 GAs (GA1~GA136) Tetracyclic diterpenes Terpenoids (terpenes) are synthesized from Isoprene diphosphate (IPP) Diterpene = a class of terpenes composed of four isoprene units Ø Discovered in association with In 1930's, bakanae or foolish seedling disease of rice (Gibberella fujikuroi) In 1930's, Ewiti Kurosawa and colleagues were studying plants suffering from bakanae, or "foolish seedling" disease in rice. Disease caused by fungus called, Gibberella fujikuroi, which was stimulating cell elongation and division. Compound secreted by fungus could cause bakanae disease in uninfected plants. Kurosawa named this compound gibberellin. Green revolution … Norman Borlaug The Nobel Peace Prize 1970 줄기신장 Wheat dwarfing genes of the Green Revolution Reduced height (Rht) genes of wheat = GA signaling component àGA에 대해 반응력이 약화됨….’. Short … 종자발아 과일성장 개화 촉진 The Plant Stress Hormone... Hihg salt... drought Various abiotic stresses like Cold... 여러가지 스트레스에 버티게 해주는 호르몬 4. Abscisic acid (ABA) Ø In 1940s, scientists started searching for hormones that would inhibit growth and development, what Hemberg called dormins. Ø In the early 1960s, Philip Wareing confirmed that application of a dormin to a bud would induce dormancy. Ø F.T. Addicott discovered that this substance stimulated abscission of cotton fruit. He named this substance abscisin. (Subsequent research showed that ethylene and not abscisin controls abscission). Vivipary (수발아) 기공 개폐 조절 Plant stress resistance... The first genetic engineering targeted for plant hormone... Falling leaf  Ripening hormone 4. Ethylene ( C2H4 ) “ gas “ Senescence hormone H H C C H H Ø Ancient Egyptians and chinese – burning gas or incense to ripen fruits… Ø In the 1800s, it was recognized that street lights that burned gas, could cause neighboring plants to develop short, thick stems and cause the leaves to fall off. Ø In 1901, Dimitry Neljubow identified that a byproduct of gas combustion was ethylene gas and that this gas could affect plant growth. Ø In R. Gane showed that this same gas was naturally produced by plants and that it caused faster ripening of many fruits.  Ethylene’s triple responses : 1) Hook 2) Thickening 3) Ageotropism 위에 장애물이 있을 때 ethylene의 영향으로 후크(구부러짐)이 생기고 두꺼워지며, 우회할 수 있음. 성공적인 발아. ripening Responses to light are critical for plant success * Photoreceptors linear tetrapyrrole 1) Phytochromes FAD pterin 2) Cryptochromes 3) Phototropin 4) UV-Bs FMN FMN Quality Quantity Direction Duration/period Flowering... Tobacco farmers in Maryland Soybean farmers Normal Maryland Soybean field tobacco Mammoth Mammoth tobacco not know when to stop Despite 2 week planting, all the soybeans making leaves and start making flowers would all set flowers at the same time… and seeds? 아무리 시간차를 두고 심어도 모두 동시에 담배식물은 어느정도 잎을 맺을 후 꽃을 피 개화하여 수확시기를 분산시킬 수 없음... 워야 하는데 이 돌연변이체는 계속 잎만 맺다 추워지면 동사하게 됨... USDA  In 1918 They looked at all factors at the time thought to affect plant development (such as nutrition, temperature, moisture, and light intensity), but failed to find a reason over a ten years period. By 1918, the only factor they did not check was the relative length of night and day during the season... Harry A. Allard (1880–1963) 오후에 식물을 field에 내다 놓았다 다음날 오전에 다시 & 들여와 인위적으로 낮의 길이를 줄이는 실험 Wightman. W. Garner à꽃을 피우지 못하던 mammoth tobacco가 Flowering !!! (1875–1956) à 광주기 (photoperiodism)의 최초 발견 In 1938 discovered that for plants required relative & short days to flowering, Karl Hamner the length of the night was actually more critical. James Bonner (1910–1996) Ø Flowering is controlled by night length, not by day length Photoperiodism and Responses to Seasons Ø Photoperiod, the relative lengths of night and day (광주기는 낮과 밤의 상대적인 길이: 밤의 길이가 중요) Is the environmental stimulus plants use most often to detect the time of year (식물이 일년 중 특정 시기를 인지하는 데 사용하는 외부자극임) Ø Photoperiodism (광주기성: 광주기에 따른 생리적 반응) Is a physiological response to photoperiod Eg: flowering ü 단일식물(short-day plants): 낮의 길이가 특정길이보다 짧으면 개화하는 식물; 국화, 포인세티아스, 콩과 식물 (late summer, fall palnts) ü 장일식물(long-day plants): 광주기가 특정 시간보다 길어야 개화함; 시금치, 무우, 상치, 붓꽃 (iris), 곡물류 (spring plants) ü 중일식물(Day-neutral plants): 개화가 광주기와 상관없는 식물; 민들레 토마토, 벼 Flowering is controlled by night length, not by day length “Night breaker”  Ø The “night break” was used to obtain the Action Spectrum, the relative effectiveness of different wavelengths of light on a defined response. Harry A. Ø In 1945, they reported that the red light was most effective, thus Borthwick the photoreceptor must absorb the red light most effectively (thus it et al should be green/blue color).  Determined the action spectrum for light-induced germination of lettuce seeds (상추 종자의 발아를 유도하는 빛의 작용스펙트럼 결정) How does the order of red and far- red illumination affect seed germination? Dark (control) 발아 미발아 (1) 적색광은 발아촉진, 근적외선은 발아억제함 (2) 최종조사한 빛의 종류가 결정인자임 Red Dark Red Far-red Dark (3) 적색광과 근적외선의 효과는 발아 미발아 가역적임 Red Far-red Red Dark Red Far-red Red Far-red Red light stimulated germination, and far-red light inhibited germination. The final exposure was the determining factor. The effects of red and far-red light were reversible. 660nm 730nm  Active form Physiologically Inactive form a suitable concentration of Pfr stimulates or inhibits physiological processes Steady state of Pfr (f) = Pfr / Pfr+ Pr = Pfr / total P  Ø Pfr promotes flowering for LDPs. Ø Pfr inhibits flowering for SDPs. LDP SDP Long day : Pfr left at end of short night..’. LDP under long day à flowering & SDP under long day à No flowering Short day : Pfr gone at end of long night..’. LDP under short day à No flowering SDP under short day à Flowering photomorphogenesis: 빛에 의한 식물 형태형성 조절 Dark Light Shade avoidance response R + FR R R +FR FR+R Biological clock Circadian clock Many plant processes Oscillate during the day (일정 환경조건 속에서도 기공개폐, 광합성관련 효소의 합성 등 식물체 내의 많은 생리작용은 24시간의 주기에 따라 조절됨) Ø 생체시계는 빛에 의해 조절되며, phytochrome과 cryptochrome들이 circadian rhythm을 매개함. Providing the biological clock with environmental cues Eg: Phytochrome conversion marks sun