cellstructure(細(xì)胞的結(jié)構(gòu))a.terms

1、BIOLOGY,AL Teaching Notes,CELL STRUCTURE(細(xì)胞的結(jié)構(gòu)),A. Terms,1. Cell - the basic unit of structure and function in living organisms. 2. Cytology - the study of cells, especially by

2、 microscopy. 3. Light microscope 4. Electron microscope,Cell Structure,Cell wall (細(xì)胞壁)Cell membrane (細(xì)胞膜)Protoplast (原生質(zhì))- the living contents within the cell: nucleus (細(xì)胞核) and cytoplasm (細(xì)胞質(zhì)),,,Cell membra

3、ne (細(xì)胞膜),Chemical components :consists of 60% protein (蛋白質(zhì)) , 35% phospholipid (磷脂) and 5% polysaccharides (多糖)Two models:Unit membrane model(單位膜模型) Fluid mosaic model (流體鑲嵌模型),The Structure of Cell membrane,,Flu

4、id mosaic model (流體鑲嵌模型). a three-layered ( trilaminar 三層 ) structure,- Hydrophobic tails of two layers of phospholipid molecules point inward to form a phospholipid bilayer (磷脂分子雙層) , while the protein molecule

5、s is embedded in the phospholipid bilayer (嵌於磷脂分子之間) or transmembrane (跨膜).  Fluidity (流動): due to the lateral movement (橫向) of phospholipid molecules. Mosaic(鑲嵌) : protein molecules are interspersed

6、(散佈) among phospholipid molecules.,Under electronic microscope,The upper and lower darker regions in the 3 layered image of cell membrane corresponds to the_______ molecules and __________ portions of phospholipids where

7、as the middle light region corresponds to the ____________ tails of the phospholipid bilayer.,Protein molecule,The protein molecules were in form of g_________ protein which can be embedded in the phospholipid molecules

8、or transmembrane.  (1) membrane g___________ - as markers, recognition sites (2) ________ proteins – transmembrane, have ________ / ionic channel that allows __ molecules and ions to pass through. They are

9、for facilitated diffusion. (3) ________ proteins - for facilitated diffusion (4) membrane bound proteins - single enzyme or aggregated to form multi-enzyme complexes to speed up chemical reactions.,Function

10、 of cell membrane,(i) Compartmentalization (分室作用)(ii) Control exchange of substances between two sides of membrane by selective / differentiate permeability (控制物質(zhì)進(jìn)出)(iii)Site of membrane-bound enzyme reaction (提供酶反應(yīng)的位置

11、)(iv) For recognition of stimuli (記認(rèn)刺激), e.g insulin (胰島素)(v)For cell identity e.g. antigen (vi) For endocytosis (胞吞) and exocytosis (胞吐作用)Provides electrical insulation (提供絕緣作用),How these components affect the perme

12、ability to different substances(這成分如何影響不同物質(zhì)的透性),Phospholipid bilayer allows lipid soluble molecules / non-polar molecules to diffuse more readily across membranes (雙磷脂層讓脂溶分子 / 非極性分子易於擴(kuò)散過膜),How these components affect t

13、he permeability to different substances(這成分如何影響不同物質(zhì)的透性),Hydrophobic inner zone forms a physical barrier to polar molecules which are polar / hydrophilic / ions (疏水的內(nèi)層對極性的 / 親水的分子 / 離子形成物理屏障)Channel proteins (通道蛋白 / 蛋白質(zhì)

14、形成孔道,讓離子/極性分子擴(kuò)散),How these components affect the permeability to different substances(這成分如何影響不同物質(zhì)的透性),Carrier proteins / proteins bind with specific molecules and bring them to the opposite side of membrane (載體蛋白 / 蛋白質(zhì)與

15、特定分子結(jié)合,將其運(yùn)至膜的另一邊)Carrier proteins facilitate diffusion of some molecules e.g glucose (載體蛋白 將某些分子易化擴(kuò)散,如葡萄糖Carrier proteins allow active transport of molecules (載體蛋白容許分子進(jìn)行主動運(yùn)輸),Nucleus (細(xì)胞核),1. In all eukaryotic cells ,

16、bounded by nuclear membrane (envelope) 2. Contains chromatin (染色質(zhì)) and nucleolus (核仁) 3. DNA + histone ? short and thickened chromosomes,Structure of Nucleus (細(xì)胞核的構(gòu)造),Nucle

17、olus is a conspicuous rounded structure inside the nucleus. There may be one or more in number, its function is to make ribosomes (核糖體) by combining rRNA with proteins.,Function of Nucleus (細(xì)胞核的功能),Controls all the acti

18、vities and functions of the cell (所有細(xì)胞活動), cell division (細(xì)胞分裂) and carries genetic information for heredity (盛載遺傳訊息)Stores genetic material e.g. DNASite of synthesis of rRNA (formation of ribosome[核糖體]) and mRNA (for

19、protein synthesis[蛋白質(zhì)製造]),Nuclear membrane (核膜),Double membrane (雙層)Similar structure as cell membraneContinuous with endoplasmic reticulum(E.R.) (與內(nèi)質(zhì)膜相連)With nuclear pores (核膜孔) for exchange of materials between

20、nucleus and cytoplasm,Nucleoplasm,Nuclear sap Gel-like (黏稠性液體)Denser than cytoplasm Contains proteins, enzymes and RNAs,Chromatin (染色質(zhì)),Consists of DNA and protein ( histone, 組蛋白 )Condense to rod-shape chromosome (緊縮

21、成棒狀染色體) just prior to nuclear division (核分裂前)Carry genetic materials which determine organisms’ characteristics (特徵) and transmit these characteristics to next generations (遺傳至下一代),Nucleolus (核仁),Composed of DNA mainly

22、Act as the manufacturing site of ribosomal rRNA (rRNA) and ribosomes (核糖體),Ribosomes (核糖體),Particles synthesis in nucleolus and then pass through the nuclear pores to the cytoplasmMade of protein and rDNAThe site for p

23、rotein synthesis (合成蛋白質(zhì)的地點(diǎn))Made of two subunits (亞基)Non-membrane bound,Endoplasmic Reticulum ( E.R.)(內(nèi)質(zhì)網(wǎng)),Membrane-bound structure (膜包圍)A system of parallel flattened membrane-bounded sacs (扁平片狀囊) called cisternae (

24、瀦泡 / 池) Continuous with the outer membrane of the nuclear envelopeAct as an intracellular transport system (胞內(nèi)運(yùn)輸系統(tǒng))There are two types of E.R - Rough ER (粗糙內(nèi)質(zhì)網(wǎng)) and smooth ER (平滑內(nèi)質(zhì)網(wǎng)),Rough E.R. (粗糙內(nèi)質(zhì)網(wǎng)),Ribosomes are a

25、ttached to its surface (表面附核糖體)Transports proteins made by the ribosomes through the cisternae to smooth ER and then to Golgi appartus (高爾基體) for further modification (加工),Smooth E.R. (平滑內(nèi)質(zhì)網(wǎng)),Without ribosomes attached

26、to its surfaceTransport lipidsSynthesis of lipids and steriod (類固醇) and glycogen metabolism (糖原的代謝),Diagram of Golgi apparatus,Golgi Apparatus,Usually located near the nucleus (近細(xì)胞核)Consists of stacks of flattened mem

27、brane bounded sacs called cisternae and many vesicles (多單層膜組成的球囊和小泡)At one end of the stacks new cisternae are constantly formed by fusion of vesicles pinched from smooth ER; at the other end, small Golgi vesicles (泡囊)

28、are pinched off constantlyTransport in vesicles of many cell materials, such as enzymes(酶) from ERInvolved in secretion (分泌作用)and lysosome formation (形成溶酶體),Lysosomes (溶酶體),A spherical sac bounded by a single membrane

29、(單膜)Contain digestive (hydrolytic) enzymes (水解酶)Intracellular digestion (胞內(nèi)消化)of food materials eg. Amoeba (變形蟲)Destroy the worn-out organelles inside cell (分解衰老的細(xì)胞器)For self-destruction of cells in developmental pro

30、cess (自體溶解),Mitochondrion (線粒體),Surrounded by an envelope of two membranes(兩層膜), the inner being folded to form cristae (嵴/脊膜/脊)Contains a matrix (基質(zhì)) with respiratory enzymes for the Krebs cycle (克雷伯氏循環(huán))Rich in cell

31、 which require large amount of energy such as sperm (精子), muscle cell (肌肉細(xì)胞),cristae,matrix,outer membrane,inner membrane,Mitochondion,The cristae increase the surface area (表面積) for attachment of respiratory enzymes, i

32、n form of spherical stalked particles (球形有柄小體), In aerobic respiration, cristae are the sites of oxidative phosporylation (氧化磷酸化作用) and electron transport (電子傳遞鏈),Function of Mitochondrion,Act as power house of a cell (

33、site of respiration) (進(jìn)行呼吸作用的地點(diǎn))The energy releasing reactions of respiration occur in matrix and on the cristae,Centrioles (中心粒),Adjacent to nucleus, outside nuclear membraneInternal structure of a centriole is simila

34、r to that of basal body of a cilium (纖毛), with 9 micotubules (微管)Forming the spindle fibres (紡錘絲) and microtubules during nuclear division to control the separation of chromosome (染色體分離),Microtubule (微管),Act as cytoskel

35、eton (細(xì)胞骨架) which support the cell (支持細(xì)胞)Involves in the movement of substances inside the cell (物質(zhì)運(yùn)動)Forming the spindle fibres which involve in the separation of chromatids and chromosome,Cell wall (細(xì)胞壁),Only found i

36、n plant cellsRigid and rather permeable (通透)Made of cellulose (纖維素)Usually modified by lignin (木質(zhì)素)with pores which are penetrated by plasmodesmata (胞間連絲),Function of Cell wall,Provides mechanical support and protect

37、ion of the cellAllows a pressure potential (壓力勢/壓力潛能) to be developed which aids in support Prevent osmotic bursting (脹破)of the cell,Chloroplast (葉綠體),Large plasmid (質(zhì)粒) containing chlorophyll (葉綠素) which absorb light

38、for photosynthesisBounded by two membrane (兩層膜)Consists of chloroplast envelope, stroma (基質(zhì)), lamella (薄片) and granum (基粒),Vacuole (液泡),Absence or small in animal cellsCommon and large in plant cellsThe enclosing mem

39、brane is called tonoplast (液泡膜)Contain the internal cell sap (細(xì)胞液) which is a concentrated solution consists of water, sugar, salts, fat, oils, proteins and pigment(色素),Function of Vacuole,Store various substances eg. F

40、ood and wastesMaintenance of turgor (硬脹) for supportContain hydrolytic enzymes (水解酶) to acts as lysosomes during life and cause autolysis (自體溶解) after death,Plant Histology (組織學(xué)),Parenchyma (薄壁組織)Collenchyma (厚角組織)Sc

41、lerenchyma (厚壁組織)Xylem Tissue (木質(zhì)部)Phloem Tissue (韌皮部),Parenchyma (薄壁組織),Plant cells with thin cell wall and living protoplasmRoughly isodiametric(等徑) (spherical, 圓形) with intercellular spacesFound in cortex (皮層) and

42、 pith (髓) of stems and root, mesophyll of leaves (葉肉) and packing tissues in xylem and phloem,Function of Parenchyma,Act as packing tissues between more specialized tissuesTurgidity (硬脹度) of these cells can provide supp

43、ort (支持作用) in herbaceous plant (草本植物)Store food (貯藏食物)Intercellular air spaces (細(xì)胞間隙) allow gaseous exchangeMetabolically active for biochemical processes such as photosynthesis and synthesis (代謝活動較活躍可進(jìn)行光合作用及合成)Their

44、 cell walls are important pathway for the water and mineral salts through the plant (for absorption of water),Leaf epidermis (葉表皮),Protective tissue[保護(hù)組織] (usually single layer)Modified from parenchyma [由薄壁細(xì)胞而形成]Elonga

45、ted cell with thin cell wall [長形]Mainly colourless (except guard cells[保衛(wèi)細(xì)胞])Compact in arrangement without intercelluar space (排列緊密沒有細(xì)胞間隙)Presence of stoma (氣孔) for gaseous exchange(氣體交換)Presence of cuticle (角質(zhì)層)to

46、 reduce transpiration (蒸騰作用),Collenchyma (厚角組織),Characterized by the deposition of extra cellulose at the corners of the cells so have thickening cell wall of their corners (只在角隅處加原)They are living cells (有生命)Cell are

47、capable of stretching (有彈性)Found in regions beneath the epidermis of stem (hypodermis[下皮]) and near the vascular tissues, eg, midrib of leaves [葉的中脈]Mechanical tissue for support (支持組織),Sclerenchyma (厚壁組織),Plant cells

48、with evenly thickened cell wall (均厚的細(xì)胞壁) which is usually lignified (木質(zhì)化)They are dead cells (死細(xì)胞)Support the cellsThere are two types: fibres (纖維) and Sclereids (石細(xì)胞),Fibre (纖維),Long narrow cell shape with tapering e

49、nds (細(xì)長,兩端尖銳), wall with few pitsFound in cortex(皮層), pericycle(柱鞘) , vascular tissues, surrounding vascular bundles (維管束),Sclereids (石細(xì)胞),Short and relatively spherical in shape (圓形)Found in almost everywhere in plant

50、 body, especially in cortex, phloem of stems and roots (根及莖的韌皮部), in fruit wall (果皮) and seed coat (種皮)Act as main cell type for mechanical support (機(jī)械性的支持作用) and protection (保護(hù)),Xylem (木質(zhì)部),Consists of tracheary eleme

51、nts (tracheids[管胞], vessels[導(dǎo)管]), fibres (纖維) and parenchyma (薄壁細(xì)胞)Tracheary elements are dead and empty cells (中空) for transporting water and support,Tracheids (管胞),Narrow elongated (長圓筒形) cell with finely tapering en

52、ds (兩端尖銳) , without protoplasm at maturity, with heavily lignified (木質(zhì)化)and pitted secondary cell wall (次生細(xì)胞壁)Passage of water from cell to cell is facilitated through pit-pairs which allow lateral transport of waterAc

53、t as the only water conducting elements in gymnosperms (裸子植物) and primitive vascular plant; (具有維管組織的低等植物) small amount in angiosperms (開花植物),Xylem vessel (木質(zhì)導(dǎo)管),Long , tubular(管狀) and hollow [中空] (end walls broken down 端

54、壁)Without protoplasm at maturityJoin each other at end walls to form longitudinal conducting tubes (細(xì)胞首尾相連接形成導(dǎo)管)Shorter, greater in diameter than tracheids,Xylem vessel,Water moves from cell to cell Cell wall lignif

55、ied (木質(zhì)化) and strengthened to prevent collapse (塌陷)More specialized for water conducting than tracheids (較管胞更專門於輸送水)Only present in angiosperms (只出現(xiàn)在開花植物),Thickening of secondary wall,Annular thickening (環(huán)狀加厚)Spiral t

56、hickening (螺紋加厚)Recticulate thickening (網(wǎng)紋加厚)Pitted thickening (紋孔加厚),Diagram of Phloem (韌皮部),Phloem Tissue (韌皮部),Sieve tube elements (篩管分子) for conduction of food (e.g. sucrose 蔗糖)Sieve tube elements are elongated ce

57、lls, end walls (端壁) are modified as sieve plates (篩板)Sieve tube elements have no nucleus, tonoplast, decrease in number of ER and ribosomes, with thin layer cytoplasm to facilitate the translocation of food (輸導(dǎo)作用),Sieve

58、 Tube Element (篩管分子),Located on the end walls(端壁) called sieve plates (篩板)Connected by sieve plates with each other to form sieve tube (篩管)Present in angiosperms (有花植物)With companion cell (伴細(xì)胞) to help metabolic activ

59、ities (代謝活動) of the sieve tube element and translocation of food (輪導(dǎo)作用),Short assignment:Discuss the structural adaptations of xylem and phloem to their functions,,Blood cell (血細(xì)胞),Is a specialized connective tissue for

60、 transportation of materials and body defence (身體防衛(wèi))include fluid medium (plasma 血漿 55%) and cellular constituents (red blood cells/erythrocytes [紅血球], white blood cells/leucocytes [白血球], platelets/thrombocytes [血小板]),N

61、eurones (神經(jīng)元),Including cell body (細(xì)胞體) and nerve fibres (神經(jīng)纖維)located in C.N.S (中樞神經(jīng)系統(tǒng))cell body is stellate in shapenerve fibres are protoplasmic extensions (原生質(zhì)的伸延) of cell body, including dendrons (樹突) and axon (軸

62、突),Skeletal muscle,Innervated by the voluntary part of nervous systemcontraction is neurogenic required nervous stimulationcontract and fatigue rapidlyattached to the skeletonlong, cylindrical with tapering or rounde

63、d ends,Functions of skeleton muscle,for the maintenance of posturefor locomotion and movements of body parts,Nerve,a group of nerve fibres bound together by connective tissues lying outside C.N.Sincluding sensory nerve