2.1 Chemicals of life (Book 1A, p. 2-3) What are the inorganic chemical constituents of organisms? A (Book 1A, p. 2-3) 1 Water (Book 1A, p. 2-3) Function Example To dissolve substances and provide a (1) ____________ (介質) for chemical reactions to take place As a solvent To (2) ____________ substances, e.g. (3) ____________ consists mainly of water, which transports nutrients, wastes and gases around the body As a (4) ___________ mammals and transpiration (蒸騰) in plants agent As a (6) ___________ To involve in some reactions, e.g. (7) ____________ (光合作用) and digestion of food (反應物) To give (8) _______________ and support to organisms, e.g. cells of young seedlings become turgid when they are full of water Providing support 2 To remove heat through (5) _______________, e.g. sweating in To provide (9) _______________ (浮力) for organisms in water Inorganic ions (Book 1A, p. 2-5) Inorganic ion I Nitrate II Magnesium III Calcium IV Iron Function a keeping bones and teeth hard and strong; involving in muscle contraction and blood clotting (凝血) b forming haemoglobin (血紅蛋白) which carries oxygen c forming proteins d activating (活化) some enzymes (酶) and forming chlorophyll (葉綠素) in plants I: (10) __________ B II: (11) __________ III: (12) __________ IV: (13) __________ What are the organic chemical constituents of organisms? (Book 1A, p. 2-6) The major organic chemical constituents of organisms are often called (14) _______________ (生物分子). They all contain (15) _______________ atoms. Ch. 2 / Cell / P.1 Biomolecule (16) ___________ Example Function (17) __________ (葡萄糖) Provide energy Starch (澱粉) (18) ____________ energy in plants (19) __________ (纖維素) Make up plant cell walls Fats and oils Act as an energy reserve Phospholipids (磷脂) Make up (20) ___________ of the cells (碳水化合物) Lipids (脂質) Fibrous proteins (纖維狀蛋白質) Build up body structures, e.g. muscles Proteins (蛋白質) (21) ___________ Enzymes speed up biochemical reactions ___________ (球狀蛋白質) Antibodies defend the body against diseases Nucleic acids Deoxyribonucleic acid Carry (22) ____________ information (核酸) (DNA 脫氧核糖核酸) (遺傳信息) 2.2 Discovery of cells (Book 1A, p. 2-8) B What is the cell theory? (Book 1A, p. 2-8) Schwann proposed the cell theory (細胞學說) in 1839. The theory states that: all organisms are made up of one or more (1) _______________; the cell is the (2) _______________ unit of life; it is the (3) _______________ unit that shows all the characteristics of life; all cells come from (4) _______________ cells. 2.3 A The basic structure of a cell (Book 1A, p. 2-12) What is the structure of animal cells? (Book 1A, p. 2-12) Animal cell structure Feature and function thin and flexible (1) _______________ surrounds the cytoplasm _______________ (2) _______________ permeable (差異透性的) controls the movement of substances into and out of the cell a (3) _______________ substance consisting of water, Cytoplasm Ch. 2 / Cell / P.2 (4) _______________ and other chemical substances holds (5) _______________ (細胞器) provides a place for (6) _______________ reactions to take place exists in all animal cells except mature (7) _______________ _______________ _______________ Nucleus round-shaped and bounded by the (8) _______________ membrane (核膜) contains the genetic material (9) _______________ controls all activities of the cell a network of interconnected membrane-bounded (11) _______________ (10) _______________ _______________ (ER) connects cytoplasm and the nuclear membrane rough ER (with (12) _______________ (核糖體) attached) is responsible for (13) _______________ synthesis smooth ER (without ribosome) is involved in the synthesis and transport of (14) _______________ Mitochondrion (17) _______________ B rod-shaped and bounded by a (15) _______________ membrane inner membrane is highly folded releases energy through (16) _______________ contains water and dissolved substances bounded by a differentially permeable membrane small or even not present in most animal cells What is the structure of plant cells? (Book 1A, p. 2-15) The basic structure of plant cells is similar to animal cells. They both have a cell membrane, cytoplasm, a nucleus, (19) _______________ and endoplasmic reticulum. Special structures in plant cells that cannot be found in animal cells: Plant cell structure Feature and function made up of (21) _______________ (20) _______________ thick and rigid ______________ (22) _______________ permeable protects, supports and gives shape to plant cells Ch. 2 / Cell / P.3 Large central vacuole contains cell sap (細胞液) (23) ______________ and located at the centre of the cell the cell becomes turgid when it is full of water, thus supports the plant Chloroplast bounded by a double membrane contains green pigment (24) _______________ which absorbs light energy for (25) _______________ 2.4 Levels of body organization (Book 1A, p. 2-19) Cell Smooth muscle cell Similar cells group together to form a (1) _______________. They work together to perform one or more particular functions. Tissue Smooth muscle tissue Different tissues group together to form an (2) _______________. They cooperate to perform one Organ or more particular functions. Stomach Several organs work together to perform a particular task. System Digestive system Different systems work together to support the life of an organism. Organism Human Ch. 2 / Cell / P.4 2.5 Using a light microscope (Book 1A, p. 2-20) The total magnification (總放大率) of the microscope is the (20) _______________ of the magnification of the eyepiece and that of the objective. The image observed under the microscope is inverted (21) _______________ _______________ and laterally. In order to make the specimens more clearly to be observed, we often use methylene blue solution (for animal cells) or (22) _______________ solution (for plant cells) to stain them. 2.6 Prokaryotic and eukaryotic cells (Book 1A, p. 2-26) Eukaryotes (真核生物) are organisms made up of (1) _______________ cells (真核細胞) which contain a true nucleus. (2) _______________ (原核生物) are organisms made up of prokaryotic cells (原核細胞) which do not have a membrane-bounded nucleus. (3) _______________ _______________ (DNA) cytoplasm cell wall (4) ______________ cell membrane Basic structure of a prokaryotic cell Differences between prokaryotic cells and eukaryotic cells: Prokaryotic cell Eukaryotic cell Size Usually smaller Usually larger Position of genetic DNA lying free in the DNA enclosed in the material (5) _______________ (6) _______________ Nuclear membrane Absent Present Absent Present Mitochondria, chloroplasts, ER Ch. 2 / Cell / P.5 May be present or absent Does not contain cellulose Present in (7) _____________ cells Cell wall but absent in (8) _____________ cells Example Contains cellulose Higher plants and higher (9) _______________ (細菌) animals The diagram below shows the structure of a cell. A B C D a Name the structures A to D. (4 marks) ____________________________________________________________________________ ____________________________________________________________________________ b Is this cell a plant cell or an animal cell? Based on the diagram, give two reasons to support your answer. (3 marks) ____________________________________________________________________________ ____________________________________________________________________________ ____________________________________________________________________________ c Give two features shown in the diagram which support that the cell is eukaryotic. (2 marks) ____________________________________________________________________________ ____________________________________________________________________________ d Which organelle involved in respiration is not shown in the diagram? (1 mark) ____________________________________________________________________________ - END - Ch. 2 / Cell / P.6 Answers Ch 2 The cell as the basic unit of life 2.1 1 medium 2 transport 3 plasma 4 cooling 5 evaporation 6 reactant 7 photosynthesis 8 shape 9 buoyancy 10 c 11 d 12 a 13 b 14 biomolecules 15 carbon 16 Carbohydrates 17 Glucose 18 Store 19 Cellulose 20 membranes 21 Globular proteins 22 genetic 1 cells 2 basic 3 smallest 4 pre-existing 5 Light microscopes 6 two-dimensional 7 surface 8 three-dimensional 1 Cell membrane 2 differentially 3 jelly-like 4 proteins 5 organelles 6 chemical 7 red blood cells 8 nuclear 9 DNA 10 Endoplasmic reticulum 11 sacs 12 ribosomes 13 protein 14 lipids 15 double 16 respiration 17 Vacuole 18 support 19 mitochondria 20 Cell wall 21 cellulose 22 fully 23 large 24 chlorophyll 25 photosynthesis tissue 2 organ 1 lenses 2 Eyepiece 3 lens 4 Body tube 5 Objective 6 Stage 7 Condenser 8 focus 9 Diaphragm 10 light 11 Coarse adjustment knob 12 rough 13 Fine adjustment knob 14 sharp 15 Arm 16 Clip 17 Base 19 reflects 20 product 21 upside down 22 Iodine 1 eukaryotic 2 Prokaryotes 3 genetic material 4 ribosome 6 nucleus 7 plant 8 animal 9 Bacteria 2.2 2.3 2.4 1 2.5 18 Mirror 5 cytoplasm 2.6 Ch. 2 / Cell / P.7 Exercise a b A: Chloroplast 1m B: Rough endoplasmic reticulum 1m C: Nucleus 1m D: Smooth endoplasmic reticulum 1m It is a plant cell. 1m Reason: Any two from: 1m × 2 It contains chloroplasts. It has a cell wall. It has a large vacuole. c Any two from: 1m × 2 It has a true nucleus. It has endoplasmic reticulum / The ribosomes are attached to the endoplasmic reticulum. It has organelles bounded by a double membrane / chloroplasts. d Mitochondrion Ch. 2 / Cell / P.8 1m