REFERENCE LIBRARY
16 JAN 1970.
育教僑頁三第張四第7
CE WAH KHU YAT PO
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CF70英文中學會考試題預習專欄
生物科
書院主編
BIOLOGY (11)
Answer to the questione of last week
(+-)
What is soil composed of? Describe an experiment which will help you to detect the different constituents present in it. Explain the occurrence and the use of nitrates in the soil?
'Ane.
The constituants of soil are f (a) Mineral, particles i
Some of these particles such as the particles of olay, sand, gravel, silt, and chalk are insolubla in water, forming the skeleton of the soil, The other particles are soluble and are composed of mineral 'salts such as silicates, sulphates, phosphates of sodium, potassium, magnesium, alumimina and iron.
The insoluble particles are formed by weathering and erosion by the aid of oxygen in air, rain, rivers, streams, wind and atorm, changes of temperatura, glãoier and, plant roots.
The mineral particles serve to supply support and nourishment to the plants as the roots of planta benetrate through then,
(b) Humusr
When plants and animals die, their non- living organic materials are decomposed by the action of aerobic and anaerobic micro-organisms and fungi. The brown or black organic material. formed from the decaying animal and plant remains is termed humus. It is a paramount component of soil as it increase the porosity of the soil. So suitable drainage and aeration are possible. In addition it increases the water- holding and water-absorbing powers of the soil because of its spongy quality. Disintegration of it by the action of micro-organisms in the soil supplies mineral substances necessary för plant growth. It is colloidal in nature and can hold zore water than its own dry weight.
(o) Soil-atmosphere:
In the soil gases are present, namely carboa dioxide, oxygen and nitrogen. Carbon dioxide in produced increasingly and oxygen production des orcases with the depth of the soil due to the
utilization of oxygen and production of carbon dioxide by soil micro-organisms and the roots of plante. Since oxygen 18. necessary for the respiration of roots, an adequate supply of air in the soil is important.
The texture of the soil affects the storage of air which would retard or accelerate the growth of plants. In poorly aerated soils toxio action which hinders ruot growth has been reported,
(d) Soil-water:
The chief source of soil water is rain and enow which enter the soil and pass downward. Much of the water is ratained in the form of thin filme about the soil particles and in the minute spaces between them. This is cappillary water which adheres so closely to the soil particles and is not affected by gravitational forca. Most of the water films around the soil particles supply water absorbed by plants. The amount of water retained in soil mostly depends on the texture of the anil,
In addition, water is the main solvent to iilute small amounts of soluble inorganic salte
efore being absorbed by the roots of the plant.
>) Living micro-organisms:
The dead organisms decay resulting in the formation of humus in the soil. Some living bacteria aid in breaking down the organic matter in humus to form soluble salts which can be taken up in solution by ruote, while certain nitrogen-fixation bacteria comrart atmospherio
itrogen to organic compounds of nitrogen. Other living organisms which help in the ploughing of 3011 are worms, fungi, und the various stages of
ngeote.
Humus
Suspension of fine clay
minerals in
the form of Solution Clay
Silf Fine Sands
Coarse Sands
Apparatus to show the Various" Sizes of soil particles.
Placed a handful of garden soil in a long) glass oylinder and together with an excess amount of water, the soil was stirred up thoroughly by means of a glass rod. When all the components were settled and noted the separation of the various soil particles. Most of the organio matters would float on the surface of the water.} Fine clay particles remained in suspension in water while fine sands and coarse sands together! with some small stones settled at the bottom.
The occurrence of nitrates in the soil - Free nitrogen can not be utilized by all the plants for synthesis of plant proteins. It must be first converted into nitrates by the action of
of decay-producing bacteria and fungi. When a plant/ or animal dies its tissues de compose into
ammónium compounds which reaching the moll'are a utilized in the metabolic processes of soil inhabiting bacteria belonging to the genus, nitrosomonas. In the course of these bacterial activities the ammonium compounds are oxidized into nitrates which in turn converted intą / nitratem by the help of other bacteria, nitrobaotor. The nitrates so formed by the › action of these nitrifying bacteria, nitrosomonas and nitrobactor, then can be absorbed by green plants and used by them in making new proteins and other nitrogenous compounds.
In addition, some leguminous plante with many root nodules which store the nitrogen-fixation bacteria can aid in conversion of free nitrogen into” nitrates in the soil. These bacteria can utilize the free nitrogen in air which diffusea into the calls of, the nodules, fixing it into complex compounds which paso through the vascular bundles to all parts of the host plant. The bacteria remaining in the nodules receive mutual and symbiotic benefit from the plant.. Furthermore, centain bacteria, Azotobactor, living/ independently in the soil are able to fix the
nitrogen in the air for the plant. Some other blue➡ green algas are able to fix nitrogen too but in relatively small quantitida.
Other ways of having nitrates in soil are by' adding manure and chemical fertilizers.
Most nitrates in the form of sodium, potassium phosphorus, magnesium, calcium, a sluminium are. absorbed by plant roote for the synthesis of
roteine in plants.
Questions for this week
I, Choose the best answers that answer the questione
or complete the statements,
1. Respiration in plants releases (1) sugari
(2) oxygen (3) carbon dioxide (4) carbohydrate)
{trogen
2. The tiny openings in the surfaces of a leaf
are the (1) chloroplasts (2) lenticels (3) outicles (4) stomata (5) micropyles -
3. What are the essential parts of the ambayo in
a osed?
Testa, radièle and plumule, a Testa, cotyledon and endosperm. 1 (3) Cotyledon, plumule and radiole. (A) ootyledon, coleoptile and coleorhiza. (5) coleoptile, coleorhiza and endosperm.
4. The laboratory procédure for removing-
chlorophyll is to boil a green leaf in (1) iodine solution (2) ether (3) alcohol (4) tap water (5) caustic soda solution.
5. The young plant in a Beed is called the
(1) cotyledon (2) endosperm (3) hypocotyl (4) epicotyl (5) embryo.
. Which one of the following seeds carries out
epigeal germination?
(1) Broad bean seed (3) pea seed
(5) maize grain
(2) Soy bean seed
(4) castor oil seed
T
7. The absorption of water in soil by the root
hairs is due to the process of (1) diffusion.
i (2) osmosis (3) transpiration (4) root
pressure (5) capillarity.
8. An instrument used for measuring the rate of
transpiration in a plant is called the (1) hydrometer (2) thermometer (3), potometer. (4) olinostat (5) auxanometer.
7. Respiration in a plant involves an exchange o..
gases. The gaseous exchange is invisible because it is by diffusion through (1 stomata
epidermie (3) vascular tissues Mesophyll
10. During the germination of a seed
Mioropyl
A. only the cotyledon is lifted above soil
level
B. both the cotyledon and plumule are lirted
above soil level
C. both cotyledon and radicle remain below th
soil level
D. only the plumule and hypocotyl ara lifted
above soil level
Which of the above indicates the epigeal germination?
(1) A (2) B (3) C (4) D (5) none of these
I.) What is a parasite?
(b) By the help of a labelled diagram, describe
the outer feature of a named plant parasite. How is this parasite adapted to its mode c life?
III. (a) What is a saprophyte?
') What are the similarities between the
parasitic and saprophytic modse of life? Why are saprophytes important an daturs?
四期星 日五十月一年〇七九一曆公年九十五國民中
..接第四張第二頁)
文中學會
學會考試題預習專欄
數學科
(十一丁一 喬仲強
(解)依合分比
(3~[bx−X2)+(3+ [ 6x-x)_
3+ √7x-x2)
'
3
וי
4(2x-3)=-3[7x-z
自樂 4x2~12x+9=6x-x2
#12A, 4A, 5x2-18x+9=0 分解,
(x-3)(5x-3) 0
以x=3代入原方程右方,可使分母為零,放不满足, 以x代入,
左方
9
3-
==女
3+
==(满足)
6) 有酒奖水混合液两桶,A桶洒典水之比需8:3, B桶為5:1.今由此两桶液体混合成4:}之酒水溪 合液,間其比应為若干?
(解)
A桶取出x,B桶取出y;則從A桶取出酒是x 水青x,從B桶取出酒苦水古集依題意得式:
£x+ Zy
7x+Ly
گنو
4
48%+554
T
18x + 17 y
72x+44y=48x+554
答:A,B两桶取出量之比為11:24
24
7)有成比例之四正數,着两外項之和為13,两內項之格 為11.又各項之平方和萬170.求此四數.
(19) 3LY-16×, U*I* 3-2, XU¥=»1%y] 則第三項為15一等依題意
x2+y2+(1)−4)2+(13-2)2=m 170
2:4-11-9: 13-% *
(1);
(2)}
@[11] 11y-y3=13x-2°C
Boy
(3)
2x2+242¬26x-224+120=0
Bp
\x2 + y2 - 13 x − 114 + ba=
==(4)]
(3)+(4),
2x2=26x+60=0,
(x-3)(x-10)=0]
・10(13-x=10:成(3)
Xx=3*~(3), 19-y2-39+11g=0,
y == 114 +30=0 (y-5)(y-2)=0}
y=5*6 To 1-y=4][5]
★ VA XI/O AX (3),'
-100-4*~130+1|Y=0|
4~114+30=0巧得结果亦相同 *:03,5,6,10; 3 3.6,5310,
F100, 5, 4, 3, 5810x6, 5:3.
(f) $2 a(txc-a)=4(c+a=1)= c(a+b=0)o d'E} /
(y+z-x) (b+c=a) == (z+x=y}{c+a=})}==(x+y=3) (a+b=c).
4+
(atb_c) (a=b+c) |
̇同理各比=
-x-4
b−c)+a{f+c=a)− f(c+a-
3+X-4
(b+c=a) (b-cTA)
-x+4-Z` (c+a-b)(c-art)`
4+7-x
(a+b-c) (a−b+c)
(t+c-a) (b-c+a)
±0,14%, (y+3−X){b+c¬a)=(3+x¬y)(c+a−b),
MUJTE,
(z+x−4) (c+a−b)=(x+y−3)(a+b−c).
• (y+3−x)(b+ca)=(3+x~y)(c+4~b)~(x+y=z)(a+b−c}
Q.E..D.
第十一次預習題
(1)兩國外切於A,A作任意直线各交两於X,YEAR 典AY之比值,典吁選直线無關。又着两园内切時,其结果老何? (2)O,P 两团交於AB.求遇A引一直线CAD典。因交於C,典
PORDIL CA=2AD.
(3)(a)輕如右图: ABCD 為正方形,
AP BQ CR-DS, AGE PQRS亦為正方形
(+) * AB-8+, AP=3), *J*}
PQRS ABCD 比
(4)已與正方形ABCD,求作其内楼正
* PQRS PQRS ABCD.
(5) P, Q, R$ 4ABC 14, AB, BC
及CA边上之桌,而有AP=4AB,
·BQ=48C, CR=4CA÷M16. 求APAR典△ABC之比,
A
P
હ
(6)己典正三角形ABC.製作其之正三角形 Pan便
APORE SAEC,
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