biology multiple choice

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97年第34條...?
如果是的話它的答案是B. (2) only, 亦即是指這statement 是對的
fish 發表於 7/3/2010 05:34 AM

                               
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嗯..我諗我打錯左-.- 係點解1係錯-0- ""
2 g of sulphur and 1 g of oxygen each occupy the same volume at room temperature and pressure

no of moles of sulphur atom=2/32=1/16mol
no of moles of oxyhen atom=1/16mol
佢地mol數1樣,,molar volume又係constant..點解唔係occupy same volume?

另外1題bio
if a human baby boy inherits a recessive allele from his mother,in which circumstance would be most likely show the trait coded for by the recessive allele?

A.the baby inherits the dominant allele from his father
B.the allele is o an autosomal chromosome and the baby is a twin
C.the allele is on the X chromosome
D.the allele is on the Y chromosome

我想問點解答案係C唔係D? 佢已經係媽媽度拎左條allele,,姐係X chromosome度已經有啦,,如果要show 個trait 唔係應該要有1條recessive allele 係爸爸(X chromsome)度先得咩? 另外不解autosomal chromosome點解= =""

unlock-YM

嗯..我諗我打錯左-.- 係點解1係錯-0- ""
2 g of sulphur and 1 g of oxygen each occupy the same volume at room temperature and pressure

no of moles of sulphur atom=2/32=1/16mol
no of moles of ox ...
小霞的fans 發表於 10/3/2010 06:05 PM

                               
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Sulphur唔係gas...

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喔原來係咁..thx^^
仲有冇人知點解vascular bundle係stem度係locate係周圍而唔係中間??有咩重要性?

fish

仲有冇人知點解vascular bundle係stem度係locate係周圍而唔係中間??有咩重要性?

Structure implies function.
Vascular bundle 包含xylem, 除transport外還有support的作用
Stem有support 整株植物的作用, 如果把Vascular bundle集中於一點的話, support 會較弱,
如果將vascular  bundle分散去周圍的話就會較強
就好像大多建築物都靠要一堆樁/柱來支撐而不是只有一條樁/柱在中間一樣

if a human baby boy inherits a recessive allele from his mother,in which circumstance would be most likely show the trait coded for by the recessive allele?

A.the baby inherits the dominant allele from his father
B.the allele is o an autosomal chromosome and the baby is a twin
C.the allele is on the X chromosome
D.the allele is on the Y chromosome

我想問點解答案係C唔係D? 佢已經係媽媽度拎左條allele,,姐係X chromosome度已經有啦,,如果要show 個trait 唔係應該要有1條recessive allele 係爸爸(X chromsome)度先得咩? 另外不解autosomal chromosome點解= =""

Autosomal chromosome = autosome = non-sex chromosome
以人為例的話就是除XY外的22對chromosome了

題目所說的是baby boy, 男性, 所以他的sex chromosome是 XY (X from mother, Y from father)
如果那個recessive trait 是在 autosome上, 那就需要一對recessive allele 才會express
如果那個recessive trait 是在 Y chromosome上, 母親是不能該把trait遺傳給兒子的(因為Y from father)
如果那個recessive trait 是在 X chromsome上, 由於男性只有一條X chromosome而且必定是由母親給予的, 所以(在這case)那個recessive trait 理論上一定會express

小霞的fans

Structure implies function.
Vascular bundle 包含xylem, 除transport外還有support的作用
Stem有support 整株植物的作用, 如果把Vascular bundle集中於一點的話, support 會較弱,
如果將vascular  bundle分散 ...
fish 發表於 11/3/2010 02:38 PM

                               
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謝謝你詳細的解答^^
我仲想呢..關於mitosis 既野..
1.at resting stage chromosomes appear as thin chromatins
2.when the cell is about to divide,replication of gentic materials begins.the chromatin threads condense to form distinct chromosomes.
3.the chromosomes become shorter and thicker.each chromosome appears as two identical chromatids.
4.the chromosomes line up in the middle of the cell.
5.the two chromatids of each chromosome seperate and move to opposite poles of the cell.the cell statrs to split into two daughter cells.
6.the chromatids become the chromosomes of the two daughter cells.

我想問1,2同埋3係唔係有1樣amount 既 genetic materials ? 係第3果度,each chromosome appears as two identical chromatids. 咁樣姐係話genetic materials double左?同第2果個replication of gentic materials 一樣?我唔係太搞得清邊d stage既genetic materials 既amount一樣..thx~

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另外仲有1題..麻煩大大><

                               
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我唔識31條
其實我想知3 contract同4 contract 既時候隻腳既動作係點..
3同4係控制腳掌?? 我唔知佢地bring out 出黎既motion .. thx

鴨

3 contract的話腳掌會變平
即是正常站立時的狀態
而4 contract的話腳掌會拉直
游水時應該會是拉直狀態吧zzz

小霞的fans

3 contract的話腳掌會變平
即是正常站立時的狀態
而4 contract的話腳掌會拉直
游水時應該會是拉直狀態吧zzz
RX78-2 發表於 25/3/2010 12:15 AM

                               
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咁點解答案係C既?
個女仔隻腳掌都唔係平架..唔係應該係4 contract咩?

ice

咁點解答案係C既?
個女仔隻腳掌都唔係平架..唔係應該係4 contract咩?
小霞的fans 發表於 27/3/2010 04:19 PM

                               
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其實她右腳掌是平的
不平的是左腳掌
所以是3 contract

fish

謝謝你詳細的解答^^
我仲想呢..關於mitosis 既野..
1.at resting stage chromosomes appear as thin chromatins
2.when the cell is about to divide,replication of gentic materials begins.the chromatin  ...
小霞的fans 發表於 23/3/2010 12:54

                               
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Statement 2中 寫明了genetic materials replicate, 所以在2跟3有一樣amount 的genetic materials.
3的 "two chromatids" 亦是由 2的replication 而衍生出來的

下面的process中, 紅字為有duplicated DNA:
resting stage -->replication --> condensation --> line up--> separate --> pinching off
我知這個界線極曖昧又有灰色地帶, 不過在CE來說...這麼說較好(?)