biology multiple choice

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1.After drinking a lot of salty soap,a healthy person will produce

A.a small voume of urine with high concentration of salt
B.a small voume of urine with low  concentration of salt
C.a large voume of urine with high concentration of salt
D.a large voume of urine with low  concentration of salt

我知一定係high concentration .. A或者C係岩..
但係個volume係small 定 large呢~? 書寫more urine with a high concentration of salt is produced. 咁應該係C !?

2.which of the following structure of mammalian skin is not involved in temperature regulation?

A.oil glands
B.nerve endings
C.erector muscles
D.blood capillaries

貌似4個都會= = ??
係唔係D ? 因為係arterioles constrict或者dilate..
唔關blood capillaries事 .. ? 謝謝..

鴨

你指的是cardiac cycle中ventricle充血時會上升pressure?
ventricle 充血時是會上升些微的pressure
因為始終會有hydrostatic pressure 壓去肌肉的
不過這並不是valve開關的關鍵

Bicuspid和tricuspid開啟的時候都是atrial pressure大過ventricular pressure的時候
關的時候就剛剛相反
而這個的關鍵在於ventricle的contraction and relaxation
在ventricle contract的時候ventricular pressure是有明顯增長的
在增長至高過atrial pressure就會關閉bicuspid和tricuspid
而在relaxation的時候低過就會關閉
你可以相像bicuspid和tricuspid都是一道只能向ventricle推開的門
當atrium的力大過ventricle中的力就會推開
而ventricle的力大過atrium的力就會關閉
那些力就是pressure

而semi lunar valve亦是同樣道理
不過那道門是設定為只能向aorta/pulmonary artery開啟罷了

主導開關的是ventricle的活動
其實記著這個就可以了

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另外呢..我想知道ventricle既blood volume同pressure既關係..
blood volume increase ==>pressure increase !?
因為我唔係太搞得清bicuspid,,tricuspid valve同semi-lunar valve幾時開幾時關閉..

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(?)

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

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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?

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

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

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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~

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