2014年11月22日 星期六

冷知識你我知——為何豬肝不宜多吃?

http://news.h1.com.hk/dailynews/headline_news_detail_columnist.asp?id=277975&section_name=wtt&kw=19

答案:雖然豬肝含維他命A有「明目」之效,但原來多吃也無益,因為維他命A不易從身體排出,攝入過量可能導致骨骼生長異常。動物肝臟是解毒和代謝器官,如肝功能下降,就會積存重金屬及殘留獸藥等有害物質。此外,豬肝膽固醇含量高,多吃會增加心血管疾病的風險。

2014年11月20日 星期四

中四生物練習:第3章

參考答案

書後練習 (P. 28 - 32)
M.C
1
2
3
4
5
6
7
8
9
10
11
C
B
C
D
A
B
B
A
C
D
C
(11)

16    a      i       葡萄糖和半乳糖                                                                                            1
                ii      小腸經氰化物處理後,這兩種糖的吸收速率減慢了。                            1
                        氰化物令小腸細胞無法釋出能量/釋出較少能量。                                1
                        主動轉運需要能量。                                                                                    1
        b      經氰化物處理後,小腸仍能吸收上表中的所有糖。                                        1
                擴散不需要能量,因此小腸經氰化物處理後擴散仍能進行。                        1
                                                                                                                                     (6)

17    a      i       磷脂                                                                                                                1
                        它由磷酸鹽團基構成頭部                                                                            1
                        和兩個脂肪酸分子構成尾部。                                                                    1
                 ii      由磷酸鹽團基構成的頭部是親水的,
                         而由脂肪酸分子構成的尾部是疏水的。                                                    1
                        疏水的尾部朝向膜中央,而親水的頭部朝向膜外,                                1
                        接觸細胞內外的水溶液。                                                                            1
    b      i       在融合後所形成的細胞,細胞膜上有紅色和綠色兩種蛋白質。            1
                        兩種蛋白質混合在一起。                                                                            1
                ii      磷脂分子可以橫向移動,令細胞膜具流動性。/
                        這讓細胞膜可以融合。/
                        蛋白質可在膜中移動,因此兩種蛋白質分子可以混合在一起。(任何兩項)                            1x 2
                                                                                                                                       (10)

Q.19
(a)(i)  (1)   紅血球細胞的水勢較週圍溶液的水勢為高………………………….            1
                  水從細胞流出…………………………………………….……………….           1
                 細胞因萎縮而及變得皺褶…………… …………………………………       1
          (2)  部分紅血球細胞的水勢比週圍的溶液高,部分則相等或較低………         1
(b)     稍待片刻,再次觀察紅血球細胞.… ………………………………………            1
          若已達到平衡,兩種不同形式的紅血球細胞比率應與前次觀察的相同        1
(c)    紅血球細胞的水勢較週圍溶液的水勢為低…………………………………               1
        水流入細胞…………………………………………………………………......              1
        紅血球細胞因而膨脹及爆裂…………………………………………………..              1
        釋出其內的血紅蛋白,令溶液變成紅色……………………………….……               1
傳意能力(C) ……………………………………………………………………       1
                                                                       10+1

Q.20

                                                                                                                                         (9)
Q.22
22    a      分子有動能。/
                它們隨意運動。/
                它們順濃度梯度淨移動。(任何兩項)                                                      1x 2
        b      開始時,膜的兩邊物質A的濃度有差異。/
                膜外物質A的濃度下降的同時,膜內物質A的濃度上升。/
                物質A由膜外移到膜內。/
                隨着膜兩邊的濃度差異減少,膜兩邊物質A濃度的變化速率亦減少。/
                膜兩邊的物質A濃度相同時,膜兩邊的濃度沒有改變。(任何三項) 1x 3
    c      i       主動轉運需要能量,擴散則不需要能量。/
                        主動轉運的過程中,分子可以逆濃度梯度運送,但在擴散的過程中,分子只可以順濃度梯度運送。/
                        主動轉運涉及膜蛋白,擴散則不涉及膜蛋白。(任何兩項)          1x 2
                ii      物質A濃度會以均速變化。/
                        濃度變化的速率會較高。/
                        膜兩邊的物質A濃度相同時,分子不會停止淨移動。(任何兩項)

                                                                                                                                          1x 2

中四生物練習:第2章

書後練習 (P. 30 - 35)
M.C
1
2
3
4
5
6
7
8
D
C
B
C
C
C
D
B
(8)

Q.11

(4)

Q.12
優點:
                電子顯微鏡可以用來觀察細胞內的細小構造。/
                電子顯微鏡可以產生放大率較大的影像。/
                電子顯微鏡可以產生解像度較高的影像。/電子顯微鏡的解像能力較高。(任何兩項)        1x 2
                缺點:
                利用電子顯微鏡觀察細胞較昂貴。/
                電子顯微鏡較難操作。/
                製備樣本的過程較複雜。/
                不能用來觀察活樣本。(任何兩項)                                                          1x 2
        b      i       47 mm                                                                                                             1
                ii      47 mm/6800                                                                                                    1
                    = 6.91 μm                                                                                                        1
        c      i       線粒體                                                                                                            1
                ii      它是進行呼吸作用以釋放能量的主要地方。                                            1
(9)

Q.14
    a      i       28000/2                                                                                                           1
                        = 14000                                                                                                           1
                ii      線粒體                                                                                                            1
                iii     呼吸作用在線粒體進行。呼吸作用釋出能量。                                        1
                        肌肉細胞需要大量能量,                                                                            1
                        供肌肉收縮。                                                                                                1
        b      肌肉細胞有細胞核/核膜,細菌則沒有。                                                        1
                肌肉細胞有由雙層薄膜包圍的細胞器,細菌則沒有。                                    1
                肌肉細胞沒有細胞壁,有些細菌則有細胞壁。                                                1
(9)
從閱讀中學習 (P.37)
1  圖中變形蟲的長度 = 2.6 cm                                                                                        1
        變形蟲的實際長度 = 2.6/150 = 0.0173 cm = 173 μm                                                  1
變形蟲是真核生物。                                                                                                    1
        它具有真正的細胞核。                                                                                                1
線粒體是釋放能量的主要地方。                                                                                1
        酶從粗糙內質網製造出來。                                                                                        1

(6)

中四生物科練習:第1章

參考答案
1.
a      1:細心觀察                                                                                                                          1
        2:提出假說                                                                                                                       1
Con: 設定問題
        3:進行實驗                                                                                                                      1
b      曾經感染牛痘的人不會染上天花。                                                                                    1
Exp: 只是女工?
c      曾經感染牛痘的人不會染上天花。                                                                                    1
                                                                                                                                                  [5]

書後練習 (P. 14)
M.C.
1
2
3
4
D
C
D
D
(5)

從閱讀中學習 (P.16)

Q.6
菸草花葉病是由細菌分泌的某些化學物所引致的。                                                1
        菸草花葉病是由一些比細菌還要細小的生物所引致的。                                        1
2      貝傑林克重複把剛受感染的菸草植物汁液過濾,然後噴灑到另一棵健康的菸草植物身上,結果發現所有健康的植物都染病,換言之汁液一直帶有傳染性。                                                1
        這個結果顯示引致菸草花葉病的物質沒有被稀釋,                                                1
        因此該物質應不是化學物,否則不會出現以上結果。                                            1
生殖                                                                                                                                1

(6)