各位大家 请进!!!

86525882UID: 2229962

ATTENTION!!!Do your know???
  Y3 P( V  x- y& Z& z2 J5 S7 S
) k4 q2 O& a0 T. ]Have u ever encounterd this question during u preparation?
2 x- t8 k1 D2 N$ Q: V) o  D( ZNO.1.Q:What is the complementary DNA strand to ‘CAT’?
* f7 J' Q0 i8 t# L" _* ?Ans:Following the rules of DNA base pairing, you can deduce that the answer is “CAT.”
I'm wondering if the ans to this one is GTA.
' n) \& _) Q) H1 N$ }" CAnyone here can translate the question and explain to me?


7 s( l( F3 d. [+ hNO.2 Another one is:
; `) e9 w$ j+ W- ?9 J) S) o7 nAll of the following statements are true EXCEPT
6 C3 S, v2 i) P/ r* G" P(A) Hydrogen ions have different chemical properties from elemental hydrogen.
) A$ \! G( W6 R  Q" q(B) Carbon isotopes have different chemical properties from elemental carbon.
9 _; f1 s  |7 B(C) Carbon-14 has six protons and eight neutrons.
' x% G2 s: \6 y$ D$ G# K(D) Hydrogen ions are missing an electron.
/ |" |/ ~! `4 C. A(E) Ions have equal numbers of protons and neutrons
The official ans to this is B     
% u8 |: r0 [) E6 }+ KIsotopes of elements share the same chemical properties as standard elements. They differ only in their number of neutrons, which has no effect on chemistry.

But I think E is also wrong,What do u think?
) d/ U$ Q, S2 I; e9 e$ y
' l9 d2 ]4 x) f$ NNo.3:
  A& K; e. l% t0 C( _7 mQuestions : refer to the following experiment and results obtained.
Dialysis bags are semipermeable membranes, allowing the transport of small molecules while prohibiting larger ones. In an experiment, students filled dialysis bags with different concentrations of sucrose solution and placed them in a beaker of distilled water. The bags were each weighed before being placed in the beaker. After two minutes, they were removed from the beaker, dried, and weighed again.
   Which dialysis bag experiences the largest percent change in mass?
(A) 0.2 M sucrose
(B) 0.4 M sucrose
0 c5 v; W4 B  q9 s& {) E(C) 0.6 M sucrose
5 J9 I) g9 F4 p; `8 }# ](D) 0.8 M sucrose
(E) 1.0 M sucrose
, G  C; L% }0 {3 T
Nonetheless ,the ans given is D.But I perfer the 5th choice.Who could explain?


4 d$ Z/ W2 x9 m8 w  JNo.4:
Mammalian cell membranes work to maintain a concentration gradient in which there is a high water concentration inside the cell and a high sodium concentration outside the cell. If the cell membrane contains transport channels, these channels would allow sodium to  
3 J* J0 g, ~# A/ ]5 ?" y8 T. _3 f% e9 h(A) flow out of the cell by simple diffusion
& M) Z/ z  L  u1 l" R(B) flow into the cell by simple diffusion
(C) flow out of the cell by facilitated diffusion
(D) flow into the cell through facilitated diffusion
6 }: ^' H6 i$ t: M* ^/ @& l(E) flow into of the cell by phagocytosis

Ans given is C. Donn't u think D is the best one?
+ Y8 K& W6 }; e:O:p:$;P:L

einsteiniiUID: 2252184

眼睛看花了,呵呵