Biology Ch.3

Topics: Cell membrane, Cell wall, Cell Pages: 2 (1359 words) Published: November 2, 2014
(Note The overseas examination boards bear no responsibility for the suggested answers contained in this publication. Answers for HKCEE and HKALE questions are not available due to copyright restrictions.) Ch 3Movement of substances across cell membrane Exercise Multiple-choice questions (p. 3-25) 1D2D3B4B5D6B7B8A9C10A11C Short questions (p. 3-27) 12HKALE Biology 2006 I Q9 13aPassive / do not require energy or ATP1m Movement down a concentration gradient / by diffusion1m bActive transport1m It occurs only when oxygen is present because energy / respiration is required.0.5m There is no uptake in curve Z.0.5m cThe concentration inside cells is higher than surrounding solution.1m dDiffusion is proportional to the concentration gradient.1m 14Water has a higher water potential than the cell contents. It moves across the differentially permeable membrane into the cells by osmosis.1m As the cell membranes of red blood cells are thin and not surrounded by cell walls, the cells burst when more and more water enters. Therefore no blood cells can be observed under the microscope.2m 15aDistilled water has a higher water potential than potato.0.5m Therefore in distilled water, water moves into potato by osmosis.1m Concentrated sugar solution has a lower water potential than potato.0.5m Therefore in concentrated sugar solution, water moves out of potato.1m Potato in distilled water becomes heavier than the one in concentrated sugar solution.1m bAny two from1m x 2 The vacuoles of the cells in distilled water are bigger than the ones in sugar solution. 1m The cell membranes are pulled away from the cell walls in the cells in sugar solution / cells in sugar become flaccid / cells become plasmolysed.1m Contents of the cells push against the cell walls in the cells in distilled water / cells in distilled water become turgid.1m 16HKALE Biology 1998 I Q4 17aIII should show two arms of membrane surrounding...
Continue Reading

Please join StudyMode to read the full document

You May Also Find These Documents Helpful

  • biology Essay
  • Biology Essay
  • Biology Chapter 3 Vocab Research Paper
  • Biology Essay
  • Biology Week 3 Assignment Research Paper
  • Biology form 4 chapter 3 Essay
  • biology Essay
  • biology Essay

Become a StudyMode Member

Sign Up - It's Free