Testing your knowledge

Cell Structure and Transport across cell membranes

Lesson Starter

Write out the paragraph choosing the correct answer at each choice. (8)Osmosis is a form of diffusion/ion uptake. It is an active/passive process that requires/does not require energy. During osmosis oxygen/water molecules move across a freely/selectively permeable membrane from a higher/lower water concentration along/against a concentration gradient.

Cell Structure

1. What is the name given to the basic units of life that can lead an independent existence? (1)

2 a. Name 4 structural features that a typical plant and animal cell have in common? (4) b. Identify 3 structural features present in an Elodea leaf cell but absent from a cheek cell? (3)3. Give the function of each of the following structures: chloroplast, nucleus, cell membrane, mitochondrion.(4)4. a. Express 1 millimetre in micrometres. (1) b. Express 1 micrometre an a decimal fraction of a millimetre. (1)

Total 14 marks

Transport through Cell Membranes1. Name 2 types of molecules present in the cell membrane?(2)2. Which of these would be destroyed (denatured) at 70°C ? (1)3. Define the terms diffusion and concentration gradient.(4)4. Name 2 essential substances that enter an animal cell by diffusion?(2)5. Name a waste material that diffuses out of an animal cell.(1)6. Explain why diffusion is important to human beings.(2)7. Predict what would happen to rate of diffusion of Explain your

answer. (2)8. Describe 3 differences between diffusion and active transport.(3)9. Name 2 factors which would affect active transport.

Total 14 marks

Osmosis

1. With reference to water concentrations involved, explain why a red blood cell bursts when placed in water yet an onion epidermal cell does not. (4)

2. Why does a red blood cell shrink when placed in a concentrated salt solution?(1)

3. Describe and explain the osmotic effect of very concentrated sugar solution on an onion epidermal cell. (2)

4. What term is used to describe a cell in this state.(1)5. How could such a cell be restored to its turgid condition?

(1)

Producing new cells

1. Describe what cell division is used for in; (i) unicellular organisms and (ii) multicellular organisms (2)

2. What term is used to describe a cell containing two matching sets of chromosomes. (1)

3. Give the term applied to replicated chromosomes before they separate during mitosis. (1)

4. State the role of spindle fibres during mitosis. (1)5. Explain why cell culture methods need aseptic techniques.

(2)6. Explain why temperature and pH must be controlled during

the cell culture process. (2)7. Describe what happens to the chromosomes of a cell before

mitosis takes place. (1) Total 10 marks

DNA and Proteins1. State the role of DNA in cells. (1)2. State what is meant by the term genetic information. (1)3. Describe the overall shape of a DNA molecule. (1)4. Give the letters by which the 4 bases that make up DNA are known. (1)5. Give the pairs of letters of the complementary bases of DNA. (1)6. Give the term that describes a section of DNA that codes for a particular

protein. (1)7. Name the molecule that takes a complementary copy of a sequence of

DNA out of the nucleus. (1)8. State the location within a cell where amino acids are assembled to

produce protein molecules. (1)

Total 8 marks