Page 1 - 10. GLM NL Sci Bio answer key 2023 (AK020)
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Unit 1: Cell structure and organisation                                                                                   Section B: Short answer questions
              Revision                                      1.   (a)   Plant cells: Q, S
                                                                    Animal cells: P, R
              1.   (a)  It is a unit of life.                   (b)   It lacks of nucleus, biconcave shape; Transports
                 (b)  They are cellular structures that perform specific   oxygen; Allows it to change shape and increase
                     functions within the cell.                     its surface area as it travels through capillaries
              2.   (a)  1:   mitochondrion   2:   chromosome   2.   Across:
                     3:   nuclear membrane                      1.   Chlorophyll   2.   Nucleus
                     4:   cell membrane  5:   ribosome          5.   Differentiate   7.   Ribosomes
                     6:   vacuole   7:   cytoplasm              9.   Protoplasm   13.  DNA
                 (b)  Nucleus                                   14.  Biconcave    15.  Mitochondria
                 (c)  (i)   vacuole   (ii)  cell membrane       Down:
                     (iii)  ribosome   (iv)  cytoplasm          1.   Chloroplast   3.   Cytoplasm
                     (v)  nucleus                               4.   Cellulose    8.   Photosynthesis

              3.   (a)  1:   nucleus   2:   chloroplast     3.  (a)  Structure  Cell X  Plant cell Animal cell
                     3:   vacuole   4:   cell wall
                     5:   cell membrane 6:   mitochondrion          Cell wall  Present  Present  Absent
                 (b)  Chlorophyll                                   Flagellum  Present  Absent  Absent
                 (c)  Cellulose. It protects cell from injury. / It gives the   Slimy
                     plant cell a fixed shape.                       capsule  Present  Absent  Absent
                                                                     Nucleus  Absent  Present  Present
              4.        Plant cell        Animal cell               Cytoplasm  Present  Present  Present
                        Present            Absent
                         Fixed             Irregular            (b)  As  cell  X  is  able  to  move,  it  needs  more
                        Present            Absent                   mitochondria  to  break  down  food  to  release
                                                                    energy for this movement.
                      One and large     Many but small          (c)   All of the cells contain cytoplasm.
                                                                    All of the cells have a cell membrane.
              5.   (a)  It is a process where cells change in shape and
                     form  so  that  they  acquire  special  features  to
                     perform specific function.             Section C: Free response questions
                 (b)  (i)   Long  and  narrow  structure  increases  the   1.   Cell wall and chloroplasts are found in plant cells but
                         surface  area-to-volume  ratio  for  efficient   not in animal cells. Plant cells have a large and central
                         absorption of water and mineral salts  vacuole but animal cells have small, numerous and
                     (ii)  Contains haemoglobin to transport oxygen/  temporary vacuoles.
                         Biconcave shape increases the surface area
                         so that the rate of diffusion of oxygen in and
                         out the cells is faster/           Unit 2: Movement of substances
                         No  nucleus  so  that  it  can  contain  more   Revision 1
                                                            1.   (a)  Diffusion  is  the  net  movement  of  a  substance
              Section A: Multiple-Choice Questions                  from  a  region  of  its  higher  concentration  to  a
                                                                    region of its lower concentration.
              1.   C    Animal  cells  do  not  have  cell  wall  and      (b)  It is the difference in concentration of a substance
                     chloroplasts.                                  between two regions.
              2.   A    Chloroplast is another organelle that is found in      (c)  Concentration  gradient,  diffusion  distance  and
                     plant cells.                                   surface area-to-volume ratio
              3.   A   Cell  wall  does  not  restrict  the  movement  of
                     substances.                            2.   (a)   False [Each substance diffuses according to its
              4.   A   X is nucleus and Y is chloroplasts.          own concentration gradient]
              5.   D   These are typical arrangement for plant cells.     (b)   False  [The  particles  of  a  substance  still  move
              6.   B   Plants are living organisms that can make their   back and forth as they have kinetic energy, but
                     own food. Plant cells have cell wall.          there will be no net movement on either side of
                                                                    the regions.]
                                                                (c)   True
                                                                (d)   False  [A  permeable  membrane  allows  any
                                                                    substance to pass through it.]
                                                                (e)   True

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