CELLS (AHL)

7.1        Membranes

7.1.1     Explain the dynamic relationship between the nucleus, rough endoplasmic reticulum (rER), Golgi apparatus and cell surface membrane.

7.1.2     Describe the ways in which vesicles are used to transport materials within a cell and to the cell surface.

7.1.3    Describe the membrane proteins and their positions within membranes.

7.1.1- A series of diagrams may be suitable to demonstrate the structural

7.1.3  relationships and how materials are moved. The continuous nature of membranes and the flow of materials through the channels or by vesicles is expected, although the chemical nature of materials is not required. Mention of pores and the fact that some intrinsic proteins are anchored is expected.

 

7.1.4     Outline the functions of membrane proteins as antibody recognition sites, hormone binding sites, catalysts for biochemical reactions and sites of electron carriers.

7.2        Cell division – mitosis

                          Notes: Builds on the key facts of mitosis by concentrating on chromosome behaviour. It also allows students to see that the ‘universal process’ (SSC 1.5) differs on somewhat in plants and animals.

7.2.1     Describe the behaviour of the chromosomes in each of the four phases of mitosis (prophase, metaphase, anaphase and telophase).

MITOSIS

 

Early Prophase

 

Late Prophase

 

Metaphase

 

Anaphase

 

Telophase

 

7.2.2    Outline the differences in mitosis and cytokinesis between animal and plant cells.

7.2.1- Here mitosis is restricted to eukaryotic cells. The ‘process’ can use

7.2.2 ‘traditional’ textbook diagrams (noting that cytokinesis is the cleavage of the cytoplasm after mitosis). The process can be summarised as the dispersing of the nuclear material, movement of centrosomes (if present) to opposite ends, microtubules developing into a spindle, supercoiling of chromatin, attachment to spindle fibres (kinetochore not required), separation and movement of chromatids. Knowledge that mitosis can occur in haploid, diploid or polyploid cells is expected. Differences in plant and animal cells restricted to the centrioles and the formation of cell plate and cell wall.

 

7.3        Differentiation and functional specialisation of cells

             Notes: The Themes of ‘Diversity’ and ‘Structure and Function’ can be developed.

 

7.3.1     State that unicellular organisms carry out all the functions of life.

7.3.2    State that cells in multicellular organisms differentiate to carry out specialised functions.

No detail of the mechanisms of differentiation or mention of ‘totipotency’ is required.

7.3.3     Define tissue.

7.3.4     Define organ.

7.3.5     Define organ system.

7.3.6    Explain the hierarchical relationship between cells, tissues, organs and organ systems in multicellular organisms.

        Simply stated that tissues are made up of cells and that organs have several tissues and that organ systems are composed of two or more organs (see definitions).

7.3.7    Calculate linear magnification of drawings.

Drawing should show cell ultra structure with scale bars e.g., 1m m

It can also be expressed as magnification. E.g., x250

7.3.8     State that cells differentiate by expressions of some of their genes and not others.

7.3.9    State that the pathway of differentiation is determined by the cell’s position relative to others and by chemical gradients.

7.3.8 – 7.3.9 No more than as stated. Embryological detail is not expected.