 What are these cells?  How are they specialised to perform their function?

C ELL S PECIALISATION Define terms differentiation & specialisation -erythrocytes, neutrophils, epithelial cells, sperm cells, palisade cells, root hair cells, xylem, Phloem & cambium

Which organism has the highest surface area to volume ratio? The single celled Amoeba Polar bear or other multi cellular organism

Which organism has the highest surface area to volume ratio? The single celled Amoeba 12:8 = 3:2 Polar bear or other multi cellular organism 20:25

Large s/a: volume All cells exposed to environment Effective exchange surface-for what? All cells perform all functions Smaller s/a: volume Not all cells in contact with external environment Therefore: Specialised cells to perform different functions Single celled organismsMulti-cellular organisms

Young cell Cell division Cell growth Cell specialisation Mature cell -Unlikely or unable to divide again What is Differentiation When a cell becomes specialised to carry out a particular job/function What categories of differentiation are there?  Change number of particular organelle e.g. muscle cell  Change the shape of the cell e.g. root hair cell  Change some of the contents of the cell e.g. RBC  ALL 3!!

Specialised CellHow the cell is specialised for its function Erythrocyte Neutrophil Sperm cell Palisade Cell Root hair cell Guard Cell Ciliated Epithelium In your group, split the cells between you. Research your cell. Later you will need to explain your findings to the rest of the group

What are tissues, organs and organ systems? Write a definition and an example of the following on the yellow post-its and stick under the appropriate heading:  Tissue  Organ  Organ system.

What are tissues, organs and organ systems? Cells make up TISSUES, groups of the same kind of cells performing a common function e.g. xylem and phloem in plants, muscle tissue in animals Groups of different types of tissues are arranged together to form organs e.g. the stomach consists of mucus membrane tissue, muscle tissue, etc Organs are grouped into systems e.g. respiratory system, reproductive system. organ systems consist of a number of organs working together to perform an overall life function.

G ROUP E SSAY In this question, one mark is available for the quality of spelling, punctuation and grammar. Below is a picture of blood showing both red and white blood cells. Describe how red blood cells, such as those shown in the picture are adapted for their function. (Allow one lined page). [6] Quality of Written Communication [1] [Total 7 marks] Think about the other side of the course too!!

1haemoglobin/haem, carries oxygen/AW; 2detail of no. of oxygen molecules carried; 3small size/large SA:V ratio, so haemoglobin never far from cell surface/AW; 4flexible/elastic/stretchy/changes shape/AW; 5small size/‘stretchiness’/AW, allows red cells to, fit/squeeze, into capillaries; 6biconcave/AW [ A ‘ dimpled’], gives, increased/AW, surface area relative to volume (for diffusion); 7no nucleus to maximise room for, haemoglobin/oxygen/AW; 8contain carbonic anhydrase; 9describe, the reaction catalysed by carbonic anhydrase/role in maintenance of diffusion gradient/AW; 10transport of carbon dioxide as carbamino-haemoglobin/CO 2 combines with Hb; 11ref buffering effect; 12AVP; e.g.further detail of oxygen carriage variable oxidation state of Fe idea that small size allows them to be close to tissue or cells lack of, other/named, named organelles, also increases room for Hb/O 2 max 6 13QWC – legible text with accurate spelling, punctuation and grammar;1[7]