Transcript F212- -Cell_Specialisation

What are these cells?
How are they specialised to perform their
function?
CELL SPECIALISATION
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
Single celled organisms
Large s/a: volume
 All cells exposed to
environment
 Effective exchange
surface-for what?
 All cells perform all
functions

Multi-cellular organisms
Smaller s/a: volume
 Not all cells in
contact with external
environment
 Therefore:
Specialised cells to
perform different
functions

Young
cell
Cell
division
Cell
growth
Cell
specialisation
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!!
Mature cell
-Unlikely or
unable to
divide again
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
Specialised Cell
Erythrocyte
Neutrophil
Sperm cell
Palisade Cell
Root hair cell
Guard Cell
Ciliated Epithelium
How the cell is specialised
for its function
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
.
GROUP ESSAY


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!!

1
haemoglobin/haem, carries oxygen/AW;
2
detail of no. of oxygen molecules carried;
3
small size/large SA:V ratio, so haemoglobin never far from cell
surface/AW;
4
flexible/elastic/stretchy/changes shape/AW;
5
small size/‘stretchiness’/AW, allows red cells to, fit/squeeze, into
capillaries;
6
biconcave/AW [A ‘dimpled’], gives, increased/AW, surface area
relative to volume (for diffusion);
7
no nucleus to maximise room for, haemoglobin/oxygen/AW;
8
contain carbonic anhydrase;
9
describe, the reaction catalysed by carbonic anhydrase/role in
maintenance of diffusion gradient/AW;
10
transport of carbon dioxide as carbamino-haemoglobin/CO2
combines with Hb;
11
ref buffering effect;
12 AVP; 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/O2 max 6
13 QWC – legible text with accurate spelling, punctuation and
grammar; 1[7]