Pages in this set

Page 1

Preview of page 1
AS Biology
Unit 1- Cells, Exchange
and Transport (F211)


Page 2

Preview of page 2

Page 3

Preview of page 3

Magnification- the number of times bigger an image is than the
Resolution- the ability to distinguish to close together points as
distinct from each other

Light Microscope Transmission Scanning
Electron Electron
Microscope Microscope
Magnification X1,500 X500,000 X100,000
Resolution 200nm 0.1nm 0.1nm
Advantages Inexpensive Good Good
magnification magnification

Page 4

Preview of page 4
Actual Size (m)

To convert from mm to m times by 1000.


Nucleus- Contains the genetic information of the cell
Nucleolus- Makes RNA and ribosomes
Nuclear envelope- Contains holes called nuclear pores,
which allow relatively large molecules to pass through
Rough endoplasmic reticulum- Transport proteins that
were made on…

Page 5

Preview of page 5
Production and Secretion of Proteins

1. The instructions to make proteins are in the nucleus of the
2. The gene containing the instructions for the production of
the hormones is copied onto a piece of mRNA
3. The mRNA leaves the nucleus through the nuclear pores
and attaches to…

Page 6

Preview of page 6
6. Golgi apparatus processes and packages the molecules,
ready for release.
7. The molecules are `pinched off' in vesicles from the Golgi
apparatus and moves towards the cell surface membrane.
8. Vesicles fuse with the cell surface membrane and the
membrane opens to release the molecules outside- this is

Page 7

Preview of page 7
No membrane bound Membrane bound
organelles organelles (mitochondria,
chloroplast etc.)
Peptidoglycan cell wall Cellulose cell wall
Spiral flagella Waved flagella
Smaller ribosomes Larger ribosomes
Single-loop chromosomes Linear chromosomes
Single-celled One or more cell
Contains plasmids Do not contain plasmids


Page 8

Preview of page 8
Cell Membrane

Cholesterol- Gives the membrane stability by sitting between the
fatty acid tails and therefore making the barrier more complete,
preventing molecules like water and ions passing through the
Glycolipids- Phospholipid molecules that have a carbohydrate
part attached. They are used for cell signaling, cell surface
antigens and…

Page 9

Preview of page 9
Channel proteins- Allow the movement of some substances,
such as the large molecule sugar, into and out of the cell as they
can't travel directly through the cell surface membrane.
Carrier proteins- Actively move substances across the cell
surface membrane.

Function of membranes:
Separate cell contents from outside environment

Page 10

Preview of page 10
Cell communication and signaling

Most messenger molecules are unable to directly cross
the membrane and must bind to the membrane bound
receptors in order to communicate with a cell.
Some integral proteins are receptors for hormones and
Different cells have specific receptors depending on the
role in our body.…


No comments have yet been made

Similar Biology resources:

See all Biology resources »