Pages in this set

Page 1

Preview of page 1


(a) State the resolution and magnification that can be achieved by a light microscope, a
transmission electron microscope and a scanning electron microscope

Light microscope ­
Resolution ­ 200nm
Magnification ­ x1500

Transmission electron microscope
Resolution ­ 0.1nm
Magnification ­…

Page 2

Preview of page 2

(e) Describe and interpret drawings and photographs of eukaryotic cells as seen under an
electron microscope and be able to recognise the following structures:
(f) outline their functions

Surrounded by nuclear envelope which contains pores
Inside is nucleolus and chromatin

Chromatin is made from DNA and controls cells activities…

Page 3

Preview of page 3
Small, round, membranebound organelle
Contains digestive enzymes which can be used to digest invading cells e.g in
Found in plant cells
Stacked up thylakiod membranes to form granum
Linked by llamale (intergranal llamale)

Site of photosynthesis
Cell membrane:
Found on the surface of animal cells and inside the…

Page 4

Preview of page 4
To support the cells organelles by keeping them in place
To strengthen the cell and maintain its shape
Transporting materials eg movement of chromosomes during mitosis
Helps the cell to move ­ e.g flagellum
(i) Compare and contrast, with the aid of diagrams and electron micrographs, the structure of

Page 5

Preview of page 5

(a) Outline the roles of membranes within cells and at the surface of cells
Separating contents of the cell from its outside environment
Separating cell components from the cytoplasm
Cell signalling
Cell recognition
Regulating transport of materials into and out of the cell
Plasma membranes: on the surface control what…

Page 6

Preview of page 6
Allow small or charger particles to go across the membrane (molecules that are too large to
diffuse through, or hydrophilic molecules)

Carrier proteins:
Actively transport molecules across the membrane

Glycolipids and Glycoproteins:
Help to stabilise the membrane
Receptor sites for drugs, hormones and antibodies
Act as antigens

(e) Outline the…

Page 7

Preview of page 7
receptor which is complementary to a hormone meaning it can bind to the receptor site to trigger
a response. An example of this is an insulin receptor.

Drugs can also bind to the receptor molecules on the cell's surface. Beta blockers are used to
prevent an increase in heart rate.…

Page 8

Preview of page 8

Moves a substance against their concentration gradient by using ATP.

Some carrier proteins can act as pumps...
They have a complementary shape to the shape of a specific molecule or ion
They carry the molecule ONE WAY across the plasma membrane
They use metabolic energy in the form…

Page 9

Preview of page 9
Water potential: the tendency of water molecules to diffuse from a region of high water potential
to a region of low water potential.

When there are substances dissolved in the water, the water potential becomes more
negative, lowering it as there are not as many "free" water molecules.

(j) recognise…

Page 10

Preview of page 10
(a) state that mitosis occupies only a small percentage of the cell cycle and that the remaining
percentage includes the copying and checking of genetic information

Mitosis only occupies a short part of the cell cycle. The remaining part is taken up by
During interphase, the genetic material is…


No comments have yet been made

Similar Biology resources:

See all Biology resources »