AS Biology- OCR- Module 1 Cells Specification Analysis and Notes

Seite 1

AS Biology- OCR

Module 1 Cells 1.1.1- Cell Structure

a) Light Microscope- x1500 Magnification- 200nm resolution

Transmission Electron Microscope (TEM)- x500,000 Magnification, 0.2nm resolution

Scanning Electron Microscope (SEM)- x100,000 Magnification, 0.2nm resolution

b) Magnification- The number of times greater an image is than the object.

Resolution- The ability to distinguish two seperate points that are distinct from each other.

c) Light Microscope- dye to distinguish between the different parts of a cell.

TEM- Electrons pass through the thin sample- some more easily which allows it to distinguish between the parts. A 2D picture is produced that can have false colour applied afterwards.

SEM- Gold coated sample- electrons bounce off and produce a 3D image

d) Magnification= Image/Actual

e) Nucleus- Contains chromosomes and instructions for proteins.

Rough Endoplasmic Reticulum- Covered in ribosomes for protein synthesis.

Smooth Endoplasmic Reticulum- Used to produce lipids for cells.

Golgi Apparatus- Turns modified proteins into vesicles.

Ribosomes- Used for protein synthesis.

Mitochondria- Respiration and an energy store.

Lysosomes- Break down materials- like neutrophils or a sperm cell.

Chloroplasts- The site of protein synthesis.

Plasma Membrane- Used for anaerobic respiration.

Flagella- moving the cell itself through a medium.

g) First a copy of the gene is created with mRNA. This leaves the nucleus through the nuclear pore. This attaches to the ribosome which assembles the protein. This pinches off in a vesicle and heads to the Golgi apparatus. This packages the molecule in another vesicle and this travels to the cell surface membrane. They fuse together and the molecule is released.

h) The cytoskeleton is used to provide mechanical strength. The protein fibres keep the

New Page