ALL UNIT 1 NOTES OCR

This is a compilement of school notes, advanced notes and ocr book notes. 

I have personally taken the time as an AS student to make these this year and have decided to share them with you in hope that they are useful to you. 

i have checked the spec and also the book thoroughly. 

I reccommend the site http://asbiology101.wordpress.com/downloads/ for soley condensed OCR book notes and also questions that you are unlikely to find elsewhere

Good Luck and I hope this all helps you!!! :) 

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  • Created by: anushiee
  • Created on: 21-02-14 01:24
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UNIT Module : CELLS
1.1 LIVING ORGANISMS CONSIST OF CELLS
Key concepts
Cells are fundamental units of life
Microscopy can be used to understand cellular structure and function
Cells share many of the same organelles and are unique to certain cell types.
There are distinguishing differences between the cells of prokaryotes and eukaryotes
Resolution: degree to which it is possible to distinguish between two objects very close together
Magnification: degree to which size of image = larger than object
no high resolution
Max mag. = X1500
Max resolution = 200 nm/ 0.2 m
Specimens
thin sections of organisms, smear of cheek and blood cells
o specimens seen
-see detail
acetin orcein
e.g. DNA (dark red)
Staining
sectioning
gentian violet e.g. bacterial cell wall
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CELL SIZE AND MAGNIFICATION
1.3 EM AND CELL DETAILS
o em max resolution = 0.…read more

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CELLS AND LIVING PROCESSES
common in muscle cells
need ATP
protein = microtubule motors
-needs ATP
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ORGANELLES; STRUCTURES AND FUNCTIONS
o Ultrastructure: details of inside of cell
o Organelle: each structure w/in cell
o Division of labour: specific role the structure has w/in cell
o RER function = transfers proteins made on attached ribosome.…read more

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STAIN USE COLOURS SEEN
Methylene blue For staining living cells Dark blue nucleus, light blue
cytoplasm
Iodine solution For staining living plant cells Dark blue-black starch grains,
nucleus stains deeper yellow,
the cytoplasm stains a lighter
yellow
Acetic orcein For staining the nucleus and Red
chromosomes
Eosin Stains the cytoplasm and some Pink
organelles of dead cells only
Movement and stability in cell
o Cytoskeleton
internal framework of cell
made from the protein fibres
maintains stability and shape of cell
actin/microtubules
1) Actin filaments
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Tubulin
move micro-organisms through liquid/ move liquid
microtubule motor proteins on microtubules can move organelle/cell contents along
fibres uses ATP
Cilia and flagella summary
o in eukaryotes, flagella and cilia structurally = the same
hair-like extension sticks out from cell surface
made from cylinder of 9 microtubules microtubules require ATP (energy)
examples:
long flagella on sperm cells
short-ciliated epithelium
o flagella occurs in 1/2s usually
o cilia usually occurs in large no.…read more

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SUMMARY OF ALL THE MICROSCOPES
Light Microscope
o 0.…read more

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Disadvantages:
2D
needs stains;
methylene blue DNA
acetin orcein DNA (dark red)
gentian violet bacterial cell wall
differential staining:
used to contrast sub-cellular parts against each other
TEM _ + SEM
o max magnification = x5000 - x 100,000
o max resolution 0.5 nm - x 0.5 nm
o stains = heavy +ve metal ions
o ultrastructure seen
o TEM; 3D SEM; 2D
o images added colour via computer (false-colour)
o Advantages:
high res and mag.…read more

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