B2 Notes

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  • Created by: matdil
  • Created on: 25-03-16 15:28

Biology Notes: B2a

Plant and Animal Cells;                                                                   

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Structure:

Function:

Found in?

Nucleus

Controls activities of cell, contains the genetic information.

Plants and animals

Cell Membrane

Controls what enters and leaves the cell.

Plants and animals

Cytoplasm

Site of chemical reactions – contains many organelles.

Plants and animals

Mitochondria

The site of respiration in cells.

Plants and animals

Chloroplast

Site on photosynthesis in plants.

Plants

Cell Wall

Holds the cell in shape (made of cellulose).

Plants

Vacuole

Contains cell sap (sugary fluid), it also helps maintain the cells rigidity.

Plants

Microscopes:

 

 

 

 

 

 

 

 

                                                                                                                    -Total magnification = magnif of eye piece lens x magnif of the objective lens

Magnification of eyepiece lens:

Magnification of objective lens:

Total Magnification:

x5

x10

x50

x5

x40

x200

x10

x15

x150

                                                                                                              Working out Magnification:

Magnification =         Image Size                 .                                                                                                                   Hello my name I actual Specimen size

Electronic Microscopes:

-         Invented in the 1930’s

-         Uses beams of electrons rather than light

-         Magnifications of over x500,000 are achieved

-         Helps us to learn details about the structure of cells and organelles

 

 

 

Bacteria Cells:

 

 

 

 

 

 

 

Structure:

Function:

Chromosomal DNA

A giant loop of DNA containing most of the genetic information. It is not contained within a nucleus like animas or plants.

Plasmid DNA

A small loop of DNA that contains extra information.

Flagellum                           (not always present)

Long, whip-like structure that bacteria use to move themselves along.

 

DNA:

-        Nucleus contains chromosomes

-        A small section of a chromosome that codes for a particular protein is called a gene.

-        Chromosomes and genes are made up of a DNA molecule.

DNA Structure:

-        Double Helix

-        Base pairs hold the 2 strands together

-        Phosphate and sugar backbone

-        Hydrogen bonds hold the bases together

-        Complementary base pairs:

§  Adenine and Thymine

§  Cytosine and Guanine             

-         Bases always pair up in the same way. This is called complementary base pairing.

-         The sequence of bases forms the genetic code.

-         These are the instructions needed to make all of the proteins.

Extracting DNA:

Process:

Why I did this?

 

Chopping the kiwi and mashing it up

Increase the surface area of the cells to expose them to the salt, washing up liquid and hot water.

Adding salt

To make the DNA stick together.

Adding washing up liquid

Dissolve fatty membranes, and opens up the cell to release the DNA

Adding hot water

Breaks down the cell walls exposing the cell wall.

Stand the boiling tube in ice

Cool it down.

Adding ethanol

DNA doesn’t dissolve in alcohol.

 

Human Genome Project:

-         Has helped scientists discover new treatments and cure for disorders e.g. gene therapy.

-

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