1. Cell Processes
SUGAR
BASE
Phosphate Group

2. Looking Inside Cells Cell Wall Cell Membrane Nucleus Mitochondria
Endoplasmic Reticulum
Ribosomes
Golgi Bodies
Chloroplasts
Vacuoles
Lysosomes
Look Inside a Cell-1
Look Inside a Cell-2

3. Nucleus
Nuclear Membrane
Chromatin
Nucleolus
Journey into the Nucleus

4. D N A DNA – the blueprint of life
DNA is a nucleic acid found in the chromatin in a cell’s nucleus
DNA holds all the information that the cell needs to carry out its functions
DNA Replication
A cell makes a copy of its DNA before mitosis occurs
ensures that each replicated cell will have all of the genetic information it needs to carry out its activities
Journey into DNA

5. Why Do We Study DNA Chromosomes & DNA
Central importance to all life on Earth
Medical benefits such as cures for diseases
Better food crops.
Chromosomes & DNA
Our genes are on our chromosomes
Chromosomes are made up of a chemical called DNA.

6. DNA-Deoxyribonucleic Acid
Made up of nucleotides (DNA molecule) in a DNA double helix
It looks like a twisted ladder or a spiral stair staircase
Nucleotide:
1. Phosphate group
2. 5-carbon sugar
3. Nitrogenous base
~2 nm wide

7. DNA Double Helix P P G C T A Mitosis Review O “Rungs of ladder”1 2 3 4 5 P O 1 2 3 4 5
Nitrogenous
Base (A,T,G or C)
“Rungs of ladder” G C
“Legs of ladder”
Phosphate &
Sugar Backbone T A
Mitosis Review

8. DNA Building Block
phosphate
The backbone of the molecule is alternating phosphates and deoxyribose sugar
The teeth are nitrogenous bases
Adenine
Thymine
Guanine
Cytosine
deoxyribose
bases

9. Structure of DNA
The two sides of the DNA ladder are made of molecules of a sugar called deoxyribose nucleic acid- (DNA) alternating with molecules known as phosphates
Each rung of the DNA ladder is made of a pair of molecules called nitrogen bases
Four kinds of nitrogen bases
Adenine - A
Thymine - T
Guanine - G
Cytosine - C
Structure of DNA

10. DNA Replication Process
DNA replication begins when two sides of the DNA molecule unwind and separate, like a zipper unzipping
The molecules separate between the paired nitrogen bases
Nitrogen bases that are floating pair up with bases on each half of the DNA molecule
Rules of Pairing:
A always binds with T
G always binds with C

11. DNA Replication Process
Once bases are attached, two new DNA molecules are formed.
The order of the bases in each new DNA molecule will exactly match the order in the original DNA molecule
Tour of DNA

12. Interesting DNA facts Each cell has about 2 m of DNA
The average human has 75 trillion cells
The average human has enough DNA to go from the earth to the sun more than 400 times
DNA has a diameter of only m
The earth is 150 billion m
or 93 million miles from
the sun.
Extraction of DNA