DNA- The code of life
Nucleic acids - Have the capacity to store the information that controls cellular
activity and development of an entire organism
- They do this by controlling the synthesis of proteins
- Making proteins is the first step in the right direction to making an
organism
- Since enzymes are proteins, they also control the chemical
processes inside cells
- Therefore, they control the structure and functioning of all living
organisms
Two nucleic acids found in cells:
- Deoxyribonucleic acid (DNA)
- Ribonucleic acid (RNA)
Genetic replication: process of producing two identical replicas of DNA from one
original DNA molecule
Who discovered the structure of DNA?
Maurice Wilkins- won noble peace prize
Rosalind Franklin- died
Francis Crick- won noble peace prize
James Watson- won noble peace prize
Crick and Watson realized that nucleic acids are arranged like a twisted ladder with 2
runners made of phosphates and sugars and bases.
Genetic replication
Watson and Crick developed the idea of genetic replication
Crick also made the discovery of the triplet codes (which are used in reading genetic
material in DNA)
Extra notes
Most DNA in a cell is found in the chromatin network in the nucleus
DNA is also found in chloroplasts and mitochondria
Chromatin- The material chromosomes are composed, consisting of protein, RNA
and DNA, in a non-dividing cell.
Anucleate- don’t have a nucleus (eg. Red blood cells)
Where is DNA found?
DNA is found mainly in the nucleus of a cell where it forms an important part of the
chromosomes that make up the chromatin network
Chromosomes- coiled up string of DNA
DNA molecules are coiled so that the long structures can fit inside the nucleus
, What is extranuclear DNA?
DNA found outside the nucleus in mitochondria and chloroplasts
How is DNA made up?
Double helix, looks like a long, twisted ladder
What units make up DNA?
A DNA molecule is a long chain (polymer) made up of small units (monomers), these
monomers are called nucleotides
Each nucleotide is made up of a:
- Sugar molecule which is deoxyribose (S)
- Phosphate molecule (P)
- Nitrogenous base
Nitrogenous base may be:
- Adenine (A)
- Thymine (T)
- Guanine (G)
- Cytosine (C)
These 4 bases are the foundation of the genetic code
Since there are 4 different nitrogenous bases, there are 4 different nucleotides
Nucleotides have to have a nitrogenous base, sugar and phosphate TOGETHER
Look on pg 130 for diagram
How is a double helix made up?
The outer 2 strands of the ladder are formed by a
chain of altering sugar/phosphate links
- The bonds between the sugar and
phosphate molecules are strong
The rungs of the ladder are formed
from pairs of bases linked by weak
hydrogen bonds
The base pairs are ALWAYS
attached to the sugar molecules
How do these 4 base pairs link up?
Nucleic acids - Have the capacity to store the information that controls cellular
activity and development of an entire organism
- They do this by controlling the synthesis of proteins
- Making proteins is the first step in the right direction to making an
organism
- Since enzymes are proteins, they also control the chemical
processes inside cells
- Therefore, they control the structure and functioning of all living
organisms
Two nucleic acids found in cells:
- Deoxyribonucleic acid (DNA)
- Ribonucleic acid (RNA)
Genetic replication: process of producing two identical replicas of DNA from one
original DNA molecule
Who discovered the structure of DNA?
Maurice Wilkins- won noble peace prize
Rosalind Franklin- died
Francis Crick- won noble peace prize
James Watson- won noble peace prize
Crick and Watson realized that nucleic acids are arranged like a twisted ladder with 2
runners made of phosphates and sugars and bases.
Genetic replication
Watson and Crick developed the idea of genetic replication
Crick also made the discovery of the triplet codes (which are used in reading genetic
material in DNA)
Extra notes
Most DNA in a cell is found in the chromatin network in the nucleus
DNA is also found in chloroplasts and mitochondria
Chromatin- The material chromosomes are composed, consisting of protein, RNA
and DNA, in a non-dividing cell.
Anucleate- don’t have a nucleus (eg. Red blood cells)
Where is DNA found?
DNA is found mainly in the nucleus of a cell where it forms an important part of the
chromosomes that make up the chromatin network
Chromosomes- coiled up string of DNA
DNA molecules are coiled so that the long structures can fit inside the nucleus
, What is extranuclear DNA?
DNA found outside the nucleus in mitochondria and chloroplasts
How is DNA made up?
Double helix, looks like a long, twisted ladder
What units make up DNA?
A DNA molecule is a long chain (polymer) made up of small units (monomers), these
monomers are called nucleotides
Each nucleotide is made up of a:
- Sugar molecule which is deoxyribose (S)
- Phosphate molecule (P)
- Nitrogenous base
Nitrogenous base may be:
- Adenine (A)
- Thymine (T)
- Guanine (G)
- Cytosine (C)
These 4 bases are the foundation of the genetic code
Since there are 4 different nitrogenous bases, there are 4 different nucleotides
Nucleotides have to have a nitrogenous base, sugar and phosphate TOGETHER
Look on pg 130 for diagram
How is a double helix made up?
The outer 2 strands of the ladder are formed by a
chain of altering sugar/phosphate links
- The bonds between the sugar and
phosphate molecules are strong
The rungs of the ladder are formed
from pairs of bases linked by weak
hydrogen bonds
The base pairs are ALWAYS
attached to the sugar molecules
How do these 4 base pairs link up?
