LIFE SCIENCE - DNA CODE OF LIFE (simple and
easy summary)
DNA-CODE OF LIFE
STRUCTURE OF A CELL:
• Plant cells have a cell wall
• Animal cells have no cell wall
• Ribosomes- site of protein synthesis, located in cytoplasm
• Nucleus - nuclear membrane has nuclear pores to allow entry and exit of substances
- Nucleoplasm contains free DNA and RNA nucleotides
- Nucleolus produces ribosomes
- Chromatin network contains DNAwhich forms chromosomes containing the genetic code of a person.
NUCLEIC ACIDS
• Two types: DNA ( deoxyribonucleic acid) and RNA (ribonucleic acid)
• Made up of monomers(smallest building blocks) called nucleotides
• Nucleotide: made up of a phosphate group, a sugar and a nitrogen base
DNA: LOCATION, STRUCTURE AND FUNCTIONS
• Location: present in the nucleus - makes up genes on chromosomes(nuclear DNA)
present in mitochondria(mitochondrial DNA),
present in chloroplasts (chloroplastic DNA) –found in plant
cells only
• Three types – nuclear DNA ,mitochondrial DNA, chloroplastic DNA
• History of Discovery of DNA
- James Watson and Francis Crick formulated the double helix structure of DNA in 1953
, - Maurice Wilkins and Rosalind Franklin also did research on DNA structure
- In 1952 Rosalind took X-ray photos of DNA which was shown to Francis Crick. Using this Watson and
Crick were able to build 3-D models of the structure of DNA
NOTE: Rosalind Franklin and Wilkins produced the first X-ray pictures of DNA
Watson and Crick put forward their model of DNA which shows a double helix with
complementary base pairs.
• Structure:
- Double stranded, strands held together by weak hydrogen bonds
- Natural shape of DNA – double helix
- DNA nucleotide made up of: phosphate group, sugar(deoxyribose) and nitrogenous bases (A,T,G,C)-
adenine, thymine, guanine and cytosine
- Pairing of bases occurs as follows: A-T, G-C
- NOTE: always an equal number of adenine and thymine and equal number of cytosine and guanine
occurs
• Functions:
- DNA makes up genes which carry hereditary information
- DNA contains coded information for protein synthesis
DNA REPLICATION
➢ Occurs to form identical copies of DNA
➢ Process takes place during Interphase of cell division
➢ PROCESS
• Double helix of DNA unwinds
• Weak hydrogen bonds break
• The two strands unzip
• to form two separate strands
• Both DNA strands serve as templates
easy summary)
DNA-CODE OF LIFE
STRUCTURE OF A CELL:
• Plant cells have a cell wall
• Animal cells have no cell wall
• Ribosomes- site of protein synthesis, located in cytoplasm
• Nucleus - nuclear membrane has nuclear pores to allow entry and exit of substances
- Nucleoplasm contains free DNA and RNA nucleotides
- Nucleolus produces ribosomes
- Chromatin network contains DNAwhich forms chromosomes containing the genetic code of a person.
NUCLEIC ACIDS
• Two types: DNA ( deoxyribonucleic acid) and RNA (ribonucleic acid)
• Made up of monomers(smallest building blocks) called nucleotides
• Nucleotide: made up of a phosphate group, a sugar and a nitrogen base
DNA: LOCATION, STRUCTURE AND FUNCTIONS
• Location: present in the nucleus - makes up genes on chromosomes(nuclear DNA)
present in mitochondria(mitochondrial DNA),
present in chloroplasts (chloroplastic DNA) –found in plant
cells only
• Three types – nuclear DNA ,mitochondrial DNA, chloroplastic DNA
• History of Discovery of DNA
- James Watson and Francis Crick formulated the double helix structure of DNA in 1953
, - Maurice Wilkins and Rosalind Franklin also did research on DNA structure
- In 1952 Rosalind took X-ray photos of DNA which was shown to Francis Crick. Using this Watson and
Crick were able to build 3-D models of the structure of DNA
NOTE: Rosalind Franklin and Wilkins produced the first X-ray pictures of DNA
Watson and Crick put forward their model of DNA which shows a double helix with
complementary base pairs.
• Structure:
- Double stranded, strands held together by weak hydrogen bonds
- Natural shape of DNA – double helix
- DNA nucleotide made up of: phosphate group, sugar(deoxyribose) and nitrogenous bases (A,T,G,C)-
adenine, thymine, guanine and cytosine
- Pairing of bases occurs as follows: A-T, G-C
- NOTE: always an equal number of adenine and thymine and equal number of cytosine and guanine
occurs
• Functions:
- DNA makes up genes which carry hereditary information
- DNA contains coded information for protein synthesis
DNA REPLICATION
➢ Occurs to form identical copies of DNA
➢ Process takes place during Interphase of cell division
➢ PROCESS
• Double helix of DNA unwinds
• Weak hydrogen bonds break
• The two strands unzip
• to form two separate strands
• Both DNA strands serve as templates
