Lifer at molecular level
DNA - deoxyribonucleic acid
- Carries hereditary information
- Enables growth by coding for protein synthesis
- Can replicate during mitosis
Where is DNA found
- Mainly in the nucleus : forms part of chromosomes that make up chromatin network
- Chromatin - chromosomal material made up of DNA, RNA and histone proteins
- DNA molecule = coiled up so that long structures can fit inside the nucleus
- 2 metres of DNA coiled in single cell
Extranuclear DNA
- Small amounts of DNA found outside nucleus inside mitochondria
How is DNA made up
- Long twisted ladder
- Two strands twist to form stable, 3D double helix
What units make up DNA
- DNA molecule is a long chain (polymer) made up of smaller units (monomers)
- Building blocks called nucleotides, each one made up of :
- Sugar molecule - deoxyribose (S)
- Phosphate molecule (P)
- Nitrogenous base :
- Adenine (A)
- Thymine (T)
- Guanine (G)
- Cytosine (C)
, How is double helix made up
- Outer two strands of the ladder are formed by a chain of alternating sugar and
phosphate links
- the rungs of the ladder are formed from pairs of bases linked by weak hydrogen
bonds
- the base pairs are attached to the sugar molecules
How do these four base pairs link up
- Adenine only bonds w thiamine : DOUBLE hydrogen bond
- Cytosine will only bond with guanine : TRIPLE hydrogen bond
How are base pairs classified
Purines Pyrimidines
Made up of 2 fused rings of nitrogen, Made up of one ring of similar atoms,
carbon and hydrogen atoms therefore - much smaller
Ex : G & A Ex : T, C & U
What is the role of DNA
- Carry hereditary information in each cell in the form of genes
- Provide a blueprint for an organism's growth and development by coding for protein
synthesis
- Can make a copy of itself so that a copy of genetic information is passed on to each
daughter cell - genetic code passed on from generation to generation
DNA - deoxyribonucleic acid
- Carries hereditary information
- Enables growth by coding for protein synthesis
- Can replicate during mitosis
Where is DNA found
- Mainly in the nucleus : forms part of chromosomes that make up chromatin network
- Chromatin - chromosomal material made up of DNA, RNA and histone proteins
- DNA molecule = coiled up so that long structures can fit inside the nucleus
- 2 metres of DNA coiled in single cell
Extranuclear DNA
- Small amounts of DNA found outside nucleus inside mitochondria
How is DNA made up
- Long twisted ladder
- Two strands twist to form stable, 3D double helix
What units make up DNA
- DNA molecule is a long chain (polymer) made up of smaller units (monomers)
- Building blocks called nucleotides, each one made up of :
- Sugar molecule - deoxyribose (S)
- Phosphate molecule (P)
- Nitrogenous base :
- Adenine (A)
- Thymine (T)
- Guanine (G)
- Cytosine (C)
, How is double helix made up
- Outer two strands of the ladder are formed by a chain of alternating sugar and
phosphate links
- the rungs of the ladder are formed from pairs of bases linked by weak hydrogen
bonds
- the base pairs are attached to the sugar molecules
How do these four base pairs link up
- Adenine only bonds w thiamine : DOUBLE hydrogen bond
- Cytosine will only bond with guanine : TRIPLE hydrogen bond
How are base pairs classified
Purines Pyrimidines
Made up of 2 fused rings of nitrogen, Made up of one ring of similar atoms,
carbon and hydrogen atoms therefore - much smaller
Ex : G & A Ex : T, C & U
What is the role of DNA
- Carry hereditary information in each cell in the form of genes
- Provide a blueprint for an organism's growth and development by coding for protein
synthesis
- Can make a copy of itself so that a copy of genetic information is passed on to each
daughter cell - genetic code passed on from generation to generation
