Strand 3: Life at molecular, cellular, and tissue level…………………………………………………………
3.1 DNA-code of life
Nucleic acids
Deoxyribonucleic Acid
DNA replication
Ribonucleic Acid
Mitochondrial DNA
Protein Synthesis
Gene Mutations
Application of DNA technology
Nucleic acids
-have the capacity to store information that
controls cellular activity and the development of an
entire organism
-control synthesis of proteins
-proteins make up the organism
-enzymes(proteins) control chemical processes
inside cells
>Deoxyribonucleic acid
>Ribonucleic acid
Deoxyribonucleic Acid -DNA
Who discovered the structure of DNA? Maurice Wilkins and Rosalind Franklin
-1950s
- X-ray crystallography (diffraction of images of
DNA)
-only wilkins got a Nobel Peace prize
Francis Crick and James Watson
-built model of DNA
-developed ideas about genetic replication
-won nobel peace prize for physiology/medicine
Where is DNA found? -mainly in nucleus
-form part of chromosomes(chromatin network)
Chromatin= chromosomal material made up of
DNA,RNA and histone proteins as found in non-
dividing cells
What is extracellular DNA -small amounts DNA found in mitochondria in
plants and animals and in chloroplasts
,How is DNA made up: Twisted double helix
-What units make up DNA Molecule is long chain(polymer) made up of small
units(monomers=nucleotides)
Each nucleotide has:
~sugar molecule -deoxyribose
~phosphate molecule
~nitrogenous base
adenine(A)
thymine(T)
guanine(G)
cytosine(C)
bases=foundation for genetic code
-double helix Outer 2 strands formed by alternating
sugar/phosphate links (strong bonds)
Rungs formed from pairs of bases linked by weak
hydrogen bonds
Base pairs attached to sugar molecules
-four base pairs linking Adenine to thymine/uracil (2 hydrogen bonds)
Cytosine to guanine (3 hydrogen bonds)
-base pair classification Purines(G and A)
Pyrimidines (T, C, U)
-do bases differ in organisms Only 4 nucleotides in all organisms
-how do organisms differ Sequence of nucleotides differs in each organism
Sequence= genetic code
Role of DNA ~carry hereditary information
~blueprint for organisms growth and development
by coding for protein synthesis
~can replicate for information to be passed down
to each daughter cell during cell division
-non coding DNA 98% = non-coding DNA
coding=exons
non-coding=axons
Form functional RNA molecules which have
regulatory functions
, Replication
Defined as process of making a new DNA molecule from an existing molecule
Why is it necessary Ensures genetic code is passed on to each new
daughter cell formed during cell division
How does it take place ~catalysed by enzyme polymerase
~double helix unwinds
~hydrogen bonds break
~each single chain is exposed
~free nucleotides in nucleoplasm become
attached to their matching, exposed base partners
~One DNA double helix therefore becomes to
identical double helices
~daughter DNA molecules each twist to form
double double helix which then winds itself around
the histones(proteins) forming chromosome
Ribonucleic acid-RNA
Made in nucleus by DNA
Involved in protein synthesis
Structure RNA also polymer made up of nucleotides but
structure differs to DNA
~single strand
~much shorter
~sugar is ribose
~bases are same but uracil replaces thymine
Function ~carries instructions from DNA in nucleus to the
ribosome in the cytoplasm where it controls the
synthesis of proteins from amino acids
Similarities to DNA ~both made of polymers
~nucleotides made up of sugar(ribose), phosphate
and nitrogenous bases
~both responsible for synthesis of proteins
Mitochondrial DNA
3.1 DNA-code of life
Nucleic acids
Deoxyribonucleic Acid
DNA replication
Ribonucleic Acid
Mitochondrial DNA
Protein Synthesis
Gene Mutations
Application of DNA technology
Nucleic acids
-have the capacity to store information that
controls cellular activity and the development of an
entire organism
-control synthesis of proteins
-proteins make up the organism
-enzymes(proteins) control chemical processes
inside cells
>Deoxyribonucleic acid
>Ribonucleic acid
Deoxyribonucleic Acid -DNA
Who discovered the structure of DNA? Maurice Wilkins and Rosalind Franklin
-1950s
- X-ray crystallography (diffraction of images of
DNA)
-only wilkins got a Nobel Peace prize
Francis Crick and James Watson
-built model of DNA
-developed ideas about genetic replication
-won nobel peace prize for physiology/medicine
Where is DNA found? -mainly in nucleus
-form part of chromosomes(chromatin network)
Chromatin= chromosomal material made up of
DNA,RNA and histone proteins as found in non-
dividing cells
What is extracellular DNA -small amounts DNA found in mitochondria in
plants and animals and in chloroplasts
,How is DNA made up: Twisted double helix
-What units make up DNA Molecule is long chain(polymer) made up of small
units(monomers=nucleotides)
Each nucleotide has:
~sugar molecule -deoxyribose
~phosphate molecule
~nitrogenous base
adenine(A)
thymine(T)
guanine(G)
cytosine(C)
bases=foundation for genetic code
-double helix Outer 2 strands formed by alternating
sugar/phosphate links (strong bonds)
Rungs formed from pairs of bases linked by weak
hydrogen bonds
Base pairs attached to sugar molecules
-four base pairs linking Adenine to thymine/uracil (2 hydrogen bonds)
Cytosine to guanine (3 hydrogen bonds)
-base pair classification Purines(G and A)
Pyrimidines (T, C, U)
-do bases differ in organisms Only 4 nucleotides in all organisms
-how do organisms differ Sequence of nucleotides differs in each organism
Sequence= genetic code
Role of DNA ~carry hereditary information
~blueprint for organisms growth and development
by coding for protein synthesis
~can replicate for information to be passed down
to each daughter cell during cell division
-non coding DNA 98% = non-coding DNA
coding=exons
non-coding=axons
Form functional RNA molecules which have
regulatory functions
, Replication
Defined as process of making a new DNA molecule from an existing molecule
Why is it necessary Ensures genetic code is passed on to each new
daughter cell formed during cell division
How does it take place ~catalysed by enzyme polymerase
~double helix unwinds
~hydrogen bonds break
~each single chain is exposed
~free nucleotides in nucleoplasm become
attached to their matching, exposed base partners
~One DNA double helix therefore becomes to
identical double helices
~daughter DNA molecules each twist to form
double double helix which then winds itself around
the histones(proteins) forming chromosome
Ribonucleic acid-RNA
Made in nucleus by DNA
Involved in protein synthesis
Structure RNA also polymer made up of nucleotides but
structure differs to DNA
~single strand
~much shorter
~sugar is ribose
~bases are same but uracil replaces thymine
Function ~carries instructions from DNA in nucleus to the
ribosome in the cytoplasm where it controls the
synthesis of proteins from amino acids
Similarities to DNA ~both made of polymers
~nucleotides made up of sugar(ribose), phosphate
and nitrogenous bases
~both responsible for synthesis of proteins
Mitochondrial DNA
