Shira Woolf MASSIVE Genetics Summary 1
DEOXYRIBONUCLEIC ACID
Watson and Crick made a DNA model (double helix with complimentary base pairs)
1. Nuclear DNA
2. Mitochondrial DNA
3. Chloroplastic DNA
STRUCTURE
Nucleotides (building blocks) à phosphate group, deoxyribose sugar, four nitrogenous bases
connected with weak hydrogen bonds: A+ T = 2 bonds, G+C= 3 bonds, pyrimidines (T+C) , purines
(G+A), double helix
FOUND IN
nucleolus, mitochondria, chloroplast
FUNCTIONS
1. Genes = hereditary info
2. Codes for protein
3. Protects genes from mutations
DNA/GENETIC MUTATIONS
Permanent alteration in the DNA sequence
1. Substitution
2. Insertion
3. Deletion
EFFECTS OF MUTATIONS
HARMFUL: genetic disorders
HARMLESS
USEFUL: have a positive effect on organism e.g., resistance
DNA REPLICATION
DNA makes exact copy during interphase. In nucleolus to double the chromosome number (genetic
material)à chromosomes which are single thread become double
1. Double helix unwinds (helicase)
2. Weak hydrogen bonds break (catalysed by polymerase)
3. Two separate strands act as a template
4. Free floating nucleotide attach to complementary base pair
5. Two new genetically identical DNA strands formed (one original/ one new)
à now MUO 2 chromatids joined by centromere
à double genetic information to share equally
DNA PROFILING
USED FOR: personal info, paternity/maternity, diagnosing inherited diseases, criminal
identification/forensics
DISADVANTAGES
Expensive, human error, false evidence, not all hospitals can carry out
RIBONUCLEIC ACID
MESSANGER RNA
mRNA = carries genetic code for DNA to ribosomes
ROLE IN PROTEIN SYNTHESIS: carry coding sequence
RIBOSOMAL RNA
rRNA = produce proteins based on info received by tRNA
ROLE IN PROTEIN SYNTHESIS: form core of cell’s ribosomes
, Shira Woolf MASSIVE Genetics Summary 2
TRANSFER RNA
tRNA= anticodons which code for specific amino acid. Complimentary to the mRNA codon\
ROLE IN PROTEIN SYNTHESIS: carry amino acids to ribosome
STRUCTURE
Nucleotides (building blocks) à phosphate group, deoxyribose sugar, four nitrogenous bases
connected with weak hydrogen bonds: A+ U, C+G
TABLE SHOWING DIFFERENCES BETWEEN DNA & RNA
DNA RNA
Double helix Singe strand
Deoxyribose sugar Ribose sugar
Always equal number of nitrogenous bases Nitrogenous bases can be arranged in any
number/ sequence
A, G, T, C A, U, G, C
Carry genes needed for protein synthesis Play role in transcription/ translation
Carry hereditary traits
PROTEIN SYNTHESIS
Proteins are made in each cell à forms enzymes + new structures for cell
Genetic code = code used to translate the info stored in DNA into proteins
1. TRANSCRIPTION
à formation of mRNA to copy gene
àsegments of DNA are transcribed into RNA molecules that encode proteins that produce mRNA
1. Double helix of DNA unwinds
2. Helicase breaks hydrogen bonds
3. One strand used as template for mRNA
4. Free mRNA nucleotides attach from nucleus
5. Complementary base pairs
6. mRNA now has coded message/copies gene for protein synthesis
7. moves through nuclear pore to cytoplasm and attaches to ribosome
2.TRANSLATION
à mRNA (codons) corresponds with tRNA (anti-codons)
à a protein is created from the formation of a polypeptide chain
1. mRNA binds to ribosome at start (AUG usually)
2. mRNA provides code for linking amino acids
3. tRNA carries specific amino acids from cytoplasm and brings the correct one to match the
codon (determined by anti-codon)
4. amino acids attach by peptide bonds to form require proteins (50 + more = protein)
DEOXYRIBONUCLEIC ACID
Watson and Crick made a DNA model (double helix with complimentary base pairs)
1. Nuclear DNA
2. Mitochondrial DNA
3. Chloroplastic DNA
STRUCTURE
Nucleotides (building blocks) à phosphate group, deoxyribose sugar, four nitrogenous bases
connected with weak hydrogen bonds: A+ T = 2 bonds, G+C= 3 bonds, pyrimidines (T+C) , purines
(G+A), double helix
FOUND IN
nucleolus, mitochondria, chloroplast
FUNCTIONS
1. Genes = hereditary info
2. Codes for protein
3. Protects genes from mutations
DNA/GENETIC MUTATIONS
Permanent alteration in the DNA sequence
1. Substitution
2. Insertion
3. Deletion
EFFECTS OF MUTATIONS
HARMFUL: genetic disorders
HARMLESS
USEFUL: have a positive effect on organism e.g., resistance
DNA REPLICATION
DNA makes exact copy during interphase. In nucleolus to double the chromosome number (genetic
material)à chromosomes which are single thread become double
1. Double helix unwinds (helicase)
2. Weak hydrogen bonds break (catalysed by polymerase)
3. Two separate strands act as a template
4. Free floating nucleotide attach to complementary base pair
5. Two new genetically identical DNA strands formed (one original/ one new)
à now MUO 2 chromatids joined by centromere
à double genetic information to share equally
DNA PROFILING
USED FOR: personal info, paternity/maternity, diagnosing inherited diseases, criminal
identification/forensics
DISADVANTAGES
Expensive, human error, false evidence, not all hospitals can carry out
RIBONUCLEIC ACID
MESSANGER RNA
mRNA = carries genetic code for DNA to ribosomes
ROLE IN PROTEIN SYNTHESIS: carry coding sequence
RIBOSOMAL RNA
rRNA = produce proteins based on info received by tRNA
ROLE IN PROTEIN SYNTHESIS: form core of cell’s ribosomes
, Shira Woolf MASSIVE Genetics Summary 2
TRANSFER RNA
tRNA= anticodons which code for specific amino acid. Complimentary to the mRNA codon\
ROLE IN PROTEIN SYNTHESIS: carry amino acids to ribosome
STRUCTURE
Nucleotides (building blocks) à phosphate group, deoxyribose sugar, four nitrogenous bases
connected with weak hydrogen bonds: A+ U, C+G
TABLE SHOWING DIFFERENCES BETWEEN DNA & RNA
DNA RNA
Double helix Singe strand
Deoxyribose sugar Ribose sugar
Always equal number of nitrogenous bases Nitrogenous bases can be arranged in any
number/ sequence
A, G, T, C A, U, G, C
Carry genes needed for protein synthesis Play role in transcription/ translation
Carry hereditary traits
PROTEIN SYNTHESIS
Proteins are made in each cell à forms enzymes + new structures for cell
Genetic code = code used to translate the info stored in DNA into proteins
1. TRANSCRIPTION
à formation of mRNA to copy gene
àsegments of DNA are transcribed into RNA molecules that encode proteins that produce mRNA
1. Double helix of DNA unwinds
2. Helicase breaks hydrogen bonds
3. One strand used as template for mRNA
4. Free mRNA nucleotides attach from nucleus
5. Complementary base pairs
6. mRNA now has coded message/copies gene for protein synthesis
7. moves through nuclear pore to cytoplasm and attaches to ribosome
2.TRANSLATION
à mRNA (codons) corresponds with tRNA (anti-codons)
à a protein is created from the formation of a polypeptide chain
1. mRNA binds to ribosome at start (AUG usually)
2. mRNA provides code for linking amino acids
3. tRNA carries specific amino acids from cytoplasm and brings the correct one to match the
codon (determined by anti-codon)
4. amino acids attach by peptide bonds to form require proteins (50 + more = protein)
