[NATS 1670] - Final Exam Guide - Ultimate 63 pages long Study Guide!

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NATS 1670
FINAL EXAM
STUDY GUIDE
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SC/NATS1670 – Concepts in Human Health and Disease
Midterm 2 – Study Notes
Midterm Date: Sunday December 6th, 2015
Topics to Study: Translation, mutations, cancer, immune system, vaccination and
passive immunization
Part A – Introduction
Mutations
- In the living cells, DNA undergoes frequent chemical change, especially when
it is being replicated
- Most of these changes are quickly repaired
Evolution is based on mutation
We are different from one generation to the other
It helps us to do better and cope with the changing environment
- Those that are not repaired quickly result in a mutation
Thus, mutation is a failure of DNA repair
DNA Repair
- Mutation can result from the incorporation of incorrect bases during DNA
replication
- Most spontaneous changes in DNA are temporary because they are
immediately corrected by processes collectively called DNA repair
- Most damage to DNA is repaired by removal of the damaged bases followed
by resynthesis of the excised region
The Length of DNA
- Human DNA of one cell is 2 meters long
- 1016 cells are produced in a human lifetime
- 2 x 1016 km of DNA
From the Double Helix to the Chromosome
- Human DNA – 2 meters long packed into the nucleus (0.006 mm) of a cell
- DNA is bound with proteins which reduce the length of the molecule
- The DNA wrap around histones (protein found in eukaryotic cell) to form
nucleosomes
- The chromosome is a result of several levels of DNA packaging
The Molecule Basis of Mutation
- A mutation is any change in an organism’s DNA sequence
- Proteins, encoded by the genotype produce the phenotype (the traits that we
can see of the mutation)
- Only about 1.5% of the genome is responsible for genes to make proteins
- Hence, the DNA affect the phenotype only when the mutation is expressed
(DNA  RNA  Protein) and the resulting functions abnormally
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- Not all mutations affect protein’s ability to function and thus do not generate
a phenotype
- One of the most common types of mutations is the point mutation, a change
in a single nucleotide
- Point mutations can result from errors in DNA replication or from exposure
to mutagenic toxins
- Many things in the environment can create mutations such as smoking
cigarettes
- Genome – an organism is the inherited instructions it carries within its
genetic code
- Phenotypes – organism’s observational characteristics
The Genetic Code
- Triplet code
- 61amino acid codons for 20 amino acids
- 3 stop codons to terminate protein synthesis
Silent Mutation
- Mutations that do not change the amino acid sequence of the protein are
known as silent mutations
- For example
CGG TAT TCG ATG AAG – original sequence
Arg Tyr Ser Met Lys
CGC TAT TCG ATG AAG – Silent Mutation
Arg Tyr Ser Met Lys
Mutations that do not change the amino acid sequence of the
protein are known as silent mutations
Missense Mutation
- A substitution in a nucleotide sequence resulting in a codon that specifies a
different amino acid
- For example
CGG TAT TCG ATG AAG – original sequence
Arg Tyr Ser Met Lys
CGG TAT TTG ATG AAG – Missense Mutation
Arg Tyr Leu Met Lys
A point mutation that causes a change in the amino acid
sequence of the protein is a missense mutation
Nonsense Mutation
- Point mutation that creates a new stop codon
- A substitution in a nucleotide sequence that causes an amino acid codon to
be replaced by a stop codon
- For example
CGG TAT TCG ATG AAG – original sequence
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Document Summary

Topics to study: translation, mutations, cancer, immune system, vaccination and passive immunization. In the living cells, dna undergoes frequent chemical change, especially when it is being replicated. Most of these changes are quickly repaired. We are different from one generation to the other. It helps us to do better and cope with the changing environment. Those that are not repaired quickly result in a mutation. Thus, mutation is a failure of dna repair. Mutation can result from the incorporation of incorrect bases during dna replication. Most spontaneous changes in dna are temporary because they are immediately corrected by processes collectively called dna repair. Most damage to dna is repaired by removal of the damaged bases followed by resynthesis of the excised region. Human dna of one cell is 2 meters long. 1016 cells are produced in a human lifetime. Human dna 2 meters long packed into the nucleus (0. 006 mm) of a cell.

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