5.2
Differences or variation in DNA are what makes us different from each other!
Each human cell contains 46 chromosomes Each cell has 3 billion base pairs of DNA (wow!)
Our DNA is 99.99% similar
Of the 6 billion base pairs of DNA, only 5% are in the genes that code for RNA and proteins.
Errors can occur when DNA is copied UV light, X-rays, chemicals, etc. affect DNA
Substitution – Exchanges one base for another. CTGGAG---- CTGGGG
Insertion – Extra base pairs are inserted.CTGGAG---- CTGGTGGAG
Deletion- Section is lost, or deleted. CTGGAG -----CTAG
Frameshift- Message is no longer read correctly.THE FAT CAT SAT --- HEF ATC ATS
AT
Cells have different ways to repair mistakes
Certain enzymes can proofread DNA such as correcting mismatched base pairs
1. The mutation causes no effect.1. Amino acids have more than 1 code2. Enough protein may be produced already
2. The effect of a mutation is minor.1. Could affect skin/eye/hair pigmentation
3. The effect of a mutation is great.1. Genetic disorder/disease
Sometimes passed from parents to offspring Sickle Cell AnemiaCystic Fibrosis (CF)HemophiliaTay- Sachs Disease Huntington’s Disease (HD)HypercholesterolemiaCancer
People can carry a tendency for a disease.Alzheimer'sEmphysemaDiabetesCancer
Their behavior can prevent it:Not smoking can prevent emphysema and many
types of cancer
Most genetic disorders cannot be cured, although progress is being made.
Families who have a history of genetic disorders are recommended to undergo counseling before having a child. They can find out how it could affect their offspring.
Some genetic disorders can be treated if diagnosed early enough, such as PKU (lacking a certain enzyme). If known, that child can be put on a certain diet
and medicine routine.
Mutation occurs on gene that codes for hemoglobin
Hemoglobin – a protein that carries oxygen in red blood cells
Mutation causes 1 amino acid to be replaced with another
Need 2 recessive genes to be affected (ss)
Can be a carrier (Ss)
5.3
Random changes in DNA can introduce new traits in an organism
Humans can breed animals to get the certain traits they want.Ex: a cow that gives
more quantities of milk
The process of selecting and
breeding parent organisms to pass on particular traits to the offspring.
Bloodhound – strong sense of smell
A sequence of DNA from an organism is first isolated, then inserted into the DNA of another organism.
The DNA inserted usually codes for a particular trait of interest
GMO – Genetically modified organism
Can make plants more insect resistant.
Create crops suitable for areas with poor soil conditions
PROS CONS
Food can be resistant to certain bacteria and pests.
Reduces chemical pesticides
Increases food production
Add nutrients
Possibly harmful to the human body but still unknown
Could risk wild population like salmon
Can be used to produce new and better drugs for treating disease
Determine the side effects of a drug on an individual
Can be used to screen for and treat genetic disorders
May soon allow scientists to correct certain recessive genetic disorders by replacing defective genes with copies of a healthy one.
First step of gene therapy is to isolate a copy of the gene.
Scientists are trying to input that gene into the cell by attaching it to a cold virus. Attempts in humans have not been successful.
However, the outlook is promising.
Crime scenes – skin, hair, blood
DNA profile – a DNA fingerprint
Everyone different except identical twins!
All the genetic material in an organism.
The human genome project wanted to sequence all of the human genome (that’s a lot)
We can then compare DNA across speciesWe have similar genes to fruit flies and
mice
A technique that uses technology to make copies.
Can be applied to a segment of DNA or a whole organism
Dolly
Place gene that codes for producing insulin
That bacteria then replicates in large numbers
Treats people with diabetes
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