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Chapter 2

BIO 103 Chapter Notes - Chapter 2: Genetic Disorder, Genetic Linkage, Sickle-Cell Disease

Course Code
BIO 103
Kristen Vadasz

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BIO 103: Intro to Biotechnology
Ch. 2
- Genes contain instructions for making cells and for work tht goes in them
- Genome = complete set of genes for an organism
- Genes made of threadlike material called DNA
a. Contains chemical bases (adenine, guanine, thymine, cytosine)
Your Unique Genome
- Each person’s genome is unique; starting from conceptions
- Sperm and eggs made from germ cells
- Genome divided into separate strands called chromosomes containg several thousand genes
a. Humans have 46 chromosomes
- Production of gametes
a. Germ cells make copy of each chromosome divides 2x to form four sperm/egg cells so
each half has 23
- Crossing over section of one chromosome switches places with the same section from its pair
a. Makes the copied chromosome a little different from the original
Dominant and recessive genes
- Chromosomes inherited from each parent correspond in size and in genes they carry
a. Exception = chromosome that determines sex
i. XX = female; XY = male
ii. X is larger and contains genes not found in Y
- Dominant = instructions are followed whenever it’s present
- Recessive = instructions followed only when neither gene in pair is dominant
How Genes Instruct Your Body
- Leads production of proteins
a. Basic chemicals tht make up struct of cells and direct their activities
- A gene in one person may carry slightly diff instruction than corresponding gene
a. Usually don’t cause health problems
b. i.e. green eyes vs brown eyes
- Variations in instruction carried by gene come from mutation
- Mutation = change that occurs to order of bases appearing in the DNA inside a cell
- Can affect the traits that show up
- Most are harmless b/c they don’t result in important changes to traits
- Some may cause problems disorders
- Sickle shaped blood
a. Found mainly in ppl who live near equator helpful against malaria
b. If inherit two copies of this gene sickle cell anemia
i. Too many sickle shaped hard for blood to flow
Genetic Testing
- Prenatal tests done before birth to embryo to see if it has genetic issues
- People may want to be tested to learn risk of passing on genetic disorders to children
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