PS102 Chapter Notes - Chapter 4: Environmental Modification Convention, Freckle, Heredity

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24 Jan 2017
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4.3 HEREDITY AND PRENATAL DEVELOPMENT
-prenatal period encompasses the nine months or so from conception to birth
-biological parents contribute half genetic material required to create new person each
-at moment of conception baby's genes and sex are set
-growth following occurs at exponential rate
In the Beginning: Genetics
Genes:
-most basic building blocks of biological inheritance
-each composed of specific sequence of deoxyribonucleic acid (DNA) molecules
-DNA and genes are arranged in strands called chromosomes found in each cell of our bodies
-in most cases each sperm and each egg have 23 chromosomes
-when sperm fertilizes egg, single-celled organism usually with 46 chromosomes, is created
-majority of conceptions containing errors in number of chromosomes end in miscarriage
-however 1/150 children are born with too many or too few chromosomes
Genotype:
-23 chromosomes contributed by each biological parent
-resulting combination is called genotype
-person's genetic inheritance
-genetic inheritance contained in 23 pairs of chromosomes
-each parent contributes one chromosome to each pair
Phenotype:
-observable manifestation of that genotype
-physical and psychological characteristics on display in each individual
-difficult to determine person's genotype solely based on phenotype
Alleles: variations of same gene (such as freckle gene)
Homozygous: if both parents contribute same allele then offspring is homozygous for the trait
-two matching alleles of same gene
Freckles:
-genetically determined, either born with them or not
-if you have freckles, you display freckles phenotype
-without further info however you cannot say what genotype is
-someone with freckles may be homozygous
-people have freckles if they inherit a freckles allele and a non-freckles allele
-this means they have phenotype of freckles but genotype is heterozygous
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Document Summary

Prenatal period encompasses the nine months or so from conception to birth. Biological parents contribute half genetic material required to create new person each. At moment of conception baby"s genes and sex are set. Each composed of specific sequence of deoxyribonucleic acid (dna) molecules. Dna and genes are arranged in strands called chromosomes found in each cell of our bodies. In most cases each sperm and each egg have 23 chromosomes. When sperm fertilizes egg, single-celled organism usually with 46 chromosomes, is created. Majority of conceptions containing errors in number of chromosomes end in miscarriage. However 1/150 children are born with too many or too few chromosomes. Genetic inheritance contained in 23 pairs of chromosomes. Each parent contributes one chromosome to each pair. Physical and psychological characteristics on display in each individual. Difficult to determine person"s genotype solely based on phenotype. Alleles: variations of same gene (such as freckle gene)

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