Developmental Psy 1

8/9/2019 Developmental Psy 1

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Biological Beginnings

Module 2

Part 1- GeneticFoundations


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The genetic process

Cell

Nucleus

Chromosomes

DNA

Genes


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Chromosomes

Threadlike structuresthat contain thegenetic substanceDNA.


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DNA (Deoxyribonucleic

acid)

A complex moleculethat contains geneticinformation.

Within cells, DNA isorganized into X-shaped structurescalled chromosomes


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Genes

Units ofhereditaryinformation composed ofDNA. Genes direct cells to

reproduce themselves andmanufacture the proteinsthat maintain life

A gene is the basic unit of

heredity in a living organism.


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Genome

The complete set ofdevelopmental instructions forcreating proteins that initiatethe making of a humanorganism.


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Mitosis

Cellular reproduction inwhich the cells nucleus

duplicates itself with twonew cells being formed,each containing the sameDNA as the parent cell,

arranged in the same 23pairs of chromosomes.


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Meiosis

A specialized form of celldivision that occurs to

form eggs and sperm.


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Zygote

A single cell formedthrough fertilization.

It is the next stage in inthe process of ofreproduction.


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Sources of variability

X chromosome and Ychromosome

Genotype- all of a personsgenetic material.

Phenotype-the way anindividual genotype isexpressed in observed and

measurable characteristics.

Heredity environmentinteraction.


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Genetic principles

Dominant recessive genesprinciple

Sex linked genes

Genetic imprinting

Polygenic inheritance


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Dominant recessive genes principle

Dominant Inheritance a pattern ofinheritance in which, when a child receivescontradictory alleles, only the dominant one isexpressed.

Recessive Inheritance a pattern of

inheritance in which a child receives identicalrecessive alleles, resulting in expression of anon dominant trait.

Alleles paired genes (alike or different) that

affect a trait. When bot

hthe alleles are t

hesame , the person is is homozygous . When

they are different the person is heterozygous.


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Homozygous possessing two identicalalleles for a trait.

Heterozygous possessing differingalleles for a trait.

Polygenic inheritance pattern ofinheritance in which multiple genes

affect a complex trait.

Multifactorial transmission acombination of genetic andenvironmental factors to produce certaincomplex traits.


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Chromosomal and gene linkedabnormalities

Down syndrome trisomy 21.

Failure of the 21st chromosome toseparate during meiosis. In some cases anextra broken piece of a 21st chromosomeis present.

Downs syndrome is characterized by-

Mental retardation.

Memory and speech problems, limitedvocabulary and slow motor development.


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Distinct physical features which include-a short stocky build, a flattened nose, a

protruding tongue, almond shaped eyes,and an unusual crease running acrossthe palm of the hand.

Others conditions include eye

cataracts, heart and intestinal defects

Short lifespan.

Difficulties in breathing and feeding.


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Other abnormalities.

Cooley anemia (R)

Cystic fibrosis (R)

Phenylketoneuria (R)

Sickle cell anemia (R)

Tay sachs disease (R)

Huntington disease (D)

Marfan syndrome (D)


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Abnormalities related to the

sex chromosomes

XYY syndrome extra ychromosome. Above avgheight, large teeth andsometimes severe acne.Intelligence male sexualdevelopment and fertilityare normal

1 in 1000 male birthsNo special treatment isnecessary.


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Triple X syndrome- extra

X chromosome . Tallnessand impaired verbalintelligence. Female sexual

development and fertilityare normal.

1in 500 to 1250 female

births

Special edu to treat verbaland ability problems.


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Klienfelter syndromeXXY extra Xchromosome. Tallness, body

fat distributing females,incomplete development ofsex characteristics atpuberty, sterility, andimpaired verbal intelligence.

1 in 900 male births .

Hormone therapy atpuberty to stimulatedevelopment of sex

characteristics.

Specialeducation to treat verbal

ability problems.


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Tuner syndrome (XO)- missingx chromosome. Short stature,

webbed neck, incompletedevelopment of sex characteristicsat puberty, sterility and impairedspatial intelligence.

1 in 2500 to 8000 female births.

Hormone therapy in childhood tostimulate physical growth and atpuberty to promote development

of sex characteristics. Special eduto treat spatial ability problems.


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References

Documents

Developmental Psy 1