PSYC 2015 Chapter Notes - Chapter 4: Lamarckism, Y Chromosome, Cytosine

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8 Feb 2017

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Biological Psychology Chapter 4
Genes- Unites of heredity that maintain their structural identity from one generation to
o Chromosomes- pairs of genes
Composed of a double stranded DNA molecule
DNA- serves as a template for the production of RNA
o Adenine, Guanine, Cytosine, and Thymine
o Adenine, Guanine, cytosine, and uracil
Order of bases determines the type of protein being produced
o mRNA- serves as a template for the synthesis of protein molecules
Homozygous- people with identical pair of genes on the two chromosomes
Heterozygous- unmatched pair of genes
Dominant Gene- shows a strong effect in either the homozygous or heterozygous
Recessive Gene- shows its effect only in the homozygous condition
Sex-linked genes- genes on the sex chromosomes (X + Y)
o Female has 2 X chromosomes
o Male has a X+Y chromosome
o Controls red-green deficiency
Man with recessive gene on his X chromosome is red-greed deficient
Women is color deficient if she has that recessive gene on both of her X
Sex-limited Genes- present in both sexes but active mainly in one sex
o Genes that control the amount of chest hair in men, breast size in women, etc.
Both sexes have the genes, but sex hormones only activate them in one
sex or the other (show effects during puberty)
Autosomal genes- all chromosomes except six-linked chromosomes
Epigenetic changes- when two people are nurtured in the same environment but have
differences in neural and physical activity
Histones-bind DNA into a shape that is more like a string wound around a ball
o After maternal deprivation, cocaine exposure, new learning, etc., the histones
can loosen the DNA and facilitate the expression of that gene
Monozygotic (identical) and dizygotic twins
o Compared to determine heritability of any characteristic
o Different genes are activated in one another
Phenylketonuria- a genetic inability to metabolize the amino acid phenylalanine
o High levels can lead to brain impairment
o Mostly hereditary but environmental conditions can modify it
Evolution- change over generations in the frequencies of various genes in a population
Lamarckian evolution- the idea where in you work out, your children with be born with
bigger muscles
o There is no evidence that it does occur
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