Chapter 3 psychology

• Genotype


  The genetic makeup of an individual based on the genetic material (DNA) inherited from one's genetic contributors
• Phenotype


  An individual's observable characteristics, such as hair color, skin color, height, and build
• Genotype and phenotype are determined by the interaction of genetic material supplied by the sperm and egg
• Allele


  A specific version of a gene
• Dominant allele


  Having the dominant allele either from one parent (Bb) or both parents (BB) will always result in the phenotype associated with the dominant allele
• Recessive allele


  An individual will only display the phenotype if they are homozygous for that recessive allele (bb)
• Homozygous


  Having two copies of the same allele
• Heterozygous


  Having a combination of alleles for a given gene
• Most traits are controlled by multiple genes, but some traits are controlled by one gene
• Cleft chin is a dominant trait, while smooth chin is a recessive trait
• If a person with a cleft chin mates with a person with a smooth chin

  The offspring's chin type depends on which alleles each parent carries
• Cleft chin


  Dominant trait
• Smooth chin


  Recessive trait
• Offspring phenotype when cleft chin parent mates with smooth chin parent

  1. Depends on which alleles each parent carries

  2. If cleft chin parent is homozygous, offspring will always have cleft chin

  3. If cleft chin parent is heterozygous, offspring have 50% chance of cleft chin and 50% chance of smooth chin
• Punnett square is a tool used to predict how genes will interact in the production of offspring
• Sickle cell anemia is a genetic disorder caused by the pairing of two recessive genes
• Phenylketonuria (PKU) is a condition in which individuals lack an enzyme that normally converts harmful amino acids into harmless byproducts
• If two individuals mate who are both heterozygous for the allele associated with PKU

  Their offspring have a 25% chance of expressing the PKU phenotype
• Mutation


  A sudden, permanent change in a gene
• Diversity in genes and associated traits allows some individuals to perform slightly better than others when faced with environmental change
• Race is not a useful variable in genetic research and its continued use represents a potential source of confusion and harm
• Range of reaction


  Our genes set the boundaries within which we can operate, and our environment interacts with the genes to determine where in that range we will fall
• Genetic environmental correlation


  Our genes influence our environment, and our environment influences the expression of our genes
• Epigenetics


  The study of how the same genotype can be expressed in different ways
• Identical twins share the same genetic information but can have different phenotypes due to epigenetic factors
• Adoptees with high genetic risk for schizophrenia


  Were much more likely to develop schizophrenia if raised in a disturbed family environment
• The study on schizophrenia in adoptees shows that both genetic vulnerability and environmental stress are necessary for the disorder to develop
• Glial cells


  Cells that provide scaffolding, insulation, and support for neurons
• Neurons


  Interconnected information processors that are essential for all tasks of the nervous system
• Neurons


  • Consist of a semipermeable membrane, nucleus in the soma, branching dendrites, axon, and terminal buttons
• Neuronal communication


  1. Electrical signal moves down the axon

  2. Neurotransmitters released into synaptic cleft

  3. Neurotransmitters bind to receptors on adjacent neuron
• Membrane potential


  Difference in charge across the neuronal membrane that provides energy for the signal
• Resting potential


  State of readiness where ions are lined up ready to move across the membrane when the neuron becomes active
• Sodium (Na+) is at higher concentrations outside the cell


  Sodium tends to move into the cell
• Potassium (K+) is more concentrated inside the cell


  Potassium tends to move out of the cell
• Inside of the cell is slightly negatively charged compared to outside


  Provides an additional force causing sodium to move into the cell
• The sodium-potassium pump actively transports three sodium ions out of the cell for every two potassium ions in, creating a net negative charge inside the cell
• Loss of the myelin sheath insulation can be detrimental to normal neuronal function, as seen in disorders like PKU and multiple sclerosis
• Specific neurotransmitters fit specific receptors in a lock-and-key relationship
• Positive ions


  Ready to move to areas with a negative charge