CCJ4601 HUMAN BEHAVIOR FINAL EXAM REVIEW FROM BOOKS Beaver ch 2 5 4 Remember the complimentary base pairs of DNA is always present but not shown The main function of genes is to code for the production of proteins o Only about 10 of the human genome actually codes for the production of proteins Genes only contain the instructions needed for a specific protein to be produced The central dogma of molecular biology transcription and translation o Transcription the process whereby a gene duplicates itself onto a new molecule called ribonucleic acid RNA Splicing transforms RNA into mRNA RNA contains uracil U instead of thymine T o Translation mRNA meets up with and attaches itself to a ribosomes which are protein manufacturing machines found in the cytoplasm On average about 1200 base pairs equating to about 400 amino acids are needed to produce one protein During transcription a gene is copied from DNA RNA During translation RNA works in conjunction with ribosomes to produce a protein The protein is what is ultimately responsible for bringing about phenotypes Genotypic variance has the potential to explain phenotypic variance Genetic locus location of where gene is found Alternative copies of a gene are referred to as alleles and genes that consist of 2 or more alleles are called genetic polymorphisms Polymorphic genes that consist of 2 identical alleles are said to be homozygous o Heterozygous is when the 2 alleles are different SNP Single nucleotide polymorphism due to a difference in a single nucleotide base where 1 alleles are indistinguishable except for a one letter difference o 90 percent of all genetic polymorphisms are SNPs o nonsynonomous SNPs that result in the production of different amino acids o synonymous SNPs that do not result in the production of different amino acids be traced to SNPs o approximately 85 of all genetic disorders including terminal diseases can Microsatellites result of allelic differences that vary in their end to end length where one allele is longer than another allele o Surface because of differences in the number of times that a short section of base pairs is repeated Minisatellites repeat sequences that occur in much larger blocks of base pairs o VNTR variable number of tandem repeats 3 ways genotypic variance can produce phenotypic variance monogenic effect one gene is the cause of one particular phenotype o can be due to recessive or dominant patterns of inheritance polygenic effect the result of multiple genes o ex human behavioral phenotypes too complex to be determined by a single gene Pleiotrophy captures the effects that a single gene has on various different phenotypes How neurotransmitters can be discarded from the synapse The presynaptic neuron can produce a transporter protein that enters the synapse caputres the neurotransmitters and returns then to the axon terminal of the presynaptic neuron REUPTAKE Production of enzymes o Enzymes breakdown neurotransmitters into inactive particles Enzymes and transporter proteins are both vitally important in maintaining normal levels of neurotransmitters in the synapse o The production of enzymes and transporter proteins in determined by genes some of which are polymorphic Dopamine is an excitatory neurotransmitter that activates postsynaptic dopamine receptors making an action potential more likely to occur in the postsynaptic neuron o Sleeping eating and sex all stimulate the release of dopamine o Dopamine levels vary in part because of the different alleles that are inherited for these polymorphic genes Serotonin is a neurotransmitter with inhibitory properties and the release of serotonin is thought to reduce innate drives regulate behaviors and control impluses o Significant relationship between low levels of serotonin and antisocial behaviors o Levels of serotonin vary from person to person because of environmental factors and because of certain genetic polymorphisms that are involved in the production transportation and degradation of serotonin Brain weight approx 3 pounds More than 60 of the entire genome codes for the brain Chapter 4 o Some of the genes that code for the brain are polymorphisms and different alleles for some of these polymorphisms have been found to correspond to variation in specific regions of the brain Limbic System Generates emotions Affects the endocrine system and the autonomic nervous system Amygdala vitally important to aggression and other antisocial phenotypes emotional hub of the brain and is responsible for generating feelings such as anger rage and fear o Involved in emotional learning and fear conditioning presence of a stimulus is paired with a response Hippocampus involved in formation of long term or declarative memories o Vitally important to the laying down of new memories o Damage to the hippocampus will not erase memories but it will preclude the ability to form new ones o Also involved in emotional learning and fear conditioning Thalamus brain s relay station o Receives incoming messages from systems throughout the body organizes and prioritizes these messages and it then dispatches them to the cerebral cortex where they are processed Hypothalamus regulation of visceral functions including the modulation of body temperature When stressful situations are encountered the hypothalamus emits the hormone corticotrophin releasing factor CRF CRF triggers the pituitary gland to release the adrenocorticotrophic hormone ACTH Last ACTH stimulates the adrenal glands to produce cortisol which is the main stress hormone Cerebral Cortex cerebrum or neocortex accounts for approximately 2 3 of the brain s volume corpus callosum large bundle of fibers that allows the 2 hemispheres to communicate with each other grey matter neuronal cell bodies and their synaptic connections has been found to be positively correlated with cognitive abilities and skills including intelligence o where info processing occurs white matter consists of myelinated axons axons covered with a fatty sheath that increases the speed with which info is processed in the brain o the means by which info is transferred throughout the brain occipital lobe back of brain vision parietal lobe center of cerebral cortex governs voluntary motor skills temporal lobe above the ears hearing and language frontal lobe behind forehead higher order cognitive functions prefrontal cortex executive controller of the brain o curtails or suppresses emotionally charged behaviors o subdivided into 3 regions o 1