Biological Psychology - the basics Flashcards
(33 cards)
What is biological psychology?
Biological psychology is the study of physiological, evolutionary, genetic and developmental mechanisms of behaviour, actions and experiences. It posits that we think and act as we do because of certain brain mechanism, which evolved because ancient animals with these traits reproduced better than animals with different mechanism.
What is the mind-body problem?
Mind-body problem: Why is there consciousness? What is the relationship between mental experience and brain activity?
What is the functional explanation?
- Describes why a structure of behaviour evolved as it did. Assumes most genes have or had a purposeful function at one time.
- Example: birdsong – Only the male sings and only during reproductive seasons and only in his territory. Attracts females, warns away other males, and only in a radius it can defend. Birdsong increase chances of mating.
What is the physiological explanation?
- Relates behaviour to the activity of the brain and other organs
- Machinery of body- chemical reactions that enable hormones to influence brain activity and the routes by which brain activity control muscle contractions.
- Example: birdsong – a particular area of birdsong brain grows by influence of testosterone; hence larger in breeding males than females or children. That brain area enables a mature male to sing.
What is the etiological explanation?
- How a structure or behaviour develops by influences of genes, nutrition experience and interactions.
- Impulse control increases with age reflecting the development of the pre-frontal parts of the brain
- Example: birdsong – a young male learns its songs by listening to adults. Development of song requires certain set of genes and opportunity to hear appropriate song during crucial period in life
What is the physiological explanation?
- Relates behaviour to the activity of the brain and other organs
- Machinery of body- chemical reactions that enable hormones to influence brain activity and the routes by which brain activity control muscle contractions.
- Example: birdsong – a particular area of birdsong brain grows by influence of testosterone; hence larger in breeding males than females or children. That brain area enables a mature male to sing.
How does inheritance occur?
Inheritance occurs through genes that maintain their structural identity from one generation to another
What are the properties of DNA?
- DNA is composed of four nucleotides in any order: Adenine, Guanine, Cytosine, Thymine
- Genes are in the nucleus of every cell in the body (except red blood cells)
- (Generally) genes come in pairs aligned along Chromosomes.
What are the properties of Chromosomes?
- Chromosomes come in pairs, with humans having 46 (23 pairs)
- Chromosomes are composed of the double stranded molecule of Deoxyribonucleic Acid (DNA)
- Sometimes genes overlap on a stretch of chromosomes, some genetic outcomes depend on pairs of two or more chromosomes.
What are the properties of RNA?
RNA consists of Adenine, Guanine, cytosine, Ucaryl
What are the properties of Proteins?
- Proteins consist of 20 amino acids, and their order depends on the order of DNA and RNA bases.
- Some proteins form part of the structure of the body. Others act as Enzymes (catalysts) that regulate chemical reactions in the body.
- Packaging DNA: Histones and non-histone proteins help condense and organse DNa in to chromatin, enabling them to fit in the nucleus of a cell
-Regulating gene expression: transcription factors and other DNA-binding proteins control which genes are turned on or off
-DNA replication and repair: Enzymes like DNA polymerases and repair proteins ensure that DNA is accurately copied and repaired
-Protein synthesis: Ribosomes, which contain proteins and RNA, are responsible for translating mRNA into proteins.
What proteins are associated with DNA?
- Histones – small, basic proteins that package DNA into structures called nucleosomes, which are the fundamental building blocks of chromatic.
- Non-histone chormosonal proteins: diverse group of proteins that contribute to chromatic structre and otganisation, include proteins involved in DNA replication, repair and transcription.
- Transcription gacots: these proteins bind to DNA to control the rate of transcription (the process of copying DNA into RNA)
- RNA polymerase: the enzyme responsible for transcribing DNA into RNA.
Types of genes?
- Homozygous – same genes.
- Heterozygous – different genes
- Genes are either dominant, recessive or intermediate.
Sex linked genes and their properties?
- Sex chromosomes X and Y are sex-linked genes.
- All other genes are autosomal genes.
-In mammals, XX is female and XY is male. X accounts for 27 proteins, Y accounts for about 1500. - When passing on genes, if 8% of human X chromosomes contain one code, 8% of men will have it but less than 1% of women (0.8 x 0.8)
Sex-limited genes and their properties?
- Sex limited genes are present in both sexes, generally on autosomal genes, but tend to be only active in one sex.
- Both sexes have them but they are acted by particular hormones, e.g. chest hair, breast development.
Types of Genetic change?
- Mutation is an hereditary change to a gene by a change in the DNA molecule.
E.g. the mutation of the FOXP2 gene in humans compared to chimpanzees, despite just two base changes, resulted in the ability for language development. - Duplication – a chromosome that should appear once might appear twice
- Deletion – a chromosome that should appear might not appear
- Microduplications and microdeletions are where part of the chromosome duplicates or deletes
–Could explain schizophrenia
What is epignetics and what two examples?
The study of heritable changes in gene expression that occur without alternation in the DNA sequence. Environmental factors and lifestyle choice (drugs, diet, exercise, toxins, maternal environment) can influence how genes are used, effectively turning them onn or off without changing the underlying code.
Examples
1. Malnourished rat mothers have children who express genes that conseve energy (which can result in obesity and heart disease in abundant societies)
2. Rats that are not loved or groomed alter gene expression in the hippocampus and are thus more vulnerable t emotional stress reactions in later life.
What is gene expression, what is the biochemical process and how does it function?
- The process of using a gene to make a protein, including transcription and translation, is called gene expression
- Proteins called histones bind DNA in a shape like string around a ball.
- The histones have loose ends at which various chemical groups can attach. To activate a gene, the DNA must be partially unwound from the histone.
- Experience, e.g. maternal deprination, cocaine exposure, new learning, etc bring new proteins into the cell or in other ways alters chemical environment.
- Acetyl groups (COCH3) fasten to the tail of histones, loosening the DNA and allowing expression of the gene.
- Adding Methyl groups (CH3) turns genes off, and removing them turns them on.
Heredity Vs Environment. What is it the difference, what are for and against arguments, what groups are generally tested, and what are commonly found hereditable behaviours?
Do observed differences amongst individuals depends more on difference in heredity or differences in environment?
- A stronger resemblance in behaviour between monozygotic and dizygotic twins suggests higher hereditability.
When using virtual (adopted) twins, similarities can be attributed to environment.
- Researchers have found evidence for significant heredity of almost all behaviour they tested. For example, certain genes are more common than average amongst people with depression. Lonliness, neuroticism, television watching, social attitudes and speed of learning a second language all show strong affinity with heredity. Only religious affiliation was shown to have little link to heredity.
- NB: Heredity is never absolute. It applies to a particular population at a particular time.
How can the environment modify hereditability?
Even a trait with hereditability can be modified by environmental interventions. For example, phenylketonuria is the genetic inability to metabolise the amino acid phenylalanine which gains toxic levels and causes mental retardation, restlessness and irritability. If diet is change to avoid certain foods, especially those containing aspartame, the chance of retardation can be significantly reduced.
How do genes affect behavior? Directly and indirectly.
- If someone says “a gene for brown eyes” then mean there is a gene that produces a protein that makes eyes brown (assuming normal health and nutrition).
- A gene for alcohol, for example, would product proteins under certain circumstances that increase the probability of alcoholism.
- Some genes control brain chemicals, others affect behaviour indirectly. E.g. really pretty girl is always shown attention and thus her personality is changed as a result of an alteration in her environment. Or imagine someone with genes promoting running speed and coordination resulting in early success at basketball. A child may spend more time on sports, and consequently less time on everything else. Genes can influence behaviours in roundabout ways.
What is the evolution of behaviour?
- Evolution is a change over generations in the frequencies of various genes in a population.
- Biologist have created evolution trees that show similarities between various species which they infer that these animals have a common ancestor.
How do species evolve?
- Offspring generally resemble their parents
- Mutations, recombination, and microduplications of genes introduce new heritable variations (good and bad!)
- Successful individuals mate more, passing on their genes. Assumption: any gene with greater reproductive success will become more prevalent in generations.
What is evolutionary psychology?
Evolutionary psychology concerns how behaviours evolved. The emphasis is on evolutionary and functional explanations, that natural selection of these genes occurred because they were or are favourable.
Example: Researchers have found that there are several genes significantly more common among people who remain healthy and alert at the age of 85 and beyond.
