IB Psychology: Hormones, Pheromones, and Genes

Neurotransmitters

Chemical signals; fast acting signals that are released into the synapse to affect neurons, muscles, or glands.

Hormones

Chemical Signals; slower activng signals released into the blood stream to affect a wide range of cells across the body.

Pheromones

Chemical Signals; released into the environment to affect other members of the same species.

What type of changes might a hormone cause in a target cell?

Hormones may change membrane permeability (that is, they may open or close gates or pumps in the cell membrane), cause a cell to make more or less of a certain protein, or may trigger cell growth.

Name one hormone and the gland it is released from.

Oxytocin is released from the pituitary gland.

Oxytocin

released from the pituitary gland; plays a role in childbirth and breastfeeding

Describe the psychological effects of one hormone.

Oxytocin promotes trust and bonding between individuals, especially between parents and children and between romantic partners. Oxytocin may also lead to increased in-group bias.

What types of behaviors are commonly associated with pheromones in animals?

Pheromones are commonly associated with mating, searching for food, and alarm signalling in other animals.

Name the pheromone studied in Mishor et al (baby study) and describe its effects

Hexadecanal is a putative pheromone found on baby's heads. In the Mishor study, hexadecanal increased aggression in women and decreased aggression in men.

What is the specialized structure found in lizards, snakes, and some mammals for detecting pheromones. Do humans have it?

Lizards, snakes, and some mammals have a specialized structure called a vomeronasal organ (VNO) for detecting pheromones. In humans, this structure is vestigial (no longer functioning)

Gene

regions of DNA that encode the information to make one protein.

Alleles

different versions of the same genes.

Genotype

the collection of alleles a person has.

Phenotype

the trait that is expressed.

Gene Expression

the production of a product (e.g. protein) from a gene.

Epigenetics

inherited OR environmentally induced changes that affect gene expression.

What are Epigenetic Modifications

change how much or whether a certain protein is produced, but do not change the DNA sequence or the structure of the protein.

type one of epigenetic modifications

methylation stops expression

type two of epigenetic modifications

histone modificaiton can increase or decress protein expression.

Mutations

random, ireversible, and change the sequence of DNA.

Epigenetic Modifications

Epigenetics are environmentally influenced, are reversible, and do not change the sequence of DNA.