Chapter 3 Flashcards
Define evolution from a biological perspective
A change in the frequency of an allele or genotype in a population over time
Describe how a gene’s expression influences phenotype
- DNA inside the nucleus is transcribed into RNA Phenotype
- RNA is translated by ribosomes in the cell into proteins
- Each protein has a specific function that contributes to determining every trait expressed by an organism. This expressed trait is called a phenotype
explain why mutations are the ultimate source of all genetic variation
mutations represent a “mistake” that occurs during DNA replication
List and explain Darwin’s 3 conditions of natural selection
- Individuals within the population must vary in phenotypic traits
- At least some of the variation must have a genetic basis (i.e., is heritable)
- This variation must influence reproductive success in terms of survival or reproduction
major components of the neuron and their function
- Cell body (soma): builds new cell components
- Dendrites: receive information
- Axons: transit information
- Axon terminal: contains synaptic vesicles filled with neurotransmitters
- Myelin sheath: increases the speed of neuronal transmission
Explain the major steps of the action potential and how they help neurons communicate via the synapse
- Electrochemical impulse traveling down the axon membrane that results in neurotransmitter release
- Triggered by a change inside the axon passing the threshold amount, depolarization occurs. Neurons quickly repolarize. In between firings, there is a very brief absolute refractory period.
what a neurotransmitter is.
Chemical messengers that allow the neuron to neuron communication.
Explain the function of a variety of major neurotransmitters
- Glutamate: increases the likelihood of neurons firing
- GABA: decreases the likelihood of neurons firing.
- Acetylcholine: influences arousal, selective attention, sleep and memory.
- Dopamine: motor function; pleasure; motivation.
- Norepinephrine: physiological arousal and stress; “Fight or Flight” response.
- Serotonin: regulate intestinal function and energy allocation; regulate emotions.
Explain 4 major methods to study the brain.
- Lesion studies.
- Electrical stimulation and single-cell recording.
- Structural neuroimaging. (X-ray CT, MRIs)
- Functional neuroimaging. (EEG, fMRI)
Compare a hormone to neurotransmitters.
- Hormones are molecules that influence particular organs.
- Neurotransmitters are chemical messengers that allow the neuron to neuron communication.
Describe the function of 3 major endocrine organs.
- Pituitary Gland: influences growth, and blood pressure.
- Adrenal Glands: releases adrenaline and cortisol during states of emotional arousal.
- Sexual reproductive glands: testes in males and ovaries in females. Both sexes manufacture testosterone and estrogen
