cueprepAP Psychology Unit 2: Biological Bases of Behavior — Complete Review
Unit 2 explores the biological machinery underlying all behavior and mental processes. You'll start at the cellular level with neurons — learning how electrical impulses travel down axons, how neurotransmitters cross synapses, and how different neurotransmitters (dopamine, serotonin, acetylcholine, GABA, glutamate, endorphins, norepinephrine) influence mood, movement, memory, and more.
From neurons, the unit scales up to brain structures. You'll study the lobes of the cerebral cortex (frontal, parietal, temporal, occipital), the limbic system (amygdala, hippocampus, hypothalamus), the brainstem, cerebellum, and corpus callosum. Understanding localization of function — which brain areas control which behaviors — is a major exam focus.
The unit also covers the nervous system's organization (central vs. peripheral, somatic vs. autonomic, sympathetic vs. parasympathetic), the endocrine system and its hormones, genetics and heredity (including twin and adoption studies), and brain imaging techniques like fMRI, PET, CT, and EEG.
Key Concepts
Neural Transmission
Neurons communicate via electrical impulses (action potentials) that travel down the axon, triggering neurotransmitter release across the synaptic gap.
Neurotransmitters
Chemical messengers including dopamine (reward/movement), serotonin (mood/sleep), acetylcholine (memory/muscle), GABA (inhibition), and glutamate (excitation).
Brain Localization
Different brain regions control specific functions: Broca's area (speech production), Wernicke's area (language comprehension), motor cortex (movement), etc.
Limbic System
Brain structures including the amygdala (fear/emotion), hippocampus (memory formation), and hypothalamus (homeostasis, hunger, thirst, body temperature).
Nervous System Divisions
The CNS (brain and spinal cord) and PNS (somatic and autonomic), with the autonomic further divided into sympathetic (fight-or-flight) and parasympathetic (rest-and-digest).
Endocrine System
Glands that secrete hormones into the bloodstream — the pituitary gland ('master gland'), adrenal glands (cortisol, adrenaline), thyroid, and gonads.
Brain Plasticity
The brain's ability to reorganize and form new neural connections, especially after injury or during learning.
Hemispheric Specialization
The left hemisphere typically handles language and logic; the right hemisphere handles spatial tasks and holistic processing. Split-brain studies (Sperry) demonstrated this.
Key Terms & Vocabulary
40 terms you need to know for Unit 2. Use our flashcards to memorize them with spaced repetition.
Study Unit 2 with Flashcards
Master Biological Bases of Behavior using spaced repetition — the science-backed method that puts concepts in long-term memory with less study time.
Frequently Asked Questions
What is AP Psychology Unit 2 about?
Unit 2 covers the biological bases of behavior, including neurons and neural transmission, neurotransmitters, brain structures and their functions, the nervous and endocrine systems, genetics and heredity, and brain imaging techniques.
How much of the AP Psychology exam is Unit 2?
Unit 2: Biological Bases of Behavior makes up approximately 8–10% of the AP Psychology exam.
What neurotransmitters do I need to know for AP Psychology?
The key neurotransmitters are dopamine (reward, movement), serotonin (mood, sleep), acetylcholine (memory, muscle activation), GABA (inhibition), glutamate (excitation), endorphins (pain relief), and norepinephrine (arousal, alertness). Know what each does and what happens when levels are too high or too low.
What brain structures are most tested on the AP Psychology exam?
The most-tested structures include the four cortical lobes (frontal, parietal, temporal, occipital), Broca's and Wernicke's areas, the amygdala, hippocampus, hypothalamus, thalamus, cerebellum, and corpus callosum.