Option E Neurobiology and Behavior IB Biology SL

Distinguish between the terms taxis and kinesis.

taxis is a directional response to a stimulus whereas kinesis is a non-directional reponse

Discuss how learning may contribute to an organism’s survival chances. 3 marks

Discuss how learning may contribute to an organism’s survival chances. acquire information from past experiences to adapt to new situations; can better obtain food / shelter; can increase mating chances; learns to avoid dangerous situations; co-operation between individuals may increase survival;

Outline how the visual stimuli is processed by the retina and brain. 2 marks

Outline how the visual stimuli is processed by the retina and brain. photoreceptor cells / rods and cones are stimulated by light; transmit the impulses to the bipolar cells; they transmit the impulse to the ganglion cells; optic nerve transmits impulse to visual cortex (of brain);

Draw and label the components of a reflex arc

receptor and sensory neuron dorsally with cell body in dorsal root ganglion; association/relay neuron within the grey matter; motor neuron and effector drawn ventrally with cell body in grey matter; Structures must be drawn and labeled correctly.

State one function of the hypothalamus. (1mark)

State one function of the Hypothalmus temperature regulation control hunger Osmoregulation Sleep Release hormones from the pituitary gland

Outline what is meant by a mechanoreceptor using a named example. (2 marks)

Outline what is meant by a mechanoreceptor using a named example. respond to a stimulus that causes movement, e.g. pressure, vibration, gravity; Pacinian corpuscle to pressure / pain receptor / free nerve ending / nociceptors in skin / touch in skin / hair cells in inner ear

State one example of an excitatory and one example of an inhibitory psychoactive drug. (2 marks)

State one example of an excitatory and one example of an inhibitory psychoactive drug. excitatory: cocaine / nicotine / amphetamines; inhibitory: benzodiazepines / alcohol / THC;

Explain the effects of cocaine on the brain. (3 marks)

excitatory (psychoactive) drug; cocaine attaches to dopamine pumps/transporters (on presynaptic membrane); blocks uptake/recycling / causes dopamine to persist in the synaptic cleft; amplifies synaptic transmission / causes constant stimulation of postsynaptic neuron; causes euphoria/feelings of happiness/pleasurable effects;

Discuss causes of addiction. (3 marks)

Discuss causes of addiction. addictive drugs trigger secretion of dopamine which causes feelings of pleasure/well-being/reward / users become dependent on feelings; genetic predisposition is most common with addiction to alcohol; social factors affect the incidence of addiction; it is not certain that a person who is genetically predisposed will develop addiction when exposed to the drug / OWTTE; although many drugs are (potentially) addictive, not every user becomes an addict; named social factors which must be explained: e.g. cultural traditions / peer pressure; social deprivation / traumatic life experiences / mental problems

Label the four parts of the ear indicated on the drawing below.

Award [1] for any two of the correct parts labelled. I. bones of (middle) ear / ossicles / malleus, incus and stapes; II. auditory nerve / cochlear nerve; III. cochlea; IV. eardrum / tympanic membrane / tympanum;

Discuss how the process of learning can increase chances of survival. (2 marks)

Discuss how the process of learning can increase chances of survival. animals learn to avoid dangerous situations / predators; animals learn how to hunt/obtain food; animals learn to adapt to changing environments; e.g. birds learn to avoid cats; (allow any other valid example)

Outline Pavlov’s experiment into conditioning of dogs. (2 marks)

called classic conditioning; Pavlov sounded bell before food (conditional stimulus); dog secreted saliva (conditioned response); dog associated two (external) stimuli (bell and food);

Define the terms stimulus and reflex. (2 marks)

Define the terms stimulus and reflex. stimulus: change in environment; reflex: rapid, unconscious/involuntary response;

Explain how excitatory psychoactive drugs affect the brain. (3 marks)

Explain how excitatory psychoactive drugs affect the brain. chemical substance that acts primarily upon the central nervous system; increase postsynaptic transmission; can cause chemical dependency / lead to substance abuse / addictions; stimulants produce psychomotor arousal/more alertness; by acting like neurotransmitters / interfering with breakdown of neurotransmitter; can affect the transmission of optic signal in the thalamus/optical cortex; example given;

Compare rods and cones. (3 marks)

Compare rods and cones

Explain the role of receptors, sensory neurons and motor neurons in the response of animals to stimuli. (3 marks)

Explain the role of receptors, sensory neurons and motor neurons in the response of animals to stimuli. receptors detect stimuli; transmit information regarding stimuli to the central nervous system; via sensory neurons; central nervous system sends impulse to effector; via motor neuron;

List four general kinds of sensory receptor. (2 marks)

List four general kinds of sensory receptor. Thermoreceptor Chemoreceptor Photoreceptor Mechanoreceptor Baroreceptor propioceptor

Distinguish between a conditioned response and an unconditioned response. (2 marks)

Distinguish between a conditioned response and an unconditioned response. a conditioned response is learned whereas an unconditioned response is innate; an unconditioned response is made to an unconditioned stimulus whereas a conditioned response is made to a conditioned stimulus;

Explain the effect of tetrahydrocannabinol (THC) on brain function. (2 marks)

Explain the effect of tetrahydrocannabinol (THC) on brain function. binds to cannaboid/pre-synaptic receptors; inhibits neurotransmitter release; therefore no excitation of post-synaptic membranes;

Label the parts of the reflex arc shown below. (3 marks)

Label the parts of the reflex arc I. dorsal root ganglion; II. grey matter; III. motor neuron;

Explain how decision-making is influenced by the central nervous system (CNS). (3 marks)

Explain how decision-making is influenced by the central nervous system (CNS). decision-making involves synapses / pre and postsynaptic neurons are required; some presynaptic neurons are excitatory and some are inhibitory; interaction between excitatory and inhibitory presynaptic neurons with the postsynaptic neuron; excitatory and inhibitory produce different neurotransmitters; the impulses from presynaptic neurons are generally summative; decision-making is a (mental) process leading to the selection of alternatives/ strategies / frontal cortex/lobes are brain regions involved in decision-making processes;

Outline how sound stimuli are detected in the ear. (2 marks)

Outline how sound stimuli are detected in the ear sound waves reaching eardrum cause it to vibrate; vibrations passed to bones of middle ear/oval window/fluid in cochlea; detected by mechanoreceptors/hair cells (in cochlea of ear);