Category Archives: HL2 Biology

E.3a Innate Behavior

pg. 326

innate behavior: genetically programmed
learned behavior: developed behavior developed as a result of an animal’s experiences


E.1 Reflexes

pg. 321

stimulus: a change in the environment, either internal or external, that is detected by a receptor and elicits a response
response: a change in the organism, produced by a stimulus
reflex: a rapid unconscious response to a stimulus
pain withdrawal reflex: co-ordinated by the spinal cord (reflex arc)

reflex arc:
– pain receptors detect the pain
– sensory neurons carry impulse
– synapses with relay neurons
– relay neurons have synapses with motor neurons
– muscle contract (motor neurons to muscle fibres)


E.4b Neurotransmitters & Personality

Psychoactive drugs:
1) Excitatory drugs
– nicotine
– cocaine
– amphetamines
2) Inhibitory drugs
– benzodiazepines
– alcohol
– tetrahydrocannabinol

– there can be interaction between the activities of the excitatory and inhibitory neurons when there are many synapses between the pre-synaptic neurons and a post-synaptic neuron


E.2a Perception of Stimuli

dbq pg. 322

1a. Santa Cruz Location (with many slugs): 83%
Lassen County Location (few slugs): 15.4%
1b. the garter snake in the Lassen County location gradually eats less slugs after 5 days. the garter snakes in the Santa Cruz location increased the number of slugs eaten after the 5 days.
2. Lassen County garter snakes survive better than the Santa Cruz garter snakes.
4. mechanoreceptors is the type of receptor used to for the snakes to detect the slugs.


6.5a: Homeostasis – Thermoregulation

dbq pg. 260

1. 2.0ms-1
2. cool
3. 1.8ms-1
4. as air temperature decreases, wind chill increases, and when wind speed increases the wind chill also increases


6.5b Synapses

dbq pg. 257

1a. L-dopa increases dopamine
1b. selegeline  still allows the dopamine to last since it inhibits breakdown of dopamine
1c. tolcapone allows dopamine to be produced
1d. ropinirole allows dopamine to be produced
1e. safinamide allows more dopamine to be available
2a. stem cells are able to replace cells that are not actively functioning in a certain area of an organism


6.5a Neurons

dbq pg. 255

1a. the reduced NA+ concentration reduces the magnitude of depolarization
1b. the reduced NA+ concentration increases the duration of the action potential
2. the reduced NA+ concentration causes the magnitude of depolarization to lower because the concentration gradient decreases
3. the time taken to get to the resting potential is long because of the reduced NA+ concentration
4. the magnitude of depolarization the shaker mutant is lower than the drosophilias’ magnitude
5. the difference in the action potential is the because of the stimulus


6.3b Defense Against Disease

dbq pg. 231

1.  1983-1993 is the decade where the life expectancy declined due to AIDS and was observed.
2. South Africa hit a high peak of life expectancy whereas Zimbabwe did not. Also, Zimbabwe’s life expectancy hit a lower number than South Africa.
3. The nations must have been developing, along with advances in hygiene and adapting to the environment.
4. Botswana has the greatest drop in life expectancy
5. Uganda did not have many changes, possibly due to society’s habits, since they must have remained the same.


6.3a Defense Against Disease

dbq pg. 227)

1. The normal pH around different parts of the body for the neonates is around 7, whereas for the adults it is around 5.5.
2. Adults skin’s pH differs since with time, the skin adapts and is exposed to more than neonates’s skin.
3. It is more irritating to neonates since their skin isn’t at the neutral pH level and the adults skin is at a neutral pH level.
4. The chemicals in the soap may be damaging to our skin.