biology essay questions
Terms
undefined, object
copy deck
- The human eye is an amazing organ. Describe how the lens, the vitreous humor, and retina all work together to play an important role in vision (5pt). What are rod and cone cells (4pt)? How many are there in the human eye? (1pt)
-
The shape of the lens can be changed by small muscles adjacent to it. (1pt). Changing the shape of the lens brings objects into sharp focus onto the retina (1pt)
The vitreous humor is an aqueous solution that is 99% water. (1pt) Its main function is to support and cushion the against external pressure and shock (1pt)
The retina is a layer of light sensitive cells that are involved in detecting light intensity and wavelength. (1pt).
Rod cells are photoreceptor cells which contain light-sensitive pigments known as rhodopsins. (1pt) they only react to differences in light intensity. (1pt). There are approximately 100 million rod cells in the human eye. (0.5pt)
Cone cells have proteins hat are sensitive to different wavelengths. (1pt) They are responsible for color vision (1pt). There are approximately 6 million cone cells in the human eye. (0.5pt) - How does the visual information that we see get processed? (4pt) Include in your discussion what brain areas are involved and how the rods and cones transmit the information. How is the information filtered?(1pt) Which lobe receives information from the
-
Visual information is processed in the visual cortex of the occipital lobes. (1pt). The rod and cone cells respond to light and activate the bipolar cells. (1pt). The bipolar cells will then activate the ganglion cells. (1pt). Since there are only 1.5 million ganglion cells connected to about 115 million rod and cone cells, the disparity results in the filtering of incoming visual signals. (1pt)The ganglion cells join and form optic fibers from each eye. (1pt)The optical fibers cross over before reaching the occipital lobe, resulting in the left occipital lobe receiving information from the right eye and the right occipital lobe receiving information from the left eye. (1pt).
Blind sight will occur because there are 2 pathways that are used for perception. The most sophisticated pathway is the visual cortex. (1pt). But another pathway leads to the primitive portion of the brain, or the reptilian brain (1pt). People who suffer from blind sight can no longer see because the visual cortex is damaged even though their eyes remain intact. (1pt). Even though they cannot see an object they can still detect movement in the non-seeing eye because the primitive visual pathway has not been damaged. (1pt) - Memory can be classified by duration. What are the 3 types of duration memory? (1 pt ea) How long does each memory type last? (0.5 pt ea) What brain region is associated with each memory type? (0.5 pt ea) What is LTP and how does it help generate long te
-
Memory types (1 pt each for name)
Sensory memory: duration- few seconds (0.5pt); brain region- sensory regions (0.5pt)
Short term memory: duration- minutes to days (0.5pt); brain region- hippocampus (0.5pt)
Long term memory: duration- months to years (0.5pt); brain region- cerebral cortex (0.5pt)
LTP (long term potentiation) aids in the formation of long term memories. Before a memory can become a long term memory the information must be rehearsed (1pt). As a person repeats the material, the cortical neurons receive repeated stimulation from the neurons in the hippocampus (1pt). The repeated stimulation will increase the rate and magnitude of firing in cortical neurons (1pt). The increase is known as LTP. To strengthen a LTP a person must rehearse the information many times. Without repeated stimulation the LTP will decline and is the basis of forgetting. (1pt) -
Memory can be classified by information. What are the 3 types of information memory? (0.5pt ea) and define each type and give an example for each (2.5 pt ea). What is a mnemonic device (1pt)
There are 3 types of memory that can b -
Declarative memory is known as explicit memory and we have a conscious awareness of accessing this type of memory (1pt). This type of memory is associated with storing information such as names, places, telephone numbers, factual information, and ideas. (1pt). Another type of declarative memory uses emotion and sensation, such as smells, sights, or song melodies to store information (0.5pt)
Procedural memory is known as implicit memory and is usually acquired and recalled subconsciously (1pt). Procedural memory is associated with motor activities and is acquired through repetition (1pt). Examples include riding a bike, playing the piano, or walking. (0.5pt)
Visual/ spatial memory is a type of memory that creates a close resemblance of objects, animals, peoples, or places in the form of a mental image (1pt). Using a map to navigate is a form of visual/spatial memory. (1pt). People who use this type of memory have an enlargement of the hippocampus as seen in with London taxi cab drivers (0.5pt).
A mnemonic device is when a person creates an association between meaningful and the meaningless. We create a meaningful story to recall the meaningless list of information. (1pt) - As seen in the videos, Clyde Wearing was a talented musician, but after an illness his brain was never the same. What caused this change in his brain? (1pt). What brain areas were damaged by the illness (1pt ea). How do these regions play a role in memor
- Clyde had viral encephalitis that damaged portions of his brain. (1pt). The main damage occurred in his cerebral cortex (1pt), hippocampus (1pt), and frontal lobe (1pt). The frontal lobe is important for integration of short term and long term memory and imparting meaning to our experiences. (1pt). The hippocampus is the brain region where short term memory is sent to and through strengthening LTP’s short term memory is converted to long term memory. (1pt). In Clyde’s case the damaged areas affected his short term memory and declarative memory (1pt) but his procedural memory remains intact, allowing his to still be able to play music (1pt). He can recognize his wife, but cannot form long term memories with her or his day to day activities (1pt). Since declarative memory and procedural memory are stored in different regions of the brain, damage to one area may only affect one. (1pt)
- Alzheimer’s disease has been on the rise over the past 100 years. Why is this occurring (1pt)? What are the 2 types of Alzheimer’s disease (0.5 pt each) and what age to the symptoms start to occur (0.5pts ea)? How does Alzheimer’s disease change th
-
Alzheimer’s disease has been on the rise because the life expectancy has increased from 47 years to 77 years. (1pt)
There are two types of the disease:
Early onset (0.5pt) which occurs typically before the age of 50, but in some patients it occur as early as in the 30’s or 40’s (0.5pt)
Late onset (0.5pt) which occurs after the age of 70. (0.5pt)
Alzheimer’s disease results from the accumulation of amyloid plaques in the brain (1pt). The plaques begin as an abnormal degradation of APP, a protein found on the surface of nerve synapse. (1pt) The degradation yields beta amyloid which accumulates around nerve cells (1pt). The protein deposits block communication between nerve cells. (1pt). Also, abnormal protein fibrils accumulate with the nerve cells. (1pt) This slows nerve transmission and eventually will lead to neuronal death. (1pt). The hippocampus is the first brain area affected by the amyloid plaques and abnormal fibril formation. (1pt) - Manic depression is characterized by 2 distinct phases. Describe each phase (6pts). Describe the 3 treatments that are used to treat this disorder. (3pt) What have researchers concluded about manic depression in a Amish community. (1pt)
-
Manic phase is characterized by exaggerated mood elation (1pt) and many also experience great anticipation or excitement for the future (1pt). The manic phase has also been associated with extreme creativity where affective individuals are driven to achieve superhuman tasks with unbounded energy. (1pt)
The depressive phase occurs shortly after the manic phase (1pt). Patients will become severely depressed and see their lives as nothing but a failure.(1pt). They often times become suicidal during this phase. (1pt)
There are 3 treatments to treat manic depression. The first would be through the administration of SSRIs such as Prozac or Paxil, which increases the serotonin levels in the brain (1pt). The second treatment would be administration of Lithium salts, which are effective in treating the manic phase. (1pt). The last resort treatment is ECT, where electrical stimulation is administered to the brain. (1pt)
Researchers have found a genetic link to members of an Amish community who suffer from manic depression. With this type of depression a single gene on chromosome 21 is responsible for the disease. (1pt) - Describe the experiments conducted in humans by Dr. Robert Heath in the early 1950’s. (3pts) In 1954, Dr. James Olds, a neurobiology researcher, made an important discoveries related to the brain reward center in rats. Describe each experiment (2.5 pt
-
Dr. Heath had experimented with implanted electrodes into the brains of patients who had untreatable depression, pain, or incurable epilepsy. (1pt). He found that when he stimulated the nucleus accumbens, the electrical sensation was similar to that of pleasure elicited by food or sex (1pt). He concluded that the nucleus accumbens was the reward center for the brain. (1pt)
The first experiment that Dr. Olds conducted was to implant electrodes into rat brains; and the rats were trained to self administer electrical stimulation to their nucleus accumbens. (1pt). The rats would press a paddle to receive the stimulation. (0.5pt). The rats would often become compulsive in paddle pressing and would press until exhaustion. (1pt). He concluded that the rats were experiencing an insatiability to the electrical stimulation, which could be similar to that of human substance abuse. (1pt)
The second experiment was to separate the paddle by an electrified grid. (0.5pt). The rats had to sustain a painful shock in order to reach the stimulation. (1pt). In addition, Dr. Olds substituted an abused drug instead of the electrical stimulation and the rats would cross the grid just as they did for electrical stimulation. (1pt). He concluded that abused substances must affect the same brain reward region that was also stimulated by the electrical signals. (1pt) - Describe what the VTA is does in the brain (2 pt). What neurotransmitter is involved with this pathway? (1pt) Cocaine and amphetamines both are targets for this area. How do they differ in their mechanism of action? (3pt ea). How are they the same? (1pt)
-
The VTA is involved with fulfillment of hunger and sexual desire. (1pt). This brain area communicates with the nucleus accumbens and the frontal lobe. (1pt). Dopamine is the neurotransmitter that is important for the production of pleasure associated with hunger and sexual desire. (1pt)
Cocaine inhibits the uptake of dopamine. (1pt). Cocaine will bind to the dopamine transporters and blocks its actions. (1pt). This leads to an accumulation of dopamine in the synaptic cleft, resulting in firing of dopamine sensitive neurons. (1pt)
Amphetamines stimulate the neurons to release large amounts of dopamine (1pt). The excessive dopamine release overwhelms the dopamine transporter’s uptake mechanism. (1pt). This results in a prolong sensation of pleasure. (1pt)
The overall effect of amphetamine and cocaine is to increase dopamine levels in the synaptic cleft, even though they have different mechanisms to achieve this result. (1pt) - What 3 brain chemicals are involved with the infatuation stage of falling in love? (3pt). What brain area does this occur in? (1pt). How does this brain area and the cortex communicate during this phase? (2pt). What brain chemicals are involved with main
-
The 3 brain chemicals involved with falling in love are: dopamine (1pt), norephinephrine (1pt), and phenylethylamine (1pt). The brain area that this phenomenon occurs in is the limbic system (1pt). The limbic system normally communicates with the cortex, but during infatuation the overpowering amount of dopamine, norephinephrine, and phenylethylamine will overpower the cortex (1pt). The signals from the cortex are then bypassed (1pt)
Oxytocin (1pt) and dopamine (1pt) are the brain chemicals responsible for maintaining long term relationships. As the infatuation phase wanes, dopamine neurons will induce areas of the midbrain to produce oxytocin (1pt).
The same physiological responses occur in that falling in love as in cocaine addiction in that there is an increase in dopamine being released into the brain. (1pt) - What does serotonin do in the brain? (2pt) What happens if a person has too little serotonin? (1pt) What is an SSRI? How does it work? (3pts). How does psilocin affect serotonin in the brain and what effect does it have on the user?
-
Serotonin is a neurotransmitter that has many neurological activities. In some parts of the brain serotonin causes neuronal activation, while in other parts serotonin acts to dampen the excitability of neurons (1pt). Its action is to counter the actions of other neurotransmitters. (1pt). If a person has too little serotonin the neuronal excitation cannot be controlled and the result is bursts of anger or aggression. (1pt) SSRIs are selective serotonin reuptake inhibitors that are used to treat depression. (1pt). They block the serotonin reuptake transporters (1pt), thus increasing serotonin in the brain (1pt).
Psilocin enters the thalamus and binds to serotonin receptors (1pt). The result is a loss of control of sensory imput. (1pt). There is a flood of sensory input to the cerebral cortex. (1pt). The main effect it has on the user is to produce hallucinations. (1pt) - Certain everyday chemicals can cause brain and behavioral alterations. One such example is David Garabedian who worked for a lawn care company. What caused him to behave so violently? (3pt) How does this chemical affect the body? (4pt). Where is acetylch
-
David worked for a lawn care company and had been mixing a large batch of insecticide (1pt). He began to act violently and aggressively to his family and later killed a woman (1pt). These event coincided with the insecticide poisoning. (1pt) The insecticide consists of a nerve agent (1pt) that functions at blocking the enzyme acetylcholine esterase. (1pt) This enzyme is responsible for degrading acetylcholine, a neurotransmitter. (1pt).In the presence of the insecticide the brain continues to produce acetylcholine, which leads to the hyperactivation of the hypothalamus neurons. (1pt)
Acetylcholine is released by hypothalamus neurons. (1pt) which initiate the fight or flight response. (1pt). Acetylcholine esterase will moderate the stimulatory effect of acetylcholine. (1pt) - What causes seizures? (1pt) Give 3 possible triggers for seizures. (1.5pt) How are petit mal seizures different from grand mal seizures. (6 pt) What treatments are available for epilepsy? (1.5pt)
-
Seizures are caused by abnormal electrophysiological activities in the brain (1pt)
Seizures can be triggered via head trauma, intoxication, drug overdose, infection, metabolic disturbances, substance withdrawl, brain abscesses, brain tumors or pregnancy (only need 3 of these, 0.5pt for ea for a total of 1.5pt)
Petit seizures last only a few seconds and may be unnoticeable. (1pt) Children with these types of seizures often have learning difficulties. (1pt)
Grand mal seizures present violent muscle contractions and rhythmic jerking of the body. (1pt). Then a period of unconsciousness follows. (1pt) They typically do not cause damage to the brain. (1pt) However if the seizures last a long period of time they can result in neuronal loss. (1pt)
Epilepsy can be treated via antiepileptic drugs (0.5pt), surgical removal of brain area associated with abnormal electrical activity (0.5pt), and the last resort would be to sever the corpus callosum (0.5pt) - Besides chimpanzees, name two species of great apes (0.5 pts each). Compare the weight of each species using males and females (2 pts). Describe the habitat that each species lives in and their diet (4 pts). What evidence is there that these species disp
-
Orangutans (0.5 pt), Gorillas (0.5 pt)
Male orangutans can weigh up to 170 lbs (0.5 pt), whereas females weigh about 100 lbs (0.5 pt)
Male gorillas weigh as much as 400 lb. (0.5 pt), whereas females weigh about 250 lb. (0.5 pt)
Orangutans live high up in the tropical rain forest trees in Borneo and Sumatra (1 pt). Their diet consists of primarily fruits, termites, eggs, and even small monkeys (1 pt).
Gorillas are ground dwelling plant eaters (1 pt), and they are only found in the tropical rain forests of Central Africa (1 pt)
Through observation, Orangutans can learn to imitate human behavior and activities. (0.5 pt) For example, they can learn to pound nails into a board with a hammer, use a hand saw to cut wood, wash socks by a lake, and paddle a canoe onto the lake using their hands. (1 pt)
Koko (a female gorilla) has learned American Sign Language. (0.5 pt) Besides words she has been taught, she also invents new signs. Through sign language, Koko can express love, humor, anger, she can be deceitful, and can tell stories. (1 pt) - What genetic evidence is there for the evolutionary relationship between humans and chimpanzees? (3 pts) How do these differences compare to those of rats and mice? (1 pt) Describe what Jane Goodall discovered about chimpanzees and tools and how did it h
-
Human and the chimpanzee genomes are identical in size, about 3 billion base pairs. (1pt) The differences between the genomes existed in only 1.5%, making the chimpanzee and the human genomes similar in 98.5% of their DNA sequences. (1 pt) The differences in the DNA sequences that encode for genes were only 3 million base pairs. (1 pt)
One of her first discoveries was that chimpanzees can make and use tools to obtain food. (1 pt) As with humans, these skills are not inborn, but rather, they are acquired by learning from others. (1 pt) Furthermore, just like in human populations, there are variations among different groups of chimpanzees in how they perform these tasks, suggesting primitive culture. (1 pt)
The genetic differences between humans and chimpanzees are ten times less than that of mice and rats. (1 pt)
In these experiments, researchers used a small room and a scale model of that same room. (0.5 pt), The test subject is shown the scale model, and an object is hidden somewhere in the scale model. (0.5 pt) The subject is then led to the life-sized room and is asked to find the hidden object. (0.5 pt)
Most children who are given this test are not able to find the object until they are over 4 years old (0.5 pt), Chimpanzees, however, can pass this test by the age of 3. (0.5 pt)
These experiments provide strong evidence that chimpanzees, just like humans, are capable of solving conceptual problems. (0.5 pt) - The fossil skeleton named Lucy was discovered in 1974. When did she live (1 pt) and what is special about her in terms of the linkage to modern humans (1 pt) Name the prevailing hypothesis about why human ancestors developed upright walking? (1 pt) What
-
Her skeleton was dated to be about 3 to 3.9 million years old. (1 pt)
She probably looked like a common chimpanzee, but she unquestionably walked upright, placing the evolution of bipedalism as early as 4 million years ago. (1 pt)
The most widely accepted hypothesis for upright walking is known as the savanna hypothesis. (1 pt) This hypothesis is based on the evidence that a drought caused the disappearance of forests across central Africa, making adaptation of the forest dwelling organisms to life on the savanna critical. (1 pt) Without the need to climb trees, bipedalism most likely evolved during this time because it is more energy efficient than knuckle walking and it frees the hands for carrying babies or food. (1 pt)
Genetic bottlenecks occur when there are few individuals in a population, so that their descendants will have low genetic variation. (1 pt)
The evidence in support of a human genetic bottleneck came from the genetic study of mitochondria DNA. (1 pt)
Unlike the nuclear DNA, the mitochondria DNA in each individual comes only from the mother. (1 pt)
Both the male and the female offspring will carry the mitochondrial DNA from only their mother. (1 pt)
By analyzing the rate of mutation and by comparing the different mutation patterns in a population, it is possible to determine the origin and the age of the modern human mitochondrial DNA. (1 pt) -
What is the physical and elemental basis of living organisms? (1.5 pt)
What is the origin of these elements? (0.5 pt)
How does genetic information provide the evidence that all living organisms share a common ancestor? (1 pt)
-
All life requires the same basic conditions: narrow range of temperate, presence of water, source of energy, and the same elements: carbon, oxygen, and hydrogen. (0.25 pt each item)
The source of all elements in the Universe are stars, as stars make all the elements in the periodic table through the production of energy. (0.5 pt)
All organisms share the same genetic code (RNA, DNA, nucleic bases) and machinery (transcription, translation), from the virus to humans, suggesting that all life shares a common ancestor. (1 pt)
The mechanisms of natural selection includes predators (a.k.a. evolutionary arms race) in which predators kill the least adapt prey but leave the hardest to kill ones alive to reproduce (1 pt), and sexual selection, in which females or competition among males select traits in males, resulting in extravagant traits, such as amazing plumage, bright colors, elaborate displays, and big brains. (1 pt)
Humans have a bilateral body plan, which was first evolved in flatworms, which allowed sensory structures (eyes) to be stereoscopic and sensory inputs to be localized in a brain which was contained within a head (1 pt).
The human brain is made of compartments, which interact with one another. (0.5 pt) This is a result of the fact that the human has evolved over time, and new compartments have been added to old ones. (0.5 pt)
The negative effect of this compartmentalization is that when different areas are damaged or there is an imbalance in the communication among parts, mental disease (manic depression) or unusual behavior can result. (1 pt)
The positive effect is that the human brain is more than the sum of its parts, allowing humans to be creative (music, art, architecture), emotional (loving, caring, compassionate), and intelligent (mathematics, science, engineering). (1 pt)