NaimExplain

Discuss how cellular structures, including the plasma membrane, specialized endoplasmic reticulum, cytoskeletal elements, and mitochondria, function together in the contraction of skeletal muscle cells. The plasma membrane of a muscle cell (the sarcolemma) is an excitable membrane, meaning that it can propagate an action potential. You need to explain how the membrane and transverse tubules (T tubules) propagate the action potential. The specialized endoplasmic reticulum of a muscle fiber (i.e., muscle cell) is called the sarcoplasmic reticulum. It stores Ca2+ (calcium ions). When released, the calcium ions cause contraction; when actively transported back into the sarcoplasmic reticulum, the dropping levels of calcium ions in the cytoplasm cause muscle contraction to cease. The cytoskeletal elements refers to the microfilaments, made of actin, and the associated proteins, such as myosin. Together, these various proteins form units called sarcomeres; these are the functional un

Describe the negative and positive feedback loops, and discuss how feedback mechanisms regulate each of the following. The menstrual cycle in nonpregnant human female.  Blood glucose levels in humans. Negative feedback loops occur when the substrate cause a decrease in the hormone that is stimulating it keeping the substrate at a constant or near constant level. For example estrogen and FSH. This can also happen if the substrate increases the hormone which regulates its excretion. For example calcium and calcitonin or glucose and insulin.

The graph below shows the response of the human immune system to exposure to an antigen. Use this graph to answer part a and part b of this question. A) Describe the events that occur during period I as the immune system responds to the initial exposure to the antigen.  B) Describe the events that occur during period II following a second exposure to the same antigen.  C) Explain how infection by the AIDS virus (HIV) affects the function of both T and B lymphocytes. A) the first time the body is exposed, selective proliferation and differentiation of lymphocytes occur. Selected B cells produce antibody-secreting effector B cells (plasma cells) and selected T cells are activated to their effector forms. Eventually, T cells clear the antigen from the body. B) The second time the same antigen is exposed, the response is faster. The antibodies produced in the secondary immune response have a greater affinity for the antigen.Clones of the T and B memory cells generate initi

Many physiological changes occur during exercise. Design a controlled experiment to test the hypothesis that an exercise session causes short-term increases in heart rat and breathing rate in humans.  Explain how at least three organ systems are affected by this increased physical activity and discuss interactions among these systems. A) Two groups made up of 100 people, all of about the same body size, and age. Each is monitored for heart rate, and respiration rate during the test. You have the test group run for 30 minutes, and have the control group simply stand for 30 minutes. After the test is done, compare the test and the control group creating graphs of both. B) Circulatory- The body increases blood flow to carry oxygen and nutrients to the working muscle cells, and to carry excess CO2 out of the body. Respiratory- The body increases the rate of respiration to expel the extra CO2 gas that is being produced by the working muscle cells while they are preforming c

Describe the following mechanisms of response to foreign materials in the human body.  A) The antigen-antibody response to a skin graft from another person.   B) The reactions of the body leading to inflammation of a wound infected by bacteria. A) The antigen recognizes the new skin as foreign. Then it is rejected by the immune system. The antigens surface to the graft cells. Then they stimulate antibody production and T cell production. B Lymphocytes are turned into plasma cells which synthesizes antibodies. The antibodies circulate to the sites needed and precipitate antigens and/or complex. The antibodies make the antigens susceptible to phagocytosis by WBCs. Then the antibodies specify and it fights off the graft and other infections that come with it. B)When injured, mast cells release their histamine which triggers dilation and it increases permeability of nearby capillaries. Activated macrophages and other cells discharge additional signals that further promote bl

Describe the processes of fat and protein digestion and product absorption as they occur in the human stomach and small intestine. Include a discussion of the enzymatic reactions involved. 1. Stomach: Region- Cardiac and pyloric sphincter Layers of muscle and thick walls Digestive Function: a) Chief cells secretes renin, lipase, and pepsinogen b) Parietal cells Secretes HCL c) mucus protects stomach Endocrine Function: Gastrin Function: stimulates production of digestive juices Presence of food: stimulus for gastrin release 2. Small Intestine: Contains villi which are blood vessels Region: duodenum Digestive Function: 3 enzymes= lipase, amylase, nuclease Function: Bile= produced in liver, stored in gall bladder, emulsifier Endocrine Function: Stimulates release of alkaline secretions by pancreas, stimulates gallbladder to release bile, stimulates pancreas to secrete digestive enzymes. 3. Pancreas: Connects to small intes. by pancreatic duct made up of exocr

Describe the structure of a mammalian respiratory system. Include in your discussion the mechanisms of inspiration and expiration. From the nasal cavity and pharynx inhaled air passes through the larynx, trachea, and bronchi to the bronchioles, which end in microscopic alveoli lined by a thin, moist epithelium. branches of the pulmonary arteries convey oxygen poor blood to the alveolar, branches of the pulmonary veins transport oxygen rich blood from the alveoli back to the heart. Air enters through the nostrils and is then filtered by hairs warmed, humidified, and sampled for odors as it flows through a maze of spaces in the nasal cavity. As the external intercostals & diaphragm contract, the lungs expand. The expansion of the lungs causes the pressure in the lungs (and alveoli) to become slightly negative relative to atmospheric pressure. As a result, air moves from an area of higher pressure (the air) to an area of lower pressure (our lungs & alveoli). During inspirati

A laboratory assistant prepared solution of 0.8 M, 0.6 M, 0.4 M, and 0.2 M sucrose, but forgot to label them. After realizing the error, the assistant randomly labeled the flasks containing these four unknown solutions as flask A, flask B, flask C, and flask D. Design an experiment, based on the principles of diffusion and osmosis, that the assistant could use to determine which of the flasks contains each of the four unknown solutions. Include in your answer (a) a description of how you would set up and perform the experiment: (b) the results you would expect from your experiments: and (c) an explanation of those results based on the principles involved. (Be sure to clearly state the principles addressed in your discussion.)

Describe the fluid-mosaic model of a plasma membrane. Discuss the role of the membrane in the movement of materials through it by each of the following processes: Active transport  Passive transport The plasma membrane is composed of a phospholipid bilayer. That is, you have two phospholipids, which look like...jellyfish, as in they have a head and tails, these tails are hydrophobic, they don't like water, so they join together on the inside of the by layer, the heads are hydrophilic, so are on the outside, facing the liquid of the cell. So in the end it looks a bit like a zip, with tails in the middle, and heads on the outside. The individual lipids are not joined to each other, to things can "float" about in the layer, mainly proteins used for active transport .

Enzymes are biological catalysts. Relate the chemical structure of an enzyme to its specificity and catalytic activity.  Design a quantitative experiment to investigate the influence of pH or temperature on the activity of an enzyme.  Describe what information concerning the structure of an enzyme could be inferred from your experiments. For an enzyme to function, there must be enzyme/substrate speceficity. This includes the intermolecular forces between the amino acids of the enzyme which contribute to the shape of the folded enzyme. Use liver catalase, which breaks down hydrogen peroxide. independent variable-pH dependent variable-amount of products produced by reaction (measures the ideality of the conditions of the reaction) control variables-temperature of the room, the concentration of enzyme, the concentration of hydrochloric acid, the volume of enzyme and hydrochloric acid solution alter pH by adding drops of acid (HCL) or base (KOH) to a set volume of liver (blended).

Describe the chemical composition and configuration of enzymes and discuss the factors that modify enzyme structure and/or function. Enzymes are a type of protein. They have four levels of structure. The primary level involves the sequence of amino acids. Each amino acid has an amino group, a carboxyl group, a hydrogen group, and an "R" group which is different for each amino acid, all attached to the alpha carbon. Depending on the "R" group, an amino acid can be uncharged, polar and uncharged, acidic, or basic. 

Explain a piece of legislation designed to preserve biodiversity. The Endangered Species Act is a piece of legislation that makes it illegal to injure, kill, or collect any species listed as threatened or endangered within the United States. This legislation also prohibits the import (for any purpose other than preservation or research) of any endangered species or any product made of endangered species. This clause is intended to keep organisms in their native habitats.

Give one example each of a direct and an indirect threat to biodiversity. A direct threat to biodiversity is something that affects organisms by interfering with them. For example, cars might run over them. An indirect threat to biodiversity impacts them through a chain of events. If urban development fragments the habitat of a species of large mammal, then the mobility of the animals will be decreased, limiting their access to resources and mating partners. If the habitat fragmentation or loss is severe enough, extinction of the population may result.

Discuss methods that have been employed in another country to curb population growth. List any two sets of the six methods mentioned Restatement: Methods that have been employed by another country to curb population growth. China: Between 1958 and 1962, an estimated 30 million people died from famine in China. Since then, China has made good progress in trying to feed its people and bring its population growth under control. Much of this reduced population growth was brought about by a drop in the birth rate from 32 to 18 per 1,000 between 1972 and 1985. China instituted one of the most rigorous population control programs in the world at an estimated cost of about $1 per person. Some features of the program included:  1) Strong encouragement for couples to postpone marriage 2) Providing married couples with free access to sterilization, contraceptives, and abortion. 3) Giving couples who sign pledges to have no more than one child economic rewards such as sa

What factors affect birth rates and death rates? List any four characteristics from the column labeled "Affected By." Restatement: Factors that affect both birth and death rates  Birth Rate 1) Importance of children as a part of the labor force 2) Urbanization 3) Cost of raising and educating children 4) Education and employment opportunities for women 5) Infant mortality rate 6) Average age at marriage 7) Pensions 8) Abortions 9) Birth Control 10) Religious beliefs Death Rate 1) Increased food supply 2) Better nutrition 3) Improved medical and public health technology  4) Improvements in sanitation and personal hygiene 5) Safer water supplies

Examine the age-structure diagrams of Sweden and Kenya below, and answer the following questions.   Compare and contrast the two age structure diagrams in terms of two population dynamics - birth rate and death rate. Restatement: Given two age-structure diagram, Sweden and Kenya for 2000, compare and contrast the diagram in terms of population dynamics.  Age structure diagrams are basically divided into three major age categories: 1) Prereproduction (0-15 years old) 2) Reproductive (16-45 years old) 3) Postreproduction (46 years old-death) Birth Rate Sweden  1) Population has nearly equal proportions of pre-reproductive and reproductive individuals. 2) Little growth over a long period of time will produce a population with about equal numbers of people in all age groups. 3) Children not required or necessary to support parents.  4) Availability and acceptance of birth control. Kenya 1) Population had pyramid-shaped age structures, with large num

The homeowners wish to incorporate green design. Discuss five techniques that the homeowners could adopt to make their home green. Restatement: Five techniques that the homeowners could adopt to make their home a green building.  Definition: A green building focuses on a whole system perspective, including energy conservation, resource-efficient building techniques and materi¬als, indoor air quality, water conservation, and designs that minimize waste while utilizing recycled materials. Green buildings are a product of a good design that minimizes a building's energy needs while reducing construction and maintenance costs over the life cycle of a building.  Techniques  •Solar collectors for space heating.  •Solar collectors for water heating.  •Photovoltaics to supply electrical energy.  •Hybrid systems that incorporate more than one power source such as wind or microhydro.  •Energy-efficient appliances (energy star: http://www.energystar.gov). 

Homeowners are discussing with their architect the possibility of using either active or passive solar design to reduce their heating and/or cooling costs. Compare these two techniques. Restatement: Active versus passive solar design.  Active Solar System: • Collectors that collect and absorb solar radiation. Optimum collector orienta¬tion is true south (the highest apparent point in the sky that the sun reaches during the day-not necessarily magnetic south). Collector orientation may deviate up to 20° from true south without significantly reducing the perform¬ance of the system. Collectors should be tilted at an angle equal to latitude plus 15° for optimum performance. A collector receives the most solar radiation between 9:00 A.M. and 3:00 P.M. Trees, buildings, hills, or other obstructions that shade collectors reduce their ability to collect solar radiation. Even partial shading will reduce heat output.  • Electric fans or pumps to transfer and distribute the solar

In what ways do Portia and her father differ in their reaction to Willie's punishment in prison and the loss of his feet? Portia, who doesn't usually drink, gets drunk. She is rightfully upset, but in spite of her fear she does not want to make waves with the white justice system. Doctor Copeland, however, who has struggled to overcome the "black anger" that used to overcome him, is ready to face that white justice system head on. When he is challenged, and abused, that anger is triggered and he fights back.

Why were the black families so hard hit with problems during the month of February? They lived in the deep South where winters usually do not get so cold or last so long. Because they are poor they lack the needed supplies and don't have the money to buy them. Work is slow and that doesn't help. Plus an epidemic of pneumonia has hit and is taking its toll.

What impact does the situation with Hitler in Europe have on Harry and Mick? Now that Harry is older, he understands what is happening in Europe and the horrible things Hitler is doing to the Jewish people. Although Harry no longer considers himself Jewish, he is still bothered by the wrong of what is happening. It interferes and overrides any desires he once had for his future. He even imagines killing Hitler. On the other hand, Mick is just beginning to understand because of what Harry tells her, and in her case she is more following the leader. She sees the wrong in what is happening, but hasn't yet formed her own opinions on what to do about it.

What do we learn about the Kellys financial situation in Part 2, Chapter 9? We learn that the Kelly family's financial situation is growing worse. They lost their home because they could not keep up the payments and they had to pay rent to stay there now. The older children were working, but it seems that there still is not enough and sometimes the younger children are hungry for several days. They were struggling since Wilbur Kelly was injured, but it is much worse since they have Baby's medical expenses to pay.

Why is Biff Brannon so drawn to Mick Kelly? Biff Brannon dreams of having children and he associates Mick and Baby to those children he'd like to have. However, he does seem to be unusually interested in her, yet it does not say if it goes beyond paternal to perhaps sexual. The fact that he watches for her and his voice deepens when he talks to her leaves one to wonder.

Why did Biff Brannon seem to be closer to his wife than they were when she was alive? While Biff Brannon took great pains to remove memories of Alice, from quickly giving away everything that was hers to remodeling the bedroom they shared, he was often overcome with memories of the better times they had had together. Now that she was dead, there was no more negativity to stand between them.

Why did Mister Singer arrange a special trip to visit Antonapoulos before his vacation? Mister Singer missed his friend very much and dreamed about him often. However, in one dream he felt something bad had happened to his friend. He did not know if anything really had happened to him, so he wanted to see for himself.

What happened as Mister Singer got more acquainted with the people in the town? As Mister Singer got more acquainted with the people in the town the people started rumors about him. A few of the people remembered him with Antonapoulos, but most of them seemed to just come up with their own ideas about who he really was. There was a growing curiosity about him.

In what way did Doctor Copeland use the Christmas party as a forum? Doctor Copeland used his party as an opportunity to speak to his patients about his beliefs and how to better the lives of the black community. It was like having a captive audience, they had to listen to be polite in his home, and they knew after he spoke there would be refreshments and gifts.

Why did Doctor Copeland have problems choosing the essay contest winner? Doctor Copeland knew the one that was best written, however he felt the ideas presented in the essay were "wild notions." The boy was advocating dividing the US and forming a separate nation for African-Americans people. Although Doctor Copeland agreed with the boy's feelings about their race, he believed in all people being equal under one nation.

What kind of offer does Lucille present to the Kellys after Bubber shoots her daughter, Baby? That they will pay all her medical expenses, for private room and nursing, and other expenses she deems fair for them to pay. In return she is not going to file charges or take them to court.

What was Mick's theory about the younger kids in a family? Mick theorized that the younger kids in a family were the toughest ones, because they have more kids before them. Even at a young age, she realizes that the attention from their parents is more divided and the hand-me-downs more worn out. They have to achieve more because they have less.

What was it about the message in red, written on a wall, that held Jake Blount's attention? Jake Blount may have felt the message was symbolic of what he felt about the mighty and rich 20% of the population who ruled over the other 80%.

What does Jake Blount mean when he speaks about "us," saying he doesn't know how many of us there are in this country? Although Jake Blount admits he is not a member of the Communist Party, his beliefs lie in that direction, so it seems when he says, "us," he is talking about communists, or people who share his beliefs.

What bothered Doctor Copeland when he attended the family reunion? He saw how contented his family was with the simplicity of their lives, and the way they accepted their lives as they were, never wanted to make more of them. This was totally different from the high aspirations he had once had for his children.

What did Doctor Copeland talk to Mister Singer about when he visited in Part 2, Chapter 3? Doctor Copeland talked to Singer about what he called the "strong true purpose." This was he desire to help the African-American people have better lives.

What question was plaguing Biff Brannon as he watched Mister Singer, Jake Blount, and Mick Kelly together? Biff wasn't even certain what it was, but he sensed something about Mister Singer that he couldn't quite put his finger on. Something just wasn't right. That was the question that plagued him.

What was it that Biff Brannon and his sister-in-law, Lucille, disagreed on? Lucille was preparing her daughter to be some kind of childhood star, and Biff felt she should let the child have a normal childhood.

Why did Mick Kelly decide she wanted to have a prom party? When she started Vocational High School, she didn't hang around with any one group of students, though she wanted to. She thought having the party would give her the chance to know them better and become part of a group.

What place did Mick Kelly favor during her long walks at night, and why? Mick found a home in the rich part of town where they listened to marvelous classical music on the radio. She would hide in the bushes near an open window and listen.

Why did Singer suddenly go away during July without warning? It's uncertain why he didn't tell anyone, except perhaps it was none of their business. Or, perhaps he didn't think it would matter. His reason was to go visit his friend, Antonapoulos, in the asylum.

Why did the four people, Mick Kelly, Jake Blount, Doctor Copeland, and Biff Brannon visit Mister Singer so often? They all had different reasons, although they stemmed from the same, he was a good listener and seemed to accept them and understand them. It gave them someone to share their thoughts and feelings with no fear of ridicule.

Why does Doctor Copeland want to contact Mister Singer? Doctor Copeland has a patient who is deaf and mute and would like get some advice from Mister Singer that might help the boy.

What regrets does Doctor Copeland have about his relationship with his family? Doctor Copeland regrets what he calls the "black, terrible Negro feeling" that would come over him. It was because of this his wife left him and took his children. Years later his wife, Daisy, is gone, and he still has a strained relationship with his daughter, Portia, and almost no relationship with his sons.

In spite of Doctor Copeland seeming to set himself above the other African-Americans in town, how did he feel about them? Doctor Copeland had a great love for his people. He wanted them to have better lives and was constantly trying to explain to them how they could get those lives.

What made Doctor Copeland different from most other African-Americans in the town? First, he was a well-educated man, who struggled and didn't give up until he got where he was. He had a nicer, brick home and dressed more formally than most of the other people.

Why did Blount return to Mister Singer's room? Jake Blount had no room of his own, and he felt good being able to spend time with someone who seemed to understand what he was trying to communicate to others.

Why did Jake Blount not feel like a stranger in a strange town? Jake Blount didn't feel like a stranger in this town because he had been to many towns like it before.

What does Blount want even more than a job? Jake Blount wants people to understand the message he is trying to leave with them. He even calls it the Gospel, because he believes this to be a vital truth they need.

How does Jake Blount react when he realizes Mister Singer was deaf and mute? Blount was surprised when he realizes Mister Singer can not hear or speak because the man seems to understand so much of what Blount says.

Why does Mick sit on the stairs for such a long time? Mick hopes their boarder, Miss Brown would turn on her radio so she could hear the music. When it doesn't happen she waits, hoping Mister Singer will invite her into his room.

Why does Mick get so upset about the way her homemade violin sounds when she tries to play it? Mick had worked very hard to put together the violin with a mishmash of items, because she very much wanted to be able to make music. When it doesn't sound very good she feels let down and frustrated.

What generally goes on inside Mick Kelly's head? She is a dreamer who also loves music. She thinks of places she would like to go, things she would like to do, but most of all she has music constantly playing in her mind.

Who is Mick Kelly? Mick Kelly is the twelve-year-old daughter of the people who run the boarding house where Mister Singer lives.

Why does Mister Singer offer to take Jake Blount home with him to spend the night? No one knows where Blount lives and he was too drunk to let wander around the street, and Biff also knew his wife would probably call the police if she found Blount there when she came downstairs.

Why does Jake Blount bring a black man into the restaurant with him when he knew blacks cannot eat in the same place as white people? Blount wants to prove a point. He disagrees with that rule and feels that all people should be equal.

What does Biff Brannon do as he stands behind the cash register in Part 1, Chapter 2? He reads the newspaper and silently observes the different people who come into his restaurant, trying to figure them out.