Biology Unit 3-Natural Selection, Diseases, and Body Systems

Bacteria are considered living organisms just like humans. In what two ways are they very different from humans?

1. Their DNA is not surrounded by a nucleus. 2.They have a cell wall to keep their structure.

Any environment has limited resources available to support life. This is a factor that allows for natural selection and evolution to occur.​Below is a graph that shows the availability of the main food source supporting a bird population over 25 years. ​Identify the following statements as TRUE or FALSE 1. Traits that promote survival and access to resources will increase in frequency in the population. 2. Population size will remain the same since the food source is still available 3.Birds will adapt based on the need for food and switch food sources. 4.Increased competition for limited resources will cause the population to decrease.

1. True 2. False 3. False 4. True

Vaccines are weakened forms of disease-causing microorganisms, which are given to patients to prevent disease. After the vaccine is administered, the immune system responds by creating a(n) _______________ to recognize the ____________.

1. antibody 2.antigen

A researcher is designing an experiment to study axolotls, a type of salamander. Unlike most fish, axolotls have external gills. Through their observations, they classify each of the movements shown as one "external gill beat". An experimental setup is designed to test the influence of turbidity on the external gill beat rate of axolotls. Turbidity(measured in ntu) is a measurement of how much light passes through the water; less turbid water allows more light through, while more turbid water allows less light through. A chamber with high turbidity is created and aquatic cameras are placed to record footage of 5 axolotls. Each axolotl is observed for 1 minute and the external gill beat rate is recorded. Hypothesis: The respiration rate of axolotls will increase as the turbidity of the water increases. The independent variable of this experiment is __________. The units for this variable are _______. The dependent variable of this experiment is __________. The units for the dependent variable is _______________.

1. turbidity 2. ntu 3. respiration rate 4. # of external gill beats/minutes

Dr. Jenna Collins rounded the corner of the hospital hallway and entered her next patient's room. There she saw Kayla Starnes lying in the hospital bed in front of her with her mother standing nearby. Picking up Kayla's chart, Dr. Collins introduced herself to Kayla. "Hi, I'm Dr. Collins. I hear you're not feeling very well." Kayla replied weakly, "Hi... am I gonna have surgery?" "I don't know Kayla. Let's take a look at things." Dr. Collins estimated Kayla's age to be seven or eight. Picking up Kayla's chart, she began assessing the situation. It turned out Kayla was seven years old. She had suffered for a couple of days with a temperature of 103 degrees and right groin pain. The emergency room diagnosis was an infected right hip joint. "Let's take a look at that infection," said Dr. Collins. Dr. Collins confirmed that the groin area was inflamed and observed abscess formation in the area. From all signs, the diagnosis seemed certain-infected hip joint caused by some type of bacteria. Surgical drainage of the fluid-filled area of infection would be required followed by antibiotic treatment. Dr. Collins made some notes on Kayla's chart and then turned back to Kayla and her mother. "Well, Kayla it looks like we will have to carry out a surgical procedure to take care of this problem after all." Dr. Collins explained the details of what would take place to Kayla's mother who sat listening intently to Dr. Collins. "We'll do the procedure today in order to prevent Kayla's condition from getting any more serious. But don't be alarmed. The procedure is routine, and we have several antibiotics in our arsenal that should take care of the infection." As Dr. Collins walked away she thought to herself, "Hmm, this procedure is routine, but what antibiotic should I choose? The hospital microbiology lab will be able to tell me what type of bacteria Kayla is carrying, but that information may not be available for a couple of days. Kayla can't wait that long. I've got to decide now." According to the text, what were some of Kayla's symptoms? A. Fever B. Pain in the right groin C. Rash D. Difficulty breathing E. Infection in the hip F. Inflammation G. Nausea H. Abscess formation I. Diarrhea

A. Fever B. Pain in the right groin E. Infection in the hip F. Inflammation H. Abscess formation

The respiratory and circulatory (cardiovascular) systems work together to move gases into and out of the body. In organisms, gas exchange happens at the cellular level. Alveoli are the functional units of gas exchange in the lungs. Red blood cells are responsible for carrying the oxygen throughout the body. The relationship between alveoli and red blood cells is depicted in the diagram below: ​Based on the information above and your understanding of interacting systems, which of the following are CORRECT? Select ALL that apply. A. If the function of the alveolus is altered, the function of the respiratory system is affected due to the lack of gas exchange between the blood and the cells of the lungs. B. The cardiovascular system is not affected by abnormalities or changes in the function of the alveoli since these are lung structures. C. If the function of the red blood cells is compromised, the function of the cardiovascular system is affected and aerobic respiration at the cellular level is jeopardized. D. If there is a functional change at the cellular level, the effects will be experienced at the tissue, organ, organ system, and organismal level.

A. If the function of the alveolus is altered, the function of the respiratory system is affected due to the lack of gas exchange between the blood and the cells of the lungs. C. If the function of the red blood cells is compromised, the function of the cardiovascular system is affected and aerobic respiration at the cellular level is jeopardized. D. If there is a functional change at the cellular level, the effects will be experienced at the tissue, organ, organ system, and organismal level.

The graph below shows the number of birds with a given beak depth in a certain location. Data was collected before (the white columns) and after (the black columns) a drought. For example, before the drought, about 30 birds with a beak depth of 8.3 mm were counted, and after about 3 birds with the same beak depth were counted. Which of the four statements below are best supported by the data in the graph? A. No birds with beaks exceeding 11 mm have been counted. B. The drought caused the bird population to increase. C. Number of Birds is the dependent variable D. Beaks shorter than 10 mm are never advantageous. E. A drought can cause some beak depths to disappear. F. Beak Depth is the dependent variable. G. Only birds with beak depths greater than 9.3 mm will survive a drought. H. Birds that survived the drought have a beak depth ranging from 7.8 mm to 10.8 mm.

A. No birds with beaks exceeding 11 mm have been counted. C. Number of Birds is the dependent variable E. A drought can cause some beak depths to disappear. H. Birds that survived the drought have a beak depth ranging from 7.8 mm to 10.8 mm.

The images below show peppered moths both before and after the Industrial Revolution.​ ​Which prediction is BEST supported by the images and graph? A. The population of dark-colored moths will increase. Because they blend into the environment, they are less likely to be eaten by predators. B. The population of dark-colored moths will increase because they can absorb more energy from UV rays. C. The population of light-colored moths will increase. Because they can fly better than dark-colored moths, light-colored moths can more easily escape predators. D. The population of dark-colored moths will increase because their offspring are more robust than those of light-colored moths. E. The population of light-colored moths will increase because they are consumed more often than dark-colored moths.

A. The population of dark-colored moths will increase. Because they blend into the environment, they are less likely to be eaten by predators.

Low blood pressure can be life- threatening. To help maintain a stable blood pressure, receptors in the heart detect changes in blood pressure. Information about blood pressure changes is then sent to the brain. If blood pressure is too low, the brain sends a message to the heart to beat faster.Based on this information, which of the following systems are directly involved in keeping blood pressure stable? A. circulatory, muscular, nervous B. circulatory, immune, skeletal C. excretory, immune, muscular D. immune, muscular, nervous

A. circulatory, muscular, nervous

The series of questions will test your knowledge of the informational texts we read in Lesson 2 of the Addie case. Each text is provided again as a reference and can be used to help answer your questions MRSA in the Community General Information About MRSA in the Community. MRSA is methicillin-resistant Staphylococcus aureus, a type of staph bacteria that is resistant to several antibiotics. In the general community, MRSA most often causes skin infections. In some cases, it causes pneumonia (lung infection) and other issues. If left untreated, MRSA infections can become severe and cause sepsis - a life-threatening reaction to severe infection in the body. In a healthcare setting, such as a hospital or nursing home, MRSA can cause severe problems such as bloodstream infections, pneumonia, and surgical site infections. For more information visit MRSA in healthcare settings. How to Prevent Spreading MRSA, Who Is At Risk, and How Is MRSA Spread In The Community? Anyone can get MRSA on their body from contact with an infected wound or by sharing personal items, such as towels or razors, that have touched infected skin. MRSA infection risk can be increased when a person is in activities or places that involve crowding, skin-to-skin contact, and shared equipment or supplies. People including athletes, daycare and school students, military personnel in barracks, and those who recently received inpatient medical care are at higher risk. How Common Is MRSA? Studies show that about one in three people carries staph in their nose, usually without any illness. Two in 100 people carry MRSA. There are not data showing the total number of people who get MRSA skin infections in the community. Can I Prevent MRSA? How? There are the steps you can take to reduce your risk of MRSA infection: Maintain good hand and body hygiene. Wash hands often, and clean your body regularly, especially after exercise. Keep cuts, scrapes, and wounds clean and covered until healed. Avoid sharing personal items such as towels and razors. Get care early if you think you might have an infection. What is MRSA Symptoms? Sometimes, people with MRSA skin infections first think they have a spider bite. However, unless a spider is actually seen, the irritation is likely not a spider bite. Most staph skin infections, including MRSA, appear as a bump or infected area on the skin that might be: RedSwollenPainfulWarm to the touch full of pus or other drainage accompanied by a fever What Should I Do If I See These Symptoms? If you or someone in your family experiences these signs and symptoms, cover the area with a bandage, wash your hands, and contact your doctor. It is especially important to contact your doctor if signs and symptoms of an MRSA skin infection are accompanied by a fever. What Should I Do if I Think I Have a Skin Infection? You can't tell by looking at the skin if it is a staph infection (including MRSA). Contact your doctor if you think you have an infection. Finding infections early and getting care makes it less likely that the infection will become severe. Do not try to treat the infection yourself by picking or popping the sore. Cover possible infections with clean, dry bandages until you can be seen by a doctor, nurse, or other health care provider. How To Prevent Spreading MRSA Cover your wounds. Keep wounds covered with clean, dry bandages until healed. Follow your doctor's instructions about proper care of the wound. Pus from infected wounds can contain MRSA so keeping the infection covered will help prevent the spread to others. Bandages and tape can be thrown away with the regular trash. Do not try to treat the infection yourself by picking or popping the sore. Clean your hands often. You, your family, and others in close contact should wash their hands often with soap and water or use an alcohol-based hand rub, especially after changing the bandage or touching the infected wound. Do not share personal items. Personal items include towels, washcloths, razors, and clothing, including uniforms. Wash used sheets, towels, and clothes with water and laundry detergent. Use a dryer to dry them completely. Wash clothes according to the manufacturer's instructions on the label. Clean your hands after touching dirty clothes. How can you prevent MRSA from spreading? Choose all that apply. A. wash clothes B. do not share personal items C. cover wounds D. clean your hands E. don't play sports F. stay in the house G. cover your face when outside H. don't go to the hospital

A. wash clothes B. do not share personal items C. cover wounds D. clean your hands

Which part of the bacteriophage in Figure 12-1 contains genetic material?

B.

​A doctor notices that many of their lactose intolerant patients have weak, brittle bones. The doctor wonders if this occurs due to the patients' reduced calcium intake, resulting in decreased blood calcium levels below 10 mg/dL. Which situation below provides evidence in support of the doctor's hypothesis? A. Low PTH and high calcitonin levels in the patients. B. High PTH and low calcitonin levels in the patients. C. Low PTH and low calcitonin levels in the patients. D. High PTH and high calcitonin levels in the patients

B. High PTH and low calcitonin levels in the patients.

The brain coordinates the circulatory and respiratory systems of the human body. The control of breathing, for example, involves neural pathways among the structures represented in the figure above. One important stimulus in the control of breathing is an increase in blood CO2 concentration, which is detected as a decrease in blood pH. Which of the following best describes the physiological response to an overall increase in cellular respiration in the body? A. In response to depleted blood CO2​ levels, the pH sensors send signals directly to the rib muscles, resulting in an increase in the rate of CO2​ uptake by the lungs and a decrease in CO2 ​utilization by the brain. B. In response to low blood pH, the pH sensors send a signal to the brain, which then sends a signal to the diaphragm, resulting in an increased rate of breathing to help eliminate excess blood CO2​. C. In response to high blood pH, the pH sensors send a signal directly to the lungs, resulting in a slower rate of breathing, and the lungs send a signal back to the heart once CO2​ availability has been restored. D. In response to an increased rate of breathing, the rib muscles send a signal to the brain, which then sends a signal to the heart, resulting in a decrease in heart activity and slower flow of blood through the body.

B. In response to low blood pH, the pH sensors send a signal to the brain, which then sends a signal to the diaphragm, resulting in an increased rate of breathing to help eliminate excess blood CO2​.

Potatoes such as the Irish Lumper (solanum tuberosum) can reproduce either sexually, using flowers which bear fruit, or asexually, using the eyes of the potatoes. In the 1980s, many of the Irish opted for the quicker method of planting the eyes and about two fifths of the population became reliant on this cheap crop. When the potato blight* reached Ireland, it wiped out almost all of these potatoes. The Irish Potato Famine drove over 1.5 million people to seek refuge in America while many others starved. *Blight: a mold by the name of phytophthora infestans which causes a disease in potatoes Which of the following explanations best describes why the blight was so effective? A. The potatoes could not increase in number because there was limited space on the island. This caused an increase in biodiversity, making it easier for the blight to destroy all of the potatoes. B. Since most of the potatoes were clones, they lacked genetic diversity. The blight was then equally effective at wiping out all of the potatoes instead of a few. C. Competition between potato plants for sunlight led to less biodiversity as only a few plants dominated the others. The blight could then infect all of those remaining. D. The potatoes mutated and adapted to best survive in Ireland but these mutations caused them to die of blight.

B. Since most of the potatoes were clones, they lacked genetic diversity. The blight was then equally effective at wiping out all of the potatoes instead of a few.

A student researching bacteria concluded a report with the following claim: All bacteria disrupt the health of organisms they inhabit, including humans. Which statement correctly addresses whether the claim is valid or not? A.The claim is valid because many studies and experiments have shown that bacteria disrupt homeostasis. B. The claim is invalid because there are many types of bacteria that help organisms maintain homeostasis. C. The claim is invalid because only microorganisms such as viruses disrupt the health of organisms. D. The claim is valid because bacteria cause disease.

B. The claim is invalid because there are many types of bacteria that help organisms maintain homeostasis.

Homeostasis of blood sugar level. When body system X releases too much sugar into the blood, the body can maintain homeostasis by making ____________. A. more hormone A, only B. more hormone B, only C. more of hormone A and B D. no hormone A or B

B. more hormone B, only

Which sequence represents structures organized from least complex to most complex? A. nerve cell → nucleus → nervous system → brain B. nucleus → nerve cell → brain → nervous system C. brain → nervous system → nucleus → nerve cell D. nervous system → brain → nerve cell → nucleus

B. nucleus → nerve cell → brain → nervous system

The series of questions will test your knowledge of the informational texts we read in Lesson 2 of the Addie case. Each text is provided again as a reference and can be used to help answer your questions MRSA in the Community General Information About MRSA in the Community. MRSA is methicillin-resistant Staphylococcus aureus, a type of staph bacteria that is resistant to several antibiotics. In the general community, MRSA most often causes skin infections. In some cases, it causes pneumonia (lung infection) and other issues. If left untreated, MRSA infections can become severe and cause sepsis - a life-threatening reaction to severe infection in the body. In a healthcare setting, such as a hospital or nursing home, MRSA can cause severe problems such as bloodstream infections, pneumonia, and surgical site infections. For more information visit MRSA in healthcare settings. How to Prevent Spreading MRSA, Who Is At Risk, and How Is MRSA Spread In The Community? Anyone can get MRSA on their body from contact with an infected wound or by sharing personal items, such as towels or razors, that have touched infected skin. MRSA infection risk can be increased when a person is in activities or places that involve crowding, skin-to-skin contact, and shared equipment or supplies. People including athletes, daycare and school students, military personnel in barracks, and those who recently received inpatient medical care are at higher risk. How Common Is MRSA? Studies show that about one in three people carries staph in their nose, usually without any illness. Two in 100 people carry MRSA. There are not data showing the total number of people who get MRSA skin infections in the community. Can I Prevent MRSA? How? There are the steps you can take to reduce your risk of MRSA infection: Maintain good hand and body hygiene. Wash hands often, and clean your body regularly, especially after exercise. Keep cuts, scrapes, and wounds clean and covered until healed. Avoid sharing personal items such as towels and razors. Get care early if you think you might have an infection. What is MRSA Symptoms? Sometimes, people with MRSA skin infections first think they have a spider bite. However, unless a spider is actually seen, the irritation is likely not a spider bite. Most staph skin infections, including MRSA, appear as a bump or infected area on the skin that might be: RedSwollenPainfulWarm to the touch full of pus or other drainage accompanied by a fever What Should I Do If I See These Symptoms? If you or someone in your family experiences these signs and symptoms, cover the area with a bandage, wash your hands, and contact your doctor. It is especially important to contact your doctor if signs and symptoms of an MRSA skin infection are accompanied by a fever. What Should I Do if I Think I Have a Skin Infection? You can't tell by looking at the skin if it is a staph infection (including MRSA). Contact your doctor if you think you have an infection. Finding infections early and getting care makes it less likely that the infection will become severe. Do not try to treat the infection yourself by picking or popping the sore. Cover possible infections with clean, dry bandages until you can be seen by a doctor, nurse, or other health care provider. How To Prevent Spreading MRSA Cover your wounds. Keep wounds covered with clean, dry bandages until healed. Follow your doctor's instructions about proper care of the wound. Pus from infected wounds can contain MRSA so keeping the infection covered will help prevent the spread to others. Bandages and tape can be thrown away with the regular trash. Do not try to treat the infection yourself by picking or popping the sore. Clean your hands often. You, your family, and others in close contact should wash their hands often with soap and water or use an alcohol-based hand rub, especially after changing the bandage or touching the infected wound. Do not share personal items. Personal items include towels, washcloths, razors, and clothing, including uniforms. Wash used sheets, towels, and clothes with water and laundry detergent. Use a dryer to dry them completely. Wash clothes according to the manufacturer's instructions on the label. Clean your hands after touching dirty clothes. According to the resource "MRSA in the Community," how is MRSA spread? Choose all that apply A. coughing B. sharing personal items C. contact with a wound D. athletics E. sneezing F. visiting daycare G. vomiting H. military

B. sharing personal items C. contact with a wound D. athletics F. visiting daycare H. military

Some strains of the bacterium Streptococcus pyogenes secrete poisonous substances called exotoxins. The genes encoding the exotoxins are thought to have originated in bacteriophages, which are viruses that infect bacteria.​​Which of the following is the most likely mechanism by which the S. pyogenes acquired the ability to produce the exotoxins? A. Bacteriophages engulfed cellular debris from dead bacteria. B. Bacteriophages in the environment activated bacterial cell division. C. Bacteriophage DNA became integrated into the bacterial chromosome as the result of a lysogenic infection. D. Bacteriophage proteins were absorbed into bacterial cells by endocytosis.

C. Bacteriophage DNA became integrated into the bacterial chromosome as the result of a lysogenic infection.

The diagram shows human body structures that are coordinated to maintain homeostasis. Which row correctly identifies the functions of these structures? A. Body system X is for circulation and organ Y is for the synthesis B. Body system X is for digestion and organ Y is for transport C. Body system X is for digestion and organ Y is for regulation D. Body system X is for circulation and organ Y is for nutrition

C. Body system X is for digestion and organ Y is for regulation

Based on your knowledge of the characteristics of life, which of these describes a difference between viruses and cells? A. Cells contain protein, and viruses contain only carbohydrates. B. Viruses have flagella, and cells have only cilia. C. Cells reproduce independently, and viruses require a host to reproduce. D. Viruses have membranes made of proteins, and cells have membranes made of nucleic acid.

C. Cells reproduce independently, and viruses require a host to reproduce.

The series of questions will test your knowledge of the informational texts we read in Lesson 2 of the Addie case. Each text is provided again as a reference and can be used to help answer your questions MRSA in the Community General Information About MRSA in the Community. MRSA is methicillin-resistant Staphylococcus aureus, a type of staph bacteria that is resistant to several antibiotics. In the general community, MRSA most often causes skin infections. In some cases, it causes pneumonia (lung infection) and other issues. If left untreated, MRSA infections can become severe and cause sepsis - a life-threatening reaction to severe infection in the body. In a healthcare setting, such as a hospital or nursing home, MRSA can cause severe problems such as bloodstream infections, pneumonia, and surgical site infections. For more information visit MRSA in healthcare settings. How to Prevent Spreading MRSA, Who Is At Risk, and How Is MRSA Spread In The Community? Anyone can get MRSA on their body from contact with an infected wound or by sharing personal items, such as towels or razors, that have touched infected skin. MRSA infection risk can be increased when a person is in activities or places that involve crowding, skin-to-skin contact, and shared equipment or supplies. People including athletes, daycare and school students, military personnel in barracks, and those who recently received inpatient medical care are at higher risk. How Common Is MRSA? Studies show that about one in three people carries staph in their nose, usually without any illness. Two in 100 people carry MRSA. There are not data showing the total number of people who get MRSA skin infections in the community. Can I Prevent MRSA? How? There are the steps you can take to reduce your risk of MRSA infection: Maintain good hand and body hygiene. Wash hands often, and clean your body regularly, especially after exercise. Keep cuts, scrapes, and wounds clean and covered until healed. Avoid sharing personal items such as towels and razors. Get care early if you think you might have an infection. What is MRSA Symptoms? Sometimes, people with MRSA skin infections first think they have a spider bite. However, unless a spider is actually seen, the irritation is likely not a spider bite. Most staph skin infections, including MRSA, appear as a bump or infected area on the skin that might be: RedSwollenPainfulWarm to the touch full of pus or other drainage accompanied by a fever What Should I Do If I See These Symptoms? If you or someone in your family experiences these signs and symptoms, cover the area with a bandage, wash your hands, and contact your doctor. It is especially important to contact your doctor if signs and symptoms of an MRSA skin infection are accompanied by a fever. What Should I Do if I Think I Have a Skin Infection? You can't tell by looking at the skin if it is a staph infection (including MRSA). Contact your doctor if you think you have an infection. Finding infections early and getting care makes it less likely that the infection will become severe. Do not try to treat the infection yourself by picking or popping the sore. Cover possible infections with clean, dry bandages until you can be seen by a doctor, nurse, or other health care provider. How To Prevent Spreading MRSA Cover your wounds. Keep wounds covered with clean, dry bandages until healed. Follow your doctor's instructions about proper care of the wound. Pus from infected wounds can contain MRSA so keeping the infection covered will help prevent the spread to others. Bandages and tape can be thrown away with the regular trash. Do not try to treat the infection yourself by picking or popping the sore. Clean your hands often. You, your family, and others in close contact should wash their hands often with soap and water or use an alcohol-based hand rub, especially after changing the bandage or touching the infected wound. Do not share personal items. Personal items include towels, washcloths, razors, and clothing, including uniforms. Wash used sheets, towels, and clothes with water and laundry detergent. Use a dryer to dry them completely. Wash clothes according to the manufacturer's instructions on the label. Clean your hands after touching dirty clothes. What are some symptoms of MRSA? Choose all that apply A. pneumonia B. fainting C. red area on the skin D. swollen area on the skin E. painful area on the skin F. area full of puss G. difficulty breathing H. fever

C. red area on skin D. swollen area on skin E. painful area on skin F. area full of puss H. fever

How do human diseases caused by bacteria and diseases caused by viruses react to antibiotics?

D. Bacterial diseases respond to antibiotics; viral diseases do not.

In 1980, farmers began noticing that pesticides they were using to defend their crops against insects stopped being effective. Insects that should have died when they came into contact with pesticides survived. Scientists found the following data trend with respect to the amount of active pesticide ingredient being used in the United States. Clearly, there is a directly proportional relationship between the increase in pesticide use the during the 1970s and the increase in pesticide resistant insect populations in the 1980s. However, this relationship merely establishes a correlation between the increase in both pesticide use and pesticide resistant insects. Which of the following would allow scientists to establish a causal relationship between these correlated events? A. The application of herbicide to weeds in the same fields causes some plants to become resistant to the herbicide, indicating that developing resistance to toxins is inevitable B. Understanding the mechanism of natural selection is enough to establish a causal relationship between increases in pesticide use and increases in pesticide resistance in insects. C. Offspring of insects that are resistant to the pesticide also have pesticide resistance. D. Scientists isolate and identify the mutation in the DNA molecule of the insects that gives them resistance to pesticides. Further, they find that the mutation only exists in insects exposed to the pesticide or their offspring.

D. Scientists isolate and identify the mutation in the DNA molecule of the insects that gives them resistance to pesticides. Further, they find that the mutation only exists in insects exposed to the pesticide or their offspring.

Vaccine schedules for children show that many vaccinations are received in multiple (2 to 4) doses. Why is that?

For many diseases, it takes more than one exposure for antibodies to be built to fight off the illness.

Fitness is the ability to survive and reproduce offspring who can also survive and reproduce. Below are descriptions of four male lions. According to the definition of fitness, which lion would biologists consider the "fittest"?

Leo

Cystic fibrosis is an autosomal recessive disorder caused by a defective gene that causes a thick buildup of mucus in and around the lungs. The increased mucous make it very difficult to breath. The mucus also traps bacteria in the lungs which can lead to upper respiratory infections and lung damage. People who have cystic fibrosis will die if not treated. In order for a person to have cystic fibrosis they must inherit the defective gene from both parents. Alice and Matt are both heterozygous for cystic fibrosis. They want to have children but are concerned they might each pass the defective gene to their children. What is the probability their first-born child will have cystic fibrosis?

There is a 25% chance their child will be born with cystic fibrosis.

Molecules in a certain medication attach to receptors on nerve cells. This prevents the normal chemical signal from binding to the receptor. One immediate result of taking this medication might be a disruption in the ability of

cells to communicate with each other

Dr. Jenna Collins rounded the corner of the hospital hallway and entered her next patient's room. There she saw Kayla Starnes lying in the hospital bed in front of her with her mother standing nearby. Picking up Kayla's chart, Dr. Collins introduced herself to Kayla. "Hi, I'm Dr. Collins. I hear you're not feeling very well." Kayla replied weakly, "Hi... am I gonna have surgery?" "I don't know Kayla. Let's take a look at things." Dr. Collins estimated Kayla's age to be seven or eight. Picking up Kayla's chart, she began assessing the situation. It turned out Kayla was seven years old. She had suffered for a couple of days with a temperature of 103 degrees and right groin pain. The emergency room diagnosis was an infected right hip joint. "Let's take a look at that infection," said Dr. Collins. Dr. Collins confirmed that the groin area was inflamed and observed abscess formation in the area. From all signs, the diagnosis seemed certain-infected hip joint caused by some type of bacteria. Surgical drainage of the fluid-filled area of infection would be required followed by antibiotic treatment. Dr. Collins made some notes on Kayla's chart and then turned back to Kayla and her mother. "Well, Kayla it looks like we will have to carry out a surgical procedure to take care of this problem after all." Dr. Collins explained the details of what would take place to Kayla's mother who sat listening intently to Dr. Collins. "We'll do the procedure today in order to prevent Kayla's condition from getting any more serious. But don't be alarmed. The procedure is routine, and we have several antibiotics in our arsenal that should take care of the infection." As Dr. Collins walked away she thought to herself, "Hmm, this procedure is routine, but what antibiotic should I choose? The hospital microbiology lab will be able to tell me what type of bacteria Kayla is carrying, but that information may not be available for a couple of days. Kayla can't wait that long. I've got to decide now." Kayla required drainage of fluid from the hip joint. After the drainage, an antibiotic treatment was given to __________________.

kill any bacteria still present in the area.

Analyze the diagram and decide if each event in the left column happens when blood sugar is above or below the body's set point (i.e. normal homeostatic value). 1. insulin is released 2. tissue take up glucose 3. the liver stores glycogen 4. glucagon is released 5. glucose is released into bloodstream

occurs when blood sugar is above the set point: insulin is released tissue take up glucose the liver stores glycogen occurs when blood sugar is below the set point: glucagon is released glucose is released into the bloodstream

According to the graph, which type of resistance developed first?

penicillin hospital-acquired

How do cells in the ovary detect a hormone from the brain?

receptor molecules on the cells of the ovary bind with the hormone

If organ Y becomes unable to produce enough hormone B, then homeostasis would be disrupted. To restore homeostasis and compensate for the lack of hormone B, one useful action would be to

reduce the carbohydrates in body system X

If body system X temporarily stops releasing sugar into the blood, a likely response of the body would be to

start to increase synthesis of hormone A

If a mutation introduces a new skin color in a lizard population, which factor might determine whether the frequency of the new allele will increase?

whether the mutation makes some lizards more fit for their environment than other lizards