science test 12/16

A vaccine for the viral disease known as chicken pox would contain

A dead or weakened form of the pathogen

pepsin works best in which type of environment?

Acidic, only

which activity would most likely increase the mutation rate in a culture of bacteria being grown in a laboratory experiment?

Exposing the culture to ultraviolet radiation

which statement explains the importance of maintaining a constant internal environment to ensure proper enzyme functioning?

Increasing the temperature and pH can alter the specific shape of enzymes

Meat tenderizer contains an enzyme that interacts with meat. If meat is coated with tenderizer and then placed in a refrigerator for a short time, how would the enzyme be affected?

Its activity would slow down

All chemical breakdown processes in cells directly involve

Reactions that are controlled by catalysts

which condition is necessary for enzymes and hormones to function properly in the human body?

These chemicals must have a specific shape

which statement describes all enzymes?

They affect the rate of chemical reactions

which type of pathogenic microbe causes aids?

a dead or weakened form of the pathogen

the disease known as malaria may result in a fever, a decrease in red blood cells, and an enlarged liver and spleen. these symptoms are evidence of

a distribution of homeostasis

Experiments revealed the following information about a certain molecule: — It can be broken down into amino acids. — It can break down proteins into amino acids. — It is found in high concentrations in the small intestine of humans. This molecule is most likely

an enzyme

which is an advantage of a change in pulse rate after exercising?

an increased blood flow carries excess waste products away from the active muscle sells

the human immune system fights infection by releasing

antibodies

cells of the immune system are able to respond to the presence of invading organisms because they recognize the

antigens present on the invaders

describe one possible immune response, other than an increase in number, that one of the cells labeled A would carry out

attack/destroy a pathogen

the sweet taste of freshly picked corn is due to the high sugar content in the kernels. enzyme action converts about 50% of the sugar to starch within one day after picking. to preserve its sweetness, the freshly picked corn is immersed in boiling water for a few minutes, and then cooled. which statement most likely explains why the boiled corn kernels remain sweet?

boiling deactivates the enzyme responsible for converting sugar to starch

state one specific way white blood cells help to protect the human body from pathogens

by producing antibodies

An enzyme known as rubisco enables plants to use large amounts of carbon dioxide. This enzyme is most likely active in the

chloroplasts

the blood of newborn babies is tested to determine the presence of a certain substance. this substance indicates the genetic disorder pku, which may result in mental retardation. babies born with this disorder are put on a special diet so that mental restardarion will not develop. in this situation, modification of the baby's diet is an example of how biological research can be used to

control a disorder

people who have aids are more likely than others to become ill with multiple infections because the pathogen that causes aids

damages the immune system

blood can be tested to determine the presence of the virus associated with the development of aids. this blood test is used directly for

diagnosis

which substances are necessary for the synthesis of most materials in an organism?

enzymes

The failure to regulate the pH of the blood can affect the activity of

enzymes that clot blood

Drugs to reduce the risk of rejection are given to organ transplant patients because the donated organ contains

foreign antigens

an individual recovers from the common cold, which is caused by rhinovirus a. the person then becomes infected with the again influenza virus, which causes the bird flu. which statement best describes what will most likely happen to this person?

he will have the symptoms of the bird flu because he is not immune to the avian influenza virus

Organisms undergo constant chemical changes as they maintain an internal balance known as

homeostasis

what term or phrase does letter X most likely represent

homeostasis

the purpose of introducing weakened microbes into the body of an organism is to stimulate the

immune system to react and prepare the organism to fight future invasions by these microbes

an infection in the body might result in a sudden

increase in the activity of white blood cells

one characteristic of all living things is that they

maintain internal stability

when the antibiotic penicillin was first introduced, it was immediately effective in combating staphylococcus bacterial infections. after a number of years, there were outbreaks of staphylococcal infections that did not respond to treatment with penicillin. the best explanation for this situation is that

members of the original population of bacteria that were penicillin resistant survived and reproduced, creating a more resistant population

certain antibacterial soaps kill 99% of the bacteria present on hands. constant use of these soaps could be harmful over time because

more pathogens may be resistant to the soap

explain how this change in the virus could come about

mutation

Microbes that enter the body, causing disease, are known as

pathogens

which statement best describes why pathogens are harmful?

pathogens can interfere with normal life functions

explain why the percentage of the population with one mutant sickle-cell gene is higher in areas where malaria is common

people with one gene survive malaria and pass the gene on to offspring

typhoid fever, a disease that causes headaches, digestive upset, and a high fever, is caused by the bacterium salmonella typhi. typhoid can be spread from person to person by contaminated water or food or by lack of cleanliness. since the 19th century, the number of individuals infected with this disease has decreased. which statement best explains why the number of people with this disease and other bacterial diseases has decreased over the last 100 years?

personal habits, such as hand washing, have greatly reduced contamination from bacteria

which phrase does not describe a way the human body responds to fight disease?

production of pathogens by white blood cells

Many viruses infect only a certain type of cell because they bind to certain

receptor sites on the surface of the cell

a six year old child ate a peanut butter sandwich at snack time in school. five minutes later, her throat became swollen and she collapsed. this allergic reaction occurred because her body

recognized an antigen in peanut butter and produced an immune response

certain processes are toxic to organisms because they interfere with the function of enzymes in mitochondria. this results directly in the inability of the cell to

release energy from nutrients

state on way telomerase could be used to treat patients who have hiv

remove blood cells from hiv patients early in the disease, add telomerase, then return back to the bodies

which row in the chart below contains correct information concerning synthesis? row 1: building blocks-glucoses molecules,substance synthesized using the building blocks-DNA row 2: building blocks-simple sugars , substance synthesized using the building blocks-protein row 3: building blocks-amino acids, substance synthesized using the building blocks-enzyme row 4: building blocks-molecular bases,substance synthesized using the building blocks-starch

row 3

A sample of food containing one type of a large molecule was treated with a specific digestive enzyme. Nutrient tests performed on the resulting products showed the presence of simple sugars, only. Based on these test results, the original large molecules contained in the sample were molecules of

starch

A new vaccine was developed and then tested on a large sample of individuals. This new vaccine will be considered effective if it helps prepare the body to fight future invasion by

stimulating the production of antibodies

If the same antibiotic is used too many times, it can become less effective against a certain type of bacteria. This observation is best explained by the

survival and reproduction of unaffected bacteria

the immune system of humans may respond to chemicals on the surface of an invading organism by

synthesizing antibodies that mark these organisms to be destroyed

the virus that causes aids is damaging the body because it

targets cells that fight invading microbes

in 1995, during an ebola virus outbreak, approximately 80% of the infected individuals died. which statement is an inference that could be made based on this information?

the individuals who survived were able to produce antibodies against the ebola virus

state what would most likely happen to the rate of enzyme action if the temperature were reduced by 10 degrees. support your answer.

the reaction will slow down because it is below the optimal temperature

explain how a prolonged, excessively high body temperature during an illness could be fatal to humans.

the role of enzymes in a human: help synthesize protein the effect of the high body temperature on enzyme activity: the activity of enzymes will slow down the reason this high body temperature can result in death: enzymes don't work