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Based on your knowledge of the polarity of water molecules, the solute molecule depicted in the figure is most likely without charge . positively charged. hydrophobic. negatively charged . nonpolar.

. positively charged.

Which discovery supports the hypothesis that evolution of the lactase-persistence trait was driven by the use of milk in pastoralist cultures? People who are lactase persistent have a mutation in the switch region of the lactase gene .The lactase gene is present in both humans and domesticated animals. Ancient pots used to hold milk are about the same age as the lactase-persistence mutations. Scientists have discovered different mutations for lactase persistence in different cultures.

Ancient pots used to hold milk are about the same age as the lactase-persistence mutations.

What did researchers discover about the genetic mutation causing lactase persistence? It is the same mutation in European and African populations. It is found in a regulatory region (a "switch") upstream of the lactase gene. It is found in the coding region of the lactase gene on chromosome 2. The mutation affects different genes in European and African populations.

It is found in a regulatory region (a "switch") upstream of the lactase gene.

Why is the enzyme lactase necessary to digest dairy products?

Lactase breaks down lactose into smaller molecules that can be absorbed by the cells that line the small intestine.

Predict what will happen to the frequency of the sickle cell allele in areas where malaria has been eradicated. The sickle cell allele will decrease in frequency. The sickle cell allele will increase in frequency. The sickle cell allele frequency will not be affected.

The sickle cell allele will decrease in frequency.

How do lactase supplements help people who are lactose intolerant? The supplements bring about genetic changes that allow lactose intolerant people to produce lactase. The supplements help replace the missing calcium and vitamins that people lack when they don't consume dairy products. The supplements provide the enzyme that breaks down the lactose in dairy products. The supplements create a nauseating feeling so that people are less likely to consume dairy products.

The supplements provide the enzyme that breaks down the lactose in dairy products.

Lactose intolerance in infants is more common in the population today than it was a hundred years ago. Why?

Today there are alternatives to breast milk, such as lactose-free formula and soy milk, so lactose intolerant infants can survive.

Suppose that a mutation for lactase-persistence occurred in each of the populations described below. In which populations would the mutation be more likely to increase in frequency over time because of natural selection? a population that raises rice and tilapia fisha population that raises wheat and sheepa population that raises potatoes and chickensa population that raises corn and beans

a population that raises wheat and sheep

Consider two solutions: solution X has a pH of 4; solution Y has a pH of 7. From this information, we can reasonably conclude that the concentration of hydrogen ions in solution Y is 1,000 times greater than the concentration of hydrogen ions in solution X. solution Y has no free hydrogen ions (H+) because the solution is neutral. the concentration of hydrogen ions in solution X is 3 times greater than the concentration of hydrogen ions in solution Y. the concentration of hydrogen ions in solution X is 30 times greater than the concentration of hydrogen ions in solution Y. the concentration of hydrogen ions in solution X is 1,000 times greater than the concentration of hydrogen ions in solution Y.

the concentration of hydrogen ions in solution X is 1,000 times greater than the concentration of hydrogen ions in solution Y.

The enzyme lactase breaks the sugar lactose into which compound(s)? sucrose fructose glucose galactose

glucose galactose

Which of the following descriptions constitutes a controlled experiment? setting up a bird feeder and compiling a list of all of the bird species seen at the feeder over a period of several weeks growing one set of 10 seedlings under white light and one set of the same type of seedlings under red light and measuring their growth over a period of two weeks using a microscope to observe organisms present in a sample of pond water and recording the number of each type of organism observed growing one set of 10 seedlings under white light at 30°C and one set of a different type of seedlings under red light at 25°C and measuring their growth over a period of two weeks

growing one set of 10 seedlings under white light and one set of the same type of seedlings under red light and measuring their growth over a period of two weeks

In a neutral solution the concentration of _____. water molecules is less than the concentration of hydrogen ions water molecules is less than the concentration of hydroxide ions hydrogen ions is greater than the concentration of hydroxide ions hydrogen ions is equal to the concentration of hydroxide ions hydrogen ions is less than the concentration of hydroxide ions

hydrogen ions is equal to the concentration of hydroxide ions

Human populations in low-UV environments tend to have more lightly pigmented skin. One explanation is that the selective pressure for dark skin decreases as UV intensity decreases. At the same time there is selection for lighter skin to absorb more UV radiation, which is needed for vitamin D production. lightly pigmented people cannot synthesize vitamin D in high-UV environments, such as equatorial Africa indigenous peoples living at high latitudes have darker skin, but they eat foods rich in vitamin D lightly pigmented people tend to be at higher risk of vitamin D deficiency red hair and light skin are typical of people of northern European descent

indigenous peoples living at high latitudes have darker skin, but they eat foods rich in vitamin D

Four individuals measured their baseline blood glucose, then drank a litre of milk. They then measured their blood glucose levels at regular 15 minute intervals for 60 minutes. The results are shown in the graph below. Which individuals are lactase-persistent? Sarah and peter went up rachel and arthur went down in glucose levels

peter and sarah

Carbon dioxide (CO2) is readily soluble in water, according to the equation CO2 + H2O ↔ H2CO3. Carbonic acid (H2CO3) is a weak acid. If CO2 is bubbled into a beaker containing pure, freshly distilled water, which of the following graphs correctly describes the results?

ph would go down

Water molecules are able to form hydrogen bonds with

polar

An equal volume (5 mL) of milk of magnesia from a freshly opened bottle is added to each of the following solutions. After complete mixing, which of the mixtures will have the lowest pH? 100 mL of pure water 100 mL of freshly brewed coffee 100 mL of household cleanser containing 0.5 M ammonia 100 mL of freshly squeezed lemon juice 100 mL of household cleanser containing 0.5 M bleach

100 mL of freshly squeezed lemon juice

Why is it important that an experiment include a control group?

A control group provides a reference by which to determine if a particular outcome may reasonably result from the variable being tested.

How does the term "lactase persistent" relate to the term "lactose tolerant"? Lactose tolerance has nothing to do with lactase-persistence. A lactase-persistent person is lactose tolerant. A lactase-persistent person is lactose intolerant.

A lactase-persistent person is lactose tolerant.

Why should we not view lactose intolerance as a disease in adult humans?

Adult humans did not consume dairy products until fairly recently in our evolutionary history.

Carbon dioxide (CO2) is readily soluble in water, according to the equation CO2 + H2O.Carbonic acid (H2CO3) is a weak acid. Respiring cells release CO2 into the bloodstream. What will be the effect on the pH of blood as that blood first comes in contact with respiring cells? Blood pH will increase slightly. Blood pH will remain unchanged. Blood pH will decrease slightly . Blood pH will first increase, then decrease as CO2 combines with hemoglobin.

Blood pH will decrease slightly.

How did Dr. Allison test his hypothesis that sickle cell disease was connected to malaria? He evaluated blood samples for malaria parasites and the presence of sickle cells. He expanded his study area beyond Kenya to the rest of East Africa to see if malaria and sickle disease were connected. He looked for the underlying genetic mechanism causing sickle cell disease. He studied the way that the malaria parasite interacts with sickle cells.

He evaluated blood samples for malaria parasites and the presence of sickle cells. He expanded his study area beyond Kenya to the rest of East Africa to see if malaria and sickle disease were connected.

In 1949, Dr. Tony Allison observed a high frequency of Kenyans carrying the sickle cell allele in coastal areas and near Lake Victoria, but a lower frequency in the highlands. What did he hypothesize? He hypothesized that there was a connection between malaria and sickle cell disease. He hypothesized that malaria causes sickle cell disease. He hypothesized that sickle cell disease was an environmental, not a genetic disease. He hypothesized that malaria is a genetic disease.

He hypothesized that there was a connection between malaria and sickle cell disease.

You've learned that two copies of the sickle-cell allele cause sickle-cell disease. One copy of the allele causes sickle-cell trait and is advantageous in areas with a high incidence of malaria. Now suppose that only one copy of the sickle-cell allele caused sickle-cell disease. If that were true, what would you predict for the frequency of the sickle-cell allele in a human population? Heterozygotes would have a survival advantage over those homozygous for the wild-type allele. Heterozygotes would have NO survival advantage over those homozygous for the wild-type allele. There would be selective pressure in favor of this mutation. There would be selective pressure against this mutation. The frequency of the sickle-cell allele would increase in the population over time . The frequency of the sickle-cell allele would decrease in the population over time.

Heterozygotes would have a survival advantage over those homozygous for the wild-type allele. There would be selective pressure in favor of this mutation. The frequency of the sickle-cell allele would increase in the population over time.

How does Dr. Allison's work provide an example of natural selection in humans? Natural selection caused the sickle cell allele to appear in east African populations. In areas with malaria, individuals with one sickle cell allele reproduced at higher rates than those with no sickle cell alleles .In areas with malaria, natural selection causes individuals to acquire the sickle cell allele as protection against malaria. In areas without malaria, individuals with two sickle cell alleles reproduced at lower rates than those without sickle cell disease.

In areas with malaria, individuals with one sickle cell allele reproduced at higher rates than those with no sickle cell alleles. In areas without malaria, individuals with two sickle cell alleles reproduced at lower rates than those without sickle cell disease.

In which country would you most likely find a higher incidence of lactase persistence?

In which country would you most likely find a higher incidence of lactase persistence?

In some populations, 1 in 500 people have sickle cell disease. What reason does the film give for why a potentially deadly, inherited disease is found at such high frequencies? Individuals with two sickle cell alleles have an evolutionary advantage because they do not get sickle cell disease or get infected with malaria. Individuals with two normal hemoglobin alleles get both sickle cell disease and are susceptible to malaria, so these alleles are eliminated from the population. Sickle cell alleles are new mutations and not enough time has gone by for these alleles to be eliminated from the population by natural selection. Individuals with one sickle cell allele are protected from malaria and do not have sickle cell disease, thus keeping the allele in the population.

Individuals with one sickle cell allele are protected from malaria and do not have sickle cell disease, thus keeping the allele in the population.

Most people are lactose intolerant as adults, but nearly everyone produces sufficient lactase as an infant. However, in some cases, genetic mutations can occur that make an infant lactose intolerant. From an evolutionary perspective -- over thousands of years -- why would lactose intolerance in infants be very rare in the population? Infants who were lactose intolerant were intolerant of all other foods as well. Lactose intolerance was such an embarrassing problem that many lactose intolerant parents chose not to have children, since the children might be lactose intolerant as well .Lactose intolerant infants could not digest breast milk and therefore usually died, never having the chance to pass the mutation on to their children .Lactose intolerant adults were not healthy enough to have children.

Lactose intolerant infants could not digest breast milk and therefore usually died, never having the chance to pass the mutation on to their children.

Which of the following statements accurately describes melanin's function?

Lighter skin has less of the dark-brown eumelanin that protects cells from UV damage.

How could milk-drinking have provided strong favorable selection for lactase persistence? Milk may have been a critical food source during times of famine. Milk was safer to drink than water and reduced exposure to pathogens. Milk is protein and fat-rich and therefore could have been an important, high-quality food source

Milk may have been a critical food source during times of famine. Milk was safer to drink than water and reduced exposure to pathogens. Milk is protein and fat-rich and therefore could have been an important, high-quality food source

Compare sickle cell disease and malaria. Sickle cell disease and malaria are both potentially lethal diseases. Sickle cell disease and malaria are both genetic diseases. Sickle cell disease and malaria are both inherited diseases. Sickle cell disease and malaria are both infectious diseases.

Sickle cell disease and malaria are both potentially lethal diseases.

Suppose that Plasmodium falciparum, the organism that causes malaria, is introduced in an area where the frequency of the sickle-cell allele in the human population is 3.0%. Over time, how is the frequency of the sickle-cell allele in this population most likely to change? he frequency will decrease due to the death of individuals from malaria. The frequency will decrease due to the death of individuals from sickle-cell disease. The frequency will increase due to the advantage of homozygotes where malaria is common. The frequency will increase due to the advantage of heterozygotes where malaria is common.

The frequency will increase due to the advantage of homozygotes where malaria is common.

If acid rain has lowered the pH of a particular lake to pH 4.0, which of the following statements about this lake is true? The hydrogen ion concentration is 1 × 104 moles per liter of lake water. The hydroxyl ion concentration is 1 × 10-4 moles per liter of lake water. The hydrogen ion concentration is 1 × 10-10 moles per liter of lake water. The hydrogen ion concentration is 4.0 moles per liter of lake water. The hydroxyl ion concentration is 1 × 10-10 moles per liter of lake water.

The hydroxyl ion concentration is 1 × 10-10 moles per liter of lake water.

Which of the following statements apply to the variation in human skin color? Human skin color variation is primarily determined by the type and amount of melanin pigment in the skin. Variability in human skin color can be explained by the activity of a single gene. The color of human skin and the skin of our closest primate relative exhibits a similar range in variability .Human skin color variation evolved recently in hominid evolution, once some populations of our human ancestors migrated out of Africa. Human skin color variation likely evolved in response to differences in the intensity of sunlight around the world.

Variability in human skin color can be explained by the activity of a single gene. Human skin color variation likely evolved in response to differences in the intensity of sunlight around the world. .Human skin color variation evolved recently in hominid evolution, once some populations of our human ancestors migrated out of Africa.

One of the buffers that contributes to pH stability in human blood is carbonic acid (H2CO3). Carbonic acid is a weak acid that, when placed in an aqueous solution, dissociates into a bicarbonate ion (HCO3 -) and a hydrogen ion (H+). Thus,H2CO3 ↔ HCO3 - + H+If the pH of the blood increases, one would expect a decrease in the concentration of H2CO3 and an increase in the concentration of HCO3 - . an increase in the concentration of H2CO3 and a decrease in the concentration of HCO3 - . an increase in the concentration of HCO3 - and a decrease in the concentration of OH-. a decrease in the concentration of HCO3 - and an increase in the concentration of H+.

a decrease in the concentration of H2CO3 and an increase in the concentration of HCO3 -.

Carbonic acid (H2CO3) serves as a buffer in human blood. Carbonic acid is a weak acid that dissociates into a bicarbonate ion (HCO3 -) and a hydrogen ion (H+). Thus,H2CO3 ↔ HCO3 - + H+A decrease in blood pH would result in an increase in the concentrations of H2CO3 and HCO3 -. a decrease in the concentration of H2CO3 and an increase in the concentration of HCO3 -. a decrease in the concentrations of H2CO3 and HCO3 -. an increase in the concentration of H2CO3 and a decrease in the concentration of HCO3 -.

an increase in the concentration of H2CO3 and a decrease in the concentration of HCO3 -.

When should a lactase supplement be taken in order to be most effective, and why? before the diary product is consumed, so the lactase has time to spread in the small intestine taking it anytime is effective, because lactase works while in the bloodstream after the dairy product is consumed, since it takes a while for the lactase to start working at the same time the dairy product is consumed, so that the lactase will be in contact with the lactose

at the same time the dairy product is consumed, so that the lactase will be in contact with the lactose

One proposal to mitigate the effects of burning fossil fuels on atmospheric CO2 concentrations is to pipe liquid CO2 into the ocean at depths of 2,500 feet or greater. At the high pressures at such depths, CO2 is heavier than water. What potential effects might result from implementing such a scheme? increased growth of corals from a change in the carbonate-bicarbonate equilibrium changes in the growth of deep sea-dwelling organisms with calcium carbonate shells increased carbonate concentrations in the deep waters increased photosynthetic carbon fixation because of the increased dissolved carbon dioxide in the deep water no effect because carbon dioxide is not soluble in water

changes in the growth of deep sea-dwelling organisms with calcium carbonate shells

Based on the risk factors discussed in the video, which of the following groups would be most likely to develop the bone disease rickets?

children born to parents with dark skin living far from the equator

If the cytoplasm of a cell is at pH 7, and the interior of an organelle is pH 8, this means that the concentration of hydrogen ions is tenfold higher in the cytoplasm than in the organelle. the organelle is more acidic than the cytoplasm . the concentration of hydrogen ions in the cytoplasm is 7/8 the concentration in the organelle. the concentration of hydrogen ions in the cytoplasm is 8/7 the concentration in the organelle. the concentration of hydrogen ions is tenfold higher in the organelle than in the cytoplasm.

the concentration of hydrogen ions is tenfold higher in the cytoplasm than in the organelle.

Darker skin is more prevalent in high-UV areas. Dr. Nina Jablonski proposed a hypothesis to explain the selective pressure for darker skin in these environments. On what evidence did she base this hypothesis?

the melanin in darkly pigmented skin protects circulating folate from being destroyed by UV radiation, and folate is important in human reproduction

The mutation resulting in the sickle-cell allele causes which of the following? the replacement of multiple amino acids downstream of the point mutation the replacement of a single amino acid downstream of the point mutationchanges in the structure of the β-globin polypeptideno changes in the structure of the β-globin polypeptidethe production of abnormal hemoglobin protein that distorts red blood cells into a sickle shape under low-oxygen conditionsthe production of abnormal hemoglobin protein that distorts red blood cells into a sickle shape under high-oxygen conditions

the replacement of a single amino acid downstream of the point mutation changes in the structure of the β-globin polypeptide the production of abnormal hemoglobin protein that distorts red blood cells into a sickle shape under low-oxygen conditions

In what way does natural selection depend on the specific environment in which an organism lives? natural selection produces traits that are always either helpful or harmful, regardless of the environment.natural selection is random, and the direction of the selective pressure cannot be predicted based on the environment. when the environment changes, traits that were beneficial to an organism may become harmful and vice versa. when an organism enters a new environment, it evolves all of the traits it needs to survive there

when the environment changes, traits that were beneficial to an organism may become harmful and vice versa.