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In 1634, Jan Baptist van Helmont did an experiment to try to understand where the mass of a tree comes from. He weighed a small willow tree and some dry soil. He then planted the tree and watered it each week. After 5 years he removed the tree from the pot and weighed it. He also dried the soil in the pot and weighed it. He found that the tree had gained almost 75 kg, but the soil had only lost 0.1 kg. Van Helmont concluded that the 75 kg of wood, bark and root was made out of water.
What should Van Helmont do to further test his idea that the molecules to make wood, bark, and roots come mostly from water?
Cut the tree open to see if there is water inside.
Plant another tree, but don't water it for 5 years.
Remove the water from the tree and weigh only its dry mass.
Plant many trees and give each different amounts of water.
In 1634, Jan Baptist van Helmont did an experiment to try to understand where the mass of a tree comes from. He weighed a small willow tree and some dry soil. He then planted the tree and watered it each week. After 5 years he removed the tree from the pot and weighed it. He also dried the soil in the pot and weighed it. He found that the tree had gained almost 75 kg, but the soil had only lost 0.1 kg. Van Helmont concluded that the 75 kg of wood, bark and root was made out of water.
Van Helmont found that the tree gained about 75 kg total (dry mass would be about half that amount). Was his conclusion that "the 75 kg of wood, bark and roots was made out of water" correct?
Yes. Most of the mass of a plant comes from water.
No. Water does not add any mass to a plant.
No. Most of the mass of a plant comes from the soil.
He was partly correct. Some atoms from water get made into food for the plant.
In 1634, Jan Baptist van Helmont did an experiment to try to understand where the mass of a tree comes from. He weighed a small willow tree and some dry soil. He then planted the tree and watered it each week. After 5 years he removed the tree from the pot and weighed it. He also dried the soil in the pot and weighed it. He found that the tree had gained almost 75 kg, but the soil had only lost 0.1 kg. Van Helmont concluded that the 75 kg of wood, bark and root was made out of water.
Before Van Helmont's experiment, most people thought that the mass of a plant comes from the soil. Does his experiment support that conclusion?
Yes, because the soil lost mass and the tree gained mass.
No, because the tree gained a lot more mass than the soil lost.
His experiment does not allow for any conclusions about soil.
In 1634, Jan Baptist van Helmont did an experiment to try to understand where the mass of a tree comes from. He weighed a small willow tree and some dry soil. He then planted the tree and watered it each week. After 5 years he removed the tree from the pot and weighed it. He also dried the soil in the pot and weighed it. He found that the tree had gained almost 75 kg, but the soil had only lost 0.1 kg. Van Helmont concluded that the 75 kg of wood, bark and root was made out of water.
Van Helmont performed his experiment before the process of photosynthesis was explained. Which of the following are reactants of photosynthesis that were NOT measured by his experiment?
The mass that comes from sunlight.
The mass that comes from molecules in the air.
The mass that comes from nutrients in the soil.
The mass that comes from new atoms produced by the plant.
How does a radish plant get carbon atoms to make fat?
Air
Water
Soil
Sunlight
How does a radish plant get hydrogen atoms to make fat?
Air
Water
Soil
Sunlight
When plants do photosynthesis, they produce as gas that is released into the air. A group of students wondered whether temperature affects the rate of photosynthesis. To answer their question, the students put a plant in five different temperatures and measured how much gas was produced by the plant when it was under a grow light for an hour. They measured the amount of gas that was produced in milliliters per hour (mL/hr). The results are shown on the points in the graph below. The students also drew a line of best fit to connect the points.
What gas was produced or given off during photosynthesis that was measured by in the experiment?
Carbon Dioxide
Water Vapor
Ethanol
Oxygen
When plants do photosynthesis, they produce as gas that is released into the air. A group of students wondered whether temperature affects the rate of photosynthesis. To answer their question, the students put a plant in five different temperatures and measured how much gas was produced by the plant when it was under a grow light for an hour. They measured the amount of gas that was produced in milliliters per hour (mL/hr). The results are shown on the points in the graph below. The students also drew a line of best fit to connect the points.
Based on the graph, at which temperature is the highest rate of photosynthesis?
20oC
23oC
26oC
30oC
32oC
When plants do photosynthesis, they produce as gas that is released into the air. A group of students wondered whether temperature affects the rate of photosynthesis. To answer their question, the students put a plant in five different temperatures and measured how much gas was produced by the plant when it was under a grow light for an hour. They measured the amount of gas that was produced in milliliters per hour (mL/hr). The results are shown on the points in the graph below. The students also drew a line of best fit to connect the points.
Based on the graph, what happened to the rate of gas production when the temperature increased from 30 to 32⁰C?
The rate of gas production doubled.
The rate of gas production increased a small amount.
The amount of gas produced decreased by half.
The rate of gas production decreased by a small amount.
Why do atoms form bonds?
Bonds form because of attractions between positive and negative charges within atoms
Bonds form to store extra energy between the atoms
Bonds form to make the molecules needed by plants and animals
What happens to energy when atoms move together to form a bond?
Energy is added to hold the atoms together
Energy is released to make electrons attract
Energy is released as the atoms move to a stable position
Energy is created as the atoms move to a stable position
The graph below compares the change in potential energy as two atoms (labeled X, Y, and Z) are moved from close together to farther apart. Which line shows two atoms that make the most stable bond at the bonding point?
X
Y
Z
Propane is a fuel used for grills and heating some homes. Ethanol is the main type of fuel made from biofuels. The molecular structure of each fuel is represented below. Use these to answer the following questions.
When propane and ethanol are burned for fuel sources, what changes are happening at the atomic level?
The atoms are turned into energy
The molecules react with oxygen to make carbon dioxide and water
The molecules are turning into different atoms
Propane is a fuel used for grills and heating some homes. Ethanol is the main type of fuel made from biofuels. The molecular structure of each fuel is represented below. Use these to answer the following questions.
How would the amount of energy released compare if equal amounts of propane and ethanol were burned?
They are both organic molecules so they will release the same amount of energy
Ethanol is a biofuel so it is a cleaner fuel source to use and therefore a better energy source
Ethanol will release more energy because it has an oxygen atom in the molecule
Propane will release more energy because it has more C-C and C-H bonds so it will react with more oxygen when it burns
Why do plants need light to grow?
Plants use energy from light to make new atoms in their leaves.
Plants use energy from light to break molecules apart into atoms so the atoms can be rearranged into new molecules.
Light is the energy source for taking in nutrients from the soil.
Light provides heat which allows the seed to germinate and the plant to begin growing.
Which of the following parts of a plant is most important for absorbing energy from sunlight?
Chloroplasts
Stomata
Veins
Roots
Which of the following parts of a plant is most important for moving water and nutrients between the different parts of the plant?
stomata
leaves
veins
chloroplasts
A group of students performed an experiment on a potted plant to look at the effect of sunlight on sugar production in plants. They covered half of some leaves with aluminum foil (to block the light) and placed the plant in natural sunlight.
After 1 day, the aluminum foil was removed from the plants’ leaves. All the leaves were soaked in iodine to show the presence of sugar in the leaves. Iodine causes sugar to turn a purplish-black color.
Which conclusion is best supported by the leaf experiment results?
The leaf with no foil covering is not as healthy as the leaf that was covered.
Plants turn a purplish-black color if they are kept in the dark too long.
Only the parts of a leaf that receive sunlight can perform photosynthesis to produce sugar.
Plants produce more sugar in the dark because they can't do photosynthesis without light.
A group of students performed an experiment on a potted plant to look at the effect of sunlight on sugar production in plants. They covered half of some leaves with aluminum foil (to block the light) and placed the plant in natural sunlight.
After 1 day, the aluminum foil was removed from the plants’ leaves. All the leaves were soaked in iodine to show the presence of sugar in the leaves. Iodine causes sugar to turn a purplish-black color.
Which of the following resources (matter and energy) do the leaves need in order to produce sugar? Check all that apply.
carbon dioxide
water
sunlight
soil
Which of the following correctly displays the energy change that happens during photosynthesis?
The Chemical Potential Energy in the beginning remains Chemical Potential Energy in the end
The Chemical Potential Energy in the beginning changes into Light Energy in the end
The Light Energy in the beginning changes into Chemical Potential Energy in the end
The Light Energy in the beginning changes into Motion Energy in the end
The prickly pear cactus gets its name from the pink fruit that it produces. Prickly pear is an important commercial crop grown in South America, North Africa, the Middle East, and the Mediterranean. Like other plants, the prickly pear cactus makes its own food through the process of photosynthesis. The broad stems, called pads, which are the large, rounded, flat segments that form the cactus’ body perform photosynthesis. Prickly pears have developed broad stems, called pads, which are the large, rounded, flat segments that form the cactus’ body. The pads are where photosynthesis occurs. Prickly pear pads are also cooked and eaten as a vegetable and the prickly pear fruit is often made into juices and jellies.
How does the Prickly Pear use water to grow?
Hydrogen atoms from water are needed to make food for the plant through photosynthesis.
Water is combined with minerals from the soil to make large organic molecules.
Water is necessary for the plant to do cellular respiration.
The water closest to the shore has more hydrogen atoms than the water on land.
The prickly pear cactus gets its name from the pink fruit that it produces. Prickly pear is an important commercial crop grown in South America, North Africa, the Middle East, and the Mediterranean. Like other plants, the prickly pear cactus makes its own food through the process of photosynthesis. The broad stems, called pads, which are the large, rounded, flat segments that form the cactus’ body perform photosynthesis. Prickly pears have developed broad stems, called pads, which are the large, rounded, flat segments that form the cactus’ body. The pads are where photosynthesis occurs. Prickly pear pads are also cooked and eaten as a vegetable and the prickly pear fruit is often made into juices and jellies.
How does Prickly Pear use nutrients from the soil to grow?
Soil nutrients are used to make food for the plant through photosynthesis.
Soil nutrients are used for energy in cellular respiration.
Soil nutrients are combined with atoms in glucose to make large organic molecules like proteins.
Soil nutrients combine with water to perform biosynthesis for growth.
The prickly pear cactus gets its name from the pink fruit that it produces. Prickly pear is an important commercial crop grown in South America, North Africa, the Middle East, and the Mediterranean. Like other plants, the prickly pear cactus makes its own food through the process of photosynthesis. The broad stems, called pads, which are the large, rounded, flat segments that form the cactus’ body perform photosynthesis. Prickly pears have developed broad stems, called pads, which are the large, rounded, flat segments that form the cactus’ body. The pads are where photosynthesis occurs. Prickly pear pads are also cooked and eaten as a vegetable and the prickly pear fruit is often made into juices and jellies.
How does Prickly Pear use gases in the air to grow?
Oxygen from the air is used to make food for the plant.
Atoms from sunlight in the air are used to make the plant grow.
Carbon dioxide from the air is used to make food for the plant.
None of the above. Air is not used to grow.
The prickly pear cactus gets its name from the pink fruit that it produces. Prickly pear is an important commercial crop grown in South America, North Africa, the Middle East, and the Mediterranean. Like other plants, the prickly pear cactus makes its own food through the process of photosynthesis. The broad stems, called pads, which are the large, rounded, flat segments that form the cactus’ body perform photosynthesis. Prickly pears have developed broad stems, called pads, which are the large, rounded, flat segments that form the cactus’ body. The pads are where photosynthesis occurs. Prickly pear pads are also cooked and eaten as a vegetable and the prickly pear fruit is often made into juices and jellies.
How does Prickly Pear use sunlight to grow?
The plant uses the sunlight as a food source to grow.
The light energy transforms soil nutrients into food for the plant.
Sunlight heats up the plant so that it can perform cellular respiration to grow.
Energy from light is used to make food that can be burned to release energy.
The prickly pear cactus gets its name from the pink fruit that it produces. Prickly pear is an important commercial crop grown in South America, North Africa, the Middle East, and the Mediterranean. Like other plants, the prickly pear cactus makes its own food through the process of photosynthesis. The broad stems, called pads, which are the large, rounded, flat segments that form the cactus’ body perform photosynthesis. Prickly pears have developed broad stems, called pads, which are the large, rounded, flat segments that form the cactus’ body. The pads are where photosynthesis occurs. Prickly pear pads are also cooked and eaten as a vegetable and the prickly pear fruit is often made into juices and jellies.
A class is investigating how Prickly Pears grows. The class grew a Prickly Pear and then dried and weighed the plants. Where does most of the dry mass of the Prickly Pear come from?
Prickly Pear gains most of its dry mass from nutrients in the soil.
Prickly Pear gains most of its dry mass from gases in the air.
Prickly Pear gains most of its dry mass from sunlight.
Prickly Pear gains most of its dry mass from water.
The prickly pear cactus gets its name from the pink fruit that it produces. Prickly pear is an important commercial crop grown in South America, North Africa, the Middle East, and the Mediterranean. Like other plants, the prickly pear cactus makes its own food through the process of photosynthesis. The broad stems, called pads, which are the large, rounded, flat segments that form the cactus’ body perform photosynthesis. Prickly pears have developed broad stems, called pads, which are the large, rounded, flat segments that form the cactus’ body. The pads are where photosynthesis occurs. Prickly pear pads are also cooked and eaten as a vegetable and the prickly pear fruit is often made into juices and jellies.
Which of the following give energy to the Prickly Pear plants?
Air
Sunlight
Soil Nutrients
Water
All of the above
The prickly pear cactus gets its name from the pink fruit that it produces. Prickly pear is an important commercial crop grown in South America, North Africa, the Middle East, and the Mediterranean. Like other plants, the prickly pear cactus makes its own food through the process of photosynthesis. The broad stems, called pads, which are the large, rounded, flat segments that form the cactus’ body perform photosynthesis. Prickly pears have developed broad stems, called pads, which are the large, rounded, flat segments that form the cactus’ body. The pads are where photosynthesis occurs. Prickly pear pads are also cooked and eaten as a vegetable and the prickly pear fruit is often made into juices and jellies.
All living cells are made up of proteins that include the following types of atoms: carbon, hydrogen, oxygen, and nitrogen. How do Prickly Pear obtain these atoms to make proteins?
Prickly Pear get all the atoms that they need from the food they produce in photosynthesis.
Prickly Pear get carbon, hydrogen, and oxygen atoms from photosynthesis and the nitrogen from cellular respiration.
Prickly Pear get oxygen from the air and the rest of the atoms from the soil.
Prickly Pear rearrange glucose molecules to get carbon, hydrogen, and oxygen atoms and they get nitrogen from the soil.
Why does EVERY CELL in the plant need oxygen?
Oxygen is necessary to release energy stored in glucose molecules.
Oxygen is necessary to produce glucose in photosynthesis.
Oxygen is necessary to get minerals out of the soil.
Oxygen is necessary for biosynthesis to grow.
EXPERIMENT: The class does an experiment to investigate how Prickly Pear Cacti grow. They started by selecting six similar Prickly Pear plants. Three of those cacti were grown in regular soil. The other three plants had 3 grams of extra soil nutrients (fertilizer) added to the pots. They put all six plants under the same conditions (same amount of light, water, temperature, etc.) and let them continue growing for one month. At the end of the month, the class recorded the mass of the plants. Their data is shown in the tables below.
One student said, “This experiment proves that plants gain most of their weight from nutrients in the soil.” Is this student's claim supported by the evidence?
Yes. The students is correct because the plants with added soil nutrients weighed 25g more than the plants that did not have extra nutrients added.
Yes. The student is correct because the plants with added soil nutrients weighed 3g more than the plants that did not have the extra nutrients added.
No. The student is incorrect because 3g of soil nutrients cannot turn into 25g of additional plant material.
No. The student is incorrect because adding soil nutrients did not affect the weight of the plants.
EXPERIMENT: The class does an experiment to investigate how Prickly Pear Cacti grow. They started by selecting six similar Prickly Pear plants. Three of those cacti were grown in regular soil. The other three plants had 3 grams of extra soil nutrients (fertilizer) added to the pots. They put all six plants under the same conditions (same amount of light, water, temperature, etc.) and let them continue growing for one month. At the end of the month, the class recorded the mass of the plants. Their data is shown in the tables below.
After the experiment another student said, “I think that plants gain most of their weight from molecules in the air.” Is this student correct?
Yes. The student is correct because most of the weight of a plant comes from nitrogen in the air.
Yes. The student is correct because most of the weight of a plant comes from carbon dioxide in the air.
No. The student is incorrect because most of the weight of plant comes from soil nutrients.
No. The student is incorrect because most of the weight of a plant comes from sunlight.
One thing that happens as trees grow is they give off oxygen gas. Where does this come from?
The oxygen molecules are made of the leftover atoms
The oxygen molecules are made so that animals can breath them
The oxygen molecules are made so that the air is cleaner
If all the plants on Earth suddenly died, what would happen to humans?
Humans would not survive due to a lack of carbon dioxide.
Humans would not survive due to a lack of oxygen.
Humans would not survive to due a lack of water.
Humans would not be affected because they could eat animals for food.
Several college students were asked when a small acorn grows to a large tree, where does most of the mass come from? Some common answers are given below. Which answer best agrees with the data we have collected in class?
The plant uses the soil as food to grow.
Plants only grow in the light, so the plants use sunlight as food to grow.
The plant makes organic molecules using atoms from the air
The rain makes the seed sprout and start to grow.
The same groups of college students were asked if the small acorn grows or the large tree had more energy? Some common answers are given below. Which answer best agrees with what we have learned in class?
The small acorn because it has potnetial to grow more than the large tree who is already full grown.
The small acorn because it has a small biomass with less organic molecules so it has more energy..
The large tree because it has a large biomass with more organic molecules so it has more energy.
The small acorn and large tree have the same amount of energy.
Which image below shows to atoms that have formed a bond?
Which point on the graph, A, B, or C, corresponds to the bonding point you selected in the previous question?
A
B
C
D
When atoms move from point D to point B, a bond is formed between two seperate atoms. What happens to the energy?
Energy increases because it is used to pull the two atoms together.
Energy increases because it is used to overcome the repulsion between the atoms.
Energy decreases because it is released when the atoms move to a more stable position.
Energy decreases because the negatives of one atom are closer to the negatives of the other atom.
When atoms move from point B to point D, bonds break apart between two seperate atoms. What happens to the energy?
Energy increases because it is used to make the atoms more stable.
Energy increases because it is used to move the atoms from a more stable position to a less stable position.
Energy decreases because it is released when bonds are broken.
Energy decreases because it is released when the negatives move away from the positives.
Two bonds are shown below. Which bond is the most stable?
Bond 1 because the distance between the atoms is smaller
Bond 1 because the energy drops to a lower point
Bond 2 because the distance between the atoms is bigger
Bond 2 because the energy drops to a higher point
Burning fossil fuels and biofuels releases energy. What change is most responsible for the biggest change in energy?
Breaking the bonds between the C-C and C-H bonds
Making organic molecules.
Changing O-O bonds into more stable C-O and H-O bonds
Making less stable ending molecules
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