Question 1

What is the normal function of fruits?

Accepted Answer

The normal function of fruits is to protect and disperse seeds. Fruits can provide a protective layer around seeds that helps them survive until they can germinate. Fruits also often have features that make them attractive to animals, which helps with seed dispersal.

Question 2

Cocklebur will not flower if exposed to 8 hours of dark and 16 hours of light.It will flower if exposed to 16 hours of dark and 8 hours of light.However,if the 16 hours of dark is interrupted with a brief period of light,the cocklebur will not flower.Which of the following will trigger cocklebur to flower?

Accepted Answer

Cocklebur flowers when exposed to long dark periods (16 hours of dark), as indicated by its failure to flower under short dark periods (8 hours of dark) and its flowering when exposed to 16 hours of dark.

Question 3

Double fertilization reduces the energetic cost of reproduction.In gymnosperms,the female gametophyte stockpiles food for the embryo in advance of fertilization.The investment is wasted if no zygote ever forms.In contrast,double fertilization ensures that an angiosperm devotes energy to the zygote only if sperm fertilizes the egg.Where is this energy stored in a fertilized angiosperm?

Accepted Answer

The energy stored in a fertilized angiosperm is in the endosperm, which is a result of double fertilization. The zygote develops into the embryo, while the endosperm serves as a source of nutrients for the developing embryo and eventually the germinating seed.

Question 4

You plant a seed into a pot containing some soil,and then add water and place the pot under a light.After the seedling emerged,complete with two green leaves,the carbon dioxide levels decreased in the closed chamber.The developing seedling was using which of the following as a source of energy during this time?

Accepted Answer

The seedling uses light as a source of energy for photosynthesis, which is why the carbon dioxide levels decreased as it was converted into oxygen and glucose.

Question 5

Senescence means that

Accepted Answer

Senescence refers to the natural aging process of plants, which can result in various changes such as leaf abscission, breakdown of molecules, and decreased synthesis of new molecules. Therefore, all of the answer options are correct.

Question 6

A region of separation that forms near the base of the leaf's petiole when the leaf is shed is the

Accepted Answer

The region of separation that forms near the base of the leaf's petiole when the leaf is shed is called the abscission zone. This zone contains specialized cells that gradually weaken and break apart, causing the leaf to fall off.

Question 7

You plant a seed into a pot containing some soil,and then add water and place the pot under a light.In the first week,before the seedling even emerged from the soil,carbon dioxide levels increased in the closed chamber.The developing plant was using which of the following as a source of energy during this first week?

Accepted Answer

During the first week, before the seedling emerged from the soil, the plant would have used starch from the seed as a source of energy for growth. This is because the initial energy reserves for the plant are stored in the seed as starch. As the plant develops and its leaves start to function, it starts using light energy for photosynthesis to produce its own sugars. So, options A, B, D, and E are not correct in this context.

Question 8

You plant a seed into a pot containing some soil,and then add water and place the pot under a light.In the first week,before the seedling even emerged from the soil,carbon dioxide levels increased in the closed chamber.This indicated that __________ was occurring.

Accepted Answer

Before the seedling emerged, there was no plant to carry out photosynthesis. Therefore, any increase in carbon dioxide levels can only be due to the process of cellular respiration by soil microorganisms or any other organisms in the pot.

Question 9

Clover will flower if exposed to 8 hours of dark and 16 hours of light.It will not flower if exposed to 16 hours of dark and 8 hours of light.However,if the 16 hours of dark is interrupted with a brief period of light,the clover will flower.Which of the following will trigger clover to flower?

Accepted Answer

Clover will flower if exposed to 8 hours of dark and 16 hours of light. It will not flower if exposed to 16 hours of dark and 8 hours of light. However, if the 16 hours of dark is interrupted with a brief period of light, the clover will flower. This means that short dark periods will trigger clover to flower.

Question 10

In the late 1870s,Charles Darwin and his son Francis discovered that if the tip of the grass was covered,phototropism did not occur,even though the rest of the grass was exposed to light.However,if the rest of the plant was covered and only the tip exposed to light,the grass bent a few centimeters below the tip.How could light striking the tip of the grass cause bending a few centimeters from the tip? Choose the most likely explanation from the below choices.

Accepted Answer

The most likely explanation is that a hormone, produced at the tip of the grass when exposed to light, is transported down to the cells a few centimeters below the tip, causing them to elongate and the grass to bend. This process is known as phototropism, where plants grow towards a light source, and it is mediated by the distribution of plant hormones like auxin.

Question 11

You plant a seed into a pot containing some soil,and then add water and place the pot under a light.After the seedling emerged,complete with two green leaves,the carbon dioxide levels decreased in the closed chamber.This indicated that _________ was occurring.

Accepted Answer

The decrease in carbon dioxide levels indicates that photosynthesis is occurring, as plants take in carbon dioxide and release oxygen during photosynthesis. Sucrose production and fertilization would not result in a decrease in carbon dioxide levels. Cellular respiration and alcohol fermentation would actually produce carbon dioxide, so they are not the correct choices.

Question 12

Which structures do fruits arise from?

Accepted Answer

Fruits arise from flowers, specifically from the ovary of a flower after fertilization has occurred.

Question 13

As a seed germinates,its shoot points upward toward light,and its roots grows downward into the soil.Turn the plant sideways,and the stem and roots bend according to the new direction of gravity.How do roots respond to gravity?

Accepted Answer

The movement of statoliths within specialized cells called statocytes is responsible for the root's response to gravity. Statoliths are dense structures that settle to the bottom of the cell under the influence of gravity, which triggers a signal transduction pathway that causes the root to grow in the direction of gravity. Thigmotropism is the growth response to touch, circadian rhythms regulate biological processes according to the time of day, light absorption by phytochromes regulates plant development, and photoperiod is the duration of light exposure that regulates flowering in plants.

Question 14

Cytokinins are water-soluble hormones produced in the root apical meristem and stimulate the growth of lateral buds.How do cytokinins reach the lateral buds?

Accepted Answer

The answer of Cytokinins are water-soluble hormones produced in the...

Question 15

The size of a plant's seeds reflects an evolutionary trade-off.Large,heavy seeds contain ample nutrient reserves to fuel seedling growth but may not travel far.Small seeds,on the other hand,store limited nutrients but tend to disperse far and wide.The crops that humans cultivate typically have larger seeds than do their wild ancestors.How has human farming altered the evolution of these crops?

Accepted Answer

Human farming practices typically involve selecting plants with larger seeds, as larger seeds can be more easily planted and harvested, and may produce larger and more reliable crops. By selecting for larger seeds, humans have removed the selective pressure that would favor smaller seeds. As a result, crop plants may have evolved to have larger seeds than their wild ancestors.

Question 16

If you wanted a grass plant to bend to the right,where would you want to apply auxin?

Accepted Answer

Auxin is responsible for the bending of the plant towards the side where it is applied in a larger quantity than the other side. So, to make the grass plant bend towards the right, we need to apply auxin on the left side of the tip of the grass. This will cause the cells on the left side to elongate, making that side of the plant grow faster than the right, causing it to bend towards the right.

Question 17

If a gardener cuts the apical meristem of a plant,lateral buds begin to grow which causes a bushier shape to develop.This is because the apical meristem normally secretes auxins that do which of the following?

Accepted Answer

The apical meristem secretes auxins that suppress the growth of lateral buds, leading to the dominance of the main stem. When the apical meristem is removed, this suppression is lifted, allowing the lateral buds to grow and the plant to become bushier.

Question 18

Packages of vegetable seeds typically include an ideal planting depth.If planted too deep,the seeds will not germinate.How do the plants sense if they are too deep?

Accepted Answer

Phytochromes are light-sensitive proteins found in plant cells that play a crucial role in the plant's understanding of its environment, particularly in detecting light. If seeds are planted too deep, the absence of light means phytochromes cannot absorb the light necessary for initiating germination processes, leading to the seeds not germinating.

Question 19

As a seed germinates,its shoot points upward toward light,and its roots grow downward into the soil.Turn the plant sideways,and the stem and roots bend according to the new direction of gravity.How do roots and shoots grow in opposite directions as the plant is rotated?

Accepted Answer

The roots and shoots respond oppositely to auxin, a plant hormone that plays a key role in regulating plant growth and development. In response to gravity, auxin accumulates on the lower side of the stem, which stimulates growth on that side, causing the stem to bend and grow upward. In roots, however, auxin accumulates on the upper side in response to gravity, inhibiting growth and causing the root to grow downward. Therefore, when the plant is rotated, the direction of auxin accumulation is also changed, leading to opposite growth directions in roots and shoots.

Question 20

In the late 1870s,Charles Darwin and his son Francis discovered that if the tip of the grass was covered,phototropism did not occur,even though the rest of the grass was exposed to light.However,if the rest of the plant was covered and only the tip exposed to light,the grass bent a few centimeters below the tip.Which of the following was sensing the light?

Accepted Answer

The experiment showed that when the tip of the grass was exposed to light, phototropism occurred, indicating that the sensing of light was happening in the tip. This was further confirmed when covering the tip prevented phototropism. Therefore, the auxin-producing cells in the tip of the grass were most likely sensing the light.

Quiz 24: Reproduction and Development of Flowering Plants