Survival Strategies

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Questions and Answers

Which macronutrient makes up almost 98% of a plant's dry weight?

Hydrogen (H)
Carbon (C)
Oxygen (O)
Nitrogen (N) (correct)

What is the main solute for osmotic regulation in plants?

Potassium (K+) (correct)
Hydrogen (H)
Carbon (C)
Oxygen (O)

Which macronutrient is an essential component of chlorophyll?

Hydrogen (H)
Magnesium (Mg+2) (correct)
Oxygen (O)
Carbon (C)

What is the most common nutritional problem for plants?

Nitrogen shortage (A) Signup and view all the answers

What is the process by which atmospheric nitrogen is converted to ammonia, nitrites, or nitrates?

Nitrogen fixation (A) Signup and view all the answers

Which of the following is true about macronutrients and micronutrients in plants?

Macronutrients are required in large amounts, while micronutrients are required in small amounts (B) Signup and view all the answers

Which of the following explains how ions/nutrients are moved into plant cells in the root systems?

Active transport (D) Signup and view all the answers

How do symbiotic relationships with bacteria, archaea, and/or fungi aid in nutrient acquisition at the root systems?

They help fix nitrogen from the air (C) Signup and view all the answers

What is the process by which water transpires from absorption at the roots to evaporation at the stomata?

Transpiration (B) Signup and view all the answers

After being produced via photosynthesis in a source cell, how do sugars move through the phloem?

From source cells to sink cells (C) Signup and view all the answers

Which of the following is an example of a nutritional adaptation in plants?

Absorbing water and nutrients from rainwater and dust (C) Signup and view all the answers

What is the main function of haustoria in parasitic plants?

To extract water and ions from the host plant (C) Signup and view all the answers

Where are most carnivorous plants typically found?

In bogs or other habitats with scarce nitrogen (B) Signup and view all the answers

Which of the following is NOT a method of obtaining water and nutrients in plants?

Absorbing from the soil (A) Signup and view all the answers

What is the main source of water and nutrients for epiphytic bromeliads?

Rainwater and organic debris collected in 'tanks' (B) Signup and view all the answers

Which of the following is a function of root hairs in plants?

To absorb water and nutrients from the soil (C) Signup and view all the answers

What is the function of the Casparian strip in the endodermis of roots?

To facilitate the movement of water and solutes into the xylem (B) Signup and view all the answers

What is the main driving force behind the upward movement of water in the xylem?

Transpiration pull (B) Signup and view all the answers

What is the role of stomata in plants?

To regulate gas exchange between the plant and the environment (B) Signup and view all the answers

What factors influence the opening and closing of stomata?

Sunlight, high CO2 concentration, and internal timing mechanism (A) Signup and view all the answers

Which of the following adaptations helps prevent excessive water loss in dry climates?

Leaves modified into spines to decrease surface area (B) Signup and view all the answers

When the stomata of plant A are closed while those of plant B are open, which plant is likely able to produce more sugars through photosynthesis?

Plant A, since it will absorb more CO2 than plant B (C) Signup and view all the answers

Which of the following routes is not used by water to travel from root hair to xylem?

Epidermal route (water flows from the epidermis directly into xylem) (D) Signup and view all the answers

Which tree has to expend more energy to move water up the trunk due to cohesion-tension and transpiration, a 5-meter tall tree A or a 10-meter tall tree B?

Tree B (A) Signup and view all the answers

Which of the following is true about transpiration?

Carbon dioxide uptake is reduced by the stomata closing to prevent excessive water loss (B) Signup and view all the answers

Which of the following is a key component of phloem sap?

Proteins (A) Signup and view all the answers

What is the main driving force behind the movement of sugars through the phloem?

Bulk flow (D) Signup and view all the answers

Which of the following is NOT a characteristic of a sugar sink?

High sugar concentration (C) Signup and view all the answers

Which of the following is a tissue where sugar exits the phloem?

Sink (C) Signup and view all the answers

What is the process by which sucrose enters companion cells from source tissues?

Facilitated diffusion (B) Signup and view all the answers

Which of the following is NOT a component of phloem sap?

Water (D) Signup and view all the answers

What is the main function of the phloem in plants?

To transport sugars from the leaves to other parts of the plant (C) Signup and view all the answers

Which of the following is NOT a characteristic of sugar concentrations in the phloem?

High in sinks (A) Signup and view all the answers

What is the pressure flow mechanism in the phloem?

Active transport of sucrose raises the pressure at the source and lowers it at the sink (D) Signup and view all the answers

How is sucrose unloaded in young, growing leaves?

By facilitated diffusion (A) Signup and view all the answers

How do leaves modified into spines decrease water loss in dry climates?

Leaves modified into spines decrease the surface area of the leaves, which decreases the number of stomata and therefore decreases the amount of water lost during the day. Signup and view all the answers

Which plant, plant A or plant B, is likely able to produce more sugars through photosynthesis when the stomata of plant A are closed while those of plant B are open?

Plant B is likely able to produce more sugars through photosynthesis when the stomata of plant A are closed while those of plant B are open. Signup and view all the answers

What is the process by which water transpires from absorption at the roots to evaporation at the stomata?

The process is called transpiration. Signup and view all the answers

What is the main function of the phloem in plants?

The main function of the phloem is to transport the products of photosynthesis from where they are made or stored to where they are needed. Signup and view all the answers

What is the main driving force behind the upward movement of water in the xylem?

The main driving force behind the upward movement of water in the xylem is transpiration. Signup and view all the answers

What are the eight micronutrients that plants require in tiny quantities?

chlorine (Cl-), iron (Fe+2), manganese (Mn+2), boron (B), zinc (Zn+2), copper (Cu+2), nickel (Ni+2), molybdenum (Mo) Signup and view all the answers

What are the six macronutrients that make up almost 98% of a plant's dry weight?

carbon (C), hydrogen (H), oxygen (O), nitrogen (N), sulfur (S), phosphorus (P) Signup and view all the answers

What are the three types of symbiotic relationships between plants and other organisms?

rhizobia (with bacteria), mycorrhizae (with fungi), mutualistic symbiotic relationships with bacteria and fungi Signup and view all the answers

How do fungi benefit from the symbiotic relationship with plants?

Fungi obtain sugars and amino acids from the plant Signup and view all the answers

How do plants benefit from the symbiotic relationship with fungi?

Plants benefit from increased nutrient absorption and water uptake from the soil through the mycorrhizal fungi Signup and view all the answers

What are the four distinct tissue layers of a root, from the outside in?

The four distinct tissue layers of a root, from the outside in, are the epidermis and root hairs, the cortex, the endodermis, and the pericycle. Signup and view all the answers

What is the role of root hairs in nutrient absorption?

Root hairs greatly increase a root's absorptive surface and contain membrane proteins that bring nutrients into the cytosol of root cells. Signup and view all the answers

What is the function of the Casparian strip in the endodermis?

The Casparian strip in the endodermis stops solutes from entering the xylem through cell walls and instead forces them to cross a plasma membrane into an endodermal cell. Signup and view all the answers

What is the main driving force behind the upward movement of water in the xylem?

The main driving force behind the upward movement of water in the xylem is transpiration, which is driven by the upward pull of evaporation at the stomata and the cohesive/adhesive properties of water in the xylem. Signup and view all the answers

What factors influence the opening and closing of stomata?

Three factors influence the opening and closing of stomata: sunlight signals guard cells to accumulate K+ and open stomata, low CO2 concentration signals guard cells to open stomata, and an internal timing mechanism (biological clock) in guard cells continues their daily rhythm of opening and closing. Signup and view all the answers

Explain how hydroponics aided in identifying macronutrients vs. micronutrients.

Hydroponic culture studies have helped identify 17 elements essential to plant growth and reproduction, including nine macronutrients that plants require in relatively large amounts. Signup and view all the answers

Explain how ions/nutrients are moved into plant cells in the root systems.

Ions/nutrients are moved into plant cells in the root systems through active transport, facilitated diffusion, and symplastic transport. Signup and view all the answers

Explain how symbiotic relationships with bacteria, archaea, and/or fungi aid in nutrient acquisition at the root systems.

Symbiotic relationships with bacteria, archaea, and/or fungi aid in nutrient acquisition at the root systems through processes such as nitrogen fixation, nutrient mobilization, and nutrient transfer. Signup and view all the answers

Describe how transpiration of water occurs from absorption at the roots to evaporation at the stomata.

Transpiration of water occurs through a combination of physical forces such as cohesion, adhesion, and tension, which create a continuous column of water in the xylem from the roots to the stomata. Signup and view all the answers

Describe the movement of sugars through the phloem after being produced via photosynthesis in a source cell.

Sugars are actively transported from source cells to companion cells, and then loaded into sieve tubes in the phloem. They are then transported via pressure flow mechanism to sink cells, where they are unloaded and used for growth and metabolism. Signup and view all the answers

What are some nutritional adaptations of plants?

Plants can absorb water and nutrients from rainwater, dust, and particles that collect in their tissues. Some plants have leaves that grow in rosettes to form “tanks” that collect water and organic debris. Parasitic plants obtain water and nutrients from a host plant. Carnivorous plants trap insects and other animals to absorb their nutrients. Signup and view all the answers

How do epiphytic bromeliads obtain water and nutrients?

Epiphytic bromeliads have leaves that grow in rosettes to form “tanks” that collect water and organic debris. Nutrients are absorbed through the leaves. Signup and view all the answers

What are haustoria and how do parasitic plants use them?

Haustoria are structures produced by parasitic plants. They can penetrate a host plant's vascular system to obtain water and nutrients. Most parasitic plants are photosynthetic and use haustoria to extract water and ions from the xylem of the host plant. Signup and view all the answers

How do carnivorous plants obtain nutrients?

Carnivorous plants kill their prey and absorb the prey’s nutrients. They make their own carbohydrates via photosynthesis, using carnivory to supplement nitrogen available in the environment. Signup and view all the answers

Where are most carnivorous plants typically found?

Most carnivorous plants are found in bogs or other habitats where nitrogen is scarce. Signup and view all the answers

What is the pressure flow mechanism in the phloem?

The pressure flow mechanism is the process by which sugars are transported through the phloem from sources to sinks. It involves active transport of sucrose into the phloem at the source, creating a high concentration of solute and generating pressure. The pressure then drives the flow of sugars through the phloem to the sink, where both sugar and water leave the phloem. This lowers the solute concentration at the sink and reduces the pressure. Finally, water leaves the phloem via osmosis and re-enters the xylem. Signup and view all the answers

How is sucrose unloaded in young, growing leaves?

Sucrose unloading in young, growing leaves occurs by facilitated diffusion. This is because sucrose is rapidly used up in the cells of these leaves. Root cells have a large vacuole that stores sucrose, surrounded by a membrane called the tonoplast. The tonoplast contains two types of protein pumps that work to accumulate sucrose in the vacuole. As protons diffuse back out of the vacuole, a proton-sucrose antiporter moves sucrose into the vacuole against its concentration gradient. Signup and view all the answers

What is the main driving force behind the movement of sugars through the phloem?

The main driving force behind the movement of sugars through the phloem is the pressure gradient created by the pressure flow mechanism. Active transport of sucrose at the source raises the concentration of solute within the phloem, resulting in water being drawn from the xylem into the phloem tube via osmosis. This generates high pressure at the source. At the sink, both sugar and water leave the phloem tube, lowering the solute concentration and reducing the pressure. Water then leaves the phloem via osmosis and re-enters the xylem, further lowering the pressure in the phloem tube. Signup and view all the answers

Why is sucrose more concentrated in companion cells than in the photosynthetic cells where it is produced?

Sucrose is more concentrated in companion cells than in the photosynthetic cells because of active transport. Sucrose enters companion cells from source tissues by secondary active transport. Companion cells have a proton pump that uses ATP to drive the transport of protons into the source cell against their concentration gradient. Then, a symporter uses the established proton gradient to move sucrose against its concentration gradient into the companion cells, while the protons move down their concentration gradient. This active transport process results in higher concentrations of sucrose in the companion cells. Signup and view all the answers

What is the process by which sucrose enters companion cells from source tissues?

Sucrose enters companion cells from source tissues by secondary active transport. This process involves the use of ATP to drive the transport of protons into the source cell against their concentration gradient. Then, a symporter uses the established proton gradient to move sucrose against its concentration gradient into the companion cells, while the protons move down their concentration gradient. This active transport process allows sucrose to be transported into the companion cells from source tissues. Signup and view all the answers

Flashcards

Plant Macronutrient Composition

Almost 98% of a plant's dry weight is composed of carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur.

Osmotic Regulation in Plants

Potassium (K+) is the primary solute used for osmotic regulation in plants, controlling water balance.