Bio 1520

Arrange the following five events in an order that explains the mass flow of materials in the phloem.

1. Leaf cells produce sugar by photosynthesis. 2. Sugar is transported from cell to cell in the leaf. 3. Solutes are actively transported into sieve tubes. 4. Water diffuses into the sieve tubes. 5. Sugar moves down the stem.

Which of the following does NOT describe how edema typically occurs in the human body?

An individual has above average levels of red blood cells and other proteins in the blood

What characterizes the rates of photosynthesis and transport in a plant on a dry cloudy day?

Both the photosynthesis and transpiration rates are low.

Why are anionic nutrients generally mobile in soils, and thus easily leached, while cationic nutrients are relatively immobile?

Cations interact with clay particles and organic materials

Why do plants use cotransporters instead of ion channels to transfer anions into cells?

Cotransporters are able to transfer anions against the membrane potential gradient, but ion channels cannot.

When a woman has her gallbladder removed, she should probably reduce her consumption of ___?

Fats

Which of the following experiments is the best way to determine if an element is essential for plant growth?

Grow a plant using hydroponics with and without the element.

Cattle are able to survive on a diet consisting almost entirely of plant material because cattle _____.

Have cellulose-digesting.... chambers of their stomach

Which of the following statements about nitrogen fiction in root nodules is correct?

Leghemoglobin helps maintain a low oxygen concentration within the nodule

The absorption of fats differs from that of carbohydrates in that ____.

Most absorbed fat first enters the lymphatic system, whereas carbohydrates directly enter the blood.

What can the mouthparts of an animal tell you about its diet?

Mouthparts of animals are specialized to obtain desired food items efficiently.

Why is it important that the xylem is adjacent to the phloem?

Pressure from xylem water moves nutrients through the phloem.

What is the correct sequence of steps during infection of plants by nitrogen-fixing bacteria?

Roots release flavonoids; rhizobia release Nod factors; rhizobia proliferate inside of root hair; infection thread grows into the root cortex; nodule forms.

Food being digested in the stomach is in a highly acidic environment. When the food is released from the stomach into the small intestine, why is the environment no longer acidic?

Secretin increases the flow of bicarbonate ions from the pancreas into the small intestine to neutralize the stomach acid

Two groups of tomatoes were grown under laboratory conditions, one with humus added to the soil and one a control without humus. The leaves of the plants grown without hummus were yellowish (less green) compared with those of the plants grown in the hummus soil. The best explanation for this is ____?

The humus contributes minerals such as magnesium and iron, needed for the synthesis of chlorophyll

Fluid is filtered out of the bloodstream into the surrounding interstitial fluid at the arteriole end of systemic capillaries because

The hydrostatic pressure of the blood is greater than the osmotic pressure of the blood

Why is the presence of clay particles important in soil?

The negative charges on clay bind to positively charged ions and prevent them from leaching.

What is the importance of the mucins that are released by salivary glands?

They are glycoproteins that make food slippery enough to slide easily through the esophagus.

Helicobacter pylori is a bacterial organism that causes ulcers and digestive disturbances. How might they survive the acid pH of the stomach?

They burrow under the mucus layer that covers the stomach epithelium.

Which of the following statements about xylem transport is true?

Water and minerals move through the root cortex into the xylem and upward through the stem and into leaves.

Iron deficiency is often indicated by yellowing in newly formed leaves. This suggests that iron is _____.

a relatively immobile nutrient in plants

Iron deficiency is often indicated by yellowing in newly formed leaves. This suggests that iron is _____?

a relatively immobile nutrient in plants

Stomach cells are moderately well adapted to the acidity and protein-digesting activities in the stomach by having _____.

a thick, mucous secretion and active mitosis of epithelial cells

Mycorrhizae enhance plant nutrition mainly by _____.

absorbing water and minerals through the fungal hyphae

Transpiration in plants requires all of the following except ____.

active transport through xylem cells

If you wanted to increase the cation exchange and water retention capacity of loamy soil, you should _____.

add clay to the soil

Blood pressure is highest in the _____.

aorta

The cells that secrete the acidic components of stomach juices___.

are the parietal cells of the stomach

In mammals, how and where are carbohydrates digested?

by amylases in the mouth and small intestine

The _____ has(have) the thinnest walls.

capillaries

Carbon dioxide enters the blood at the _____.

capillaries of the head, forelimbs, abdominal organs, and hind limbs

Only mammals chew their food. Which of the following is NOT an alternative used by other animals to facilitate digestion?

cation exchange

Clay in soils represents a trade-off in nutrient availability such that _______

cations are less likely to leach out of soil but are difficult for plants to extract

The following factors may sometimes play a role in the movement of sap through xylem. Which one depends on the direct expenditure of ATP by the plant?

concentration of ions in the symplast

Glucose is transported from the intestinal lumen into epithelial cells through _____ and from the intestinal epithelium into circulation by _____.

cotransport with sodium; facilitated diffusion

Movement of phloem sap from a source to a sink ____.

depends on active transport of sugar into sieve tube elements

Atria contract _____.

during systole

The digestive system of most animals is lined with cells through which nutrients are absorbed. What is the embryonic origin of these cells?

endoderm

Which tissue acts as a filter on the water absorbed by root hairs?

endodermis

What is the main force by which most of the water within xylem vessels moves toward the top of a tree?

evaporation of water through stoma

The only vertebrates in which blood flows directly from respiratory organs to body tissues without first returning ore the heart are the ____.

fishes

The only vertebrates in which blood flows directly from respiratory organs to body tissues without first returning to the heart are the _____.

fishes

If you found a vertebrate skull in the woods and the teeth were sharp and scissor-like what type if viid would you expect this animal to eat?

flesh of another animal

The function of mechanical digestion is to break down large chunks of food into smaller pieces. Why is this important? Smaller pieces of food _____.

have more surface area for chemical digestion than do larger pieces of food

A relatively long cecum is characteristic of animals that are_____.

herbivores

What soil composition would be best for availability of nutrients, water, and root development?

higher proportion of humus, lower amounts of clay and sand

Root hairs are most important to a plant because they _____.

increase the surface area for absorption

Villi and microvilli in the small intestine _____.

increase the surface area to increase the efficiency of nutrient absorption

Compared to plants form other environments, the cells of many desert plants contain high concentrations of solutes. This helps them survive in their arid surroundings because the high solute concentrations create relatively ____, which help reduce water loss.

low solute potentials

Compared to plants from other environments, the cells of many desert plants contain high concentrations of solutes. This helps them survive in their arid surroundings because the high solute concentrations create relatively _____, which help reduce water loss.

low solute potentials

Which of the following are problems associated with intensive irrigation?

mineral runoff, aquifier depletion, soil salinization

Carnivorous plants have evolved mechanisms that trap and digest small animals. The products of this digestion are used to supplement the plant's supple of _____.

nitrogen and other minerals

Carnivorous plants trap and digest insects to overcome _____.

nitrogen deficiency in low-nitrogen soils

Which elements are most often the limiting nutrients for plant growth?

nitrogen, potassium, and phosphorus

The active ingredient orlistat acts to decrease the amount of fat that is absorbed by attaching to enzymes that digest fat. Which of the following are potential targets of orlistat?

pancreatic lipase

Which of the following features of plant cells allows for apoplectic movement of water?

porous cell walls

What would enhance water uptake by a plant cell?

positive pressure on the surrounding solution

The semilunar valves of the mammalian heart ____.

prevent back flow of blood in the aorta and pulmonary arteries

Research by Natalie De Witte and MS has shown that proton pumps are localized un the membrane of companion cells of the source tissue. The function of this pump is to move ____.

protons from inside of companion cell to outside

In ruminants, the majority of bacterial fermentation occurs in the _____.

rumen

Which term describes an area where sugars are used or stored?

sink

In which plant cell or tissue would the pressure component of water potential most often be negative?

stem xylem

Which of the following structural features of plants would not be expected to reduce transpiration?

stomata on upper and lower surfaces of the leaves

What is the role of microorganisms in the guts of mammals?

synthesize essential vitamins for host

What is not an adaptive advantage of having a triple loop system and 4 chambered heart of reptiles over a two chambered heart and single loop system?

the additional chamber increases the speed of blood flow to the respiratory organ.

Agricultural lands frequently require nutrient fertilization because ______

the nutrients that become the biomass of plants are not culled back to the soil on lands where they are harvested.

Which criterion allow biologists to divide chemicals into macronutrients and micronutrients?

the quantities of each required by plants

The velocity of blood flow is the lowest in capillaries because _____.

the total cross-sectional area of the capillaries is greater than the total cross-sectional area of the arteries or any other part of the circulatory system

The velocity of blood flow is the lowest in capillaries because _____.

the total cross-sectional area of the capillaries is greater than the total cross-sectional area of the arteries or any other part of the circulatory system.

What would enhance the water uptake by a plant cell?

the uptake of solutes into the cell

Certain nutrients are considered "essential" in the diets of some animals because _____.

these animals are not able to synthesize these nutrients.

What is the function of proton pumps localized in the plant plasma membrane?

to create a membrane potential

Fat digestion yields fatty acids and glycerol, whereas protein digestion yields amino acids; both digestive processes _____.

use water molecules when breaking bonds (hydrolysis)

What is the QRS segment in the EkG tracing?

ventricular depolarization

What would happen to someone treated with a drug that inhibited the release of bile salts?

weight loss

Under what conditions does the rate of transpiration decrease?

when stomata close at night

Damage to the senatorial node in humans ___

would disrupt the rate and timing of cardiac muscle contractions.