Digestion
Which of the following is the primary physiological function of the large intestine?
A. mechanical breakdown of food
B. nutrient absorption
C. water absorption and feces elimination
D. enzymatic digestion of macromolecules
C. water absorption and feces elimination
Symbiosis can best be described as _________.
A. The presence of microbes inside animal and plant cells
B. A relationship where both partners benefit
C. The ecological community of microorganisms associated with a host
D. The stable interaction between two organisms living closely together with possible co-evolution
E. Two organisms living in the same environment without affecting each other
D. The stable interaction between two organisms living closely together with possible co-evolution
The velocity of blood is ________.
A. the same at all locations in the circulatory system
B. slower in the arteries than in capillaries because arteries possess a relatively large diameter
C. slower in the veins than in the capillaries because veins have a large diameter
D. slowest in the capillaries because the total cross-sectional area is the greatest
D. slowest in the capillaries because the total cross-sectional area is the greatest
Which statement best describes the development of gut microbiota in humans?
A. Diversity decreases in early childhood; abundance increases throughout adulthood; composition stays fixed after the first year.
B. Diversity and abundance are established at birth; composition remains constant throughout life.
C. Diversity increases in early childhood; abundance stabilizes around one year; composition continues to vary throughout life.
D. Diversity increases in early childhood; abundance stabilizes around one year; composition becomes identical across individuals.
C. Diversity increases in early childhood; abundance stabilizes around one year; composition continues to vary throughout life.
What is Amylase?
A digestive enzyme that digests starch and is primarily secreted in the oral cavity by the salivary glands
(note it can also be found in the small intestine, secreted by the pancreas)
Which statement best describes mechanisms allowing stomach cells to survive the acidity and protein-digesting activities in the stomach?
A. because gastric mucous cells secrete a thick mucus and bicarbonate.
B. because chief cells secrete a thick mucus and enzymes.
C. because parietal cells secrete bicarbonate and enzymes.
D. All of the above
A. because gastric mucous cells secrete a thick mucus and bicarbonate.
Which statement is TRUE regarding the relationship between plants and bacteria in the rhizosphere with respect to nitrogen?
A. Bacteria in the rhizosphere are largely pathogenic, resulting in plant roots growing away from the bacteria
B. Plants use N2 produced by denitrifying bacteria
C. Plants’ ability to absorb N2 from the atmosphere is compromised due to high concentrations of nitrogen-fixing bacteria in the rhizosphere.
D. Plants obtain nitrogen as NO3- or NH4+ through the actions of nitrogen-fixing, ammonifying, and nitrifying soil bacteria.
D. Plants obtain nitrogen as NO3- or NH4+ through the actions of nitrogen-fixing, ammonifying, and nitrifying soil bacteria.
Which process provides the main force driving water within xylem vessels?
A. loading of sugars produced during photosynthesis leads to osmosis
B. transpiration of water through stoma and water cohesion pull water from roots to shoots
C. osmosis generates positive pressure
D. diffusion facilitates rapid transport over long distances
B. transpiration of water through stoma and water cohesion pull water from roots to shoots
After absorption in the small intestine, amino acids and monosaccharides enter the hepatic portal vein rather than directly entering systemic circulation. Which of the following is a primary physiological consequence of this routing?
A. It allows the liver to chemically modify and regulate nutrients before distribution
B. It bypasses liver metabolism
C. It increases the diffusion rate of nutrients into tissues
D. It prevents nutrients from entering the bloodstream
A. It allows the liver to chemically modify and regulate nutrients before distribution
How did chloroplasts evolve?
An oxygenic phototrophic bacterium was engulfed by a eukaryotic cell and was not digested. These photosynthetic endosymbionts then evolved into chloroplasts, providing host cells with the capacity for photosynthesis. Over evolutionary time, these once-independent bacteria became integrated organelles, losing many original genes and becoming dependent on their host cells.
Which answer best describes a mechanism involved in plant acquisition of cations such as Ca2+ and Mg2+?
A. Roots acquire CO2 and H+ from the soil
B. Roots release CO2 and H+ into the soil
C. Roots release NO3- to acquire Ca2+ and Mg2+
D. Roots absorb H⁺ from the soil, making the soil more alkaline and releasing cations from soil particles
B. Roots release CO2 and H+ into the soil
An example of _____ is when endophytic Rhizobium bacteria within the root nodules of legumes supply _____ to the plant while the plant provides the bacteria with ______ and an environment that is __________.
A. parasitism, flavonoids, sugars, aerobic
B. mutualism, NH4+, sugars, anaerobic
C. commensalism, N2, Nod factors, aerobic
D. mutualism, NH4+, sugars, high in N2
B. mutualism, NH4+, sugars, anaerobic
In the human heart, oxygenated blood is carried from the lungs to the heart by the _____.
Ignoring all other factors, what weather conditions would result in the fastest delivery of water and minerals to the leaves of an oak tree?
A. a cool, dry day
B. a warm, dry day
C. a warm, humid day
B. a warm, dry day
What are two types of chemical signals microbiotes send to the brain?
neurotransmitters and SCFAs
A. Bile from the gallbladder neutralizes the stomach acid.
Which feature of the gut microbiota tends to be the most consistent across healthy individuals?
A. The microbial species present
B. The functional capacity (genes and metabolic functions)
C. The relative abundance of bacterial species in the community
D. The abundance, diversity, and composition of microbes in the community
B. The functional capacity (genes and metabolic functions)
Which evolutionary innovation distinguishes amphibian circulation from fish circulation?
A. Development of a four-chambered heart
B. A pulmocutaneous circuit, creating double circulation
C. A partial septum dividing the ventricle
D. Use of negative pressure to drive bulk flow
B. A pulmocutaneous circuit, creating double circulation
What is meant by vascular tone in arterioles?
A. The ability of arteries to generate electrical signals
B. The degree of smooth muscle contraction in arteriole walls
C. The amount of blood volume stored in veins
D. The rhythmic contraction of the heart chambers
B. The degree of smooth muscle contraction in arteriole walls
Most microbiota are nonculturable, how do we get past this limitation?
metagenomics and 16S sequencing
Cows and horses eat grass, but their bodies do not produce cellulose-digesting enzymes. How can they still get nutrients from plant material?
A. Bacteria in their digestive tracts ferment the cellulose
B. Pancreatic amylase digests the cellulose in the small intestine
C. Pepsin in the stomach breaks down the cellulose
D. Extensive chewing breaks the cellulose into glucose
A. Bacteria in their digestive tracts ferment the cellulose
When used appropriately by a patient, antibiotic treatment can effectively reduce bacteria populations and help fight infections. However, antibiotic treatments can have unintended effects. What is one concern when using antibiotics?
A. Antibiotics would increase digestion of plant materials, like cellulose.
A paleontologist discovers the fossilized heart of an extinct animal. The evidence indicates that the organism's heart was large, was well-formed, and had four chambers, with no connection between the right and left sides. Which of the following conclusions is best supported by these observations?
A. the animal was most closely related to fish
B. the animal had little to no need to regulate blood pressure
C. the animal relied on phloem and xylem for transport
D. the animal was endothermic and had a high metabolic rate
D. the animal was endothermic and had a high metabolic rate
If you added a chemical to leaves that prevents stomata from opening, what would happen to water movement in the xylem?
A. Water in the xylem would move faster.
B. The upward movement of water in the xylem would slow dramatically.
C. Water in the xylem would begin flowing downward, from leaves to roots.
D. Phloem sap would leak into the xylem.
B. The upward movement of water in the xylem would slow dramatically.
Which of the three types of digestive systems do humans have?
Monogastric