UMaine Bio 200 Homework 7-11

Which of the following structures is NOT part of the plant's apoplast?

The cell wall of a root hair.

The area around a xylem vessel.

The cytoplasm of a leaf mesophyll cell.

The cell wall of a mesophyll cell.

Cytoplasm of a leaf mesophyll cell

Which cells are responsible for the movement of photosynthates through a plant?

sieve-tube elements (phloem), companion cell

The ________ forces selective uptake of minerals in the root.

endodermis

The movement of water across biological membranes can best be predicted by

water potentials

Water flows into the source end of the phloem because

sucrose has been actively transported into the phloem, making it hypertonic.

Which of the following has an effect on water potential (Ψ) in plants?

physical pressure

water-attracting matrices

dissolved solutes

osmosis

All of the above

Which of the following does not involve active transport across membranes?

the movement of sugar from one sieve-tube element to the next

Which of the following would be least likely to affect osmosis in plants?

Proton pumps in the membrane.

A difference in solute concentrations across a membrane.

A difference in water potential across a membrane.

Aquaporins.

Active transport proteins in the membrane.

Active transport proteins in the membrane.

Active transport involves all of the following except

transport of solute against a concentration gradient.

hydrolysis of ATP.

diffusion of solute through the lipid bilayer of a membrane.

specific transport proteins in the membrane.

pumping of solutes across the membrane.

diffusion of solute through the lipid bilayer of a membrane.

When stomata open, what occurs?

Water vapor is lost to the external environment, increasing the rate of transpiration.

What is the role of proton pumps in root hair cells?

What is the role of proton pumps in root hair cells?

A water molecule could move all the way through a plant from the soil to root to leaf to air and pass through a living cell only once. The living cell in question would b part of which structure?

The endodermis

Which of the following statements about bulk flow is false?

It is more effective than diffusion over distances greater than 100 μm.

It may be the result of either positive or negative pressure potential.

It depends on the force of gravity exerted on a column of water.

It is driven primarily by a pressure potential.

It depends on a difference in pressure potential at the source and sink.

It depends on the force of gravity exerted on a column of water.

Plants do not have a circulatory system like that of some animals. If a water molecule did circulate (that is, go from one point in a plant to another and back in the same day), it would require the activity of

both the xylem and the phloem.

An open beaker of pure water has a water potential (Ψ) of

0.0 (zero)

Water potential is generally most negative in which of the following parts of the plant?

mesophyll cells in the leaf

Which of the following statements is false?

Water enters the plants through root hairs and exits through stoma.

Negative water potential draws water into the root hairs. Cohesion and adhesion draw water up the phloem. Transpiration draws water from the leaf.

Water potential decreases from the roots to the top of the plant.

Negative water potential draws water into the root hairs. Cohesion and adhesion draw water up the xylem. Transpiration draws water from the leaf.

Negative water potential draws water into the root hairs. Cohesion and adhesion draw water up the phloem. Transpiration draws water from the leaf.

The value for Ψ in root tissue was found to be -0.15 MPa. If you take the root tissue and place it in a 0.1 M solution of sucrose (Ψ = -0.23 MPa), the net water flow would

be from the tissue into the sucrose solution

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 to the heart are the

fishes.

The fluid that moves around in the circulatory system of a typical arthropod is

the interstitial fluid.

Air rushes into the lungs of humans during inhalation because

the rib muscles and diaphragm contract, increasing the lung volume.

Gas exchange is more difficult for aquatic animals with gills than for terrestrial animals with lungs because

water contains much less O2 than air per unit volume.

Circulatory systems compensate for

the slow rate at which diffusion occurs over large distances.

Which of the following respiratory systems is not closely associated with a blood supply?

The tracheal system of an inscet.

Sponges, cnidarians, and flatworms lack a specialized gas exchange surface because

nearly all of their cells are in direct contact with the external environment.

Countercurrent exchange in the fish gill helps to maximize

diffusion

Compared with the insterstitial fluid that bathes active muscle cells, blood reaching these cells in arteries has a...

higher PO2.

Where do air-breathing insects carry out gas exchange?

Across the membranes of their cells.

The set of blood vessels with the slowest velocity of blood flow is

the capillaries.

The circulatory system of bony fishes, rays, and sharks is similar to

the portal systems of mammals, where two capillary beds occur sequentially, without passage of blood through a pumping chamber.

Pulse is a direct measure of...

heart rate

In negative pressure breathing, inhalation results from...

contracting the disphram.

A human red blood cell in an artery of the left arm is on its way to deliver oxygen to a cell in the thumb. From this point in the artery, how many capillary beds must this red blood cell pass through before it returns to the left ventricle of the heart

two

Air-breathing insects carry out gas exchange

across the finest branches of the trachea and cell membranes.

Damage to the sinoatrial node in humans

would disrupt the rate and timing of cardiac muscle contractions.

The semilunar valves of the mammalian heart

prevent backflow of blood in the aorta and pulmonary arteries.

Organisms with a circulating body fluid that is distinct from the fluid that directly surrounds the body's cells are likely to have

a closed circulatory system.

Gas exchange in the aquatic salamander known as the axolotl is correctly described as

simple diffusion of oxygen into the salamander from the water.

In which of the following organisms does blood flow from the pulmocutaneous circulation to the heart before circulating through the rest of the body?

frogs

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.

During most daily activities, the human respiration rate is most closely linked to the blood levels of

carbon dioxide

Which of the following is the correct sequence of blood flow in reptiles and mammals?

vena cava → right atrium → right ventricle → pulmonary circuit

In order for a plant to initiate chemical responses to herbivory,

volatile signal compounds must be perceived.

Where does meiosis occur in a flowering plant?

megasporocyte and microsporocyte

Which of the following statements regarding flowering plants is false?

a) The sporophyte is the dominant generation.

b) Female gametophytes develop from megaspores within the anthers.

c) Pollination is the delivery of pollen to the stigma of a carpel.

d) The food-storing endosperm is derived from the cell that contains two polar nuclei and one sperm nucleus.

e) Flowers produce fruits from the ovaries.

Female gametophytes develop from megaspores within the anthers.

In some angiosperms, other floral parts contribute to what is commonly called the fruit. Which of the following fruits is derived mostly from an enlarged receptacle?

apple

In a plant's male reproductive organs, development of pollen takes place in a structure known as the ________.

microsporangium

Which of the following vegetables is botanically a fruit?

green beans

Which of the following could be considered an evolutionary advantage of asexual reproduction in plants?

increased success of progeny in a stable environment

Which of the following is the correct order of floral organs from the outside to the inside of a complete flower?

sepals → petals → stamens → carpels

Which of the following is the most likely plant response to an attack by herbivores?

production of chemical compounds for defense or to attract predators

Which of the following types of plants are incapable of self-pollination?

dioecious

What is typically the result of double fertilization in angiosperms?

Both a diploid embryo and triploid endosperm are formed.

When an arborist prunes a limb off a valuable tree, he or she usually paints the cut surface. The primary purpose of the paint is to

block entry of pathogens through the wound.

Which of the following is the correct sequence during the alternation of generations life cycle in a flowering plant?

sporophyte → meiosis → gametophyte → gametes → fertilization → diploid zygote

All of the following are primary functions of flowers except

photosynthesis.

At the conclusion of meiosis in plants, the end products are always four haploid...

spores.

What is the probable role of salicylic acid in the defense responses of plants?

to activate the systemic acquired resistance of plants

In the life cycle of an angiosperm, which of the following stages is diploid?

microsporocyte

In cases where plants exhibit generalized defense responses in organs distant from the infection site, this is termed

systemic acquired resistance.

A plant will recognize a pathogenic invader

if it has the specific R gene that corresponds to the pathogen molecule encoded by an Avr gene.

After double fertilization, a zygote and ________ form.

endosperm

What is the term for a fruit that develops from tissues other than the ovary?

accessory fruit

Which of the following statements is true of most angiosperms?

They have a triploid endosperm within the seed and an ovary that becomes a fruit.

In flowering plants, pollen is released from the

anther

Which of the following would be considered a multiple fruit?

pineapple

Which of the following would only be activated or upregulated after a plant has already been infected by a pathogen?

salicylic acid

The ovary is most often located on/in the...

carpel

Which of the following is a correct sequence of processes that takes place when a flowering plant reproduces?

meiosis → pollination → nuclear fusion → formation of embryo and endosperm

A newly discovered hormone contains four amino acids linked together. Under which chemical class would this hormone be classified?

peptide hormone

Which endocrine glands are associated with the kidneys?

adrenal glands

Which class of hormones can diffuse through plasma membranes?

lipid-derived hormones

Which of the following hormones is not produced by the anterior pituitary?

oxytocin

When blood calcium levels are low, PTH stimulates:

osteoclasts

Which of the following statements are true?

Question options:

Hormones regulate celular functions, and generally negative feedback regulates hormone levels.

The ducts of endocrine glands always release their contents into the circulatory system.

The circulating levels of all hormones are held constant through a series of positive feedback loops.

Both lipid-soluble and water-soluble hormones bind to intracellular protein receptors.

Hormones regulate celular functions, and generally negative feedback regulates hormone levels.

Testosterone is an example of...

an androgen

What hormone is produced by beta cells of the pancreas?

insulin

Which of the following statements about the hypothalamus is INCORRECT?

It secretes tropic hormones that act directly on the gonads.

Which of the following statements about hormones that promote homeostasis is INCORRECT?

A response at the target cell causes more hormone to be released from the original endocrine gland.

Drinking alcoholic beverages causes an increase in urine output. This most likely occurs because alcohol:

inhibits ADH release

The secretion of hormone A causes a change in the amount of protein X in an organism. If this mechanism works by positive feedback, which of the following should occur.

An increase in A would cause an increase in X.

A rise in blood glucose levels triggers release of insulin from the pancreas. This mechanism of hormone production is stimulated by:

humoral stimuli

What effect will a cAMP inhibitor have on a peptide hormone-mediated signaling pathway?

It will prevent activation of protein kinases.

FSH and LH release from the anterior pituitary is stimulated by ________.

GnRH

Estradiol is an example of...

an estrogen

only certain cells in the body are target cells for the steroid hormone aldosterone. Which of the following is the best explanation for why these are the only target cells that respond to this hormone?

Only target cells have receptors for aldosterone.

The main target of tropic hormones are...

endocrine glands.

Which mechanism of hormonal stimulation would be affected if signaling and hormone release from the hypothalamus was blocked?

hormonal and neural stimuli

A new antagonist molecule has been discovered that binds to and blocks plasma membrane receptors. What effect will this antagonist have on testosterone, a steroid hormone?

It will not affect testosterone-mediated signaling.

Which of the following statements about hormones is incorrect?

They are used to communicate between different organisms.

Which of the following is an endocrine gland?

parathyroid gland

Which hormone causes the re-growth of the endometrial lining of the uterus?

both progesterone and estrogen

Which hormone causes FSH and LH to be released?

GnRH

Which of the following statements about the menstrual cycle is false?

Menstruation occurs just after LH and FSH levels peak.

Progesterone is made during the third trimester by the:

Placenta

Which of the following statements about T cells is false?

MHC II is a receptor found on most body cells, while MHC I is a receptor found on immune cells only.

How many eggs are produced as a result of one meiotic series of cell divisions?

One

Which of the following cells in spermatogenesis is diploid?

primary spermatocyte

Autoantibodies are probably involved in:

systemic lupus erythematosus