Plant senses Hw

Which of the following are aspects of a hypersensitive response? 1. restoration of infected cells 2. production of anti-microbials 3. up-regulation of mitosis 4. cell death at the site of infection

2,4

Sequence the events of a wound response in plants 1. cells with the systemin receptor bind systemin 2. systemin moves through the phloem 3. caterpillars chew on plant leaves 4. caterpillars ingest inhibitors that interfere with digestion 5. transcription of defense genes is activated by jasmonic acid 6. jasmonic acid is produced 7. wounded leaves produce systemin

3,7,2,1,6,5,4

Increasing the flow of Na ions into a neuron at rest would trigger A) depolarization B) hyperpolarization C) repolarization D) active transport

a

One important difference between the anatomy of roots and the anatomy of leaves is that A) a waxy cuticle covers leaves but is absent in roots B) only leaves have phloem and only roots have xylem C) the cells of roots have cell walls and leaf cells do not D) vascular tissue is found in roots but is absent from leaves

a

In the vertebrate ear, the transduction of sound waves into electrical signals takes place A) within the tectorial membrane as it is stimulated by the hair cell B) within hair cells as they are bent against the tectorial membrane, causing them to depolarize and release neurotransmitter that stimulates sensory neurons C) as the basilar membrane becomes more permeable to sodium ions and depolarizes, intiating action potential in a sensory neuron D) within the middle ear as the vibrations are amplified by the malleus, incus and stapes

b

Many plants exhibit gravitropism, which means they move in a particular direction in response to gravity. Where is gravity perceived in the root and the shoot of plants that exhibit gravitropism? A) gravity is perceived in the meristem of the shoot and in the endodermal B) gravity is perceived in the endodermal cells of the shoot and in the root cap of roots C) gravity is perceived in the apex of the shoot and in the phloem of roots D) gravity is perceived in the xylem of the shoot and in the root hairs of the roots

b

Sensory receptors send a regular series of action potentials, even when at rest, to the CNS because A) they are regularly receiving messages from sensory neurons B) increasing and decreasing in the frequency can provide valuable information to the CNS C) the receptors constantly receive stimuli from the environment D) neurotransmitters are released by the cells supporting the receptors

b

Spatial summation of graded potentials occurs when A) two or more stimuli are received by a neuron in quick succession B) stimuli are received at multiple regions of the dendrites and/or cell body at the same time C) stimuli are received on the dendrites and axon at the same time D) a sensory neuron sends two ore more action potentials to the CNS in rapid succession

b

What stimulus triggers photoperiodic responses in plants? A) day length B) night length C) summer length D) sun position

b

Which of the following is an example of circadian rhythm in plants? A) the hormone auxin only travels from the top of a plant downward. It does not travel up the plant stem. B) during the day, legumes have their leaves horizontal for maximum light exposure. At night, the leaves fold down. C) upon stimulation by touch, the Venus flytrap changes the position of it leaves from opened to closed to trap prey D) in temperate habitats, the leaves of trees change colors and are shed during the autumn season

b

Why are action potentials usually conducted in only one direction along an axon? A) the nodes of Ranvier can conduct potentials in only one direction B) the brief refractory period prevents reopening to voltage-gated Na channels C) the axon hillock has a higher membrane potential than the terminals of the axon D) ions can flow along the axon in only one direction

b

In the avian and mammalian eye, lens remains stationary but changes shape in order to focus on objectives at various distances. This is called "accommodation" and is accomplished through adjusting muscle control of the lens in order to A) convert light energy into electrical signals by the retina B) control the amount of light admitted to the eye through the pupil C) bend light rays to varying degrees according to the angle at which light enters the eye D) alter the sensitivity of the eye to varying light levels

c

Root hairs are most important to a plant because they A) anchor a plant in the soil B) store starches C) increase the surface area for absorption D) provide a habitat for nitrogen-fixing bacteria

c

What do you predict would happen if flower growth became indeterminate? A) the flowers would lose their distinct shape B) the flower size would be reduced C) the flowers would be enormous D) pollen and see production would cease

c

In the nervous system, glial cells function to do all of the following except: A) provide structural support B) speed the movement of action potentials down the axon C) provide metabolic support to neurons D) allow the movement of ions into the cytoplasm of the neuron

d

Primary growth leads to an increase in the A) width of the stem B) amount of wood in a tree trunk C) number of root hairs on a root D) length of the taproot

d

The electrochemical gradient that determines how a charged ion will move through a permeable membrane depends upon A) the electrical forces acting on that ion B) the difference in concentration of that ion on either side of the membrane C) the ration between the charge on the ion and its atomic mass D) the combined effects of electrical forces and concentration differences across the membrane

d

What is thigmotropism in plants? A) a plant's stem grows slowly, gets thicker, and begins to curve to grow past an obstruction B) a plant's shoot bed toward a light source as they grow C) a plant's roots bend in order to grow downward, and its shoots bed to grow upward D) a plant's stem bends toward something the stem touches

d

What wold be a plant adaptation that allows a plant to increase its exposure to light in a dense forest? A) closing of the stomata B) lateral buds C) radial symmetry D) modular growth

d

Which of the following sensory receptors is incorrectly paired with its category? A) hair cell-mechanoreceptor B) meissner corpuscle- mechanoreceptor C) taste receptor- chemoreceptor D) olfactory receptor - electromagnetic receptor

d