exam 2 study guide
The thin filament in skeletal muscle contains _____ molecules.
All of the choices are correct except for myosin
Smooth muscle and cardiac muscle cells differ from skeletal muscle because they:
Are connected by gap junctions
What is the role of the sarcoplasmic reticulum in muscle contraction?
It stores Ca2+ ions for release during contraction.
Which statement about a myosin filament in skeletal muscle is true?
Myosin heads have ATPase activity and interact with actin.
What allows an earthworm to move through soil?
NOT: antagonistic pairs of muscles that pull NOT: alternating contractions of circular and longitudinal muscles
Which statement about the endoskeletons of vertebrates is true?
Not: at least one skeletal structure is required NOT: endoskeletons consist of chitin/ calcium
The frequency of sound is obtained through the _____ of the hair fell on the _____
Position, basilar membrane
Which response in the vertebrates is controlled by the voluntary, rather than the involuntary( autonomic) nervous system?
Shaking of the head
Sensory systems encode all of the following features about the stimulus EXCEPT:
Stimulus color
Fast-twitch skeletal muscle fibers, called white muscle cells, are characterized by
The rapid development of High tension
What purpose do the various cell layers of the retina ( other than rods and cones) serve in the visual process
They process visual signals to obtain more precise visual information
Slow-twitch fibers
are well supplied with mitochondria.
An animals sensory process an able it to detect and respond to
Both internal and external factors
In muscle function at the sarcomere level, the binding of ___ ions to ____ regulates the formation of cross-bridges.
calcium, troponin
"_______" is the term used for the state of the adductor muscles of a scallop as it maintains a contraction for an extended period of time.
catch
Which of the following types of skeletons must be shed typically for an animal to grow?
exoskeleton
Excitable cells can
generate and send electrical signals called action potentials
The name of the sensory cell in the auditory system is a _______________cell, which is a _______________.
hair cell - mechanoreceptor
The role of Ca2+ in the control of muscle contraction is to
initiate changes in protein conformation that expose myosin-binding sites on actin.
Exoskeletons are used for movement by which of the following animals?
insects and crustaceans
Brushing against a doorway as you enter a room will trigger which type of sensory response?
mechanoreceptor
The thick filament is composed almost entirely of _____ molecules.
myosin
Which of the following proteins contains an ATP binding site?
myosin
A scientist looking through a microscope at a piece of shoulder muscle would see which of the following features?
striated with unbranched fibers
Skeletal muscles are
striated, voluntary, and have unbranched fibers.
Vertebrate skeletal muscles are categorized as excitable cells because
their membranes generate and conduct action potentials.
Skeletal muscle cells are multinucleate because
they form from fusion of many embryonic cells.
What is the role of calcium in muscle contractions?
to bind with troponin, changing its shape so that binding sites on the actin filament are exposed
During vertebrate evolution, which part of the brain has shown the greatest increase in size?
Cerebral hemisphere
When light is absorbed by a photoreceptor:
Confirmation changes, a G- protein is activated, a secondary message is generated, and sodium channels open
Release of cross-bridges depends most directly on
adenosine triphosphate
When animals die, muscles stiffen in rigor mortis because
actin and myosin cannot separate without ATP.
Cross-bridges form between _____ and _____ during muscular contraction.
actin, myosin