Chapter 39 - Motor Mech & Behavior

Actin forms microfilaments that contain ____.

many identical subunits in a double helix

A biological clock ____.

directs periodic gene expression & cellular activity

During the course of muscle contraction the potential energy stored in ATP is transferred to potential energy stored in _____.

the myosin head

The release of _____ ions from the sarcoplasmic reticulum is required for skeletal muscle contraction.

calcium

Myosin heads bind to _____, which they then pull and cause to slide toward the center of the sarcomere.

thin filaments

Of these events, the first to occur when a motor neuron stops sending an impulse to a muscle is _____.

pumping of calcium (CA2+) ions out of the cytosol and back into the SR

In a vertebrate, during skeletal muscle contraction, calcium ions _________.

bind with troponin and changes its shape so myosin-binding sites are exposed.

Which muscle type is involved in the function of the digestive tract and blood vessels?

Smooth muscle

True or false? Myofibrils are the alternating light-dark units that produce the banded appearance of muscle fibers.

False. Sacromeres that make up the myofribrils is what makes the striped appearance.

Which molecules form the thick filaments of sarcomeres?

Myosine.

Remember: THICK = myosin; THIN = actin

Which of the following interactions is the molecular basis of muscle contraction?

Which step constitutes the power stroke of muscle contraction?

the phosphate ion is released and the myosin head moves back to the original.

Which of the following statements about the stimulation of muscle cells is true?

An action potential in a muscle cell ultimately results in the release of calcium ions into the cell.

How does cardiac muscle differ from the other types of muscle?

They contain branched cells. They are branched by the intercolated disks…

Which of the following interactions is the molecular basis of muscle contraction?

Myosin and thin filaments (actin).

An unlearned behavior directly linked to a stimulus that is carried to completion once initiated and is essentially unchangeable is _____.

fixed action pattern

Which of the following is true of innate behaviors?

expressed in most individuals in a population

A learning process that can occur only during a limited period of the individual's development is called __________.

imprinting

Every morning a graduate student turns on the light in the laboratory and then feeds the fish in the aquarium. After a couple of weeks of this routine, the graduate student notices that the fish come to the surface to feed as soon as the lights are turned on. The behavior of the fish is a result of _____.

associative learning

Which of the following statements describes a proximate cause?

People sleep at night because a molecule that accumulates during the day has an effect on the sleep centers of the brain.

Which of the following statements describes an ultimate cause?

Birds have hollow bones because hollow bones increased the fitness of their ancestors by allowing them to run faster and capture prey more efficiently.

You observe a large black bird with a shiny black crest engaging in courtship behavior with a little brown bird. It would be reasonable to hypothesize that these birds are in what type of mating relationship?

Polgyamgy (because we do not know their sex we cant say anything else but theyre not the same looking so it cant be monogamy).

According to Hamilton's rule, __________.

natural selection favors altruistic acts when the resulting benefit to the recipient, corrected for relatedness, exceeds the cost to the altruist.

In a species in which females provide all the needed food and protection for the young, __________.

Males are likely to be promiscous

A motor unit is __________.

a motor neuron and the muscle fibers it innervates. Strength depends on the number and size of motor units.

A fruit fly’s stimulus-response chain during mating behavior consists of which type of signal?

→ tacticle

→ chemical

→ visual

→ auditory

Tetanus __________.

is the result of too much action potentials leading to sustained (and painful) muscle contraction without relaxation.

The role of ATP in muscle contraction is __________.

to release the myosin head from actin when it binds to myosin and to provide energy when hydrolyzed to form myosin’s high-energy form

According to the concept of kin selection, __________.

examples of altruism are usually between relatives

Smooth muscle contracts relatively slowly because __________.

It doesnt have a well developed sarcoplasmic recticulum, thus Ca2+ enters through the cell membrane.

What is the role of calcium ions (Ca²⁺) in muscle contraction?

Calcium ions bind to troponin causing tropomyosin to move away from the myosin-binding sites on the actin filament.

Proximate causes __________.

are immediate causes of behavior such as environmental stimuli; concerns “how” a behavior occurs or is modified

A crow that aids its parents in raising its siblings is increasing its __________.

inclusive fitness

In which of the following animal groups does a hydrostatic skeleton not typically provide the primary support for locomotion in adults?

arthropods

The cross-fostering of California mice in white-footed mice nests provides evidence for __________.

the influence of the early social environment on the expression of aggressive and parental behaviors

Which of the following descriptions is an example of a fixed action pattern?

Male stickleback attacking anything with a red underside

Which of the following is an oxygen-storing protein?

Myoglobin

Glycolytic fast-twitch skeletal muscle differs from oxidative slow-twitch skeletal muscle in its __________.

→ myoglobin content

→ rate of exhaustion

→ source of ATP

→ concentration of mitochondria

The capacity of a bone to support the mass of the body depends directly on its __________.

cross-sectional area

In associative learning, __________.

animals learns by associating something pleasent or harmful with a specific stimulus/event.

Insect muscle differs from vertebrate muscle in ___________.

having a higher maximum contraction frequency

When striated muscle fibers contract, __________.

the Z lines are pulled closer together

The structural polysaccharide of insect cuticle is __________.

chitin

Curare, a substance that blocks the acetylcholine receptors on skeletal muscle, will cause __________.

muscle cell relaxation

What do skeletal, cardiac, and smooth muscle have in common?

They have thick & thin filaments.

What force(s) must animals overcome in order to move?

friction & gravity

A human baby performs a sucking behavior perfectly when it is put in the presence of the nipple of its mother's breast. What form of animal behavior is this?

Innate behavior

Upon observing a golden eagle flying overhead, a prairie dog on "guard duty" gives a warning call to other members of the prairie dog community that are foraging. What form of animal behavior is this?

altruistic behavior

Male elephant seals routinely fight (sometimes to the death) in order to mate with large groups of female elephant seals. What kind of mating behavior is this an example of?

intrasexual selection

While on a field expedition in Ethiopia, you come across a group of baboons. After watching them for several days, you notice that one male baboon frequently mates with many different females. You also don't see any other males in the group. What type of mating system best describes these baboons?

polgyny