Exam 4

If you wanted to study the use of ATP during a single contraction cycle within a muscle cell, which of the following processes would you use?

• Summation

• Twitch

• Treppe

• Tetanus

Which of the following statements about muscle metabolism is false?

• Skeletal muscles at rest obtain most of their energy from muscle glycogen and blood glucose

• ATP can be quickly obtained by combining ADP with phosphate derived from creatine phosphate

• Exercise intensity is related to the maximum rate of oxygen consumption

• ATP is required for the pumping of the Ca2+ back into the sarcoplasmic reticulum

Motor neurons stimulate muscle contraction via the release of

• Ca2+

• ATP

• acetylcholine

• hormones

Which of the following statements best describes the sliding filament mechanism of muscle contraction?

• actin and myosin filaments do not shorten, but rather, slide past each other

• actin and myosin filaments shorten and slide past each other

• as they slide past each other, actin filaments shorten, but myosin filaments do not shorten

• as they slide past each other, myosin filaments shorten, but actin filaments do not shorten

Worms use a hydrostatic skeleton to generate movement. How do they do this?

• Their bones are filled with water, which provides the weight of the skeleton

• The change in body structure is caused by contraction of muscles compressing the watery body fluid

• The muscles contain water vacuoles, which, when filled, provide a rigid internal structure

• The term hydrostatic simply refers to moist environment. They generate movement just as an arthropod does

Exoskeletons and endoskeletons differ in that

• an exoskeleton is rigid, and an endoskeleton is flexible

• endoskeletons are found only in vertebrates

• exoskeletons are composed of calcium, and endoskeletons are built from chitin

• exoskeletons are external to the soft tissue, and endoskeletons are internal

Place the following events in the correct order.

1. Sarcoplasmic reticulum releases Ca2+

2. Myosin binds to actin

3. Action potential arrives from neurons

4. Ca2+ binds to troponin

• 1, 2, 3, 4

• 3, 1, 2, 4

• 2, 4, 3, 1

• 3, 1, 4, 2

The potential for social interactions among individuals should be maximized when individuals

• are randomly distributed in their environment

• are uniformly distributed in their environment

• have a clumped distribution in their environment

• none of the above

Source-sink metapopulations are distinct from other types of metapopulations because

• exchange of individuals occurs only in the former

• populations with negative growth rates are a part of the former

• populations never go extinct in the former

• all populations eventually go extinct in the former

In a population subjected to high levels of predation,

• individuals should invest little in reproduction so as to maximize their survival

• individuals should produce few offspring and invest little in any of them

• individuals should invest greatly in reproduction because their chance of surviving to another breeding season is low

• individuals should stop reproducing altogether