Module 1.2: Introduction to Cellular Homeostasis and Metabolism

Question 1

The concept of homeostasis was explained by ____ in 1865.

Answer 1

Claude Bernard

Question 2

___ is defined as a self-regulating process by which a living organism can maintain internal stability while adjusting to changing external conditions.

Answer 2

homeostasis

Question 3

The word homeostasis is coined from two (2) words and it was by ____ in 1926.

Answer 3

1. homeo = same
2. stasis = staying

Walter Bradford Cannon

Question 4

What are the general themes for metabolism? (5)

Answer 4

1. Organisms or cells maintain specific internal concentrations of inorganic ions, metabolites, and enzymes. Cell membranes provide the physical barrier that segregates cell components from the environment.
2. Organisms extract energy from external sources for each reaction.
3. Metabolic pathways in each organism are specified by genes it contains in its genome and are highly regulated.
4. Organisms and cells interact with the environment.
5. Organisms and molecules are not static assemblies of molecules

Question 5

____ is the process in which part of the output of a system is returned to its input in order to regulate its further output.

Answer 5

feedback

Question 5

True or False

Some reactions are reversible, while some reactions are irreversible.

Answer 5

True

Question 6

Metabolic reactions are catalyzed by ___.

Answer 6

enzymes

Question 7

____ occurs when the output of a system acts to oppose changes to the input of the system. It consists of reducing the production or activity of any organ or system back to its normal range of functioning.

Answer 7

negative feedback

Question 8

The ____ is the sensing component that checks and responds to changes in the environment.

Answer 8

receptor

Question 9

A ____ loop occurs when the output of a system acts to enhance the changes to the input of the system.

Answer 9

positive feedback

Question 10

Give one (1) of a positive feedback mechanism.

Answer 10

Ferguson reflex (involving oxytocin)

Question 11

How is the Ferguson reflex an example of positive feedback?

Answer 11

The Ferguson reflex is an example of positive feedback because it is a self-reinforcing cycle. As the cervix dilates during labor, it puts pressure on the baby’s head, which stimulates the release of oxytocin. Oxytocin causes the uterus to contract, which further dilates the cervix, creating a positive feedback loop.