Homeostasis

Question 1

What is homeostasis?

Answer 1

The process by which an organism maintains its internal environment within a narrow range for optimal cell function in spite of changing external environment.

Question 2

Why do animal cells need homeostasis?

Answer 2

Animal cells need a relatively constant internal environment to survive.

Question 3

What does the internal environment of an organism represent?

Answer 3

A dynamic constancy that is constantly changing but within a narrow range.

Question 4

What factors does the body actively adjust to maintain homeostasis?

Answer 4

Ongoing internal and external changes.

Question 5

What are some key aspects of homeostasis?

Answer 5

Body temperature, water and salt concentrations, glucose concentrations, pH (acid-base balance), oxygen and carbon dioxide concentrations.

Question 6

What can happen if there is too big a shift in homeostasis?

Answer 6

It can lead to disease or death.

Question 7

Why are cells particular about their surroundings?

Answer 7

Animal cells are constantly generating and using large quantities of ATP to sustain life processes.

Question 8

What do cells require to generate ATP?

Answer 8

Continuous supplies of high-energy molecules (primarily glucose) and O2.

Question 9

Why is the level of glucose and oxygen important?

Answer 9

Energy production partially explains the importance of glucose and oxygen levels.

Question 10

What determines the optimal functioning of proteins and enzymes?

Answer 10

They only function optimally in a narrow range of conditions.

Question 11

What are proteins made up of?

Answer 11

Amino acids, which have functional groups that interact with other amino acids.

Question 12

What determines how a protein folds into a 3D shape?

Answer 12

The sequence of amino acids and the environment the protein is in.

Question 14

What is the primary level of protein structure?

Answer 14

Sequence of amino acids.

Question 15

What characterizes the secondary level of protein structure?

Answer 15

An alpha-helix and beta-pleated sheet.

Question 16

What is the tertiary level of protein structure?

Answer 16

Complex foldings of the protein.

Question 17

What defines the quaternary level of protein structure?

Answer 17

Occurs when multiple protein chains are linked together.

Question 18

What environmental factors affect protein and enzyme activity?

Answer 18

pH, temperature, and salts (ion concentration).

Question 19

What happens to protein structure when conditions are too high or low?

Answer 19

The structure is unfolded (denatured).

Question 20

How does shape relate to protein function?

Answer 20

Shape determines function/activity.

Question 21

Why are cells particular about their surroundings?

Answer 21

Temperature, salt concentration, and pH directly affect enzyme structure.

Question 22

What substances affect a cell’s ability to make ATP?

Answer 22

Glucose, O2, and CO2 concentrations.

Question 23

What is the effect of CO2 and water in cells?

Answer 23

They form a weak acid, shifting pH.

Question 24

What is homeostasis in relation to enzyme activity?

Answer 24

Conditions need to be carefully maintained for optimal enzyme activity.

Question 25

How does temperature affect enzyme activity?

Answer 25

Low temperatures slow molecular movement; high temperatures can denature enzymes.

Question 26

What is the effect of low temperatures on enzymes?

Answer 26

Enzyme and substrate are less likely to bump into each other.

Question 27

What happens to enzymes at high temperatures?

Answer 27

They undergo violent shaking and can unfold/denature.

Question 28

What is the optimal functioning range for most enzymes?

Answer 28

Most enzymes function optimally only within a very narrow range of conditions.

Question 31

What is homeostasis?

Answer 31

Homeostasis is the ability to maintain stable internal conditions in an organism.

Question 32

Which animals are highly efficient at homeostasis?

Answer 32

Birds and mammals are highly efficient at homeostasis for all internal conditions.

Question 33

Which animals have reduced or absent homeostasis?

Answer 33

Many marine invertebrates cannot regulate the overall concentration of their bodily fluids.

Question 34

What are endotherms?

Answer 34

Endotherms generate most of their heat through metabolic reactions. ## Footnote Examples include birds and mammals.

Question 35

What are ectotherms?

Answer 35

Ectotherms derive body heat from the environment and maintain this heat through behavioral activities. ## Footnote Examples include reptiles, amphibians, fishes, and invertebrates.

Question 36

How is homeostasis regulated?

Answer 36

Homeostasis is regulated through feedback systems.

Question 37

What are the two types of feedback systems?

Answer 37

The two types of feedback systems are negative feedback and positive feedback.

Question 38

What is negative feedback?

Answer 38

Negative feedback counteracts changes in the internal environment to maintain homeostasis.

Question 39

What is positive feedback?

Answer 39

Positive feedback drives rapid, self-limiting changes, enhancing or continuing the change.

Question 40

What is the most important mechanism governing homeostasis?

Answer 40

Negative feedback is the most important mechanism governing homeostasis.

Question 41

What are the three principal components of negative feedback systems?

Answer 41

The three components are a sensor, a control center, and an effector.

Question 42

What is an example of a negative feedback system?

Answer 42

A home heating system is an example of a negative feedback system. ## Footnote The sensor is the thermometer, the control center is the thermostat, and the effector is the heater.

Question 43

How does negative feedback control body temperature?

Answer 43

If body temperature falls below the normal set point, the hypothalamus activates mechanisms to increase temperature, such as shivering and blood vessel constriction.

Question 44

What is homeostasis?

Answer 44

Homeostasis is the process by which biological systems maintain stability while adjusting to conditions that are optimal for survival.

Question 45

What role does negative feedback play in homeostasis?

Answer 45

Negative feedback helps maintain homeostasis by counteracting changes, such as when temperature increases past the set point.

Question 46

How does the hypothalamus respond to increased temperature?

Answer 46

The hypothalamus sends signals that cause blood vessels leading to the skin to dilate, allowing warm blood to flow to the skin.

Question 47

What is the effect of dilated blood vessels in response to heat?

Answer 47

Dilated blood vessels allow warm blood to flow to the skin, where it can be radiated out to the air.

Question 48

How do sweat glands contribute to temperature regulation?

Answer 48

Sweat glands secrete fluid, cooling the body by evaporating water from the skin.

Question 49

What happens to the body during fatigue and discomfort?

Answer 49

The body slows down, generating less heat.

Question 50

What is positive feedback?

Answer 50

Positive feedback is a process where a change produces a response that intensifies the initial change.

Question 51

Is positive feedback common in biological systems?

Answer 51

Positive feedback is relatively rare in biological systems.

Question 52

In what context does positive feedback occur?

Answer 52

Positive feedback occurs during childbirth.

Question 53

What is the overall effect of positive feedback?

Answer 53

Positive feedback enhances the effects of changes.