Homeostasis and Cell Function

Question 1

Define Homeostatis

Answer 1

Maintenance of nearly constant conditions in the internal environment. It is the condition in which the body’s internal environment remains relatively constant within limits

Question 2

An organism is said to be in homeostasis when its internal environment has…?

Answer 2

Optimum concentrations of gases, nutrients, ions, and water. Optimal temperature. And optimal pressure for the health of the cells.

Question 3

What is stress?

Answer 3

Stress is any stimulus that creates an imbalance in the internal environment

Question 4

List the basic differences between extracellular and intracellular fluid compartments

Answer 4

Extracellular: Most abundant cation = Na+; Anion = Cl-
Intracellular: Cation = K+

Question 5

What is a feedback system?

Answer 5

Circular situation in which the information about the status of something is continually reported to a central control region.

Question 6

What is a homeostatic mechanism made up of?

Answer 6

Adaptive responses

Question 7

What is Negative feedback?

Answer 7

The response reverses the direction of the initial condition.
A change in some parameter causes a response that results in a return of that parameter to normal (baseline)

Question 8

Give an example of negative feedback

Answer 8

Baroreceptors associated with the carotid system sense increase in arterial pressure. Baroreceptors send inhibitory signals to vasomotor receptors in medulla.
Heart pumping capacity is reduced and blood vessels dilate. Arterial pressure decreases.

Question 9

What is a Positive feedback?

Answer 9

The change is some parameter causes a response that continues to change that parameter in the same direction as before. There is no natural end in most cases. Death usually results

Question 10

Give an example of Positive feedback

Answer 10

Birth
Stretch of cervix sends back signals that increase force of uterine contractions, which then increase the stretch on the cervix

Question 11

What is Gain?

Answer 11

Gain is the degree of effectiveness with which a control system maintains constant conditions

Question 12

In the uncontrolled system: Pressure rises from 100 to 200
In the controlled system: pressure rises from 100 to 125
What is the correction, the error and gain?

Answer 12

Correction = 125-200 = 75
Error = 125-100 = 25
Gain = 75/25 = 3

Question 13

Which of the following would have to be a transmembrane protein?
Receptor protein
Protein binding to the cytoskeleton
Channel protein
Phosphorylase

Answer 13

Channel protein

Question 14

What is the function of the cell membrane?

Answer 14

Separates the intracellular from the extracellular environments and regulates what enters and leaves the cell. Plays a role in information exchange and involved in exocytosis and endocytosis

Question 15

What is the structure of the cell membrane?

Answer 15

Phospholipid bilayer with cholesterol inserted among the phospholipids. And proteins are associated with the membrane. Permeable to hydrophobic molecules.

Question 16

What is an intergral protein?

Answer 16

Proteins inserted into the membrane on one side or the other or pass all the way through and are exposed on either side of the membrane

Question 17

What is a peripheral protein?

Answer 17

Proteins loosely attached to one surface of the membrane or the other. Easily removed

Question 18

Which organelle(s) is/are associated with intracellular trafficking?

Answer 18

Golgi Apparatus and SER

Question 19

Which organelle(s) is/are associated with most ATP production?

Answer 19

Mitochondrion

Question 20

Which organelle is directly associated with the synthesis of proteins for secretion?

Answer 20

RER

Question 21

Pits coated with what are often associated with endocytosis?

Answer 21

Clatherin

Question 22

Compare pinocytosis to phagocytosis

Answer 22

Both are endocytosis processes. Pino is cell drinking and phago is cell drinking

Question 23

Endocytosis form what?

Answer 23

phagocytic vesicles

Question 24

What makes a membrane thermodynamically unstable?

Answer 24

When a membrane has a free edge. Membrane must always be part of a continnum

Question 25

What do lysosomes contain?

Answer 25

Hydrolytic enzymes at a low pH. Result of a hydrogen - ion pump

Question 26

Protein synthesis involves what parts of the cell?

Answer 26

Ribosomes and ER

Question 27

Proteins bound for lysosomes or for secretion are synthesized on what?

Answer 27

The RER to which the ribosomes attach

Question 28

Explain digestion in the cell

Answer 28

Lysosomes fuse with phagocytic vesicles to form secondary lysosomes. Undigested material is left behind in residual bodies to be eliminated via exocytosis.

Question 29

Proteins bound for the cytoplasm, nucleus, mitochondria, or other cell membranes are synthesized where?

Answer 29

Free ribosomes

Question 30

What is the function of the Golgi apparatus?

Answer 30

Packaging proteins for secretion, forms lysosomes, modifies proteins from the RER

Question 31

Explain Glycolysis

Answer 31

Begins with glucose, occurs in the cytoplasm of all cells.
Does not require oxygen
Produces pyruvic acid (latic acid) and small amount of ATP

Question 32

What is anaerobic respiration?

Answer 32

Glycolysis, does not require oxygen

Question 33

Explain the Kreb’s cycle and ETC

Answer 33

Untilizes pyruvic acid from glycolysis
Only occur in the mitochondria
Requires oxygen as the final electron recepor
Produces CO2 and H2O
Produces many ATP

Question 34

What are the three forms of locomotion

Answer 34

Amoeboid movement
Cilia and Flagella
Microtubules

Question 35

What process does not require the presence of mitochondria?

Answer 35

Breakdown of glucose to pyruvic acid