Homeostasis and Cell Function Syed

Question 1

What is human physiology?

Answer 1

Study of the functional organization of the human body

Question 2

What are homeostatic mechanisms made up of?

Answer 2

Adaptive responses - a change occurs, we act, then return to original state

Question 3

An organism is said to be in homeostasis when its internal environment:

Answer 3

• Contains the optimum concentrations of gases, nutrients, ions, and water
• Has an optimal temperature
• Has an optimal pressure

Question 4

Which cations/anions are in the extracellular vs. intracellular?

Answer 4

Extracellular: Na+, Cl-
Intracellular: K+, MG2+, Phosphate

Question 5

Example of negative feedback loop?

Answer 5

In increase in the production of TSH releasing factor results in an increase in the release of thyroid stimulating hormone, which results in the release of more thyroxine, which results a decrease in the production of TSH releasing factor.

Question 6

What is a negative feedback loop?

Answer 6

A change of a parameter that causes a response, that results in a return of that parameter back to it’s normal. The response reverses the direction of the initial condition.

Question 7

Give another example of a negative feedback loop

Answer 7

Regulation of arterial blood pressure - Baroreceptors in the arterial walls can sense increase in arterial pressure. They send inhibitory signals to the vasomotor receptors in the medulla (controls heart rate). The pumping is reduced and blood vessels dilate. Pressure decreases.

Question 8

What is a positive feedback loop?

Answer 8

A change of a parameter that causes a response to continue to change that parameter in the same direction. The input is intensified.

Question 9

Give an example of positive feedback loop

Answer 9

Childbirth: Stretch of cervix sends back signals that increase the force of uterine contractions, when then increase the stretch on the cervix.

Question 10

What is Gain?

Answer 10

It’s the degree of effectiveness with which a control system maintains constant conditions. Equation: Correction/Error

Question 11

Calculate gain: Uncontrolled - 100 to 175

Controlled - 100 to 125

Answer 11

The correction is -50. The error (uncorrected increase) is 25. -50/25 = -2

Question 12

Which of the following would have to be a transmembrane protein:
A receptor protein
A protein binging to the cytoskeleton
A channel protein
A phosphorylase

Answer 12

A channel protein

Question 13

What can be considered organelles?

Answer 13

Something that has a membrane - so no microtubules

Question 14

How are peripheral proteins attached to the membrane?

Answer 14

By proteins called Glycophosphatidylinositol = GPA-anchored proteins

Question 15

How does cholesterol affect the cell membrane?

Answer 15

Cholesterol is relatively inflexible, so it reduces membrane fluidity. More cholesterol = less fluidity

Question 16

Difference between integral and peripheral membrane proteins

Answer 16

Integral proteins are inserted into the lipid bilayer and can go through the whole thing
Peripheral proteins are linked indirectly to the membrane by protein-protein interactions.

Question 17

What organelles are associated with intracellular trafficking?

Answer 17

Golgi, ER(smooth and rough), and technically microtubules and vesicles too

Question 18

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

Answer 18

Rough ER

Question 19

Difference between pinocytosis and phagocytosis

Answer 19

Both are a form of endocytosis. Pinocytosis is cell fluid drinking. Phagocytosis is cell eating.

Question 20

Explain Lysosomal digestion

Answer 20

The primary lysosomes fuse with phagocytic vesicles to form secondary lysosomes.
Undigested material is felt behind within residual bodies
(Figure 2-12)

Question 21

Explain the difference between the two protein synthesis ribosome locations

Answer 21

• Proteins bound for lysosomes or for secretion are synthesized on Rough ER to which ribosomes attach
• Proteins bound for the cytoplasm, nucleus, mitochondria, or to other cell membranes are synthesized on free ribosomes

Question 22

What are the duties of the Golgi Apparatus

Answer 22

• Plays a role in protein packaging for secretion
• Forms lysosomes
• Modifies proteins from the Rough ER

Question 23

What are some methods of locomotion?

Answer 23

Amoeboid movement - Used by macrophages and some other leukocytes
Flagella (sperm cells) and Cilia - Cilia move material though a layer of mucous that coats a layer of ciliated cells. Cells remain stationary
Microtubules - provide tracks