Homeo

Question 1

What is essential for homeostasis in the body?

Answer 1

Communication within the body is essential for homeostasis

Question 2

Which systems are chiefly responsible for communication in the body?

Answer 2

The nervous and endocrine systems

Question 3

What are the information carriers used by the nervous and endocrine systems?

Answer 3

Neural electrical impulses and blood-borne hormones

Question 4

What is the variable in a homeostatic control mechanism?

Answer 4

The factor or event being regulated

Question 5

How many components are involved in all homeostatic control mechanisms?

Answer 5

At least three components

Question 6

What is the role of the receptor in homeostasis?

Answer 6

It is a sensor that monitors the environment and responds to stimuli

Question 7

What does the receptor send information along to?

Answer 7

The afferent pathway to the control center

Question 8

What is the function of the control center in homeostasis?

Answer 8

It determines the set point and analyzes input to determine the appropriate response

Question 9

What is a set point in the context of homeostasis?

Answer 9

The level (or range of levels) at which a variable is to be maintained

Question 10

What type of information flows from the control center to the effector?

Answer 10

Output information

Question 11

What is the effector’s role in the homeostatic process?

Answer 11

It carries out the control center’s response to the stimulus

Question 12

Fill in the blank: Information traveling along the _______ pathway approaches the control center.

Answer 12

afferent

Question 13

Fill in the blank: Information exits from the control center along the _______ pathway.

Answer 13

efferent

Question 14

What happens to the stimulus as a result of the effector’s response?

Answer 14

It can be reduced or enhanced

Question 15

True or False: The effector’s response can only reduce the stimulus.

Answer 15

False

Question 16

What influences the effect of the stimulus in homeostasis?

Answer 16

The results of the response from the effector

Question 17

What does the fluid mosaic model of membrane structure depict?

Answer 17

The plasma membrane as a thin structure composed of a lipid bilayer with proteins dispersed in it

The model is characterized by a constantly changing mosaic pattern formed by proteins.

Question 18

What is the thickness range of the plasma membrane?

Answer 18

7-10 nm

This measurement indicates the exceedingly thin nature of the plasma membrane.

Question 19

What primarily composes the lipid bilayer of the plasma membrane?

Answer 19

Phospholipids, with smaller amounts of cholesterol

The lipid bilayer forms the basic ‘fabric’ of the membrane.

Question 20

What is the orientation of the hydrophilic heads of phospholipids in the membrane?

Answer 20

They lie on both the inner and outer surfaces of the membrane

This orientation is due to their attraction to water.

Question 21

What do the nonpolar tails of phospholipids do in the membrane?

Answer 21

They line up in the center of the membrane, avoiding water

This creates a sandwich-like structure in biological membranes.

Question 22

What is the general structure of all biological membranes?

Answer 22

Two parallel sheets of phospholipid molecules lying tail to tail

The polar heads are bathed in water on either side.

Question 23

What property of phospholipids encourages biological membranes to self-assemble?

Answer 23

Their self-orienting property

This property helps membranes to reseal themselves when torn.

Question 24

How does the plasma membrane’s consistency compare to everyday substances?

Answer 24

It is similar to olive oil

This indicates the dynamic fluid nature of the plasma membrane.

Question 25

How do phospholipids move within the plasma membrane?

Answer 25

They move freely from side to side, parallel to the membrane surface ## Footnote They rarely flip-flop or move between the bilayer halves.

Question 26

What percentage of membrane lipid is cholesterol?

Answer 26

20% ## Footnote Cholesterol plays a role in stiffening the membrane.

Question 27

What are the two distinct populations of proteins found in the plasma membrane?

Answer 27

Integral and peripheral proteins ## Footnote Integral proteins are embedded in the membrane, while peripheral proteins are attached to the surface.

Question 28

What role do proteins play in the plasma membrane?

Answer 28

They allow the cell to communicate with its environment ## Footnote Proteins are responsible for most specialized membrane functions.

Question 29

True or False: Proteins make up about half of the plasma membrane by mass.

Answer 29

True ## Footnote This highlights the significant role of proteins in membrane structure.

Question 30

Fill in the blank: The polar heads of phospholipids are attracted to _______.

Answer 30

water ## Footnote This attraction is due to the hydrophilic nature of the heads.

Question 31

What happens to the inward-facing and outward-facing surfaces of the plasma membrane?

Answer 31

They differ in the kinds and amounts of lipids they contain ## Footnote These variations help determine local membrane structure and function.