PHY2011 - topic 1 and 2

In which part of the body is the most water found?

The four main cations in cells are [blank_start]Na+, K+, Ca++ and Mg++[blank_end]

The major intracellular cation is

The [blank_start]cell membrane[blank_end] defines a cell, and acts as a continuous barrier between the inside and outside, allowing for the creation of an internal environment

Which organelles are vesicles containing enzymes for the breakdown of material?

What is the purpose of the rough endoplasmic reticulum (RER) being continuous with the outer nuclear membrane?

Specialised junctions called [blank_start]desmosomes[blank_end] link adjacent cells without sealing them into a sheet, giving them some degree of flexibility and being able to withstand stress

The lipids of the cell membranes contain two [blank_start]non-polar[blank_end] fatty acid chains stuck together by a [blank_start]polar[blank_end] head group

Which component of the membrane regulates fluidity?

Which proteins are not inserted into the membrane but rather associate with the membrane itself or another membrane protein?

Integral proteins [blank_start]cannot[blank_end] be removed from the membrane without ripping it apart

Which of the following increases the permeability of the membrane?

The cell membrane is selectively permeable as it allows [blank_start]only some substances[blank_end] to pass freely

The advantages of a selectively permeable cell membrane include (more than one correct answer):

Which of the following is a characteristic of passive transport?

[blank_start]Diffusion[blank_end] is the passive [blank_start]net[blank_end] movement of molecules from one location to another, through thermal agitation

Diffusion reaches equilibrium over time, and at equilibrium, there is [blank_start]no net flux[blank_end]

Which of the following is NOT a factor influencing the rate of simple diffusion?

Fick's law equation in words is net flux = [blank_start]permeability constant*surface area*[blank_end](concentration gradient)

Which two properties of molecules control their ability to permeate a cell membrane?

Which of the following best defines facilitated diffusion?

To transport a molecule via facilitated diffusion, the carrier protein has to bind to it, and only molecules with the appropriate part can fit into the specific binding site and thus be transported; this is known as [blank_start]specificity[blank_end]

Which of the following is NOT a class of direct or primary active transport mechanisms?

P-class ion pumps are made of [blank_start]a single protein[blank_end] with [blank_start]4[blank_end] trans-membrane subunits

Secondary/coupled active transport involves the accumulating of amino acids and sugars in transport processes which are driven by [blank_start]ion[blank_end] gradients

The difference between active and passive transport is that active transport [blank_start]expends[blank_end] energy (usually in the form of [blank_start]ATP[blank_end])

Which of the following regarding membrane proteins is correct?

One striking feature of plasma membrane structure is its symmetry, with the extracellular and cytoplasmic surfaces virtual mirror images of each other

One function of integral membrane proteins in the plasma membrane of cells is to form channels to allow passage of nonpolar solutes into the cell