bio3.txt

Osmotic pressure is:


the ability of a solution to affect the fluid volume and pressure in a cell.
the pressure required to open aquaporins (water channels) on the plasma membrane.
the pressure exerted on a membrane by water.
equal to the pressure needed to stop the movement of water from one side of a membrane to the other.

An increase in the permeability of the plasma membrane to a certain type of moleculewould _________ the rate of diffusion of those molecules through the plasma membrane. increase decrease not change

An increase in the surface area of the cell would _________ the rate of diffusion of molecules through the plasma membrane. increase decrease not change

An increase in the "steepness" of the concentration gradient would _________ the rate of diffusion of those molecules through the plasma membrane. increase decrease not change

An increase in molecule size would _________ the rate of diffusion of molecules through the plasma membrane. increase decrease not change

An increase in temperature would _________ the rate of diffusion of molecules through the plasma membrane. increase decrease not change

The plasma membrane is made primarily of ________ molecules, but ________ make up about 50% of the membrane weight.

protein; lipids
lipid; proteins
protein; monosaccharides
cholesterol; proteins

There is a limit to how large a cell can be, why is bigger not necessarily better?

As cell size increases, the surface area doesn't increase as much as the volume inside the cell, making it more difficult for the cell to exchange nutrients and wastes with the extracellular fluid.
Larger cells would limit the space available for extracellular fluid, which means fewer nutrients would be available to the cells.
Larger cells need more organelles to support themselves and this would use too much energy.
As cell size increases, the surface area increases more than the volume inside the cell, leaving less room for organelles to carry out the functions of the cell.

A 0.9% solution of NaCl is isotonic to red blood cells. What happens if red blood cells are placed in 1.5% NaCl? Why?



The cells swell and burst (hemolysis occurs). This happens because the concentration of solutes is higher inside the cell, causing water to flow into the cell.
The cells swell and burst (hemolysis occurs). This happens because the concentration of solutes is lower inside the cell, causing water to flow into the cell.
The cells shrivel (crenation occurs). This happens because the concentration of solutes is higher outside the cell, causing water to flow out of the cell.
The cells shrivel (crenation occurs). This happens because the concentration of solutes is lower outside the cell, causing water to flow out of the cell.

What is the difference between facilitated diffusion and active transport?
Facilitated diffusion moves substances "up" or against a concentration gradient whereas active transport moves substances "down" or with a concentration gradient.
Facilitated diffusion can only be used for small molecules, larger molecules must use active transport.
Active transport uses energy for transport and facilitated diffusion does not.
Active transport uses carrier proteins and facilitated diffusion does not.

Which organelle has functions that include synthesis of proteins and lipids and detoxification of alcohol and other drugs?

nucleus
endoplasmic reticulum
centriole
lysosome
Golgi complex

Which organelle is made of microtubules and plays an important role in cell division?

peroxisome
centriole
mitochondria
nucleus
endoplasmic reticulum

what are the fxn of the plasma membrane:

In an isotonic solution what will happen to a cell? hypertonic? hypotonic?

Give two example of active transport:

which of the following is not a type of active transport?

A. movement of a molecule up the concentration gradient
B. endocytosis
C. exocytosis
D. facilitated diffusion

_________ referst to 'cellular eating'

A. pinocytosis
B. hydrolysis
C. phagocytosis
D. exocytosis

what will happen to a cell when it is submerged in a hypertonic solution?

A. lysis
B. clotting
C. stays normal
D. crenation