Unit 3: Cells Study Guide Diffusion, Osmosis, and facilitated diffusion are all passive processes, explain the difference between the three. Diffusion

Unit 3: Cells

Study Guide

  1. Diffusion, Osmosis, and facilitated diffusion are all passive processes, explain the difference between the three.

Diffusion is movement of particles from areas of high concentration to areas of lower concentration.

Osmosis is diffusion of water across a membrane

Facilitated diffusion is movement of particles from areas of high concentration to areas of lower concentration through a membrane protein (channel or carrier).



  1. What similarities do diffusion, osmosis and facilitated diffusion share?

All three involve movement of substance from high concentration to low concentration.



  1. What is active transport?  What is required for active transport?

Active transport is movement of particles from low concentration to high concentration.  Energy and a (carrier) protein are required for active transport.



  1. What is an aquaporin and why are they important?

An aquaporin is a channel protein that is responsible for allowing water to cross the phospholipid bilayer.  Water is polar and would thus have a hard time crossing the nonpolar region of the bilayer with the help of this protein.  



  1. What types of molecules can be transported through a cell membrane by diffusion?

Nonpolar and small polar molecules can diffuse through a cell membrane



  1. What types of molecules can be transported through a cell membrane by facilitated diffusion?

Large polar molecules and ions



  1. How do channel and carrier proteins differ?  What are each used for?

Channel proteins are open like a hallway and allow a variety of substances through.  Channel proteins can be used for facilitated diffusion.

Carrier proteins are more like a locked gate that open and close with a specific (key) substance.  Carrier proteins are used for facilitated diffusion or active transport.



  1. Label the following diagram with polar head, nonpolar tail, channel protein, phospholipid.




  1. On the diagram again, label three locations polar molecules could be found.  Also label a nonpolar region.



  1. Describe what happens to a cell when it is placed in a hypotonic solution.

A cell in a hypotonic solution will have water move into the cell causing it to swell and increase in size/mass.



  1. Describe what happens to a cell when it is placed in a hypertonic solution.

A cell in a hypertonic solution will have water move out of the cell causing it to shrink and decrease in size/mass.



  1. Describe what happens to a cell when it is placed in an isotonic solution.

A cell in an isotonic solution will have the same amount of water move into and out of the cell causing it to remain the same size/mass.



  1. For each scenario below, complete the diagram with an arrow to show the movement and fill in any blanks.



  1. What are the original 3 tenets of cell theory?

-Cell is the functional unit of structure and function in living things

-All organisms are made of one or more cells

-Cells arise from other cells through cell division



  1. With new technology additions were added to cell theory, what were those additions?

-Hereditary Information is passed from cell to cell

-All cells have the same basic chemical composition

-Energy flow occurs within cells



  1. How did technology make these additions possible?

Technological improvements such as better microscopes allowed scientists to better view the inside of cells and have a better understanding about what they are composed of and how they function.



  1. Compare electron microscopes to light microscopes.  When might each be used?

Electron microscopes are larger, more expensive, and have much higher magnification than traditional light microscopes.  They are used to look (with incredible precision) at the three dimensional surface of an object (Scanning Electron microscope) as well as at a flat, very thin object (Transmission electron microscope).  The former bounces beams of electrons off of an object.  The latter shoots a beam of electrons through an object.


Light microscopes use light to image a thin transparent object (like a cell).  



  1. How are prokaryotic and eukaryotic cells different?  If you are looking at a cell how can you determine if it is prokaryotic or eukaryotic?

Prokaryotic cell do not have a nucleus or membrane bound organelles.  Prokaryotic cells are also smaller than eukaryotic cells. Eukaryotic cells do have a nucleus and membrane bound organelles such as mitochondria.  Looking at a cell you would look for the presence of a nucleus to determine if it is prokaryotic or eukaryotic.



  1. What do prokaryotic and eukaryotic cells have in common?

Both prokaryotic and eukaryotic cells have a cell membrane, ribosomes, vacuoles, and could have a cell wall.(Plants)



  1. Eukaryotic cells can be described as animal or plant cells, how do these eukaryotic cells differ?

Plant cells have a cell wall, chloroplasts and a large central vacuoles while animal cells do not.  Animal cells have lysosomes and centrioles while most plant cells do not.



  1. Cell membranes and nuclear membranes are both membranes!  How does the cell membrane differ from a nuclear envelope?

Cell membrane is one phospholipid bilayer thick.  Its purpose is to regulate what enters or leaves the cell and it serves as the cell’s outermost boundary.  A nuclear membrane contains nuclear pores for the movement of genetic material and is studded with ribosomes.  It is a double bilayer.



  1. Some plant cells have very few chloroplasts while others have a lot of chloroplasts.  What do you think those with a lot of chloroplasts may do a lot of?

Plant cells with a lot of chloroplast will be able to convert my sunlight to chemical energy through photosynthesis than those cells with less chloroplasts.



  1. How are vacuoles different in plant cells compared to vacuoles in animal cells?  What are they called in plant cells?

Plant cells typically have a central vacuole, which is a single large vacuole that mainly stores water inside the plant cell.  Animal cells typically have many small vacoules throughout the cell.




  1. Show the levels of organization from an organelle to an organism.

Organelles -> cell -> tissue -> organ -> organ system -> organism



  1. What is the difference between a tissue and an organ?

Tissues are groups of cells working together while an organ is a group of tissues working together to perform a function.



  1. Give examples of an organ.  Give examples of an organ system.

Organ: Heart, Brain, Lungs, Liver, Pancreas, Kidneys, etc

Organ System: Digestive System, Muscular System, Nervous System, etc



  1. Be able to describe the function and type of cell each of the following organelles are found in.

  1. Mitochondria

Produces energy for the cell (in the form of ATP), found in all Eukaryotic cells (plants and animals)



  1. Chloroplast

Converts sunlight to chemical through photosynthesis, found in plant cells



  1. Ribosome

Produces proteins (protein synthesis), found in all cells



  1. Endoplasmic Reticulum (ER)

Site of protein and lipid production, transports proteins and lipids, detoxifies,  found in all Eukaryotic cells (plants and animals)



  1. Golgi Body

Modifies and Packages proteins,  found in all Eukaryotic cells (plants and animals)



  1. Lysosome

Breaks down materials in the cell, removes waste from cell, found in mostly animal cells



  1. Nucleus

Control center of the cell, contains genetic information (DNA),  found in all Eukaryotic cells (plants and animals)



  1. Centrioles

Serve as cell skeletal system, aid in cell division, found mostly in animal cells



  1. Cell Membrane

Regulates material entering and leaving cell, found in all cells



  1. Cell Wall

Provides structure, protection, and strength for cell, found in prokaryotic and plant cells



  1. Cytoplasm

Fluid within the cell, holds structures in place, found in all cells



  1. What is the difference between the rough and smooth endoplasmic reticulum?  How can you tell them apart when looking at them?

Rough endoplasmic reticulum (ER) has ribosomes on it and is the location of protein synthesis.  Smooth ER does not have ribosomes on it and is the location of lipid production, also used to detoxify.



  1. Mitochondria and chloroplasts are complex!  Explain the origins of these complicated structures (endosymbiont theory):

Mitochondria and chloroplasts used to be their own prokaryotic cells.  They were incorporated into larger heterotrophic cells in the past and are now inseparable from those cells.  They have a symbiotic relationship with the host cell.  



They both have their own genetic material, they are the size of prokaryotes, have a double membrane, their own ribosomes, and self replicate. 



  1. Label the parts in the cell below, is this an animal or plant cell?    animal cell____


  1. We often call organelles “membrane bound structures”.  Why?  What is the significance of their membranes?  Which organelles are in actuality just membrane sacs? 

Almost all organelles are wrapped in a membrane.  These membranes are similar but have differences between organelles.  Several organelles are just membrane sacs:  lysosomes, ER, vesicles, golgi bodies, and vacuoles.



  1. Fill in the venn diagram comparing and contrasting prokaryotic, plant and animal cells.




  1. Label the organelles in the cell below.  What type of cell is it? ___Plant cell_____




  1. Identify the following microscope images as plant, or animal cells, then label organelles visible.