What particles are unableto pass through a cell membrane?

What particles or materials are able to pass through a cell membrane?

Osmosis deals with the movement of ______from an area of high/low (circle one) concentration to a area of high/low (circle one) concentration

What is the function of the cell membrane?

What is homeostasis?

How does the cell membrane maintain the internal balance inside the cell?

Sodium ions are "pumped" from a region of lower concentration to a region of higher concentration in the nerve cells of humans using energy. This process is an example of

  1. DiffusionC. Active transport
  2. OsmosisD. Passive transport

The arrows in the diagram represent the movement of materials in and out of a single celled organism.

The movements indicated by the arrows are all directly involved in

  1. The maintenance of homeostasis
  2. Photosynthesis only
  3. Excretion only
  4. The digestion of minerals

Consider the following scenarios. Remember that Osmosis moves from high/low (circle one) to high/low (circle one). Draw which way water will move in each scenario. Label where the high and low concentration of water is in each situation.

  1. Water was 90% inside the cell and 95% outside the cell
  1. Protein was 30% inside the cell and 35% outside the cell
  1. Water was 95% inside the cell and 90% outside the cell
  1. Water and protein was equal inside and outside the cell
  1. The diagram below represents a cell in water. O2 and CO2can both move freely through the cell membrane.
  1. What will happen to the concentration of CO2 inside the cell?
  2. What will happen to the concentration of O2 inside the cell?

Consider the following scenarios. Label passive as “P”, active as “A”, or “N” for not possible.

Movement of molecules / ATP used or not used / Active, Passive, or Not Possible?
High concentration  Low concentration / ATP used
High concentration  Low concentration / ATP not used
Low concentration  high concentration / ATP used
Low concentration  high concentration / ATP not used

The cell above is a leaf cell from Elodea, a plant species. The picture on the left shows the cell before a solution was added to the cell’s surroundings; the picture on the right is after the solution was added.

Circle which solution was most likely added to the cell’s surroundings.

A Salt solution

B Iodine solution

C Tap Water

D Protein solution

The diagram below represents the change that occurred after a fluid was added to a wet mount of Elodea leaf cells.

Which fluid was most likely added to the cell’s surroundings?

  1. Salt solutionC. Iodine solution

B. Tap waterD. Distilled water

IP # 1

  1. 20 oxygen molecules on the inside, 10 on the outside. The oxygen CAN move. What will happen?
  1. 15 salt molecules on the outside, 10 salt molecules on the inside. The salt CAN’T move. What will happen?

IP # 2

  1. 3 starch molecules on the outside, 10 starch molecules on the inside. The starch CAN’T move. What will happen?
  1. 10 Carbon dioxide molecules on the outside, 1 Carbon dioxide molecule on the inside. The Carbon dioxide CAN move. What will happen?

IP # 3

  1. 5 water molecules on the outside, 8 water molecules on the inside. The water CAN move. What will happen?
  1. 10 sugar molecules on the inside, and 10 sugar molecules on the outside. The sugar CAN’T move. What will happen?

ACTIVITY 2, group practice

You get a blood-sucking leech (parasite—ewww!) stuck to your leg while swimming in a pond. The pond water is not salty. You’ve heard an old rumor that pouring salt on the slug will kill it, and therefore get it off of you safely. With your group, decide if there is any truth to this rumor. Draw some sketches to support your claim!

ACTIVITY 3, group practice

For the most part, plants and animal live in either a salt water environment or a fresh water environment, not both. Explain why this is the case, using pictures and words.

Then, explain what would happen if you took a fresh water fish and put it in the salty ocean, or took a ocean fish and put it in your bathtub! Use pictures!!


Diffusion / Osmosis / Facilitated
Diffusion / Active Transport
Moves with the gradient
(high to low concentration)
Moves against the gradient
(low to high concentration)
Needs a protein
Needs ATP
Moves large particles like sugars and salts
Moves water
Moves small particles like gasses and ions

The circle below represents a cell. The square dots represent sugar molecules. The large dark square represents a protein. The arrow shows the movement of particles over time.

  1. Identify low and high concentration of sugar molecules.
  1. Are the sugar molecules moving with or against the concentration gradient?
  1. Is this active or passive transport?
  1. Is a protein required?
  1. What type of transport is this, specifically (facilitated, diffusion, osmosis, active)? How do you know?
  1. Identify low and high concentration of sugar molecules
  1. Are the sugar molecules moving with or against the concentration gradient?
  1. Is this active or passive transport?
  1. Is a protein required?
  1. What type of transport is this, specifically (facilitated, diffusion, osmosis, active)? How do you know?

  1. Label the lipid bilayer and protein channel in the diagram on the left.
  2. Draw an arrow to predict how hydrogen ions would move if this was facilitated diffusion
  3. Draw an arrow to predict how hydrogen ions would move if this was active transport

The picture below shows a picture of a cell (the nucleus is the circle in the middle) and the concentration of carbon dioxide (CO2) and oxygen (O2) inside and outside the cell.

Identify if the below concentrations are inside or outside the cell.

  1. High concentration of O2:
  1. Low concentration of O2:
  1. High concentration of CO2:
  1. Low concentration of CO2:
  1. Gas molecules like those above can undergo passive transport. Which type of transport do they under go (osmosis, difussion, facilitated diffusion)
  1. Predict how oxygen (o2) will move by drawing an unshaded arrow on the diagram above.
  1. Predict how carbon dioxide (Co2) will move by drawing a shaded arrow on the diagram above.

Below, the image shows a before and after picture of two cells connected by a semi permemable membrane (represented by the dotted line). The black dots reprresent salt molecules. The dotted line represents a semi permeable membrane that does NOT allow salt to cross. However, water can move across the boundary.

  1. Label the concentrations of SALT molecules.
  1. Using a blue colored pencil, label the high and low concentration of water.
  1. Draw a line in blue to indicate how WATER will move.

BEFORE

  1. In the “after” picture to the left, draw the change in the water level. Also be sure to draw the concentration of salt molecules on either side of the membrane.

Is this an example of active or passive transport? If passive, what type of passive transport (facilitated, osmosis, diffusion)?

  1. Homeostasis – how organisms maintain a constant internal balance in a ______environment
  2. STERNGRR (Life Process) = ______
  3. Examples of Homeostasis
  4. Internal ______– maintained by shivering (heat up) and sweating (cool down)
  5. Internal _____ – steady pH in body maintained by buffers
  6. Internal ______Balance – maintained by kidneys through osmosis
  7. Blood ______balance – maintained by insulin protein
  8. Semi-Permeable Cell Membrane – maintains ______for the cell by controlling what enters and leaves the cell
  9. Semi-Permeable or selectively permeable- selects what materials can leave and enter through membrane.
  10. Cell Membrane structure
  11. Lipid ______– made up of two layers of phospholipids
  12. ______channels – allow molecules to enter/leave
  13. Cell transport – process by which cell membrane moves ______(salt or sugar molecules) and ______through the cell membrane
  14. Concentration – relative amount of molecules in a given area.
  15. Concentration gradient – the change of concentration over distance.
  16. Moving with the gradient = downhill. ______concentration
  17. Moving against the gradient = uphill. ______concentration
  1. Types of Transport
  2. Passive transport – moves solutes (particles) or water ______the concentration gradient (high to low). Requires no ______(ATP).
  3. Diffusion – movement of gasses and small ions from ______to ______through cell membrane. No ATP needed. No protein needed.

  1. Osmosis – movement of ______ molecules from high to low. No ATP needed. No protein needed
  1. Facilitated diffusion – movement of large molecules like salts, sugars, and amino acids from ______to ______ by way of a ______channel. No ATP needed. Protein needed.
  1. Active transport – moves solutes (particles) such as ions, sodium, and potassium ______the concentration gradient (______to ______) using ATP. Always requires a protein “pump”.