Question

quest: cell defense
plasma membrane

directions: read the steps here and all the information on the chromebook screen. follow
all the steps carefully filling in all the blanks.

step 1: click start a new game!, then select continue to start the game. you want to move
to the \choose your challenge!\ menu. from the menu choose \build a membrane!\ dr.
vial has a vile weapon (note the play on words) that destroys plasma membranes. without
____________________ cells of living things will die because they are unable to maintain
____________________.

step 2: zoom in on the plasma membrane, from the \urgent message\ you learn that
phospholipids are a ____________ head and __________ ____________ tails.
the heads are ________________________ which means ________________________
the tails are ________________________ which means ________________________
the heads face out towards the ____________ and the tails facing __________ ____________.
draw and label the phospholipid in the box: box
step 3: repair the phospholipid membrane.
how many phospholipids did it take? ______
step 4: what do you have to put into
the membrane in order to help stabilize it?
____________________________ how many did you add? ____
step 5: what is another word for selectively permeable? ______________________________.
what does that mean? _________________________________________________________
______________________________________________________________________________.
step 6: what 2 molecules easily pass through the membrane? record why for each.
molecule 1 | molecule 2

Explanation:

To solve the questions related to the "Cell Defense: Plasma Membrane" activity, we analyze each step based on cell membrane structure and function:

Step 1

Without a plasma membrane, cells die as they can’t maintain homeostasis (stable internal environment).

Step 2

Phospholipids have a hydrophilic (water - attracting) head and two hydrophobic (water - repelling) tails.

• Heads: Hydrophilic (attracted to water).
• Tails: Hydrophobic (repelled by water).
• Heads face the cytoplasm (inside) and extracellular fluid (outside), tails face each other (inside the bilayer).

Step 3

To repair the phospholipid membrane, it typically takes 20 phospholipids (varies by game version, but common answer is 20).

Step 4

To stabilize the membrane, add cholesterol. The number added is usually 4 (varies slightly).

Step 5

Another word for selectively permeable is semi - permeable. It means the membrane allows some substances (small, non - polar, or with transporters) to pass, but blocks others.

Step 6

• Molecule 1: Oxygen (O₂) – Small, non - polar, moves via diffusion (down concentration gradient).
• Molecule 2: Water (H₂O) – Small, uses aquaporins (facilitated diffusion) or simple diffusion (slow).

Answer:

s (Key Blanks):
Step 1: plasma membrane; homeostasis
Step 2: hydrophilic; two hydrophobic; hydrophilic (water - loving); attracted to water; hydrophobic (water - fearing); repelled by water; cytoplasm/extracellular fluid; each other
Step 3: 20 (approximate)
Step 4: cholesterol; 4 (approximate)
Step 5: semi - permeable; allows some substances to pass, blocks others
Step 6: Molecule 1: Oxygen (O₂) – small, non - polar, diffuses; Molecule 2: Water (H₂O) – small, uses aquaporins or diffuses

(Note: Exact numbers for Steps 3/4 may vary based on the game’s setup.)