Question

step 7: what 3 molecules cannot easily pass through the membrane? record why for each.
molecule 1\tmolecule 2\tmolecule 3
what does polar mean?

step 8: insert channel proteins into the membrane. transport substances across the membrane. note: you can only transport substances using channel proteins until there were
_________________________________________________________________________
what is this process called?

step 9: moving from ____ to __ concentration requires the use of energy to __ substances. this is called __________________ transport and uses: (place answer in table)
\t1.\t2.
\t\twhich is cell __________

step 10: carbohydrates are like identification badges. cells that have different membrane carbohydrates do different __________. the immune system uses the carbohydrates to ________ that your cells belong to __ and are not __________, or other foreign cells.
what does the immune system do to foreign invaders?
what kind of cell does this?

step 11: next take the “membrane structure challenge!”
step 12: take the “diffusion challenge!”
step 13: take the “energy and transport challenge!”
how many atp did you use? ____ what type(s) of protein(s) were used? __________
____________________________________ explain when each type was used. __________
_________________________________________________________________________

step 14: take the “osmosis challenge!”
what is osmosis? ____________
what is the name of the special proteins that let water pass through? ____________
is this passive or active transport? ____________

step 15: from your scores sheet record:
lab score (% correct): ____________
number correct:

Answer:

To answer these questions, we analyze each step based on cell membrane and transport concepts:

Step 7: Molecules & "Polar"

• Molecules that cannot easily pass through the cell membrane (a phospholipid bilayer, non - polar interior):
• Molecule 1: Ions (e.g., \( \text{Na}^+ \), \( \text{Cl}^- \)) – charged, repelled by non - polar membrane interior.
• Molecule 2: Large polar molecules (e.g., glucose) – too big and polar to cross non - polar region.
• Molecule 3: Large non - lipid - soluble molecules (e.g., proteins) – too large and insoluble in lipid bilayer.
• “Polar” means a molecule has a partial positive and partial negative charge (due to unequal electron sharing, e.g., in \( \text{H}_2\text{O} \), oxygen is slightly negative, hydrogens slightly positive).

Step 8: Channel Proteins & Process Name

• Inserting channel proteins to transport substances (down concentration gradient, no energy) is facilitated diffusion (passive transport using protein channels for molecules/ions that can’t cross lipid bilayer directly).

Step 9: Concentration & Transport

• Moving from low to high concentration requires energy (ATP) to move substances. This is active transport.
• 1. Energy source: ATP (adenosine triphosphate).
• 2. Active transport is used for cell homeostasis (maintaining internal conditions) or moving molecules against gradient (e.g., \( \text{Na}^+/\text{K}^+ \) pump).

Step 10: Membrane Carbohydrates

• Membrane carbohydrates (glycoproteins/glycolipids) act as identification badges. Cells with different membrane carbohydrates do different functions. The immune system uses carbohydrates to recognize that your cells belong to your body and are not pathogens (foreign invaders).
• Immune system vs. foreign invaders: It detects, attacks, and destroys them (e.g., bacteria, viruses).
• Cell type: White blood cells (e.g., lymphocytes, phagocytes) do this (phagocytes engulf invaders; lymphocytes produce antibodies).

Step 13: ATP & Proteins in Challenges

• ATP used: Depends on active transport steps (e.g., if you used active transport, ATP is consumed; passive transport uses 0).
• Proteins used:
• Channel proteins: For facilitated diffusion (passive, down gradient, e.g., ion channels).
• Carrier proteins: For active transport (against gradient, uses ATP, e.g., \( \text{Na}^+/\text{K}^+ \) pump) or some facilitated diffusion (e.g., glucose transporters).
• Explanation: Channel proteins are used when moving down concentration gradient (passive, no ATP). Carrier proteins are used in active transport (against gradient, needs ATP) or some facilitated diffusion (e.g., glucose).

Step 14: Osmosis & Aquaporins

• Osmosis: Diffusion of water across a selectively permeable membrane, from high water potential (low solute) to low water potential (high solute).
• Special proteins for water: Aquaporins (channel proteins for water).
• Transport type: Passive (no energy, water moves down its concentration gradient).

Step 15: Lab Score

• Record your lab score (e.g., if you scored 80% correct, write “80%”) and number of correct answers (e.g., “12” if 12 out of 15 were correct).

Final Answers (Key Points):

• Step 7: Ions, Glucose, Large Proteins (reasons: charge, size, polarity); Polar = unequal charge distribution.
• Step 8: Facilitated diffusion.
• Step 9: Low → High; move; Active; 1. ATP; 2. Homeostasis.
• Step 10: Functions; recognize; your body; pathogens; Immune: destroy invaders; Cell: White blood cells.
• Step 13: ATP (varies); Proteins: Channels (passive) & Carriers (active); Explanation: Channels (down gradient), Carriers (against/down).
• Step 14: Osmosis = water diffusion; Aquaporins; Passive.
• Step 15: Lab Score (e.g., “90%”), Number Correct (e.g., “13”).

(Note: Some answers depend on actual lab performance, like ATP used and score.)