Chapter 3

Question 1

Extracellular Materials

Answer 1

• Extracellular fluids
• Cellular secretions
• Extracellular matrix

Question 2

Membrane Lipids

Answer 2

polar hydrophilic head + nonpolar hydrophobic tail

Question 3

Integral (intrinsic) proteins

Answer 3

firmly inserted into lipid bilayer

Question 4

Peripheral (extrinsic) proteins

Answer 4

attach loosely to integral proteins or have a
hydrophobic region that anchors into membrane

Question 5

Membrane Carbohydrates and the Glycocalyx

Answer 5

Allow cells to identify one another or other
molecules

Question 6

Cell Junctions

Answer 6

Tight junctions
Desmosomes
Gap junctions - communicating junction between adjacent cells

Question 7

Hypertonic solutions

Answer 7

Cells lose water by osmosis and
shrink in a hypertonic solution
(contains a higher concentration
of nonpenetrating solutes than
are present inside the cells)

Question 8

Primary active transport by the Na+-K+ pump transports

Answer 8

Na+ out of the cell and K+ into the cell.

Question 9

Which of the following statements is generally true regarding extracellular sodium and potassium ion concentrations?

Answer 9

Sodium ion concentrations are high outside the cell relative to inside the cell.

Question 10

The key role of K+ in generating the resting membrane potential

Answer 10

STEP 1, diffuses out of the cell along its concentration gradient
STEP 2 As more and more K+ leaves the cell, the negativity of the inner membrane face becomes great enough to attract K+ back toward and even into the cell.
STEP 3 At a membrane voltage of -90mV, potassium’s concentration gradient is exactly balanced by the electrical gradient (membrane potential), and one K+ enters the cell as one leaves.

Question 11

cell adhesion molecules (CAMs)

Answer 11

¡ Anchor cell to extracellular matrix or to each other
¡ Assist in movement of cells past one another
¡ Attract WBCs to injured or infected areas
¡ Stimulate synthesis or degradation of adhesive
membrane junctions
¡ Transmit intracellular signals

Question 12

Membrane receptor proteins

Answer 12

Contact signaling + Chemical signaling

Question 13

Cytoskeleton - 3 types of rods

Answer 13

microfilaments
intermediate filaments
microtubules

Question 14

Chromatin

Answer 14

Composed of DNA, histone proteins, RNA chains

Question 15

Mitosis—four stages of nuclear division:

Answer 15

Prophase Metaphase Anaphase Telophase

Question 16

Messenger RNA (mRNA)

Answer 16

Carries coded info to cytoplasm, for protein synthesis

Question 17

Transfer RNA (tRNA)

Answer 17

¡ Ferry amino acid sequence to the ribosomes
¡ Decode mRNA message for amino acid sequence in the polypeptide to be built