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Chapter 8: Cells and their Environment
Word Parts:
Word Part
Phospho-
Type
Meaning
Lipid
ExoCyto
Section 1: Cell Membrane
Phospholipid: specialized lipid made of a phosphate “head” and two fatty acid
“tails
Lipid bilayer:
I. Every cell is surrounded by a cell membrane.
A.
B.
C. Helps cell maintain constancy and control
II. Homeostasis
A. Living things respond to their environment
B. The maintenance of stable internal conditions in a changing environment
C.
D. Cell Membrane
1.
2. provides structural support to cytoplasm
3.
4.
III. Lipid Bilayer
A. Phospholipid – specialized lipid made of a phosphate “head” and
fatty acid “tails”
two
B. Structure
1. water inside and outside will produce a lipid bilayer
2.
3.
C. Barrier
1.
2. ions and polar substances are repelled by lipid bilayer
IV. Membrane Proteins
A. Types of Proteins
1.
a. chain of sugars acts like a marker to identify type of cell
2.
a. enable cell to sense its surroundings
3.
a. help with important biochemical reactions inside cell
4.
a. aid the movement of substances that cannot pass through
membrane on their own
Section 2: Cell Transport
Equilibrium:
Concentration Gradient: one area has higher concentration than another
Diffusion: movement of a substance from an area of high concentration to an
area of low concentration
Carrier Protein: protein that transmits substances across a cell membrane
Osmosis:
I. Passive Transport
A.
B.
C. Movement is down a concentration gradient
D. Diffusion
1.
2.
3. small molecules diffuse faster than large ones
E. Osmosis
1.
2. Hypertonic Solution: Concentration of solutes outside is greater
than inside the cell
a.
3. Isotonic Solution: Concentration of solutes outside is equal to
inside the cell
a.
4. Hypotonic Solution: Concentration of solutes outside is less
than inside the cell
a.
WHAT HAPPENED TO THE EGG IN THE CLASSROOM
DEMONSTRATION?
II. Active Transport
A.
B.
C. Often involves carrier proteins pumping ions and molecules across a
membrane
D. Bulk Movement:
1. Exocytosis:
2. Endocytosis:
a. Pinocytosis:
b. Phagocytosis:
Section 3: Cell Communication
Signal:
Receptor Protein: protein that binds specific signal molecules, which
causes the cell to respond
I. Sending Signals
A.
B. Targets
1.
2. communicate locally with cell a few cells away from existing cells
3. hormones signal cells in another part of body
II. Receiving Signals
A. Binding Specifically
1
III. Responding to Signals
A. Cell may respond to a signal by changing its membrane
permeability by activating enzymes by forming a second messenger