BI110 Lecture Notes - Lecture 15: Cell Wall, Cell Membrane, Protist
Bi110 lesson 15
cell surface
• ● the plasma membrane contains molecular systems that metabolize food molecules (or
light energy) into the chemical energy of ATP
• ● prokaryotic cytoskeleton maintain cell shape and function in cell division
• ● hairlike pili attach the cell to surfaces or other cells
○ a special sex pilus joins bacteria during mating
eukaryotic cells
• ● the domains of eukaryotes are protists, fungi, plants, animals
• ● eukaryotic cells have a membrane-bound compartment called the nucleus
• ● the cytoplasm contains a system of membranous organelles, specialized to carry out
functions of energy metabolism and molecular synthesis, storage, and transport
• ● the cytosol participates in energy metabolism and molecular synthesis and functions
in
support and motility
➢ eukaryotic plasma membrane
● carries out various functions through several types of embedded proteins
○ channel proteins transport substances in and out of cells
○ receptors recognize and bind specific signal molecules in the cellular
environment and trigger internal responses ○ immune system proteins label cells as “self”
• ➢ cell wall
o ● functions
surrounds and supports the plasma membrane of fungal, plant, and many protist
cells
protect cells against invading bacteria and fungi
contain the pressure produced in the central vacuole
o ● cell walls consist of cellulose fibres
▪ ○ the primary cell wall is relatively soft and flexible
▪ ○ the secondary cell wall consists of additional layers of cellulose fibres
and
branched carbohydrates laid down between the primary wall and the
