BIOL 2401 Cytoplasm Lecture Notes

Cytoplasm
o All cellular material that is located between the plasma membrane
and the nucleus
 Composed of:
 Cytosol: gel-like solution made up of water and
soluble molecules such as proteins, salts, sugars,
etc.
 Inclusions: insoluble molecules; vary with cell type
(examples: glycogen granules, pigments, lipid
droplets, vacuoles, crystals)
Organelles
 Metabolic machinery structures of cell; each with specialized function;
either membranous or nonmembranous
 ___Membranous______________________
o Nucleus
o Mitochondria
o Endoplasmic reticulum
o Golgi apparatus
o Peroxisomes
o Lysosomes
 ___Nonmembranous______________________
o Ribosomes
o Cytoskeleton
o Centrioles
Membranous organelles:
1) ___Nucleus______________________
o Largest organelle; contains the genetic library of blueprints for synthesis
of nearly all cellular proteins
 Responds to signals that dictate the kinds and amounts of
proteins that need to be synthesized
o The nucleus has three main structures:
 A. ____Nuclear envelope_____________________
 Double-membrane barrier that encloses the jelly-
like fluid, the nucleoplasm
 _______Nuclear pores__________________ allow
substances to pass into and out of nucleus;
 B. ___Nucleolus______________________

,  Dark-staining spherical body within nucleus that is
involved in ribosomal (RNA) synthesis
 C. ___Chromatin______________________
 The genetic material (DNA)
 Uncoiled DNA
 __Chromosomes_____ are condensed chromatin

2) _____Mitochondria____________________
o Called the “power plant” of cells because they produce most of cell’s
energy molecules (ATP) via aerobic (oxygen-requiring) cellular
respiration
o Enclosed by double membranes
o Mitochondria contain their own DNA, RNA, and ribosomes
o Resemble bacteria; capable of same type of cell division bacteria use,
called fission

3) ______Endoplasmic Retculum___________________
o Consists of series of parallel, flattened membranous tubes that enclose
fluid-filled interiors
o Is continuous with nuclear membrane
o Two types:
 A. ____Rough ER_____________________
 External surface appears rough because it is studded
with ________ribosomes_______________
 Site of synthesis of proteins
 B. _____Smooth ER____________________
 Network of looped tubules continuous with rough ER
 ________Lacks ribosomes_________________
 Functions in lipid synthesis, detoxification, etc.

4) ______Golgi apparatus___________________
o Stacked and flattened membranous sacs
o Modifies, concentrates, and packages proteins and lipids received from
rough ER

5) _______Peroxisomes__________________