Lesson 1 - chapter 2 - cell Flashcards
2 major parts of cell
nucleus
cytoplasm
nucleus is separated from the cytoplasm
by a
nuclear membrane
cytoplasm is separated
from the surrounding fluids by a
cell membrane, also
called the plasma membrane.
different substances that make up the cell
protoplasm
Protoplasm is composed
mainly of five basic substances
water 70-85%
electrolytes,
proteins 10-20%
lipids, and
carbohydrates.
principal fluid medium of the cell
present in most cells, except for fat cells,
70-85%
Many cellular chemicals are dissolved
water
ions/electrolytes:
K+ potassium,
MG+2 magnesium,
PO4 -3 phosphate,
SO4 -2 sulfate,
CHO3- bicarbonate
smaller quantities of sodium, chloride, and calcium
provide inorganic chemicals for cellular reactions and also are necessary for operation of some of the
cellular control mechanisms
IONS
2nd most abundant substances
in most cells are
proteins
present in the cell mainly in
the form of long filaments that are polymers of many
individual protein molecules.
A prominent use of such intracellular filaments is to form microtubules that provide
the “cytoskeletons” of such cellular organelles as cilia,
nerve axons, the mitotic spindles of cells undergoing
mitosis, and a tangled mass of thin filamentous tubules that hold the parts of the cytoplasm and nucleoplasm together in their respective compartments.
structural proteins
mainly the enzymes of the cell and, in contrast to the
fibrillar proteins, are often mobile in the cell fluid.
functional proteins
are found outside the cell, especially in the collagen and elastin fibers of connective tissue and in blood vessel walls, tendons, ligaments, and so forth.
Fibrillar proteins
soluble in fat solvents
lipids
Especially important lipids which together constitute only about 2% of the total cell mass
phospholipids and cholesterol
triglycerides, also called neutral fat
fat cells, triglycerides often account for
as much as ________ of the cell mass
95%
The fat stored in
these cells represents the body’s main storehouse of
energy-giving nutrients that can later be used to provide
energy wherever in the body it is needed
lipids
1% of total cell mass,
3% in muscles,
6% in liver): glycogen
carbohydrates
which is an insoluble polymer of glucose that can
be depolymerized and used rapidly to supply the cells’ energy needs.
glycogen
MEMBRANOUS STRUCTURES
OF THE CELL:
cell membrane,
nuclear membrane,
membrane of the endoplasmic reticulum,
membranes of the mitochondria, lysosomes, and Golgi apparatus
_________ in the membranes provide a barrier that
impedes movement of water and water-soluble substances from one cell compartment to another because water is not soluble in lipids
lipids
molecules providing specialized pathways, often organized into actual pores, for passage of specific substances through the membrane
protein
proteins that catalyze a multitude of
different chemical reactions, discussed here and in subsequent chapters
enzymes
cell membrane (also called the plasma membrane)
envelops the cell and is a thin, pliable, elastic structure
only 7.5 to 10 nanometers thick.
cell membrane (also called the plasma membrane)
approximate composition or cell membrane:
proteins, 55%
phospholipids, 25%
cholesterol, 13%
other lipids, 4% and
carbohydrates, 3%