Chapter 2 - Guyton Flashcards
Two major parts of the cell.
nucleus and cytoplasm
Water composes how much of the cell?
70-85%
After water, the most abundant substance in most cells is?
protein (10-20% of cell mass)
What is the main structural difference between structural proteins and functional proteins?
structural - composed mainly of long filaments; functional - tubular-globular form
What is the significance of carbohydrate to the cell?
little function structurally except as part of glycoprotein but plays a major role in nutrition for the cell
What provides “specificity” to the cell?
proteins
Examples of integral proteins.
channels, pores, carriers, enzymes
Examples of peripheral proteins.
enzymes, intracellular signal mediators
Which type of proteins (integral or peripheral) are the majority of glycoproteins?
integral
The carbohydrates on the glycocalyx have what charge?
negative (repel other substances)
How does cholesterol contribute to the membranes structurally?
decreases fluidity and permeability while increasing flexibility and stability
Which organelle is similar to (and contiguous with) the plasma membrane?
ER
Pathway of newly formed substances to exit cell.
granular ER–>smooth ER–>transport vesicles–>Golgi apparatus–>secretory vesicles–>exit cell membrane
What happens to proteins when they are “processed”?
crosslinked, folded, glycosylated (N-linked), cleaved
What is synthesized in the smooth ER?
lipids (phospholipids and cholesterol)
General characteristics of Golgi apparatus.
membrane composition similar to that of the smooth ER and plasma membrane, composed of 4 or more stacked layers of flat vesicular structures
What occurs at the Golgi apparatus?
receives transport vesicles from the smooth ER, substances formed in the ER are phosporylated and glycosylated, substances are concentrated, sorted, and packaged for secretion
What occurs during exocytosis?
secretory vesicles diffuse through the cytosol and fuse to the plasma membrane, lysosomes fuse with internal endocytotic vesicles
What occurs during secretion?
secretory vesicles containing proteins synthesized in the RER bud from the Golgi apparatus, fuse with plasma membrane to release contents
What are the two types of secretion?
constitutive (random) and stimulated (trigger)
Lysosomes
vesicular organelle formed from budding Golgi, contain hydrolytic enzymes, fuse with pinocytotic or phagocytotic vesicles to form digestive vesicles
What occurs during lysosomal storage diseases?
absence of one or more hydrolases (not synthesized, inactive, not properly stored and packaged), so lysosomes become engorged with undigested substrate
Examples of lysosomal storage diseases.
acid lipase A deficiency, I-cell disease (non-specific), Tay-Sachs disease (HEX A)
Peroxisomes
similar physically to lysosomes, two major differences are formed by self-replication and they contain oxidases, function is to oxidize substances that may be otherwise poisonous (alcohol)
The vesicular membrane of which organelle continuously replaces the cell membrane after it forms phagocytotic or pinocytotic vesicles.
Golgi apparatus
Energy from ATP is used to promote three major categories of cellular functions:
1) transport of substances through multiple
membranes in the cell; 2) synthesis of chemical
compounds throughout the cell; 3) mechanical
work
The double nuclear membrane and matrix are contiguous with the ____________ ___________.
ER…bet you won’t forget
What is found in the nucleoplasm?
chromatin (condensed DNA)
General characteristics of the nucleolus.
one or more per nucleus, contains RNA and proteins, not membrane delimited, functions to form the granular subunits of ribosomes
Receptor-mediated endocytosis
molecules attach to cell-surface receptors concentrated in clathrin-coated pits, receptor binding induces invagination, also ATP-dependent and involves recruitment of actin and myosin
A maximum of how many aTP are formed per molecule of glucose degraded.
38
During ATP production, glucose from carbohydrates, amino acids from protein, and fatty acids from fats are converted into what?
acetyl CoA
Two locations in the body cilia.
inside surfaces of the human airway and fallopian tubes
Composition of each cilium.
11 microtubules (9 double tubules, 2 single tubules), each cilium is an outgrowth of the basal body and is covered by an outcropping of the plasma membrane
Ciliary movement is dependent on what?
ATP and also calcium and magnesium
Ameboid locomotion
continual endocytosis at the “tail” and exocytosis at the leading edge of pseudopodium, attachment of pseudopodium is facilitated by receptor proteins carried by vesicles, forward movement results through interaction of actin and myosin (ATP-dependent)
What is chemotaxis?
most important factor in controlling ameboid movement, either move toward the
source of a chemotactic substance (positive chemotaxis) some cells move away from the source (negative chemotaxis)
The only means by which large macromolecules can enter the cell?
pinocytosis
Only certain cells have the capability to perform this function and it involves particles rather than the macromolecules such as in pinocytosis.
phagocytosis
