Chapter 2: Cell Physiology Flashcards
1
Q
Major Cell Divisions
A
- Plasma Membrane: bounds the cell
- Nucleus: contains DNA
Important concepts: roles of RNA, Human genome and proteome, epigenetics, and lipidome - Cytoplasm: consists of various organelles, the cytoskeleton, and the cytosol
Cytoplasm is the portion of the cell interior not occupied by the nucleus
2
Q
Endoplasmic Reticulum (ER)
A
- elaborate fluid-filled membranous system
- distributed extensively throughout the cytosol
- Primary Function: produce proteins and lipids
- Rough-ER synthesizes proteins for secretion and membrane construction
- Smooth-ER packages new proteins in transport vesicles
3
Q
ER and Segregated Synthesis
A
- misfolded proteins are destroyed by the ubiquitin-proteasome pathway
- tagged with ubiquitin, “doom tag”
- labels the flawed proteins for degradation
- labels undamaged or unneeded intracellular proteins for degradation in proteasomes
4
Q
Golgi Apparatus
A
- consists of a stack of flattened, slightly curved, membrane-enclosed sacs
- they do not come in contact with each other
- Vesicular transport from one Golgi sac to the next: accomplished through action of membrane-curving coat protein 1 (COP1)
- In secretory cells, the Golgi complex packages proteins for export by exocytosis
5
Q
Exocytosis
A
- a secretory vesicle fuses with the plasma membrane, releasing the vesicle contents to the cell exterior. The vesicle membrane becomes part of the plasma membrane
6
Q
Endocytosis
A
- materials from the cell exterior are enclosed in a segment of the plasma membrane that pockets inward and pinches off as an endocytic vesicle
- internalization of extracellular material within a cell
Processes:
Pinocytosis
Receptor-Mediated Endocytosis
Phagocytosis
7
Q
Lysosomes
A
- small, membrane-enclosed degradative organelles
- digest extracellular material brought into the cell by phagocytosis and remove worn-out organelles
8
Q
Pinocytosis
A
- solute molecules and water molecules are outside the plasma membrane
- membrane pockets inward, enclosing solute molecules and water molecules
- pocket pinches off as endocytic vesicle containing sample of ECF.
9
Q
Receptor-Mediated Endocytosis
A
- substances attached to membrane receptors
- membrane pockets inward
- pocket pinches off as endocytic vesicle containing target molecule
11
Q
Phagocytosis
A
- white blood cell engulfs a worn out red blood cell and breaks it apart
12
Q
Peroxisomes
A
- membranous organelles
- produce and decompose hydrogen peroxide (H2O2) while degrading potentially toxic molecules
- house oxidative enzymes that detoxify various wastes
Oxidative enzymes use oxygen (O2) to strip hydrogen from certain organic molecules
13
Q
Mitochondria
A
- energy organelles of the cell
- extract energy from food nutrients and transform it into a usable form for activities
- enclosed by tow membranes that form the cristae
- form a mitochondrial reticulum in some cell types
- play a major role in generating ATP
Processes:
Glycolysis
Citric Acid Cycle
Oxidative Phosphorylation
14
Q
Glycolysis
A
- conducted in cytosol of cell
- pyruvate-> citric acid cycle
15
Q
Mitochondria and ATP Productions
A
Aerobic Conditions
- more energy is generated in these conditions than in anaerobic conditions
Energy Stored within ATP
- used for synthesis, transport, and mechanical work
Programmed Cell Death
- mitochondria plays a role
16
Q
Vaults
A
- non-membranous organelles
- shaped like octagonal barrels and have a hollow interior
- may serve as cellular transport vehicles
- believed to pick up nucleus molecules and transport elsewhere in the cell
- may transport mRNA from nucleus to ribosomal sites for protein synthesis
- may play an undesirable role in bringing about multi-drug resistance displayed by cancer cells
