Lesson 3 Flashcards
organelles
internal structures of a cell that carry out specialized metabolic tasks
non-membranous organelles
do not have a membrane surrounding them
- cytoskeleton, microvilli, centrioles, cilia, ribosomes, and proteasomes
membranous organelles
surrounded by a membrane
- nucleus, ER (rough and smooth), golgi complex, lysosomes, peroxisomes, and mitochondria
cytosol
clear, viscus, watery, colloid within the cell
- contains enzymes and other proteins, amino acids, ATP, electrolytes, dissolved gases, and metabolic waste
cytoskeleton
a network of protein filaments and cylinders
- structural support, determines cell shape, organizes cell contents
- directs movement of materials within the cell, contributes to movements of the cell as a whole
microfilaments
smallest
- made of actin
- form terminal web aka membrane skeleton
- 6 nm thick
intermediate filaments
- within skin cells
- 8 to 10 nm thick
- made of keratin
- give cell shape and resist stress
microtubules
largest
- consists of protofilaments made of tubulin
- maintain cell shape
- hold organelles
- act as railroad tracks for walking motor proteins
- make axonemes of cilia and flagella
- form mitotic spindle
- 25 nm thick
______ provide mechanical strength by anchoring cytoskeleton to plasma membrane proteins
microfilaments
______ interact with cytosolic proteins to adjust liquidity of cytosol.
microfilaments
these filaments are the most stable and durable of all cytoskeletal elements
intermediate filaments
intermediate filament functions (4)
- provide mechanical strength/durability to the cell
- maintains shape
- stabilizes organelle position
- stabilized cells onto substrates/other cells
_____ _____ in the superficial layers of the skin are intermediate filaments
keratin fibers
microtubule functions (5)
- attaches to the centrosome
- provides strength to the cell/stabilizes organelle positions
- changes in microtubules change cell shape
- can be used as a “highway system” in the cell for motor proteins
- form spindle apparatus
motor proteins called _____ and _____ can use ATP energy to move organelles along microtubules
kinesin, dynein
microvilli
extensions of the plasma membrane that serve to increase surface area
the core of microvilli is composed of _____
microfilaments
on some adaptive cells, they are very dense and appear as a fringe called the _____ _____
brush border
cilia
small hair like processes composed of microtubules, can be motile or not
where can motile cilia be found?
respiratory tract, uterine tubes, ventricles of the brain, ducts of testes
centriole
a short, cylindrical assembly of microtubules arranged in nine groups of three microtubules each
ribosomes
small granules of protein and RNA responsible for producing proteins
proteasomes
hollow, cylindrical organelles that dispose of surplus proteins, contain emzymes
rough ER
synthesizes phospholipids and proteins
smooth ER
synthesizes lipids and steroids
golgi complex
a system of membranous cisterns that synthesizes carbohydrates and modifies newly synthesized proteins
lysosomes
package of enzymes bound by a membrane
primary lysosome
formed by the Golgi complex, enzymes inside are inactive
secondary lysosome
formed when the primary lysosome fuses to an endosome or fuses with damaged organelles, activating the enzymes inside
autophagy
digestion of cell’s surplus organelles
autolysis
digestion of a cell by itself, “cell suicide”
Tay-Sachs disease
rare genetic disease
lack of lysosomal enzyme causes a buildup or lipids in brain cells leading to death of those cells
- infantile for of disease leads to death of the child by age 4
peroxisomes
resemble lysosomes but contain different enzymes and are produced by ER and mitochondria and from other peroxisomes
what is the enzyme within peroxisomes?
catalase, breaks down hydrogen peroxide to water and oxygen
