The Cell Flashcards
3 tenets of cell theory
- all living things are composed of cells
- the cell is the basic functional unit of life
- cells arise only from preexisting cells
nuclear pores
in the nuclear membrane
allow for selective two-way exchange of material into and out of the nucleus
where is rRNA synthesized?
nucleolus
extranuclear inheritance
transmission of genetic material independent of the nucleus
eg mitochondria - contain some of their own genes and replicate independently of the nucleus via binary fission
apopotosis
programmed cell death
mitochondria can kill the cell by release of enzymes from the electron transport chain
mitochondria
powerhouse of the cell
lysosomes
membrane-bound structures containing hydrolytic enzymes that are capable of breaking down many different substrates, including substances ingested by endocytosis and cellular waste products
rough vs. smooth ER
rough endoplasmic reticulum contains ribosomes for protein synthesis
smooth ER is for lipid synthesis and transport of proteins from rough ER to Golgi apparatus
Golgi apparatus
consists of stacked membrane-bound sacs
materials from the ER are transported to Golgi in vesicles
cellular products undergo modification
contents are released via exocytosis
peroxisomes
primary function: breakdown of fatty acid chains via beta-oxidation
microfilamnets
made up of solid polymerized rods of actin
organized into bundles and networks
resistant to compression and fracture (provide protection for the cell)
microtubules
hollow polymers of tubulin proteins
radiate throughout the cell
cilia and flagella
cilia primarily for movement along surface of the cell, whereas flagella primarily for movement of cell itself like sperm
9+2 structure = nine pairs of microtubules forming an outer ring with two microtubules in the center
intermediate filaments
diverse group of filamentous proteins
include keratin, desmin, vimentin, lamins
involved in cell-cell adhesion or maintenance of the overall integrity of the cytoskeleton
able to withstand a tremendous amount of tension, making the cell rigid
epithelial tissues
cover the body and line its cavities, providing a means for protection against pathogen invasion and desiccation
tightly joined to layer of connective tissue called basement membrane
simple/stratified/pseudostratified and squamous/cuboidal/columnar