3.4 Flashcards
cytoskeleton (def)
network of protein filaments and cylinders that:
structurally support a cell
determine its shape
organize its contents
direct the movement of materials w/in the cell
contribute to movements of the cell as a whole
cytoskeleton is composed of…
microfilaments
intermediate filaments
microtubules
microfilaments (def)
thin filaments
made of protein actin
crucial role in:
embryonic development
muscle contraction
immune function
wound healing
cancer metastasis
cell migration
intermediate filaments (def)
thicker and stiffer than microfilaments
give cell:
its shape
resist stress
participate in junctions that attach cells to their neighbors
microtubules (def)
cylinders made of 13 parallel strands called protofilaments
each protofilament is a long chain of tubular (globular proteins)
radiate from area of cell called centrosome
hold organelles in place
form bundles that maintain cell shape and rigidity
act like monorail tracks
organelle (def)
internal structure of a cell that carries out specialized metabolic tasks
membranous organelles (def)
organelles surrounded by membranes
membranous organelles (examples)
nucleus
mitochondria
lysosomes
peroxisomes
endoplasmic reticulum
Golgi complex
organells w/o membranes (examples)
ribosomes
proteasomes
centrosomes
centrioles
basal bodies
nucleus (def)
largest organelle
contains cell’s chromosomes –> genetic control center of cell activity
anuclear (def)
cells that don’t have a nucleus
ex.
mature red blood cells are anuclear
multinuclear (def)
cells that have multiple nuclei
ex.
skeletal muscle cells, liver cells, bone-dissolving cells
nuclear envelope (def)
double membrane that encloses nucleus
nuclear pores (def)
pores in nuclear envelope
regulate molecular traffic thru the envelop
holds the 2 membrane layers together
nuclear lamina (def)
a web of intermediate filaments
densely fibrous zone
inside the nuclear envelop
nucleoplasm (def)
material inside nucleus
includes chromatin and nucleoli
chromatin (def)
fine threadlike matter of DNA and protein
part of nucleoplasm in nucleus
nucleoli (def)
mass where ribosomes are produced
part of nucleoplasm in nucleus
endoplasmic reticulum (def)
system of interconnected channels called cisterns
enclosed by a unit membrane
rough endoplasmic reticulum (def)
cisterns are parallel, flattened sacs
covered in ribosomes
cisterns of RER are continuous w/ cisterns of SER
smooth endoplasmic reticulum (def)
cisterns are more tubular, branch more extensively, and lack ribosomes
cisterns of SER are continuous w/ cisterns of RER
rough ER (function)
synthesizes steroids and lipids
detoxifies alcohol and other drugs
manufactures nearly all membranes of the cell
produces phospholipids and proteins of the plasma membrane
synthesizes large amounts of protein
smooth ER (function)
present in cells that engage extensively in detoxification (liver and kidney cells)
abundant in cells of the testes and ovaries that synthesize steroid hormones
what is function of nucleolus?
ribosome production
the Golgi complex packages cellular products that will be exported from the cell into which structures?
secretory vesicles
organelle comprised of stacked cistern that synthesize carbs
golgi complex
skeletal and cardiac muscle cells store calcium in extensive networks of which organelle?
smooth ER
lysosome (def)
membrane-bound organelle that contains a mixture of enzymes that function in digesting forming matter, pathogens, and expired organelles
where are proteins, such as enzymes, that are to be secreted form the cells produced?
ribosomes on ER
which organelle adds carb groups to proteins produced at the ER?
Golgi
which organelle contains enzymes needed to neutralize free radicals, detoxify alcohol, other drugs, and blood-borne toxins?
peroxisome
a cell uses organelles called ___ to get rid of nonfunctional proteins
proteasomes
___ are the organelles that digest and dispose of worn-out mitochondria and other organelles by a process called autophagy
lysosomes
what are small granules of RNA and protein that provide a site for protein synthesis?
ribosomes
mitochondria has a ___ unit membrane
double
the Golgi complex packages cellular products that will be exported from the cell into which structures?
secretory vesicles
centrosome (def)
comprised of 2 centrioles
which organelle participates in cell division?
centrioles
the membrane-bound organelle that contains enzymes and oxygen used to oxidize organic material is the ___
peroxisome
which are not essential to cell survival?
inclusions
most of a cell’s proteins are broken down by which organelles?
proteasomes
which of the following are components of nucleotides?
nitrogenous bases
phosphate gropus
sugars (ribose or deoxyribose)
cytosine is a ___ that binds with ___
pyrimidine that binds w/ guanine
adenine is a ___ that binds with ___
purine that binds w/ thymine
thymine is a ___ that binds with ___
pyrimidine that binds w/ adenine
guanine is a ___ that binds with ___
purine that binds w/ cytosine
the pyrimidines are ___ and ___
thymine and cytosine
the purines are ___ and ___
adenine and guanine
basal bodies and the axonemes of flagella and cilia originate from which non-membranous organelles?
centrioles
inclusions (def)
accumulated cell products such as glycogen granules, pigments, and fats
a cell uses organelles called ___ to get rid of nonfunctional proteins
proteasomes
adenine and thymine form ___ hydrogen bonds w/ each other
2
cytosine and guanine form ___ hydrogen bonds w/ each other
3
in the nucleus, DNA is complexed w/ proteins to form a fine filamentous material called ___
chromatin
a centromere holds ___ together
sister chromatids
which is a characteristic of RNA?
contains nitrogenous bases A, U, C, G
it leaves the nucleus and can be found in the cytoplasm
it plays an important role in the production of proteins
DNA (characteristics):
contains a sugar called ___
contains nitrogenous bases ___
consists of ___ nucleotide chains (___ helix)
it functions in the ___
it codes for ___
sugar called deoxyribose
nitrogenous bases A, T, C, G
2 nucleotide chains (double helix)
functions in the nucleus
codes for synthesis of RNA and protein
RNA (characteristics):
contains a sugar called ___
contains nitrogenous bases ___
consists of ___ nucleotide chain
it functions in the ___
it carries ___
sugar called ribose
nitrogenous bases A, U, C, G
1 nucleotide chain
functions mainly in cytoplasm
carries out the instructions in DNA
centromere (def)
where 2 sister chromatids are joined together
