cell bio final Flashcards

Largest filament, hollow tubes made of tubulin dimers (dimers made of protofilaments) , outer diameter of 25nm, more rigid than actin filaments

Facilitates intracellular transport, guides organelle movement, separates chromosomes in cell division, form structural basis for cilia & flagella (dyneins)

Tubulin

Medium-sized filament made of fibrous proteins

provides structural support, anchors organelles (nucleus), maintains cell to cell connections. Make up the nuclear lamina beneath the inner nuclear membrane, in epithelial tissue they span the cytoplasm from cell-cell junction

Keratin, vimentin, lamins

thinnest filament, helical polymers of the protein actin

mainly involved in cell movement, muscle contraction, and maintaining cell shape, highly conc. in cortex (beneath plasma membrane)

actin

actin linking protein in parallel bundle (doesn’t allow for myosin II). Abundant in GI tract

actin-linking protein for support in cardiac and skeletal muscle (allows for myosin II).

found in the nervous system, mutation can cause failure in neuron ventricles (aggregates)

motor protein, moves retrograde (transports back to cell body, - end)

motor protein that moves anterograde (away from the cell body, +end )

cataracts, cloudy lens, glaucoma

mutations in cardiac muscle that can cause cardiomyopathy, enlarge heart chambers, leading to heart failure

can cause loss of structure, can cause epidermolysis bullosa which is the development of blisters on the body and internally.

muscular dystrophy, damage causes muscles to weaken, and can cause deformities in the skeletal system

leukodystrophy affects white matter of CNS

Myosin

muscle contraction

ATP, binds

released from lumen of SR --> cytosol --> lumen of t-tubule (extracellular space)

produces two identical daughter cells that have the same number of chromosomes as the parent cell, occurs in somatic cells, produces identical cells for growth and repair

produces four different daughter cells with half the number of chromosomes as the parent cells, occurs in gametes, crossing over of homologous chromosomes leads to genetic diversity

cell growth and DNA replication

cell growth

DNA replication

cont. cell growth, preparation for mitosis

cell physically divides into two daughter cells by separating replicated chromosomes and dividing the cytoplasm

chromosomes made of sister chromatids condense

breakdown of the nuclear envelope, chromosomes attach to spindle microtubules

chromosomes aligned at equator of the spindle; kinetochore attaches sister chromatids via. microtubules

sister chromatids separate to form two daughter chromosomes, move to opposite poles

two sets of daughter chromosomes arrive at opposite poles and decondense, and a new nuclear envelope is formed

division of cytoplasm, divided into two by a contractile ring of actin and myosin filaments

concentration varies, synthesized and degraded at certain points in the cell cycle

is INACTIVE without the cyclin, stable concentration, phosphorylates for activation

initiates DNA replication through the transition of G1 -->S, highest conc. late G1

induction of DNA replication, highest conc. S --> G2, ends early mitosis

triggers cells' entry into mitosis, highest conc. at G2/M transition

p27

suppresses G1/S-Cdk and S-Cdk activites in G1, helps cells withdraw from cell cycles.

Wee & Cdc25

Phosphorylates inhibitory sites in Cdks, suppresses Cdk1 activity before mitosis

removes inhibitory phosphates from Cdks, mainly involved in controlling Cdk1 activation at the onset of mitosis

APC/C

catalyzes ubiquitination of regulatory proteins involved in exit from mitosis (securing and S- & M-cyclins

creates the poles of the mitotic spindle (S phase)

holds sister chromatids together during DNA replication (until cell reaches anaphase)

attaches chromosomes to spindle microtubules to ensure separation during cell division

programmed

Active process, a natural process that occurs during development and aging, non-inflammatory, cell shrinks and nucleus condenses, plasma membrane blebs but remains intact

Passive process, inflammatory, caused by external factors such as injuries, infections, diseases, cell and mitochondria swells, plasma membrane loses its integrity, Can be fatal if left untreated

accidental

key enzymes in the apoptotic pathway, acting as the first step in triggering programmed cell death by activating downstream executioner caspases

apoptotic pathway triggered by death receptors

mitochondrial damage

key enzymes responsible for the direct cleaving and dismantling various cellular proteins to execute cell death, amplifies response via proteolytic cascade

binding to other proteins, acting as a bridge to connect different signaling molecules within a cellular pathway

Caspase-activated deoxyribonuclease (CAD)

Inhibitor of Caspase-Activated Deoxyribonuclease (ICAD)

proteins that play crucial roles in cell death pathways

induces cell death through interaction with Fas receptor

can trigger various cellular responses including inflammation and apoptosis depending on the receptor it binds to

homotrimer protein located on the target cell that triggers apoptosis (after it is activated by the FAS ligand on a lymphocyte)

an adaptor protein that is a central component of the death-inducing signaling complex (DISC) that mediates that activation of caspase 8

protein-protein interaction domains that regulate apoptosis, component of the DISC to trigger apoptosis

a multiprotein complex that triggers apoptosis, composed of: death receptor, FADD, procaspase-8, cFLIP

cytochrome C floats around as an apoptotic stimulus

allows the release of pro-apoptotic proteins like cytochrome C from the intermembrane space into the cytosol, triggering the cascade of events leading to cell death

is released into the cytoplasm when a cell receives apoptotic signals, where it then binds to Apaf-1 to activate the caspase cascade

Apaf-1 (apoptotic protease activating factor-1)

activate via proteolytic cleavage during apoptosis, dismantle the cell into apoptotic bodies

regulates apoptosis by acting as either inhibitors or promoters of cell death. Bcl –2 -> anti-apoptotic

a family of proteins that regulate cell death and survival by blocking caspases

seals gap between epithelial cells, prevents substances from seeping through, found towards apical surface

connects actin filament bundle in one cell with one in the adj cell

connects intermediate filaments in one cell to those in the next cell.

allows the passage of small water-soluble molecules from cell to cell, electrically connects cells to each other/ communication

anchors intermediate filaments in a cell to the extracellular matrix (basal layer)

transmembrane cell adhesion proteins, form connections between adjacent cells, more cadherins = connection stability

intracellular proteins that link cadherins to actin cytoskeletons, anchors cells together for coordinated cell behavior in a tissue by maintaining adhesion and communication.

made of GAG (glycosaminoglycan chains)

collagen

integrins

Lamin, muscle, muscular dystrophy, embryo death at implantation

Ig superfamily counterreceptor (ICAM), white blood cells, impaired recruitment of leucocytes, leucocyte adhesion deficiency & impaired inflammatory responses.

Fibrinogen, platelets, Bleeding, no platelet aggregation (Glanzmann’s disease), Mild osteoporosis (otherwise same as the α mutation)

Laminin, hemidesmosomes, Severe skin blistering and defects in other epithelia , Same as α mutation

Cell junction in which the cytoplasmic face of the plasma membrane is attached to actin filaments.

Ubiquitin ligase that catalyzes the ubiquitylation and destruction of securin and M- and S-cyclins, initiating the separation of sister chromatids in the metaphase-to-anaphase transition during mitosis.

Heptamer of Apaf1 proteins that forms on activation of the intrinsic apoptotic pathway; it recruits and activates initiator caspases that subsequently activate downstream executioner caspases to induce apoptosis

Member of the large cadherin superfamily of transmembrane adhesion proteins. Mediates homophilic Ca2+-dependent cell–cell adhesion in animal tissues.

Intracellular protease that is involved in mediating the intracellular events of apoptosis

Reproductive cycle of a cell. The orderly sequence of events by which a cell duplicates its chromosomes and usually the other cell contents, divides into two.

Protein phosphatase that dephosphorylates Cdks and increases their activity

Short cylindrical array of microtubules, closely similar in structure to a basal body. A pair of centrioles is usually found at the center of a centrosome

Centrally located organelle of animal cells that is the primary microtubule-organizing center (MTOC) and acts as the spindle pole during mitosis

Structure composed of a very long DNA molecule and associated proteins that carries part (or all) of the hereditary information of an organism.

Complex of proteins that holds sister chromatids together along their length before their separation

Fibrous protein rich in glycine and proline that is a major component of the extracellular matrix in animals, conferring tensile strength.

Water-filled pore in the plasma membrane formed by a ring of six connexin protein subunits. Half of a gap junction: connexons from two adjoining cells join to form a continuous channel through which ions and small molecules can pass

Protein kinase that has to be complexed with a cyclin protein in order to act. Different cyclin–Cdk complexes trigger different steps in the cell-division cycle by phosphorylating specific target proteins

Protein that periodically rises and falls in concentration in step with the eukaryotic cell cycle. Cyclins activate crucial protein kinases (called cyclin-dependent protein kinases, or Cdks) and thereby help control progression from one stage of the cell cycle to the next.

System of protein filaments in the cytoplasm of a eukaryotic cell that gives the cell shape and the capacity for directed movement. Its most abundant components are actin filaments, microtubules, and intermediate filaments

Transmembrane receptor protein that can signal the cell to undergo apoptosis when it binds its extracellular ligand

Anchoring cell–cell junction, usually formed between two epithelial cells. Characterized by dense plaques of protein into which intermediate filaments in the two adjoining cells insert.

Extracellular protein that forms extensible fibers (elastic fibers) in connective tissues.

cytoskeletal protein that crosslinks actin filaments

Communicating channel-forming cell–cell junction present in most animal tissues that allows ions and small molecules to pass from the cytoplasm of one cell to the cytoplasm of the next.

Long, linear, highly charged polysaccharide composed of a repeating pair of sugars, one of which is always an amino sugar

a protein that prevents the DNA-degrading enzyme caspase-activated deoxyribonuclease (CAD) from breaking down DNA.

Long period of the cell cycle between one mitosis and the next. Includes G1 phase, S phase, and G2 phase.

Member of one of the two main classes of motor proteins that use the energy of ATP hydrolysis to move along microtubules.

Large protein complex that connects the centromere of a chromosome to microtubules of the mitotic spindle.

Extracellular matrix fibrous protein found in basal laminae, where it forms a sheetlike network.

The first of two rounds of chromosome segregation following meiotic chromosome duplication; segregates the homologs, each composed of a tightly linked pair of sister chromatids.

The second of two rounds of chromosome segregation following meiotic chromosome duplication; segregates the sister chromatids of each homolog

cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus typical of ordinary tissue growth.

Protein that uses energy derived from nucleoside triphosphate hydrolysis to propel itself along a linear track

Type of motor protein that uses the energy of ATP hydrolysis to move along actin filaments.

a molecule consisting of one or more glycosaminoglycan chains attached to a core protein.

A transcription regulatory protein that is activated by damage to DNA and is involved in blocking further progression through the cell cycle

Tightly linked pair of chromosomes that arise from chromosome duplication during S phase. They separate during M phase and segregate into different daughter cells

Cell–cell junction that seals adjacent epithelial cells together, preventing the passage of most dissolved molecules from one side of the epithelial sheet to the other.

The protein subunit of microtubules