Unit 4 Flashcards
Cell Cycle
Life of a cell form its formation until it devied
Histones
Protein found in chromatin
Nucleosomes
DNA gets warps in Histones(Protein)
Chromatin is non-condensed
Cell is not actively dividing
Chromatin
String of nucleosomes
Chromosomes
Visible in prophase, after DNA replication, chromosomes condenses
Sister Chromatids
Copies of chromosomes joint together
Centromere
Region of a chromosomes to which the microtubules of the spindle attach(Kinetochore and mitotic spindle microtubules attach)
Kinetochore
Protein that’s link each sister chromatids in centromere. Microtubules spindle can attach to it.
Genome
All cells genetic information
Prokaryotes
Single, circular DNA
Eukaryotes
one or more linear chromosomes
Homologous Chromosomes
Two identical chromosomes
Stomatic Cell
Two sets of chromosomes, one set from each parent(2n)
Gametes Cells
Reproductive cells(egg/sperms)(n)
Interphase
G1-> S -> G2 -> M
G1 phase
“First Gap” phase: Cell growth and carries out normal function
S phase
“Synthesis” phase: DNA replication and chromosomes duplicate occurs
G2 phase
“Second Gap” phase: final growth and preparation for mitosis
Mitosis
nuclear divides
Results: 2 doughter cells
Cytokinesis
Cytoplasm divides
Prophase
*Chromatin fibers become more tightly coiled.
*Duplicated chromosomes appears as two identical sister chromatids joined at their centromeres.
*Mitotic spindle begins to from
*Centrosomes move away from each other
* Sister chromatids going to condense chromosomes, DNA wraps with histone.
Prometaphase
*Microtubules extending from each centrosomes
*Chromosomes become more condensed
* Two chromatids of each chromosomes now have Kinetochore
*Some Microtubules are attached to Kinetochore
*non-kinetochore microtubules interact with those form the opposite poles of the spindle
Metaphase
*Sister chromatids are lined up in middle, metaphase plate
* Kinetochore microtubules comes out from centrosomes bind to kinetochore in the centromere of chromosomes
*Centrosomes at opposite poles of the cell
Anaphase
*Sister chromatids split, when the cohesion protein are cleaved.
*Microtubules goes through depolymerization(Shorter) kinetochore
Telophase and Cytokinesis
*Two daughters nuclei form
*nucleoli reappear
*Chromosomes become less condensed
*Division of cytoplasm(Animals: Cleavage furrow, pinch)
G1 checkpoint
Checks: cell growth, growth factor, DNA damage
Stops: enters G0 stage
G0 stage
Some cell stay in forever(muscle or nerves) but some can be called back into cell cycle(liver)
G2 checkpoint
Check: completion of DNA replication and DNA damage
Stop: attempt to repair damage
Apoptosis
damage can not be repaired
Suicide of the cell
M(Spindle) checkpoint
Check: microtubules attachment to chromosomes at the kinetochores at metaphase
Stops: let spindles finish attaching to chromosomes
Cyclins
A family of proteins that have no enzymatic activity of their own but activate CDKs by binding to them
Cyclin-Dependent Kinases(CDKs)
Once Activated it target protein, which helps regulate key events in the cell cycle
Growth Factors
Hormones released by cell that stimulate cell growth
Contact(or density) inhibition
Cells stop G1 phase( cells growing) when they are in contact with another cell
Anchorage Dependence
Cells rely on attachment to other cells or else it divids
Benign Tumor
Cells are unable to spread elsewhere in the body
Malignant tumor
cells that grow uncontrollably and spread locally and/or to distant sites
Metasis
Cell separates and spread
Negative Feedback
Reduces the effect of the stimulus
Positive Feedback
Increases the effect of a stimulus
Signal Transduction
internal cellular changes
Activation or deactivation of enzymes
Phosphorylation by kinases
Secondary messengers amplify the signal
Homologous
Same relation
cAMP
Autocrine
cells signal themselves with their own receptors and ligands
Proto-oncogenes
Regulate apoptosis in the cell cycle
Local Regulators
Release chemical message that travel a short distance
Paracrine Signaling
growth factors signal near by
Synaptic Signaling
Occurs in animal nervous system
Long Distance Signaling
signals are produced by specialized cells and released into the bloodstream, which carries them to target cells in distant parts of the body.
Juxtacrine
Contact dependent
Plant Long Distance
Vascular Tissue or through the air to reach target tissues
Endocrine
Hormonal, travel through bloodstream
Reception
Detection and receiving of a ligand by a receptor in the target cell
Ligand
signal molecule
Receptor
bind to ligand to get a response
Plasma Membrane Receptors
Bind to ligand that are polar and large (GPCR and Ligan gate channel)
Intracellular Receptors
Cytoplasm or nucleus of target cell
bind ligan to pass through the plasma membrane (hydrophobic)
Transduction
Conversion of extracellular signal to an intercellular signal that will bring about a cellular response
Protein Kinase
Adding Phosphate
Protein Phosphatase
Removing Phosphate
Second Messenger
small molecules and ions that relay signals received by cell-surface receptors to effector proteins.
Response
Final molecule in the signaling pathway convert to a response that will alter or cellular process
GPCRs
Bind to a G protein that can bind to GTP which is energy molecule similar to ATP
Cytoplasmic
Allow G protein to bind to GPCR
Activate the GPCRs and G protein
Ion Channels
Opens gate when ligand is attached to GPCR, allowing ion to go in.
