Autocrine
This type of cell communication is when a cell sends signals to itself (maturation, or some response or change)
Paracrine
This type of cell communication is when a Cell sends signals to a nearby cell
Juxtactine
This type of cell communication is when a cell sends signals to another cell that it is physically connected to
Endocrine
This type of cell communication is when a cell signals from one type of tissue to another across long distances via the blood stream
Gap Junction Channel
Cells have physical contact. Through this, they may send and receive signals from each other.
Homeostasis
Stability or equilibrium
Quorum Sensing
Bacteria release signals that allow them to activate when there are enough of them (ie activate pathogenicity)
Transduction and Amplification
The second step in a signal transduction pathway: After reception, a signal travels through a cell and is converted into multiple pathways
Cellular response
Step 3 in a signal transduction pathway
Intracellular Receptors
Not membrane proteins. When signal molecules are hydrophobic / nonpolar, they bind to these inner proteins.
Membrane proteins
These proteins receive polar signals that cannot diffuse through the phospholipid bilayer
Genome
A cell’s genetic information / DNA
Chromosomes
DNA is packaged into these
Chromatin
Complex of DNA and proteins with chromosome building material
Sister chromatids
After DNA replication, a chromosome becomes densely folded into 2 _________
Centromere
Each chromosome has a _______ (region containing specific DNA sequences)
Mitosis
Division of genetic material in a nucleus
Cytokinesis
Division of the cytoplasm
Interphase
90% of the cell cycle → Dividing and growing chromosomes in preparation for division
G1
“First Gap Phase”
Cell comes out of mitosis and grows in preparation for DNA replication
Checkpoints:
-Growth Factors stimulate signals inside cells, rising cyclin concentration
-p53 protein: if DNA is damaged, p53 stops progression by inhibiting CDK-cyclin.
S
“Synthesis”
Cell replicates DNA. At the end of this phase, a cell has 2 sets of chromosomes.
Checkpoint: DNA is monitored for replication errors
-Once the S-phase cyclins reach a threshold, CDK-cyclin signals the cell to duplicate DNA.
-Breaks in DNA strands activate the ATM protein. This stops the cycle and activates repairing proteins.
G2
“Second Gap Phase”
Cell continues to grow and prepare for division. All chromosomes have to be fully replicated w/o dmg.
Checkpoint:
-If there is no DNA damage, CDK-cyclin activates
-If there is DNA damage, p53 protein will stop the cell cycle. If damage is impossible to fix, p53 can initiate cell death.
Mitosis
the process of splitting a cell into two daughter cells
It is used for growth, reproduction, and healing (replace + repair)
Checkpoint: Check if all sister chromatids attached to the mitotic spindle
- M-phase cyclins and CDKs activate a protein complex called the anaphase-promoting complex / cyclosome (APC/C). THis is activated when all chromosomes are attached to the mitotic spindle. APC/C breaks the centromeres of the chromosomes
- WHen chromosomes are not properly attached, MAD proteins inhibit the APC/C and prevent entry into anaphase
IPMAT
Order of Mitosis
Prophase
Step 1 of mitosis
- Chromatin fibers become tightly coiled
- Duplicated chromosome sister chromatids
- Nuclear envelope fragments
Metaphase
Step 2 of mitosis
- Chromosomes line up in cell center
- Each sister chromatid is attached to a spindle fiber
Anaphase
The third and shortest phase of mitosis
- Sister chromatids part
- Cell elongates: 2 ends have complete chromosomes
Telophase
The fourth and last phase of mitosis
- 2 daughter nuclei in cell
- Mitosis is done
- Chromosomes are less condensed
Tumor supression proteins
These proteins stop the cell cycle if needed at various checkpoints
Apoptosis
Programmed cell death
G0
A cell can enter this phase when it no longer divides
Can re enter cell cycle from appropriate cues
May be held in specific stage in cell cycle
Performs specific structural functions