Cell Communication
This allows bacteria to sense local population density
Concentration of signaling molecules
The G2 checkpoint assesses this
Success of DNA replication and if there are DNA or chromosomal errors
Crossing over leads to the formation of these kind of chromosomes
Recombinant chromosomes
Name one reason that mitosis occurs.
- reproduction of unicellular organisms
- growth and development in multicellular organisms
- replacement of dead/injured cells
Define germ-line cell division
Process of one diploid germ-line cell dividing to form four haploid cells
ATP is converted to cAMP with the help of this enzyme
Adenylyl cyclase
In cytokinesis, this structure begins to form around the cells, allowing for the separation of the daughter cells
Cleavage furrow
In chromosomes, the location at which crossing over occurs is called...
Chiasma (sl.)
Chiasmata (pl.)
This is the diploid number in humans.
46
Explain density-dependent inhibition
Cells inhibit individual growth of other cells when it becomes too crowded
Pathways that lead to the release of calcium ions from intracellular stores involves these two compounds
Inositol triphosphate (IP3)
Diacylglycerol (DAG)
G2 Cyclin accumulates and attaches to Cdk following this phase of the cell cycle
G2 Phase
These three steps in Prophase I of meiosis also occur in Prophase of mitosis
Chromatin becomes chromosomes
Mitotic spindle forms
Nuclear membrane breaks down
What happens in the S phase of interphase?
DNA replication
What is the different between cell-surface receptors and intracellular receptors?
Cell-surface receptors bind to hydrophilic ligands and intracellular receptors bind to hydrophobic ligands
Briefly explain why Ca2+ is an important second messenger for cells.
Cells are able to finely regulate the concentrations of Ca2+ using Ca2+ stores such as the ER and mitochondrial matrix.
Centrosomes move to opposite poles in this step of mitosis
Prometaphase
Genetic diversity is important for these two reasons
Allows populations of species to survive in face of major changes in their environment
Limits the probability of genetically inherited diseases
These 2 proteins are needed to form the contractile ring used for the cleavage furrow in animal cells
How do scaffolding proteins increase signaling efficiency?
By grouping together proteins involved in the same pathway
Paracrine signaling
A chemotherapy drug called vincristine disrupts mitosis by binding to tubulin and interfering with microtubule assembly and disassembly. What major step in mitosis would not occur?
Separation of sister chromatids (anaphase)
Explain why there are only half the number of chromosomes available between meiosis I and meiosis II
Chromosome duplication does not occur again, resulting in haploid cells
Describe all events that occur in Prophase of mitosis (Hint: at least 3 things happen)
- nuclear membrane breaks down
- centrosomes move to opposite poles
- kinetochore microtubules attach to centromeres
- nonkinetochore microtubules attach to each other
What are the 3 basic types of signaling molecules discussed in lecture?
1. Small, hydrophobic (testosterone, estradiol, cholesterol)
2. Water-soluble (peptides, proteins)
3. Gas (NO)