Cell-cell communication

Question 1

Whats the definition of Homeostasis?

Answer 1

The maintenance of a steady state in an organism by coordinate processes to overcome fluctuations in the outside environment

(produced an appropriate response to a stimuus before returning back to equilibrium)

Question 2

Name a cell-cell signalling that prokaryotes use and one that eukaryotes use?

Answer 2

Prokaryotes: Quorum sensing

Eukaryotes: Sexual signalling

Question 3

Tell me about Quorum sensing?

Answer 3

• Continually produce a pheromone
• Coordinates gene expression according to the density of their local population
• Bacterial populations coordinate signals or social insects use quorum sensing to determine where to nest
• First observed in Vibrio Fischeri (a bioluminescent bacterium)
• Can function as a decision-making process in any decentralised system, as long as the individual components have:

1. A means of assessing the number of other components they interact with
2. A standard response once a threshold number of components is detected

Question 4

What division do both haploid and diploid cells undertake?

Answer 4

mitosis, with daughter cells budding off of mother cells

Question 5

What are haploid cells capable of mating with ?

Answer 5

other haploid cells of the opposite mating e.g. a cells with alpha cells

Question 6

When can diploid cells undergo meiosis?

Whats produced?

Answer 6

upon facing stressful conditions

The products of this reaction are; 2 a spores and 2 alpha spores

Question 7

Can haploid cells undergo meiosis?

Answer 7

no

Question 8

Whats the cycle of Dyctiostelium discoidum ?

Answer 8

cAMP –> PKA activation –> aggregation into slug