DNA is not translated/Stem cells (BIOL5)

Question 1

Define totipotent cells

Answer 1

Cells that can mature into any body cell

Question 2

Define multipotent cells

Answer 2

Cells can develop into few types of cells

Question 3

Features of stem cells and expression

Answer 3

• During development, totipotent cells translate only part of DNA, resulting in specialisation
• Under right cond. some genes are expressed, others ‘switched’ off
• mRNA only transcribed fr spec genes:
  
  • mRNA from genes is translated into proteins
  • protein modify cells - determine cell structure
    
    • cell changes by proteins cause cell to become specialised

Question 4

Totipotent cells in plants

Answer 4

• Plants have stem cells found in areas where plant is growing (shoots/roots)
• Totipotent cells can be used to grow plant organs or whole new plants (in vitro)

Question 5

Producing whole plants artificially (in vitro)

Answer 5

1. Single totipotent cell taken from growing area of plant (shoot/root)
2. Cell placed in medium containing nutrients; medium sterile - microorg can’t complete w/ plant
3. Plant stem cell grows/divides into mass in unspecialised cells. If cond. suitable, will become specialised
4. Cells grow/specialise to form plant organ/entire plant