Cell Development and Differentiation

Question 1

Unicellular versus multi-cellular organisms

Answer 1

Unicellular organisms are made up of only one cell that carries out all of the functions needed by the organism, while multicellular organisms use many different cells to function.

Question 2

DNA

Answer 2

DeoxyriboNucleic Acid
‘Blueprint of life’
Long and complex molecule, made up of many atoms; found in nucleus of our cells; hereditary material; contains all of the information necessary for an organism to develop, survive, and reproduce

Question 3

Introns and Exons

Answer 3

You have non-coding sections called introns and sections of DNA (or RNA) that code for proteins called exons.

All the genes of a multicellular organism is called the genome. (Human genome contains ~21 000 genes)

Question 4

Protein Synthesis

Answer 4

DNA codes for chemicals called amino acids. Different sequences of DNA will code for different amino acids.
Many amino acids can be joined to form a protein (proteins include antibodies, enzymes, hormones).
These proteins are made by unwinding the DNA strand, creating a copy of the DNA, and delivering this copy to the ribosome, where proteins can be synthesised.

Question 5

Cell Differentiation

Answer 5

Stem cell differentiation involves the changing of a cell to a more specialized cell type, involving a switch from proliferation to specialization.

Cells which proteins are produced to become specialised.
Genes can be switched on/off through
Activators – ‘opens up’ DNA and allows the DNA to be ‘read’
Repressor – make a region of DNA tightly coil and unable to be ‘read’

Question 6

Gene Expression

Answer 6

Gene expression is the process by which the information encoded in a gene is turned into a function. This mostly occurs via the transcription of RNA molecules that code for proteins or non-coding RNA molecules that serve other function

Environmental factors can lead to changes in the genes that are expressed