Lecture 1 Flashcards
Where is DNA in a prokaryotic and eukaryotic cell?
Prokaryote - single, long circular (occasionally linear) chromosome free in cytoplasm
In an area called the nucleoid; plasmids (small circular pieces of DNA) are sometimes found free in the cytoplasm
Eukaryotic - DNA found in nucleus
What is DNA?
Controls every aspect of cell function
Acts as a blueprint for making proteins
Proteins do the work in the cell but DNA controls what is made and how much
Where is the genetic code found and what does this consist of?
The chromatin - consists of the DNA and proteins (including a group called histenes)
How many pairs of chromosomes, base pairs and genes do humans have?
23 pairs of chromosomes
3.4x10^9 base pairs
20,000-25,000 genes
What is the genome of an organism?
The total DNA within a cell of an organism
What is a gene?
A linear sequence of nucleotides within a DNA molecule which contains the I for,action necessary to produce a specific polypeptide via a mRNA intermediate
Genes code for proteins
What is the bridge between DNA and protein synthesis?
RNA
Every cell has the same DNA but does every cell have the same proteins?
When a gene is transcribed into RNA and translated into protein it is said to be expressed
Gene expression requires energy and raw materials so if the protein is not required it would be a waste
Gene expression is tightly controlled in cells
If DNA replication is not accurate what can the differences result in?
Mutations leading to genetic diseases like cystic fibrosis and deuchene muscular dystrophy
