The Central Dogma: DNA, Genes & Chromosomes

Flashcards based on lecture notes about the central dogma of molecular biology, DNA, genes, and chromosomes.

What is the flow of information according to the central dogma of molecular biology?

DNA → RNA → Protein

What do genes contain instructions for?

Genes contain instructions for making proteins.

What do organized segments of DNA, or genes, encode to synthesize?

Encode the primary sequence of DNA to synthesise a final biological product

What types of cell division require DNA to be copied before they can occur?

Mitosis and Meiosis

What type of genes make proteins?

Structural genes make proteins.

Besides structural genes, what other sequences can be found when looking at how genes use DNA?

Regulatory sequences (promoter/enhancer regions, UTR)

Approximately what percentage of the human genome encodes proteins?

<1.5% of the genome encodes proteins

What is the function of telomeres?

Help stabilize chromosomes

What is the function of the centromere?

Attachment point to link chromosome to mitotic spindle

What are the two main parts of genes, and what are their functions?

Exons -- protein coding, Introns -- non-protein coding

What is an intron?

Non-coding sequence within a gene (spliced out of mRNA)

What is an exon?

Coding sequence within a gene

Give examples of non-coding DNA

Regulatory sequences, repeated sequences (i.e. telomeres)

How is DNA organized differently in eukaryotes, prokaryotes, and viruses?

Eurkaryotes = linear, Prokaryotes = usually circular, Viruses = circular or linear

Why is it important for DNA to be organized to allow the following?

Packing of large DNA molecules within cells and access of proteins to enable DNA replication and transcription

What is the definition of negative supercoiling?

The DNA twisted to the left in the opposite direction from the twists in the DNA helix. The DNA strands unwind slightly so become underwound.

What is the definition of positive supercoiling?

The DNA is twisted to the right in the same direction of the turns in the helix. It becomes overwound.

What protein allows for negative solenoidal supercoiling?

Histones

What is a nucleosome?

DNA wrapped around a histone core

How is the structure of DNA different in Eukaryotes, Prokaryotes, and Viruses?

Eurkaryotes = linear, Prokaryotes = usually circular, Viruses = circular or linear

How is the DNA arranged in Prokaryotic cells?

Circular, with one chromosome and 1+ plasmids.