The Central Dogma

Genome

• Definition

• What are genomes organized into?

• Definition: The complete set of genetic information stored in an organism’s cells.

• Chromosome sets

Chromosome

• Definition

• What 2 things do chromosomes contain?

• What are chromosomes wrapped around?

• Definition: A long continuous DNA molecule packaged with proteins

• Chromosomes contain genes and spacer DNA

• Chromosomes are wrapped around proteins called histones

Spacer DNA

• Where is it found?

• What purpose does it serve?

• Found in chromosomes

• Helps regulate and organize genes

Histones

• Definition

• What are its functions?

• Definition: Proteins that DNA wraps around

• Functions:

(1) Packaging chromosomes to fit inside the nucleus

(2) Protecting DNA from damage

(2) Organizing and providing structure to chromosomes

What does the central dogma of molecular biology describe?

It describes the flow of genetic info from DNA to RNA to proteins

DNA motifs

• Definition

• Give key example

• Definition: Specific repeated or recognizable nucleotide patterns on a DNA strand with regulatory or structural functions.

• TTAGG indicates a chromosome’s end (or its telomere)

RNA polymerase

• What is it?

• What does it do?

• RNA polymerase is an enzyme.

• It reads a DNA template and builds a complimentary RNA strand.

What are the three post translational modifications we should know for this midterm?

1. Splicing: Removing introns on genes and stitching together extrons

2. Poly-A tail: Hundreds of adenines are added to the end, adding to the RNA’s lifespan

3. 5’ Methyl Cap: Allows mRNA to exit the nucleus

Order of events required for mRNA synthesis (transcription)

1. RNA polymerase reads the DNA template and builds an RNA strand

2. Post-translational modifications are made

3. mRNA leaves nucleus

Introns and exons

• Where are they located?

• What are introns? What are exons?

• They are located on genes

• Introns are non-coding regions, while exons are coding regions.

Ribosomes

• What are they?

• What do they do? What do they create?

• Organelles that read and translate mRNA codons

• They create polypeptide chains, which makes up proteins.

DNA mutations

• What are they?

• What do they affect?

• Changes in the DNA sequence.

• Can affect cell behavior or an organism’s ability to survive (whether negative or positive)