Central Dogma & Bacterial DNA – Lecture Review

These flashcards review key concepts from the lecture, covering the central dogma, bacterial genome structure and examples, DNA/RNA chemistry, and the mechanics of DNA replication.

What does the Central Dogma of Molecular Biology describe?

The flow of genetic information: DNA → RNA → Protein.

Which process converts DNA language into RNA language?

Transcription.

Which process converts RNA language into the amino-acid language of proteins?

Translation.

In which direction is new DNA synthesized?

5′ → 3′ direction.

Give the correct order of key enzymes during bacterial DNA replication.

1) Helicase 2) Primase 3) DNA polymerase 4) Ligase.

What term describes the overall genetic material of an organism that encodes its inheritable traits?

Genome.

What is a distinctive structural feature of most bacterial chromosomes?

They are usually single, closed, circular DNA molecules.

Are bacteria typically haploid or diploid?

Haploid; they possess only one copy of each gene.

Approximately how many base pairs are in the Escherichia coli genome?

About 4 million base pairs.

Why is bacterial DNA supercoiled?

To compact the DNA so it fits inside the small bacterial cell.

Besides chromosomal DNA, what extra-chromosomal DNA elements may bacteria carry?

Plasmids.

How does the size of a typical bacterial genome compare with the human genome?

It is over 1,000 times smaller than the human genome.

Which organism had the first complete bacterial genome sequenced?

Haemophilus influenzae.

Which bacterium is highly radiation-resistant and has two chromosomes plus two plasmids?

Deinococcus radiodurans.

Which bacterial pathogen is responsible for Lyme disease?

Borrelia burgdorferi.

How many strands do DNA and RNA molecules usually possess?

DNA is double-stranded; RNA is usually single-stranded.

Which sugar is found in DNA and which in RNA?

DNA contains deoxyribose; RNA contains ribose.

Which nitrogenous base found in DNA is replaced by uracil in RNA?

Thymine.

What type of covalent bond links adjacent nucleotides in a DNA strand?

Phosphodiester bond.

What model describes how each new DNA molecule contains one parental and one new strand?

Semi-conservative replication.

What is the starting point for replication on a circular bacterial chromosome called?

Origin of replication (ORI).

During replication of a circular chromosome, what structure forms and expands in both directions?

Replication bubble with two replication forks.

Name the primary roles of the three major RNA types.

mRNA: carries the transcript; tRNA: delivers amino acids; rRNA: forms the core of ribosomes.