DNA Replication and Gene Expression

These flashcards cover key concepts from the lecture on DNA replication, transcription, translation, and the effects of mutations.

What is the role of DNA in a cell?

DNA stores hereditary information, must be retained intact, copied during DNA replication, transcribed into mRNA, and translated into proteins.

What is DNA replication?

The process by which DNA is copied to make new cells.

What is the transforming principle discovered by Avery, MacLeod & McCarty?

DNA is the transforming principle that can change avirulent bacteria into virulent forms.

What did Hershey & Chase conclude regarding genetic material?

DNA is the genetic material, as it entered E. coli cells during bacteriophage infection.

What is the structure of DNA?

DNA is a double-stranded double helix made of nucleotides, with A paired with T and G with C.

What is semiconservative DNA replication?

A process where each new DNA molecule consists of one old strand and one newly synthesized strand.

What initiates DNA replication in bacteria?

The DnaA protein binds to the origin of replication (oriC) and recruits helicase and primase.

What is the main purpose of transcription?

To create a complementary RNA strand from a DNA template.

What are the types of RNA involved in gene expression?

mRNA (messenger RNA), tRNA (transfer RNA), and rRNA (ribosomal RNA), each fulfilling distinct roles.

How are proteins made during translation?

Ribosomes decode mRNA sequences, matching codons with tRNA anticodons to form polypeptides.

What is a silent mutation?

A mutation that does not alter the amino acid sequence of a protein.

What is a frameshift mutation?

A mutation caused by insertions or deletions of nucleotides that shift the reading frame of the coding sequence.

What are the effects of ultraviolet light on DNA?

UV light can cause induced mutations such as thymine dimers.

What is post-transcriptional processing?

The modification of pre-mRNA, including adding a 5' cap and a poly(A) tail and splicing out introns.

What does the central dogma of molecular biology state?

The flow of genetic information from DNA to RNA to protein.

How is transcription terminated in bacteria?

By Rho-dependent or Rho-independent mechanisms that signal RNA polymerase to detach from DNA.

What is the function of molecular chaperones?

They assist in the correct folding and refolding of polypeptides into functional proteins.

What difference exists between monocistronic and polycistronic mRNA?

Monocistronic mRNA encodes a single protein, while polycistronic mRNA can encode multiple proteins.

What is the role of telomerase in DNA replication?

Telomerase extends the ends of linear chromosomes, addressing the problem of incomplete replication of chromosome ends.

What is translocation in the context of translation?

The process by which the ribosome moves along the mRNA, allowing for the addition of new amino acids to the growing polypeptide.