Biologia DNA Practice Quiz

DNA is made up of nucleotides, each containing a sugar, a phosphate group, and a nitrogenous base. Amino acids build proteins, while monosaccharides and fatty acids serve other functions in the cell.

In DNA, adenine forms a hydrogen bond with thymine, ensuring proper base pairing. Uracil is typically found in RNA, and the other options do not pair with adenine in DNA.

The DNA molecule consists of two strands that twist to form a double helix. This double-stranded structure is essential for replication and maintaining genetic integrity.

Cytosine is one of the four nitrogenous bases present in DNA. Uracil is found in RNA, while ribose and deoxyribose are sugars, not bases.

DNA polymerase adds nucleotides to the growing DNA strand by reading the template strand. Other enzymes, like RNA polymerase, helicase, and ligase, play different roles during replication.

Helicase unwinds the DNA double helix to separate the two strands, which is essential for replication. The other enzymes listed have roles in primer synthesis, fragment joining, or error correction.

A point mutation involves the alteration of a single nucleotide base within the DNA sequence. The other options describe larger-scale chromosomal or segmental changes.

RNA polymerase is responsible for synthesizing RNA by reading the DNA template during transcription. The roles of DNA polymerase, ligase, and primase are associated with DNA replication processes.

Translation is the process during which ribosomes use mRNA as a template to synthesize proteins. Transcription, in contrast, is the process of creating an mRNA copy from DNA.

Degeneracy in the genetic code means that several codons can code for the same amino acid, providing a buffer against potential mutations. This redundancy is a key feature that helps maintain protein integrity.

Frameshift mutations occur when nucleotides are inserted or deleted, causing a shift in the codon reading frame. This alteration often leads to significant changes in the resulting protein.

RNA uses uracil in place of thymine, so adenine pairs with uracil during RNA synthesis. In DNA, adenine normally pairs with thymine.

The promoter is a DNA sequence where RNA polymerase binds to initiate transcription. It does not code for proteins or participate in mutation repair.

PCR is a widely used technique to amplify specific DNA segments exponentially. The other methods are used for analyzing, separating, or detecting DNA rather than amplification.

Complementary base pairing ensures that each nucleotide pairs specifically with its partner, which is critical for accurate DNA replication. This precise matching minimizes errors and preserves the integrity of the genetic code.

Although a silent mutation does not change the amino acid sequence, it can affect the efficiency of translation and the folding of the protein. Such subtle changes may impact how the protein functions in the cell.

Mutations in regulatory regions can disrupt the binding of transcription factors, leading to significant changes in gene expression. Unlike coding mutations, they do not alter the protein's structure directly but can still have profound effects on the phenotype.

Telomerase adds repetitive nucleotide sequences to the ends of chromosomes (telomeres), preventing the loss of important genetic information during replication. This activity is especially important in cells that divide frequently.

Southern blotting involves transferring DNA fragments onto a membrane and using labeled probes to detect specific sequences. This method is essential in genetic diagnostics, whereas Northern and Western blotting target RNA and proteins respectively, and ELISA is used for protein detection.