bio2exam

mutation

A change in the DNA sequence of an organism that can lead to variations in traits, which may be beneficial, harmful, or neutral.

point mutation

A change in a single nucleotide in the DNA sequence, which can result in a different amino acid in a protein or have no effect at all.

silent mutation

A type of point mutation that does not change the amino acid sequence of a protein, resulting in no observable effect on the organism's phenotype.

missense mutation

A type of point mutation that results in the substitution of one amino acid for another in a protein, potentially altering its function.

nonsense mutation

A type of point mutation that creates a premature stop codon in the protein sequence, leading to a truncated and usually nonfunctional protein.

frameshift mutation

A type of mutation caused by insertions or deletions of nucleotides that shift the reading frame of the genetic code, often resulting in a completely different protein sequence. hc

chromosome

A thread-like structure made of DNA and proteins that carries genetic information. Chromosomes are found in the nucleus of eukaryotic cells and are crucial for cell division and inheritance.

chromatin

The complex of DNA and proteins that forms chromosomes within the nucleus of eukaryotic cells. Chromatin exists in two forms: euchromatin, which is less condensed and actively involved in transcription, and heterochromatin, which is more tightly packed and typically inactive.

chromatids

The two identical halves of a duplicated chromosome, joined together at the centromere, that separate during cell division. onservac

conservative replication

A model of DNA replication where the original double helix remains intact and serves as a template for the synthesis of a new complementary strand. This results in one original and one newly synthesized strand in each daughter molecules

semiconservative replication

A model of DNA replication where each of the two daughter DNA molecules contains one original strand and one newly synthesized strand. This method ensures that genetic information is accurately passed on during cell division.

dispersive replication

A model of DNA replication where the parental DNA is fragmented and mixed with newly synthesized DNA, resulting in daughter molecules that contain both old and new DNA segments.

helices

are structures formed by the coiling of the DNA double helix during replication, allowing the strands to separate and serve as templates.

topoisomerase

An enzyme that alleviates the torsional strain generated ahead of the replication fork by introducing temporary breaks in the DNA strands, allowing them to unwind.

primase

An enzyme that synthesizes short RNA primers to provide a starting point for DNA synthesis during replication.

primers

Short RNA sequences that provide a starting point for DNA synthesis during replication.

dna polymerase

An enzyme responsible for synthesizing new DNA strands by adding nucleotides to a pre-existing strand during DNA replication.

dna ligase

An enzyme that joins together short DNA fragments, sealing nicks in the sugar-phosphate backbone during DNA replication and repair.

telomeres

The repetitive nucleotide sequences at the ends of chromosomes that protect them from deterioration or fusion with neighboring chromosomes.

polymerase chain reaction

laboratory method used to make copies of a dna segment to match tissues for analysis or amplification in various applications, including cloning, genetic analysis, and forensic science.

tag polymerase

A heat-stable enzyme used in PCR that synthesizes DNA by adding nucleotides to a growing strand.