Quiz 2 (FC)

These flashcards cover key vocabulary and concepts related to DNA structure and replication as discussed in the genetics lecture.

DNA structure

The arrangement of nucleotide strands into a double helix, consisting of a sugar-phosphate backbone and nitrogenous bases.

DNA replication

The biological process by which a cell makes an exact copy of its DNA.

Molecular genetics

The field of biology that studies the structure and function of genes at a molecular level.

Conservative replication

A hypothesis suggesting that the original DNA strands remain together after replication, while new strands are formed.

Semiconservative replication

The correct model of DNA replication where each new DNA molecule consists of one original strand and one newly synthesized strand.

Dispersive replication

A hypothesis that suggests DNA strands are broken into pieces during replication and then reassembled.

Meselson and Stahl experiment

An experiment that provided evidence for the semiconservative model of DNA replication using heavy and light nitrogen.

Nitrogenous bases

The building blocks of DNA, which include adenine (A), thymine (T), cytosine (C), and guanine (G).

Origin of replication

The specific DNA sequence where replication begins, marked by various proteins.

Replication fork

The Y-shaped region that forms when DNA is unwound during replication.

Topoisomerase II

An enzyme that prevents supercoiling ahead of the replication fork during DNA replication.

Single-strand binding proteins

Proteins that stabilize single-stranded DNA after it has been separated, preventing it from re-annealing.

DNA helicase

An enzyme that unwinds the DNA double helix by breaking hydrogen bonds between the bases.

Okazaki fragments

Short sequences of DNA synthesized discontinuously on the lagging strand during DNA replication.

Primase

An enzyme that synthesizes short RNA primers necessary for DNA polymerase to initiate DNA synthesis.

DNA polymerase III

The primary enzyme involved in DNA replication, responsible for adding nucleotides to the growing DNA strand.

Leading strand

The strand of DNA that is synthesized continuously in the direction of the replication fork.

Lagging strand

The strand of DNA that is synthesized discontinuously away from the replication fork, in segments called Okazaki fragments.

Hydrogen bonds

Weak chemical bonds that hold the nitrogenous bases of the DNA together.

Bidirectional replication

A mode of DNA replication where the process occurs in two directions from the origin of replication.

Exonuclease site

A part of DNA polymerase that removes incorrectly paired nucleotides and corrects errors during DNA synthesis.

Phosphodiester linkage

The bond that connects nucleotides in the backbone of a DNA strand.

Adenine

A nitrogenous base that pairs with thymine in DNA.

Thymine

A nitrogenous base that pairs with adenine in DNA.

Cytosine

A nitrogenous base that pairs with guanine in DNA.

Guanine

A nitrogenous base that pairs with cytosine in DNA.

Nucleotide

The basic building block of DNA, consisting of a phosphate group, a deoxyribose sugar, and a nitrogenous base.

Base pairing rules

The rules stating that adenine pairs with thymine, and cytosine pairs with guanine in DNA.

RNA primer

A short strand of RNA that provides a starting point for DNA polymerase during replication.

DnaA proteins

Proteins that bind to the DnaA boxes at the origin of replication to initiate DNA replication.

GATC methylation sites

Specific DNA sequences that are recognized for methylation, influencing the identification of old versus new strands.

AT-rich region

A section of DNA with a high proportion of adenine and thymine, making it easier to separate the strands.

Bidirectional replication

Replication that proceeds in both directions from the origin of replication.

Protein interactions with DNA

The relationships between DNA and proteins that regulate DNA processes like replication.

Chromosomes

Structures within cells that contain DNA and associated proteins; the carriers of genetic information.