Abeka Biology Quiz 36 (2024)

FAQs

What term refers to the two-spiral structure of the DNA molecule? ›

​Double Helix

Double helix, as related to genomics, is a term used to describe the physical structure of DNA. A DNA molecule is made up of two linked strands that wind around each other to resemble a twisted ladder in a helix-like shape.

Each nucleosome is made of DNA wrapped around eight histone proteins that function like a spool and are called a histone octamer. Each histone octamer is composed of two copies each of the histone proteins H2A, H2B, H3, and H4.

Within a molecule of DNA, pairs of bases are chemically bonded together by hydrogen bonds. These bonds hold the two strands of the molecule together. Bases pair up with each other in a consistent way, and this process is called complementary base pairing, or Watson-Crick base pairing.

A DNA molecule consists of two long polynucleotide chains composed of four types of nucleotide subunits. Each of these chains is known as a DNA chain, or a DNA strand. Hydrogen bonds between the base portions of the nucleotides hold the two chains together (Figure 4-3).

Deoxyribonucleic acid (abbreviated DNA) is the molecule that carries genetic information for the development and functioning of an organism. DNA is made of two linked strands that wind around each other to resemble a twisted ladder — a shape known as a double helix.

DNA molecules first wrap around the histone proteins forming beads on string structure called nucleosomes. Nucleosomes further coil and condense/gather to form fibrous material which is called chromatin.

The unique structure of chromosomes keeps DNA tightly wound around spool-like proteins, called histones. Without such packaging, DNA molecules would be too long to fit inside cells!

The entire structure is called a nucleosome, each of which includes an octamer of histone proteins and 146 to 147 base pairs of DNA. [2][3] The millions of nucleosomes tightly coil the continuous DNA strand into chromatin which is further condensed into the chromosome classically visualized during cell division.

The rungs of the DNA ladder made of four types of nitrogenous bases. These are Adenine (A), Guanine (G), Cytosine (C) and Thymine (T). These nitrogen bases pair as A-T and C-G with the help of two and three Hydrogen bonds respectively. Was this answer helpful?

Short Answer: Genetic information is encoded in a DNA molecule through the linear sequence of nucleotide bases (A, T, C, G). This sequence determines the genetic code, with each set of three nucleotides (codon) corresponding to a specific amino acid.

Which components bond with adenine in A section of double-stranded DNA? ›

Within a double-stranded DNA molecule, adenine (A) forms hydrogen bonds with thymine (T), and cytosine (C) forms hydrogen bonds with guanine (G).

In molecular biology, the term double helix refers to the structure formed by double-stranded molecules of nucleic acids such as DNA. The double helical structure of a nucleic acid complex arises as a consequence of its secondary structure, and is a fundamental component in determining its tertiary structure.

The double helix is a description of the molecular shape of a double-stranded DNA molecule. In 1953, Francis Crick and James Watson first described the molecular structure of DNA, which they called a "double helix," in the journal Nature.

Replication is the process by which a double-stranded DNA molecule is copied to produce two identical DNA molecules. DNA replication is one of the most basic processes that occurs within a cell.

The structure of DNA is a double helix. In other words, it is a double stranded molecule that twists like a spiral staircase.