Biochem-Nucleotides

Heredity is the transfer of characteristics, anatomical as well as biochemical, from generation to generation.

The transmission of heredity starts with the parent and is passed down at the molecular level.

The unit of heredity; a DNA segment that codes for one protein or one type of RNA

Deoxyribonucleic acid carries the hereditary information.

That is, the genes are carried in the DNA

The macromolecule of heredity in eukaryotes and prokaryotes. it is composed of chains of nucleotide monomers of a nitrogenous base, 2-deoxy-D-ribose, and phosphate.

Purines and pyrimidines, which are components of nucleotides, DNA, and RNA

• Adenine (A)
• Guanine (G)
• Cystosine (C)
• Thymine (T) DNA Only
• Uracil (U) RNA Only

Purines: Adenine (A) and Guanine (G)

• DNA Pyrimidines
• Cytosine (C) and Thymine (T)

• RNA Pyrimidines
• Cytosine (C) and Uracil (U)

A compound composed of ribose or deoxyribose and a base

D-ribose

ribonucleic acid = RNA

2-deoxy-D-ribose

deoxyribonucleic acid = DNA

A nucleoside bonded to one, two, or three phosphate groups

nucleotides

• 1. A base
• 2. A monosaccharide
• 3. A phosphate

Nucleoside = Base + Sugar

Nucleotide = Base + Sugar + Phosphate

Nucleic acid = A chain of nucleotides

A polymer composed of nucleotides

The arrangement in which two strands of DNA are coiled around each other in a screw-like fashion.

In the DNA double helix, the two polynucleotide chains run in opposite directions. Thus, at each end of the double helix, there is one 5' -OH and one 3' -OH terminus.

The sugar-phosphate backbone is on the outside, exposed to the aqueous environment, and the bases point inward.

The paired bases form hydrogen bonds with each other; two for A-T and three for G-C, thereby stabilizing the double helix.

The combination of a purine and a pyrimidine base that hydrogen bond together in DNA.

• Primary: -ATTGAC-
• Secondary: Double Helix
• Higher-Order: The way DNA coils around histones forming units called nucleosomes and is further condensed into chromatin within the body...

The DNA complexed with histone and nonhistone proteins that exists in eukaryotic cells between cell divisions.

A coil wound in the form of a helix

• 1. DNA has four bases A, G, C, and T.
• RNA has three of these bases A, G, and C but its fourth base is U, not T

• 2. In DNA, the sugar is 2-deoxy-D-ribose.
• In RNA, the sugar is D-ribose

• 3. DNA is almost always double-stranded, with a helical structure.
• There are several kinds of RNA, none of them with a repetitive double-stranded structure.

Messenger RNA - The RNA that carries genetic information from DNA to the ribosome and acts as a template for protein synthesis.

mRNA molecules are produced in the process called transcription and they carry the genetic information from the DNA in the nucleus directly to the cytoplasm where most of the protein is synthesized.

Transfer RNA - The RNA that transports amino acids to the site of protein synthesis in ribosomes.

Ribosomal RNA - The RNA complexed with proteins in ribosomes

Small spherical bodies in the cell made of protein and RNA; the site of protein synthesis.

Small Nuclear RNA - Function is to help with the processing of the initial mRNA transcribed from DNA into a mature form that is ready for export out of the nucleus. A process often referred to as splicing

The removal of an internal RNA segment and the joining of the remaining ends of the RNA molecule.

RNA-based enzymes

Micro RNA - Play important roles in cancer, stress responses, and viral infections. They inhibit translation of mRNA into protein and promote the degradation of mRNA.

Small Interfering RNA - Small RNA molecules that are involved in degradation of specific mRNA molecules. This process serves as a protective mechanism in many species, with the siRNAs being used to eliminate expression of an undesirable gene.

1. Transfer RNA (tRNA): Transports amino acids to site of protein synthesis

2. Ribosomal RNA (rRNA): Combines with proteins to form ribosomes, the site of protein synthesis

3. Messenger RNA (mRNA): Directs amino acid sequence of proteins

4. Small nuclear RNA (snRNA): Processes initial mRNA to its mature form in eukaryotes

5. Micro RNA (miRNA): Affects gene expression; important in growth and development

6. Small interfering RNA (siRNA): Affects gene expression; used by scientists to knock out a gene being studied.

Stretches of DNA that spell out (encode) the amino acid sequence to be assembled are interrupted by long stretches that seemingly do not code for anything. The coding sequences are called exons, short for "expressed sequences" and the noncoding sequences are called introns short for "intervening sequences".

Nucleotide sequence in DNA or mRNA that codes for a protein

A nucleotide sequence in DNA or mRNA that does not code for a protein

The process by which copies of DNA are made during cell division.

1. It reproduces itself (replication)

2. It supplies the information necessary to make all the RNA and proteins in the body, including enzymes.

The point in a DNA molecule where replication starts.

The point on a DNA molecule where replication is proceeding.

In all known forms of replication, the primer is made out of RNA, not DNA.

In eukaryotic cells, DNA is located in the cell nucleus and in mitochondria.

RNA is synthesized from DNA in the nucleus, but further use of RNA (protein synthesis) occurs on ribosomes in the cytoplasm.

Thymine and uracil are both based on the pyrimidine ring. However, thymine has a methyl substituent at carbon 5, whereas uracil has a hydrogen. All of the other ring substituents are the same.

D-Ribose and 2-deoxy-D-ribose have the same structure except at carbon 2.

D-Ribose has a hydroxyl group and hydrogen on carbon 2, whereas deoxyribose has two hydrogens.

Neither. The name "nucleic acid" derives from the fact that the nucleosides are linked by phosphate groups, which are the dissociated form of phosphoric acid.

Anhydride bonds

In RNA, carbons 3' and 5' of the ribose are linked by ester bonds to phosphates. Carbon 1 is linked to the nitrogen base with an N-glycosidic bond.

Two

Electrostatic interactions

The superstructure of chromosomes consists of many elements. DNA and histones combine to form nucleosomes that are wound into chromatin fibers. These fibers are further twisted into loops and minibands to form the chromosome superstructure.

DNA is wound around histones, collectively forming nucleosomes that are further wound into solenoids, loops, and bands.

rRNA

mRNA

Ribozymes, or catalytic forms of RNA, are involved in post-transcriptional splicing reactions that cleave larger RNA molecules into smaller, more active forms.

For example, tRNA molecules are formed in this way.

Immediately after transcription, messenger RNA contains both introns and exons. The introns are cleaved out by the action of ribozymes that catalyze splicing reactions on the mRNA.

No

Satellites are short sequences of DNA that are repeated hundreds of thousands of times but do not code for any protein in RNA.

The specificity between the base pairs, A-T and G-C

Four.

In semiconservative DNA replication, the new daughter DNA helix is composed of one strand from the original (or parent) molecule and one new strand.

Helicases are enzymes that break the hydrogen bonds between the base pairs in double-helix DNA and thus help the helix to unwind. This prepares the DNA for the replication process.

The leading strand or continuous strand is synthesized in the 5' to 3' direction.

DNA ligase

From the 5' to the 3' direction.

One of the enzymes involved in the DNA base excision repair (BER) pathway is an endonuclease that catalyzes the hydrolytic cleavage of the phosphodiester backbone. The enzyme hydrolyzes on the 5' side of the AP site.

A beta-N-glycosidic bond between the damaged base and the deoxyribose.

5'ATGGCAGTAGGC3'