9,10,11 DNA & RNA

Study.com College Biology 101

Alternative Splicing

A principle that explains how single genes are able to code for multiple proteins.

Reiji Okazaki

A molecular biologist who first put forth the theory of discontinuous DNA replication in the 1960s.

Replication Bubbles

Places within a DNA molecule where replication occurs that look like bubbles. Grow outward until they join together, forming two new strands of DNA. Allows for replication to occur quickly.

Okazaki Fragments

Small stretches of DNA made by DNA polymerase during the process of DNA replication. They are joined together by DNA ligase and used during discontinuous replication of the lagging strand.

The Three Steps of Translation

Initiation, elongation, and termination

Transcription

The process of using a DNA blueprint to make an RNA copy. Genetic information is copied from DNA to RNA when this occurs.

RNA Primase

An enzyme that synthesizes a primer that allows for the start of replication.

RNA: Nitrogenous Bases

Guanine Cytosine Adenine Uracil

Ribosomal RNA (rRNA)

A type of RNA found within a ribosome for structural purposes

DNA Helicase

This enzyme acts to unwind the double helix that is found in DNA.

Nucleic Acid

An important biological molecule responsible for the storing, transfer, and expression of genetic information

Oswald Avery

Performed experiments to determine the transforming principle as discovered by Frederick Griffiths work with mice Determined that DNA is the hereditary molecule in cells

DNA Polymerase

A large enzyme that adds nucleotides to a growing daughter DNA strand by using the parent strand as a template. Requires an RNA primer to start, and reads a strand in a 3 to 5 direction.

Major Types of RNA

Messenger RNA (mRNA) Ribosomal RNA (rRNA) Transfer RNA (tRNA)

Anticodon

Three consecutive bases within a tRNA molecule that complementary base pair with a codon on an mRNA

Relationship Between DNA and the Three Types of RNA

A short stretch of DNA is used as a template to make an mRNA copy, which then joins up with a ribosome (which contains rRNA). Then tRNA brings in amino acids to make a protein.

Purines and Pyrimidines

Purines: nitrogenous bases that contain two rings in their chemical structure, includes adenine and guanine Pyrimidines: nitrogenous bases that contain one ring; includes cytosine and thymine

Transfer RNA (or tRNA)

Made in the nucleus, shaped in the cytoplasm. Pairs with an mRNA codon in the active site of a ribosome using its anti-codon sequence, adding the correct amino acid to the protein being produced.

Semi-Conservative Model

The correct model that describes how DNA replication occurs. States that each DNA strand serves as a template for a new strand so that each new double helix has one new and one old DNA strand

Leading Strand

One of the two parent strands of DNA that runs 3 to 5 Replication is continuous on this strand and only requires a single RNA primer.

DNA: Nitrogenous Bases

Adenine (A), cytosine (C), guanine (G), and thymine (T)

Lagging Strand

One of the two parent strands of DNA that runs 5 to 3 Replication is discontinuous on this strand and requires the use of Okazaki fragments.

Messenger RNA (mRNA)

The type of RNA that is read by a ribosome and serves as a template for the production of a protein. It is formed during the central dogmas first step.

Function of DNA

Provides the instructions for the creation of proteins, which are used to build the components of cells

Complementary Base Pairing in DNA

Cytosine and guanine always base pair together, forming three hydrogen bonds Adenine and thymine always base pair together, forming two hydrogen bonds

Replication Forks

Two found in every replication bubble Allow for replication to take place in both directions away from the replication bubble

James Watson and Francis Crick

Scientists that used X-ray images of DNA and base-pair ratio experimental data to develop a double-helix structural model of the DNA molecule

Phosphodiester Bond

A chemical bond in a polynucleotide molecule between a sugar and a phosphate group

Deoxyribonucleic Acid (DNA)

Double-stranded helix of nucleotides made up of a sugar (deoxyribose), a phosphate, and one of four nitrogenous bases (adenine, cytosine, guanine, and thymine)

Translation

Changes a heritable trait from the nucleic acid language into the amino acid language Produces a protein using an mRNA template

Codon

A set of three sequential bases in a strand of mRNA that code for a specific amino acid during translation For example, AGU codes for the amino acid serine.

Antiparallel

Nucleic acids have 2 ends. The phosphate end is called 5, the sugar end is 3. In DNA, the 2 parallel strands go in opposite directions. The 5 end of one lines up with the 3 end of the other.

RNA Splicing

The process of removing stretches of nucleotides (called introns) out of an RNA molecule and rejoining the remaining pieces (called exons) Changes the final sequence of the translated protein

Central Dogma

Describes how heritable information in a cell is expressed, a DNA recipe is transcribed into mRNA, which is then translated (or cooked) into a protein made up of amino acids.

RNA Polymerase

This enzyme uses either strand of a DNA template to join nucleotides together, producing strands of RNA. It starts working by binding to a promoter region found on a molecule of DNA.

DNA: Complementary Base Pairings

These occur due to the way nitrogenous bases connect. Purines hook to pyrimidines, which means that cytosine pairs with guanine and adenine pairs with thymine.

Codon Recognition

A process that occurs when codons and the proper amino acids are connected. Translation is used to accomplish this.

Ribonucleic Acid (RNA)

Single-stranded nucleic acid made up of a sugar (ribose), a phosphate, and nitrogenous bases (adenine, cytosine, guanine, and uracil). It is less stable than another nucleic acid, DNA.

Semi-Conservative Model: Conservation of Parent Strands of DNA

This model for DNA replication asserts that daughter DNA molecules conserve one parental strand of DNA.

Complementary Base Pairing in RNA

Cytosine and guanine always base pair together, forming three hydrogen bonds Adenine and uracil always base pair together, forming two hydrogen bonds

Gene Transcription: Location

All stages of this process must be carried out within the nucleus of a cell.