Molecular Genetics Vocabulary

Flashcards to help learn key vocabulary terms associated with molecular genetics.

DNA

Codes genetic information and stores it till it is ready to use. Genes are not active all the time

DNA Copy

Important to make exact copies or else mutations will happen

DNA Transmit

Passing genetic information from one generation to the next is a necessary part of life. Loss or additions to DNA during transmission can have adverse affects.

Deoxyribose

Pentose sugar that makes up DNA

Nitrogenous base

Makes up DNA

Complementary Strands

Each strand is complementary meaning that they read equal but opposite

Anti-Parallel Strands

The strands run anti-parallel meaning that they always read to the 5’ to 3’ direction. 5’ and 3’ refer to specific carbons on the pentose sugar.

Pyrimidines

Cytosine and Thymine

Purines

Adenine and Guanine

Cell Cycle S Phase

DNA replication happens in interphase (S) of the cell cycle.

Helicase

Unzips the hydrogen bonds between the double helixes to form replication forks.

DNA Primase

Adds an RNA primer to the DNA to act as a recognition site for DNA Polymerase.

DNA polymerase

Pairs nucleotides to form the complimentary sequence. It runs only in the 5’-3’ direction

DNA Ligase

Connects Okazaki Fragments.

Endonuclease

Makes any corrections by cutting out incorrect regions and letting DNA polymerase try again

Topoisomerase

Unwinds the DNA and reduces tension on the strands.

Origin of Replication

where helicase starts to open up the DNA

Replication fork

There are two forks per origin of replication (one running in either direction). Each have a helicase that is running and opening up DNA.

Leading strand

This is the strand that DNA polymerase is able to bind and build 5’ to 3’ while following right behind helicase as the DNA is opening up.

Lagging strand

This is the strand that DNA polymerase is running backwards and has to loop around to catch up with the direction helicase is moving.

Okazaki fragments

Discontinuous fragments of DNA only found on the lagging strand.

Telomeres

Repetitive sequences at the ends of chromosomes that don’t code for a gene.

Telomerase

Builds an additional track of RNA onto the end of the chromosome to allow DNA polymerase to extend its run.

Gel electrophoresis

Used to see if a select gene is present in a sample.

Polymerase Chain Reaction (PCR)

A technique that uses DNA polymerases to replicate/amplify DNA in vitro.

DNA sequencing

Used to figure out what is the nucleic acid code for a certain length of DNA.

Gene Expression

Genes must be turned “on” for it to be expressed.

Transcription

The process of synthesizing a single stranded RNA from a double stranded DNA template. It produces a mRNA.

messenger-RNA (mRNA)

This is the RNA that codes for a specific protein sequence. It is used to make a protein.

ribosomal RNA (rRNA)

Joins with ribosomal proteins to make the complex known as the ribosome.

Transfer RNA (tRNA)

Brings amino acids to the Ribosome complex for translation.

RNA Polymerase

Enzyme that opens up DNA, creates an RNA strand, and then finishes transcription.

TATA box

A well known promoter sequence is TATA

Template strand

DNA strand used to match RNA nucleotides off of.

Coding strand

The DNA strand that is not used as a template but its nucleotide sequence mimics that of the RNA.

Terminator

Transcription stops when RNA polymerase reaches a section of DNA

Transcription Factors

Proteins that facilitate or inhibit transcription.

Activator

A positive transcription factor which helps RNA polymerase attach to the promoter.

Repressor

A negative transcription factor which prevents RNA polymerase from attaching to the promoter.

Intron

Non-coding sections of nucleic acid found between coding regions of RNA

Exon

Coding regions of nucleic acid in RNA.

Splicing

A process in which the introns of a pre-mRNA are removed and exons are joined together.

Poly A Tails

Long chains of adenines that are attached to the ends of RNAs. These provide stability and reduce the chance of the RNA degrading during transport/translation

Endonuclease

Family of enzymes that can sever and cut DNA at certain regions.