Unit 6: Gene Expression and Regulation Flashcards

Flashcards covering key vocabulary terms from Unit 6: Gene Expression and Regulation.

Translocation

When the tRNA in the large ribosomal subunit moves to the next site so that elongation may occur.

Inversion

A nucleotide is added into a codon, a framework mutation

Deletion

A nucleotide is deleted from a codon, a framework mutation

Horizontal gene transfer

The process by which a gene or genes from one organism is transferred to another organism.

Transformation

When a bacteria takes in a plasmid from its environment if another cell sheds it or that cell dies.

Conjugation

Plasmid can be shared directly with another bacteria that lacks that gene. One cell with the desired plasma will use a structure called a pilus to transfer the plasmid to the other cell because it contains a fertility factor (or F factor) in its DNA.

Transposition

Transposons (pieces of DNA) hop randomly to different parts of a DNA sequence

Point mutation

One nucleotide is changed, affecting only that specific codon

Duplication

A DNA sequence is repeated

Transduction

Virus inserts DNA into bacteria to make essentially a virus-making bacteria factory by hijacking the bacteria, parasitic.

Substitution

A type of point mutation that involves replacing a nucleotide with another, only affecting that codon.

Silent mutation

Mutation in DNA sequence that doesn’t affect the resulting amino acid

Missense mutation

When one nucleotide change creates a different protein

Nonsense mutation

Mutation in DNA sequence that results in a stop codon from forming

Frameshift mutation

A mutation where the removal or addition of an amino acid affects all the following amino acids

Operon

Usually prokaryotic, system of genes that has controlling elements, can be turned on or off

Promoter

Region where RNA Polymerase binds, TATA box for eukaryotes

Operator

Part of operon where repressor binds, where system is regulated

Inducible

An operon that is otherwise off but can be turned on if an inducer is present. ex. lac operon

Cytoplasmic determinants

When eggs are developing, affect gene expression and determine differentiation

Regulatory gene

Codes for regulatory proteins, usually the repressor protein

Histone acetylation

Loosens up DNA winding around histones and allows transcription to happen

Histone methylation

Affects how DNA is wound around histones and inhibits transcription

Epigenetic inheritance

Epigenetics is when DNA is modified or its expression is changed without affecting the nucleotides. These modifications can be passed down through generations.

Differentiation

Cells differentiate because they express different genes, despite the fact that all cells in an organism share the same genome

Morphogenesis

The development of an organism or cell

Repressible

An operon that is otherwise always on, can be repressed if co-repressor is present. ex. trp operon

Homeotic genes

Genes that regulate differentiation during morphogenesis

Gel electrophoresis

Biotech tool: Allows DNA to move through gel. DNA (negatively charged) moves toward positive. Longer pieces will move faster than shorter ones.

PCR

Replicates DNA sequence so that it’s visible to the eye, important for gel electrophoresis

Restriction enzymes

Find specific sites and cut parts of DNA. If you use the same restriction enzymes, you’ll be able to add fragments of a specific DNA to other sequences

TATA box

It’s a non-coding sequence of nucleotides that tells transcription factors where to bind, so that RNA polymerase can attach there

Enhancer region

Increase the probability that a gene will be transcribed

Gene

Instructions to build proteins are encoded in these segments of DNA

Genome

Set of all DNA instructions in an organism

Plasmid

Prokaryotes have a circular shape of DNA that helps DNA erode less quickly

Double helix

Shape of DNA

Nucleotide

Their organization is transcribed to create proteins

Nitrogenous base

Adenine, guanine, thymine, cytosine, and uracil bond together with hydrogen bonds

5’ Phosphate group

End of a nucleotide

3’ Hydroxyl

Bottom of sugar end of a nucleotide

Directionality

DNA runs from 5’ to 3’

Semi-conservative

Term that describes DNA replication, as one strand of DNA is from a parent molecule and the other is new

Topoisomerase

Prevents strain by relaxing supercoiling

Helicase

Enzyme that initiates DNA replication by finding the origin of replication sequence and breaking the hydrogen bonds, splitting the two strands

Primase/RNA polymerase

Lays down the RNA primers so that DNA Polymerase III can start replication

Origin of replication

Sequence of nucleotides that helicase recognizes

DNA polymerase III

Sets down matching nucleotide bases while reading the bases from the parent molecule strand, goes in 5’ to 3’ direction

Telomeres

Nucleotide sequence “caps” placed on the ends of DNA that don’t code for anything and protect the DNA

Telomerase

Places the telomeres on the DNA

DNA polymerase I

Replaces RNA primers with DNA

DNA ligase

Seals the gaps between Okazaki fragments

Single strand binding proteins (SSBPs)

Ensure that the double helix doesn’t rewind during replication

Parent strand

Strand of DNA from original, untouched molecule

New strand

Strand of DNA that was synthesized during replication

Central dogma

Concept that describes how genetic information creates proteins

Transcription

DNA to RNA (in cytoplasm for prokaryotes, nucleus for eukaryotes)

Translation

From RNA to proteins (in cytoplasm for eukaryotes and prokaryotes)

Coding, sense, or plus strand

Strand of DNA that the mRNA is a copy of, originally paired with the template strand

Template, Noncoding, antisense, or minus strand

Strand of DNA that gets transcribed into RNA

mRNA

Strand coded by RNA polymerase, contains codons important for transcription / translation

Initiation for transcription

When RNA polymerase attaches to the promoter region, called the TATA box for eukaryotes

RNA Polymerase

Enzyme that initiates transcription by reading the DNA sequences of nucleotides and pairing complementary RNA nucleotides, goes 3’ to 5’

Elongation

mRNA is peeled away from the DNA as it is constructed, going 5’ to 3’. The DNA double helix is reformed as RNA polymerase keeps moving

Termination

The sequence of nucleotides that signal the release of the pre-mRNA strand

mRNA processing (eukaryote only)

mRNA must undergo modifications before it is mature enough to leave the nucleus and start translation

Codon

mRNA nucleotide triplets

Start codon (AUG)

The first codon read by RNA polymerase

Stop codon

The codon that signals for the end of protein synthesis (translation)

5’ GTP cap

A pre-mRNA modification= the 5’ end is given a cap of guanines

3’ poly-A tail

A pre-mRNA modification= the 3’ end is given several adenine nucleotides

Intron

Non-coding sequences between exons on mRNA

Exon

Expressed sequences of mRNA. Multiple combinations of these can create multiple proteins from that one gene

Splicing

Getting rid of introns and having exons be joined together

Alternative splicing

When different combinations of exons are joined together, creating variants of one gene

rRNA

RNA that makes up ribosomes, important for translation

Ribosome

Complex made up of units where translation occurs. Sites A, P, and E are where stages of translation occur.

A site

Arrival site, where tRNA arrives with its amino acid

P site

Placement site, where tRNA attaches its amino acid to the ongoing chain and holds it temporarily

E site

End site, where tRNA moves to leave the ribosome in order to find more amino acids

tRNA

Transfer RNA that brings amino acids to ribosomes during translation, have anticodons

Anticodon

The complementary RNA sequence to each codon of mRNA

Purines

Double ring

Pyrimidines

Single ring