AP Bio Unit 6 - Gene Expression and Regulation

DNA replication

The process in which DNA makes a duplicate copy of itself.

DNA Polymerase

Enzyme involved in DNA replication that joins individual nucleotides to produce a DNA molecule

genes

sequence of DNA that codes for a protein and thus determines a trait

nucleotide

monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base

double helix

two strands of nucleotides wound about each other; structure/shape of DNA

adenine

nitrogen base found in DNA and RNA; pairs with thymine in DNA and with uracil in RNA

cytosine

A nitrogenous base found in DNA and RNA; pairs with guanine

guanine

A nitrogenous base found in DNA and RNA; pairs with cytosine

thymine

A nitrogenous base found in DNA (but not in RNA); pairs with adenine

uracil

A nitrogenous base found in RNA (but not in DNA); pairs with adenine

DNA

A complex molecule containing the genetic information that makes up the chromosomes,

deoxyribonucleic acid

RNA

A single-stranded nucleic acid that passes along genetic messages,

ribonucleic acid

deoxyribose

A five-carbon sugar that is a component of DNA nucleotides

ribose

a five-carbon sugar present in RNA

chromosomes

threadlike structures made of DNA molecules that contain the genes

mRNA

messenger RNA; type of RNA that carries instructions from DNA in the nucleus to the ribosome

rRNA

ribosomal RNA; type of RNA that makes up part of the ribosome

tRNA

transfer RNA; type of RNA that carries amino acids to the ribosome

transcription

process where the DNA sequence in a gene is copied into mRNA

translation

Process by which mRNA is decoded and a protein is produced

DNA helicase

An enzyme that unwinds the DNA double helix during DNA replication

mutation

A change in a gene or chromosome.

codon

three-nucleotide sequence on messenger mRNA that codes for a single amino acid

anti-codon

group of three bases on a tRNA molecule that are complementary to an mRNA codon

ribosome

site of protein synthesis

semi-conservative replication

in each new DNA double helix, one strand is from the original molecule, and one strand is new

protein

An organic compound that is made of one or more chains of amino acids and that is a principal component of all cells

RNA polymerase

Enzyme similar to DNA polymerase that binds to DNA and separates the DNA strands during transcription

start codon

AUG (methionine)

amino acids

monomers/building blocks of proteins

inversion mutation

A mutation involving a piece of a chromosome that breaks off and reattaches in reverse orientation.

translocation mutation

mutation in which one part of one chromosome breaks off and attaches to another chromosome

frameshift mutation

mutation that shifts the "reading" frame of the genetic message by inserting or deleting a nucleotide

point mutation (substitution)

one nucleotide is replaced with a different nucleotide.

Watson and Crick

Developed the double helix model of DNA.

DNA ligase

An enzyme that connects two fragments of DNA to make a single fragment during DNA Replication

DNA extraction

the opening of cells to separate/isolate DNA from other cell parts

Primase (RNA polymerase)

An enzyme that joins RNA nucleotides to make the primer using the parental DNA strand as a template.

leading strand

the new complementary DNA strand synthesized continuously along the template strand toward the replication fork in the mandatory 5' to 3' direction

lagging strand

A discontinuously synthesized DNA strand that elongates by means of Okazaki fragments, each synthesized in a 5' to 3' direction away from the replication fork.

Okazaki fragments

Small fragments of DNA produced on the lagging strand during DNA replication, joined later by DNA ligase to form a complete strand.

pre-mRNA

precursor mRNA; the first strand of mRNA produced by gene transcription that contains both introns and exons

poly-A tail

a sequence of 50-250 adenine nucleotides added onto the 3' end of a pre-mRNA molecule

operon

group of genes operating together

promotor

A region of DNA with a specific sequence that tells RNA polymerase where to begin transcription.

repressor

A protein that binds to an operator and physically blocks RNA polymerase from binding to a promoter site

Biotechnology

A form of technology that uses living organisms, usually genes, to modify products, to make or modify plants and animals, or to develop other microorganisms for specific purposes.

restriction enzymes

Enzyme that cuts DNA at a specific sequence of nucleotides

gel electrophoresis

Procedure used to separate and analyze DNA fragments by placing a mixture of DNA fragments at one end of a porous gel and applying an electrical voltage to the gel

Recombinant DNA

DNA that has been formed artificially by combining constituents from different organisms.

transformation

insertion of foreign DNA into host cells, in order to have the host produce new proteins and traits

vectors

An organism that transmits DNA or disease by conveying DNA or pathogens from one host to another, ex. bacteriophages and viruses

PCR (polymerase chain reaction)

A laboratory technique for amplifying DNA in vitro (testtube) by incubating with special primers, Taq polymerase molecules, and nucleotides.

Central Dogma

DNA-transcription-RNA-translation-protein-trait

transcription factors

A regulatory protein that binds to DNA and affects transcription of specific genes.

inducible operon

usually off, but can be stimulated (induced) when a specific small molecule interacts with a regulatory protein (example lac operon)

repressable operon

transcription is usually on but it an be inhibited

activators

proteins that turn operons on by binding to DNA, make it easier for RNA polymerase to bind to the promoter

endonuclease

An enzyme that cleaves its nucleic acid substrate (DNA) at internal sites in the nucleotide sequence.

template strand

The DNA strand that provides the pattern, or template, for ordering, by complementary base pairing, the sequence of nucleotides in an RNA transcript, the 3' to 5' strand.

coding strand (sense strand)

the strand of DNA that is not used as a template during transcription, because it is already complimentary to the Template strand, the 5' to 3' strand.

introns and exons

In most eukaryotic genes, coding regions (exons) are interrupted by noncoding regions (introns). During transcription, the entire gene is copied into a pre-mRNA, which includes exons and introns. During the process of RNA splicing, introns are removed and exons joined to form a contiguous coding sequence, before leaving the nucleus.

silent mutation

A mutation that changes a single nucleotide, but does not change the amino acid created.

missense mutation

A base-pair substitution that results in a codon that codes for a different amino acid.

nonsense mutation

A mutation that changes an amino acid codon to one of the three stop codons, resulting in a shorter and usually nonfunctional protein.