APBIO: Unit 6: Gene Expression and Regulation - Topics 1-8

Purines

Nitrogenous bases with two rings (adenine and guanine)

Pyrimidines

Nitrogenous bases with one ring (cytosine and thymine/uracil)

Antiparallel

DNA strands run in opposite 5' to 3' directions

Plasmids

Small circular DNA molecules found in bacteria

RNA

Single-stranded nucleic acid involved in protein synthesis

DNA

Double-stranded nucleic acid that stores genetic information

Origins of replication

Sites where DNA replication begins

Replication fork

Y-shaped region where DNA is being unwound

Helicase

Enzyme that unwinds the DNA double helix

Topoisomerase

Enzyme that relieves tension ahead of the replication fork

Primase

Enzyme that synthesizes RNA primers

Primers

Short RNA sequences that start DNA synthesis

DNAP III

Enzyme that adds nucleotides to build new DNA strand

DNAP I

Enzyme that replaces RNA primers with DNA nucleotides

Leading strand

DNA strand synthesized continuously

Lagging strand

DNA strand synthesized in fragments

Okazaki fragments

Short DNA fragments on the lagging strand

DNA ligase

Enzyme that joins Okazaki fragments

Telomeres

Repetitive DNA at chromosome ends that protect genes

Telomerase

Enzyme that extends telomeres

Nuclease

Enzyme that cuts DNA

Mismatch repair

System that fixes errors in DNA replication

Transcription

Process of making RNA from DNA

Gene expression

Process by which information from a gene is used to make a product

Template strand

DNA strand used to synthesize RNA

Codon

Three-nucleotide sequence on mRNA that codes for an amino acid

rRNA

RNA component of ribosomes

tRNA

RNA that carries amino acids to the ribosome

5' Cap

Modified G nucleotide added to mRNA for protection and binding

Poly-A tail

Chain of adenines added to mRNA for stability

mRNA

Messenger RNA that carries genetic code to ribosome

Redundancy

Multiple codons code for the same amino acid

Reading frame

Grouping of codons in mRNA

Alternative splicing

Process where different mRNAs are made from same gene

RNA splicing

Removal of introns and joining of exons

Translation

Process of protein synthesis from mRNA

Anticodon

Three-nucleotide sequence on tRNA that matches codon

Stop codon

Codon that signals end of translation

Operons

Groups of genes regulated together in prokaryotes

Promoter

DNA sequence where RNA polymerase binds

Operator

DNA segment that controls operon access

Inducible

Operon that is turned on by a molecule

Cytoplasmic determinants

Molecules in egg that influence development

Allosteric inhibitor

Molecule that binds enzyme and reduces activity

Regulatory gene

Gene that controls expression of other genes

Allosteric activator

Molecule that increases enzyme activity

Control elements

DNA sequences that regulate transcription

Histone acetylation

Addition of acetyl groups to histones to increase transcription

DNA methylation

Addition of methyl groups to DNA to decrease transcription

Epigenetic inheritance

Heritable changes in gene expression without DNA change

Gene expression

Process of producing gene products

Differentiation

Process where cells become specialized

Morphogenesis

Development of organism shape

Repressible

Operon usually on but can be turned off

Induction

Activation of gene expression

Homeotic genes

Genes that control body structure development

Apoptosis

Programmed cell death

Pattern formation

Development of spatial organization in organisms

Mutations

Changes in DNA sequence

Genotype

Genetic makeup of an organism

Phenotype

Observable traits of an organism

Nondisjunction

Failure of chromosomes to separate properly

Translocation

Movement of chromosome segments to new location

Inversion

Reversal of chromosome segment

Deletion

Loss of chromosome segment

Horizontal gene transfer

Transfer of genes between organisms

Transformation

Uptake of DNA from environment

Conjugation

Transfer of DNA via cell-to-cell contact

Transposition

Movement of DNA segments within genome

Point mutation

Change in a single nucleotide

Duplication

Repetition of a chromosome segment

Transduction

Transfer of DNA by viruses

Substitution

Replacement of one nucleotide with another

Gel electrophoresis

Technique to separate DNA by size

PCR

Technique to amplify DNA

DNA sequencing

Determining the order of nucleotides in DNA