AP Bio Unit 6

3' poly-A tail

String of adenine nucleotides added to mRNA.

5' GTP cap

Modified guanine added to mRNA for stability.

5' to 3' direction

Direction of mRNA synthesis by RNA polymerase.

Acetylation

Addition of acetyl groups, enhancing gene expression.

Adult stem cell

Multipotent stem cell found in adult tissues.

Alternative splicing

Process allowing multiple protein forms from a single gene.

Alternative splicing

Process generating multiple mRNA variants from one gene.

Alternative splicing

Produces different mRNA versions from one gene.

Amino acid changes

Alterations in protein structure due to mutations.

Anticodon

Three-nucleotide sequence on tRNA complementary to mRNA codon.

Anticodon

tRNA sequence complementary to mRNA codon.

Antiparallel strands

DNA strands run in opposite directions.

Bacterial transformation

Process of introducing DNA into bacterial cells.

cAMP

Cyclic AMP, a signaling molecule in lac operon regulation.

CAP

Catabolite activator protein enhancing lac operon transcription.

Cell differentiation

Process where cells develop distinct functions.

Cell specialization

Process where cells develop unique functions.

Chargaff's Rule

Equal amounts of A-T and C-G in DNA.

Chromosomal mutation

Large-scale changes in chromosome structure or number.

Chromosome number changes

Alterations leading to new phenotypes.

Codon

Three-nucleotide sequence coding for an amino acid.

Codon

Triplet of nucleotides on mRNA.

Common genetic code

Universal code shared by nearly all organisms.

Complementary base pairing

Specific pairing of nitrogenous bases (A-T, C-G, A-U).

Conjugation

Direct transfer of DNA between two bacterial cells.

Conservative missense mutation

Amino acid change similar in properties.

Conservative mutation

Similar amino acid replaces original, minimal effect.

Corepressor

Molecule that enhances repressor activity in gene regulation.

Cytoplasm

Location of ribosomes for translation in cells.

DNA mutation

Change in nucleotide sequence of DNA.

DNA polymerase

Enzyme that synthesizes new DNA strands.

DNA replication

Process of copying DNA for cell division.

DNA sequencing

Determining the nucleotide order in DNA.

Double helix

Structure of DNA with two intertwined strands.

Down syndrome

Genetic disorder caused by Trisomy 21.

Electrophoresis

Technique separating molecules by size and charge.

Embryonic stem cell

Pluripotent stem cell from early embryos.

Energy in translation

Required for initiation, elongation, and termination.

Environmental context

Surrounding conditions affecting mutation impact.

Enzymes are responsible for:

DNA replication

Epigenetic changes

Reversible modifications affecting gene expression.

Epigenetic inheritance

Transmission of gene expression changes without DNA sequence alteration.

Euchromatin

Loosely packed DNA, generally active in transcription.

Eukaryotic cells

Cells with linear chromosomes and membrane-bound nucleus.

Exons

Coding sequences retained in mRNA.

Frameshift mutation

Insertion or deletion altering reading frame of DNA.

Frameshift mutation

Insertion or deletion alters reading frame of DNA.

Gene products

Proteins or RNA produced by genes.

Genetic flow

Process of information transfer: DNA to RNA to protein.

Genetic variation

Diversity in gene frequencies within a population.

Genotype

Genetic constitution of an organism.

Genotype

Genetic makeup of an organism.

GTP cap

Added to the 5' end of mRNA.

Helicase

Enzyme that unwinds DNA during replication.

Heterochromatin

Tightly packed DNA, generally inactive in transcription.

Hybrid vigor

Increased biological fitness in hybrid offspring.

Inducer

Molecule that activates gene expression by inactivating repressors.

Introns

Non-coding sequences removed from mRNA.

Lac operon

Inducible operon regulating lactose metabolism in E. coli.

Ligase

Enzyme that joins Okazaki fragments on lagging strand.

Meiosis errors

Mistakes during gamete formation affecting phenotype.

Methylation

Addition of methyl groups, often repressing gene expression.

miRNA

Micro RNA involved in post-transcriptional gene regulation.

Missense mutation

Mutation resulting in a different amino acid.

Missense mutation

Results in a different amino acid in protein.

Mitosis errors

Mistakes during cell division affecting phenotype.

mRNA

Carries genetic information from DNA to ribosome.

mRNA

Messenger RNA carrying genetic information for protein synthesis.

Mutation

Change in DNA sequence affecting gene function.

Mutation

Change in DNA sequence affecting phenotype.

Natural selection

Process where advantageous traits increase in frequency.

Negative mutation

Detrimental change reducing survival or reproduction.

Neutral mutation

Change with no significant effect on phenotype.

Nitrogenous base

Building blocks of DNA and RNA: A, T, C, G, U.

Noncoding strand

Also known as the antisense strand.

Nonconservative missense mutation

Amino acid change differing in properties.

Nonconservative mutation

Different amino acid replaces original, significant effect.

Nondisjunction

Failure of chromosomes to separate properly during division.

Nonsense mutation

Mutation creating a premature stop codon.

Operator

DNA segment where repressor binds to inhibit transcription.

Operon

Group of genes transcribed together in prokaryotes.

Phenotype

Observable characteristics resulting from genotype.

Phenotype

Observable traits determined by gene expression levels.

Phenotype

Observable traits determined by genotype.

Plasmids

Extrachromosomal DNA molecules in prokaryotes and eukaryotes.

Point mutation

Change in a single nucleotide in DNA.

Poly-A tail

Added to the 3' end of mRNA.

Polymerase chain reaction (PCR)

Method to amplify specific DNA fragments.

Polypeptide chain

Sequence of amino acids linked together.

Positive mutation

Beneficial change enhancing survival or reproduction.

Post-translational control

Modifications after protein synthesis affecting function.

Prokaryotic cells

Cells with circular chromosomes and no nucleus.

Promoter

DNA sequence where RNA polymerase initiates transcription.

Protease

Enzyme that breaks down proteins.

Proteasome

Complex degrading ubiquitinated proteins.

Purine

Double-ring nitrogenous bases: adenine and guanine.

Pyrimidine

Single-ring nitrogenous bases: cytosine, thymine, uracil.

Regulatory sequences

DNA stretches controlling transcription via protein interaction.

Repressor

Protein that inhibits gene expression by blocking transcription.

Retroviruses

Viruses that reverse transcribe RNA into DNA.