Week 7 Genetics and Molecular Biology — Vocabulary Flashcards (DNA, RNA, Mutations, PCR, CRISPR, Cloning, and More)

Vocabulary flashcards covering hdr gene, Mendelian genetics (including ABO and X-linked traits), DNA profiling, central dogma, protein synthesis, mutations, GMOs, CRISPR, stem cells, gene therapy, and cloning.

hdr gene (H = normal, h = mutant)

Alleles for the hdr gene; H is the normal allele and h is the mutant allele.

Homozygous

Having two identical alleles for a gene (e.g., HH or hh).

Heterozygous

Having two different alleles for a gene (e.g., Hh).

Monohybrid cross

Cross examining one gene; e.g., hh × HH yields Hh offspring.

DNA profiling

Identifying individuals by DNA sequences; formerly DNA fingerprinting; often uses STRs.

Short Tandem Repeats (STRs)

Repeating DNA sequences used in identity testing; 13 STRs commonly used in humans.

ABO blood group system

Blood types determined by IA, IB, i alleles; IA and IB are codominant, i is recessive.

IA and IB codominance

Both IA and IB alleles express in Type AB individuals.

Type O universal donor

Type O (ii) blood is compatible with all other types (no IA/IB expressed).

Type AB universal recipient

Type AB can receive from all ABO types.

Blood transfusion compatibility

Cross-matching to prevent immune reactions; incompatibility can cause clumping and vessel blockage.

X-linked (sex-linked) trait

Trait on the X chromosome; often more severe in males (XY) and can be carrier in females (XX).

Red-Green color blindness

X-linked disorder affecting color perception; common in males (~8%) more than females (<1%).

Adrenoleukodystrophy (ALD)

X-linked disorder with missing enzyme; waste buildup destroys myelin; newborn screening recommended.

Pedigree

Family tree showing inheritance across generations; circles=females, squares=males, shaded=affected.

Polymerase Chain Reaction (PCR)

Technique that amplifies DNA through repeated heating/cooling cycles using DNA polymerase and primers.

Transcription

DNA → RNA; occurs in the nucleus; RNA polymerase synthesizes mRNA using a promoter.

Translation

RNA → protein; occurs at ribosomes; tRNA delivers amino acids; codons determine amino acids.

Promoter

DNA sequence where RNA polymerase binds to initiate transcription.

mRNA (messenger RNA)

RNA that carries the genetic code from DNA to the ribosome for protein synthesis.

Ribosome

RNA-protein complex that reads mRNA and forms peptide bonds between amino acids.

Ribosomal RNA (rRNA)

RNA component of the ribosome.

Transfer RNA (tRNA)

RNA that delivers amino acids to the ribosome and contains an anticodon.

Codon

Three-nucleotide sequence in mRNA specifying an amino acid.

Anticodon

Three-nucleotide sequence on tRNA that pairs with a codon.

Start codon (AUG)

Initiates translation; codes for methionine.

Stop codons (UAA, UAG, UGA)

Signals termination of translation.

Genetic code

Sets of codons mapping to amino acids; 64 codons total; universal and redundant.

64 codons

Total number of three-nucleotide codons; 61 encode amino acids, 3 are stop signals.

Substitution mutation

Single base change; may alter an amino acid or be silent.

Frameshift mutation

Insertion or deletion that shifts the reading frame, often producing a nonfunctional protein.

Neutral mutation

Mutation that does not affect protein function or phenotype.

Mutation effects on polypeptides

Mutations can change amino acid sequence, potentially altering protein function.

Genetically Modified Organisms (GMOs)

Organisms whose genomes have been altered by genetic engineering.

CRISPR

Gene-editing technology using guide RNA and Cas enzyme to target and modify DNA.

Guide RNA

RNA that directs the CRISPR system to the target DNA sequence.

Cas enzyme

Nuclease that cuts DNA at the target site in CRISPR systems.

CRISPR in plants/animals

Used to improve traits, nutritional content, disease resistance, or medical applications.

Trisomy 21 (Down syndrome)

Presence of an extra copy of chromosome 21; discussed as a chromosomal abnormality.

Stem cells

Undifferentiated cells capable of becoming multiple cell types; embryonic and adult forms.

Embryonic stem cells

Pluripotent stem cells derived from embryos; can differentiate into many cell types.

Adult stem cells

Multipotent stem cells in tissues that maintain and repair them.

Gene therapy

Replacing defective genes with functional ones to treat or cure disease.

Somatic cell gene therapy

Targets only affected cells; restores proper protein production without altering germline DNA.

Cloning

Creating genetically identical organisms via nuclear transfer; e.g., Dolly the sheep.

Nuclear transfer

Transplanting a somatic nucleus into an enucleated egg cell.

Ethical considerations

Moral debates about cloning, genetic modification, and related technologies.