DNA & Genetics Vocabulary

These flashcards cover key vocabulary and concepts related to DNA, genetics, mutations, and associated experiments, aiding in the review and understanding for exams.

DNA

The molecule that carries genetic information.

Nuclein

Old name for DNA (Miescher).

Nucleotide

Building block of DNA/RNA (sugar + phosphate + base).

Sugar

Part of nucleotide (DNA = deoxyribose, RNA = ribose).

Nitrogenous base

A, T, C, G (or U in RNA).

Purines

Big bases with 2 rings (A, G).

Pyrimidines

Small bases with 1 ring (T, C, U).

Phosphate group

Part of nucleotide backbone.

Phosphodiester bond

Links nucleotides together.

Hydrogen bond

Weak bond between A-T or C-G.

Double helix

DNA shape like a twisted ladder.

Antiparallel strands

DNA strands run in opposite directions.

Major/minor grooves

Spots on DNA where proteins attach.

Replication fork

Where DNA is being copied.

Origin of replication

Place where copying starts.

Helicase

Unwinds the DNA.

SSB proteins

Keep strands from sticking back together.

Topoisomerase/DNA gyrase

Stops DNA from getting too twisted.

Primase

Makes a short RNA piece to start DNA copying.

RNA primer

Short starter for DNA polymerase.

DNA Polymerase III

Builds new DNA strand.

DNA Polymerase I

Replaces RNA primers with DNA.

DNA Ligase

Joins pieces of DNA together.

Leading strand

Made continuously.

Lagging strand

Made in small pieces (Okazaki fragments).

Proofreading

DNA polymerase fixes mistakes while copying.

Mismatch repair

Fixes wrong bases after copying.

Nucleotide excision repair

Fixes damage like thymine dimers.

Telomerase

Keeps ends of chromosomes long (in eukaryotes).

Mutation

Change in DNA.

Point mutation

One base is changed.

Frameshift mutation

Insertion/deletion changes the reading frame.

Chromosome mutation

Big changes (inversion, duplication, translocation, fusion).

Transforming principle

DNA can transfer traits (Griffith).

Chargaff’s rules

A = T, C = G.

X-ray diffraction

Used to see DNA shape (Rosalind Franklin).

Semi-conservative replication

Each new DNA has one old and one new strand.

Conservative replication

Old DNA stays, new DNA is separate.

Dispersive replication

DNA pieces mix with new DNA.

Meselson & Stahl experiment

Proved semi-conservative replication.

Hershey & Chase experiment

Showed DNA is genetic material.

Gel electrophoresis

Separates DNA by size.

Capillary electrophoresis

Same as gel but in a tiny tube, faster.

Sanger sequencing

Determines DNA sequence using special nucleotides.

Electropherogram

Graph showing DNA sequence.

Trait

Characteristic (flower color, eye color).

Allele

Version of a gene.

Dominant

Shows up even if only one copy is present.

Recessive

Hidden if dominant allele is present.

Homozygote

Two same alleles (PP or pp).

Heterozygote

Two different alleles (Pp).

Genotype

The actual alleles (PP, Pp, pp).

Phenotype

What you see (purple, white).

Zygote

First cell after fertilization.

Gene

DNA section that controls a trait.

Locus

Place on the chromosome where a gene is.

True breeding

Always makes same traits.

Parent generation (P)

Original parents.

F1, F2

First and second offspring generations.

Backcross

Offspring crossed with a parent.

Self cross

Plant fertilizes itself.

Test cross

Checks if a dominant trait is homozygous or heterozygous.

Monohybrid cross

One trait cross.

Dihybrid cross

Two traits cross.

Trihybrid cross

Three traits cross.

Law of Segregation

Alleles separate when gametes form.

Law of Independent Assortment

Traits inherited independently.

Punnett square

Shows possible offspring from a cross.

Incomplete dominance

Blended trait (pink from red + white).

Multiple alleles

More than 2 versions of a gene.

Sex-linked/X-linked trait

Gene on X chromosome.

Lethal allele

Can cause death if two copies are present.

Pedigree

Family tree showing traits.

Probability

Chance of an event happening.

Multiplicative law (AND)

Multiply probabilities for multiple events.

Additive law (OR)

Add probabilities for multiple ways an event can happen.

Chromosomal crossover

Genes swapped during meiosis.

Epistasis

One gene hides another gene’s effect.