Comprehensive Genetics: Classical, Molecular, Cytogenetics, and Cell Division

Vocabulary practice flashcards covering all primary topics across 9 biology lecture notes: history of genetics, DNA/RNA molecular structure, replication, protein synthesis, gene mutations, transcriptional regulation (lac operon and eukaryotic factors), mitosis, and meiosis.

Genetics (Genetika)

The biological science that studies heredity and the inheritance of traits.

Classical (Mendelian) Genetics

The branch of genetics founded by Gregor Mendel ($1822-1884$), who crossed pea plants with differing traits to study inheritance patterns and formulate the laws of inheritance at the organismal level.

Cytogenetics

The branch of genetics established by Thomas Hunt Morgan ($1866-1945$), who studied fruit flies to demonstrate that hereditary factors are located on chromosomes, examining inheritance at the cellular level.

Molecular Genetics

The branch of genetics initiated by the discovery of the double-helix structure of DNA in $1953$ by James Watson, Francis Crick, and Rosalind Franklin.

Genetic Engineering (Genetičko inženjerstvo)

The modern field of genetics focused on the direct manipulation and alteration of genetic material.

Population Genetics

The subfield of genetics that investigates patterns of heredity and gene dynamics at the population level.

Evolutionary Genetics

The field of genetics that provides molecular and hereditary evidence supporting Charles Darwin's theory of evolution.

Phenotype (Fenotip)

The observable physical characteristics, organ size, physiological processes, intellectual abilities, or individual traits of an organism, directly determined by proteins.

Genotype (Genotip)

The complete set of genes or specific individual genes in an organism that provide instructions for protein synthesis.

Nucleotide

The basic monomer of nucleic acids, consisting of a phosphate group ($PO_4^{3-}$), a five-carbon sugar (deoxyribose or ribose), and one of four nitrogenous bases.

Purine Bases

Nitrogenous bases containing two carbon-nitrogen rings: Adenine ($A$) and Guanine ($G$).

Pyrimidine Bases

Nitrogenous bases containing a single ring: Cytosine ($C$) and Thymine ($T$) in DNA, or Uracil ($U$) in RNA.

Phosphodiester Linkage

The covalent bond that connects adjacent nucleotides in a single polynucleotide strand between the $5'$ phosphate of one nucleotide and the $3'$ carbon of the deoxyribose of the next.

Complementary Base Pairing Rule (DNA)

The specific pairing across antiparallel strands where Adenine pairs with Thymine via 2 hydrogen bonds ($A=T$) and Cytosine pairs with Guanine via 3 hydrogen bonds ($C \equiv G$).

DNA Double Helix Dimensions

A DNA molecule has a uniform diameter of $2\,\text{nm}$, with each full helical turn measuring $3.4\,\text{nm}$ and containing 10 base pairs.

Gene (Gen)

A specific sequence of sequentially linked nucleotides (averaging approximately $1345\,\text{bp}$) that carries the genetic code to synthesize a specific protein.

Genome (Genom)

The complete, total set of DNA sequences contained within a single cell or organism.

Semiconservative Replication

The mechanism of DNA duplication where the parental double helix unwinds and separates, resulting in two daughter molecules that each consist of one original template strand and one newly synthesized strand.

DNA Polymerase

The primary enzyme responsible for synthesizing new DNA strands in the $5' \rightarrow 3'$ direction by adding complementary nucleotides to the template strand.

Ribonucleic Acid (RNA)

A single-stranded nucleic acid composed of ribose sugars, phosphate groups, and the bases Adenine, Uracil, Cytosine, and Guanine.

Messenger RNA (mRNA)

The RNA transcript that carries the protein-building instructions copied from the template DNA in the nucleus to the ribosomes in the cytoplasm.

Transfer RNA (tRNA)

The RNA molecule that transports specific amino acids to the ribosome during translation, matching its anticodon to the corresponding mRNA codon.

Ribosomal RNA (rRNA)

The structural and functional RNA component that combines with proteins to construct the ribosome.

Amino Acid

The fundamental monomer of proteins, characterized by a central carbon bound to an amino group ($-NH_2$), a carboxyl group ($-COOH$), and a variable side chain ($R$).

Peptide Bond

The covalent linkage formed between the carboxyl group of one amino acid and the amino group of an adjacent amino acid during protein synthesis.

Transcription (Transkripcija)

The enzymatic process in the cell nucleus where genetic instructions from a DNA coding strand are transcribed into a complementary mRNA molecule.

Translation (Translacija)

The cytoplasmic process at the ribosome where the codon sequence of an mRNA molecule is decoded into a specific sequence of amino acids to form a protein.

Genetic Code (Kod)

A sequence of 3 consecutive nucleotides on a DNA strand that codes for a specific amino acid, yielding $4^3 = 64$ possible triplets for the 20 biological amino acids.

Codon (Kodon)

A triplet of three consecutive nucleotides on an mRNA molecule that corresponds to a specific amino acid, a start signal, or a stop signal.

Anticodon (Antikodon)

A triplet of three nucleotides located on a tRNA molecule that base-pairs complementarily with an mRNA codon during translation.

Start Codon

The specific mRNA triplet $AUG$, coding for Methionine (Met), which initiates all protein synthesis.

Stop Codons

The three mRNA triplets ($UAA$, $UAG$, and $UGA$) that signal the termination of translation and do not encode an amino acid or pair with a standard tRNA anticodon.

Point Mutation (Točkasta mutacija)

A permanent structural alteration occurring in a single nucleotide base pair within a DNA sequence.

Base Substitution (Supstitucija)

A point mutation wherein one nucleotide base pair in the DNA sequence is replaced by a different base pair.

Base Addition (Adicija)

A mutation involving the insertion of an extra nucleotide base pair into a DNA strand.

Base Deletion (Delecija)

A mutation characterized by the loss or removal of a nucleotide base pair from a DNA sequence.

Missense Mutation (Zamjenska mutacija)

A mutation where a nucleotide alteration changes a codon so that it codes for a different amino acid (e.g., Phe to Leu).

Nonsense Mutation (Besmislena mutacija)

A mutation that converts an amino acid-specifying codon into a premature STOP codon, yielding a truncated, nonfunctional protein.

Silent Mutation (Istoznačna mutacija)

A base change in a codon that, due to the degeneracy of the genetic code, continues to specify the same amino acid, resulting in no change to protein function.

Frameshift Mutation (Pomak okvira čitanja)

A mutation resulting from the addition or deletion of nucleotide pairs that disrupts the triplet reading frame downstream, altering the entire amino acid sequence.

Mutagens

External physical factors (such as X-rays, UV radiation, and heat) or chemical agents (organic and inorganic compounds) that damage DNA and induce mutations.

Spontaneous Mutations

Genetic mutations that arise naturally within an organism without an identifiable external physical or chemical cause.

Promoter (Promotor)

A specific regulatory region of DNA located upstream of a gene where RNA polymerase and transcription factors bind to initiate transcription.

Operator

A regulatory DNA sequence in prokaryotes situated between the promoter and structural genes to which a repressor protein can bind.

Lac Operon

An inducible gene regulatory system in Escherichia coli controlling the transcription of genes for lactase synthesis; blocked by a repressor in the absence of lactose, but transcribed when lactose is present.

Transcription Factors (Transkripcijski čimbenici)

Proteins in eukaryotes that bind to promoter regions to regulate the activation, rate, and inhibition of gene transcription.

Cellular Differentiation (Diferencijacija stanica)

The developmental process by which unspecialized cells acquire specific structures and functions due to the asymmetric distribution of maternal transcription factors in the zygote activating distinct subsets of genes (approx. $15\%$ per cell type).

Histones

Basic nuclear proteins around which chromatin DNA threads wrap to package DNA into compact chromosomes.

Sister Chromatids

Two identical copies of a replicated chromosome joined together at a central region known as the centromere.

Centromere (Pričvrsnica)

The specialized DNA region of a duplicated chromosome that holds sister chromatids together and serves as the attachment point for spindle fibers.

Diploid ($2n$)

A cell or organism carrying two complete sets of chromosomes ($2n = 46$ in humans), typical of somatic cells.

Haploid ($n$)

A cell containing a single set of unpaired chromosomes ($n = 23$ in humans), characteristic of mature gametes (sperm and egg cells).

Interphase

The non-dividing stage of the eukaryotic cell cycle comprising the $G_1$ phase (protein synthesis and cell growth), $S$ phase (DNA replication), and $G_2$ phase (preparation for division).

Mitosis

The nuclear division of somatic cells that separates sister chromatids to produce two genetically identical daughter cells retaining the diploid chromosome number ($2n$).

Prophase (Mitosis)

The first phase of mitosis where chromatin spiralizes into visible chromosomes, the nuclear envelope degrades, and centrosomes construct the mitotic spindle.

Metaphase (Mitosis)

The stage of mitosis where duplicated chromosomes align along the equatorial plane (metaphase plate) and attach via their centromeres to spindle fibers.

Anaphase (Mitosis)

The mitotic stage where spindle fibers shorten, pulling sister chromatids apart toward opposite poles of the cell as single chromosomes.

Telophase and Cytokinesis

The final stage of cell division where two new nuclear envelopes assemble around single chromosomes and the cytoplasm divides, yielding two distinct daughter cells.

Meiosis

A two-stage reduction division occurring in gonads (testes and ovaries) that reduces chromosome ploidy from diploid to haploid ($2n \rightarrow n$), generating four genetically diverse gametes.

Homologous Chromosomes

Pairs of matching maternal and paternal chromosomes (23 pairs in humans) that have the same shape, size, and carry genes for the same traits.

Conjugation (Konjugacija)

The physical pairing of maternal and paternal homologous chromosomes during Prophase I of meiosis to form bivalents.

Bivalent

A four-chromatid structure formed by the tight synapsis and alignment of a pair of homologous chromosomes during Meiosis I.

Crossing Over

The reciprocal exchange of genetic material between non-sister chromatids of homologous chromosomes during Prophase I, producing recombinant chromosomes.

Anaphase I (Meiosis)

The meiotic stage where homologous pairs are separated and pulled to opposite poles as intact, duplicated chromosomes, directly achieving ploidy reduction ($2n \rightarrow n$).

Meiosis II

The second meiotic division, mechanistically identical to mitosis without an intervening DNA replication, which separates sister chromatids into four haploid, genetically unique single-chromatid gametes.