Ch 6 From Chromosomes to Genomes

Vocabulary flashcards covering the basics of genetics, DNA structure, genomics, chromosome variations, and the stages of meiosis.

Hereditary

The study of inheritance, which is the transmission of genes from one generation to the next.

Genes

Lengths of DNA, made up of a sequence of nucleotides that code for a specific protein.

Gene locus

The specific physical position of a gene on the DNA or chromosome.

Alleles

Different versions or alternative forms of a gene that occupy the same locus but have slightly different base sequences.

DNA (Deoxyribonucleic acid)

A large macromolecule in the form of a double polymer composed of two long strands of nucleotides wound in a Double Helix.

Polymer

A long macromolecule made up of repeating subunits or monomers.

Nucleotide

A subunit of DNA consisting of a $5$-carbon deoxyribose sugar, a negatively charged phosphate group, and a nitrogenous base.

Nitrogenous Bases

The four kinds of molecules in DNA that pair together: Adenine (A), Thymine (T), Guanine (G), and Cytosine (C).

Complementary Base-pairing Rule

The rule stating that Adenine (A) always pairs with Thymine (T) and Cytosine (C) always pairs with Guanine (G).

Genome

The sum of all DNA in an organism, measured in the number of nucleotide bases in a haploid set of chromosomes.

Genomics

The study of genomes, including the mapping and sequencing of all base pairs in a species.

Bioinformatics

The science of managing and analysing biological data using advanced computing techniques, often used to compare gene sequences and diagnose infections.

Histone proteins

Proteins that DNA molecules wrap around to condense into visible chromosomes during mitosis.

Chromatids

The two halves of a replicated chromosome, often called sister chromatids, which are connected at the centromere.

Centromere

The point of connection between two sister chromatids in a replicated chromosome.

Telomere

A structure located at the ends of a chromosome.

Karyotype

An arrangement of all the chromosomes of a cell, showing them in pairs of various sizes and centromere positions.

Autosomes

The $22$ pairs of human chromosomes that are homologous (similar in size and shape) and do not determine sex.

Sex chromosomes

The final pair of chromosomes that determine gender; matched in females ($XX$) but unmatched in males ($XY$).

Diploid ($2n$)

The number of chromosomes in a somatic cell, representing the normal pairing of homologous chromosomes inherited from two parents.

Linked genes

Genes located on the same chromosome that tend to be inherited together.

Aneuploidy

A condition where there is an addition or loss of one chromosome from a cell (e.g., $n+1$ or $n-1$), usually resulting from non-disjunction.

Non-disjunction

The incorrect separation of homologous chromosomes during gamete formation (meiosis).

Trisomy

A type of aneuploidy where a gamete has one extra chromosome.

Monosomy

A type of aneuploidy where a gamete has one less chromosome.

Polyploidy

A condition where a cell has extra sets of homologous chromosomes (e.g., $3n$, $4n$, $6n$); common in plants but lethal in humans.

Meiosis

A complex process of cell division consisting of two successive divisions that results in four haploid gamete cells.

Independent assortment

The process during meiosis where the chromosomes of each homologous pair separate to each gamete at random.

Synapse (Bivalent)

The pairing of homologous chromosomes during Prophase I of meiosis.

Crossing over

The exchange of genetic material between homologous chromosomes occurring at the chiasmata during Prophase I.

Monoploid

Fully functioning organisms (such as some male colony insects) that have only one copy of each chromosome ($1n$).

Parthenogenesis

A process where an entire organism is created from a single haploid egg without fertilization.

Cytosol

The region in a prokaryote cell where the single circular chromosome is found, as there is no nucleus.

Plasmids

Small rings of DNA found in prokaryotes that can replicate independently of the main chromosome.

Mitochondrial DNA

Circular DNA found in mitochondria that codes for some mitochondrial proteins and is inherited only from the mother.

Endosymbiotic theory

The theory that eukaryotic organelles like mitochondria and chloroplasts evolved from free-living prokaryotes that were engulfed by an ancestral host cell.