Van Gen naar Eiwit: Het Erfelijk Materiaal

Flashcards covering human genetics, chromosome structure, DNA composition, karyotyping, and mitochondrial inheritance based on the lecture material.

DNA (Deoxyribonucleic Acid)

A double helix molecule that carries genetic instructions; in humans, each cell nucleus contains an identical complement of chromosomes made of DNA.

Karyogram

A visual representation of the complete set of chromosomes in a cell, ordered by criteria such as size, centromere position, and banding pattern.

Homologous Chromosomes

A pair of chromosomes (one from each parent) that are similar in shape, size, and genetic content; humans have 2 sets of 23 different chromosomes.

Autosomes

The 44 chromosomes in a human karyotype that are not involved in determining sex.

Sex Chromosomes

The pair of chromosomes (X and Y) that determine the biological sex of an individual; females are XX and males are XY.

Metacentric Chromosome

A chromosome where the centromere is located in the middle, making the arms (p and q) roughly equal in length.

Submetacentric Chromosome

A chromosome where the centromere is positioned such that one arm is clearly shorter than the other.

Acrocentric Chromosome

A chromosome where the centromere is located very near one end, resulting in a very short p arm.

Heterochromatin

Densely packed, transcriptionally inactive DNA that appears as dark bands on a chromosome.

Euchromatin

Loosely packed, transcriptionally active DNA that appears as lighter bands on a chromosome.

Band Number 7q36

A specific location on a chromosome referring to the long arm (q) of chromosome 7, zone 3, band 6.

47, XY, +21

A male karyotype with 47 chromosomes, including an extra copy of chromosome 21 (Down syndrome).

45, X

A female karyotype with 45 chromosomes, where one X chromosome is missing (Turner syndrome).

Nucleotide

The basic building block of DNA, consisting of a phosphate group, a deoxyribose sugar, and one of four nitrogenous bases.

Purines

Category of nitrogenous bases with a double-ring structure, including Adenine (A) and Guanine (G).

Pyrimidines

Category of nitrogenous bases with a single-ring structure, including Cytosine (C) and Thymine (T).

Phosphodiester Bond

The chemical bond that links the $5'$ phosphate group of one nucleotide to the $3'$ hydroxyl group of the sugar of the next nucleotide.

Watson-Crick Base Pairs

The specific pairing rules in DNA where Adenine (A) pairs with Thymine (T) and Cytosine (C) pairs with Guanine (G).

Minor and Major Grooves

Indents in the DNA double helix caused by the offset of the sugar-phosphate backbones; the major groove is typically $2.37\,nm$ and the minor groove is $3.40\,nm$ (pitch).

Nucleosome

The fundamental unit of chromatin, consisting of DNA wrapped around a core of histone proteins, often described as 'beads-on-a-string'.

30 nm Fiber

A level of DNA organization where nucleosomes are coiled into a thicker chromatin fiber.

Exons

The coding sequences of a gene that remain in the final mature RNA and represent about $2\%$ of the human genome.

Introns

Non-coding sections of a gene that are removed during processing; they account for about $23\%$ of the human genome.

STR (Short Tandem Repeats)

Also known as microsatellites; small repetitive DNA sequences of 2-10 base pairs, such as $(CA)_n$ or triplet repeats.

VNTR (Variable Number of Tandem Repeats)

Also known as minisatellites; larger repetitive DNA sequences ranging from 10-60 base pairs.

Retrotransposon

A type of mobile genetic element that moves via an RNA intermediate using reverse transcriptase (e.g., Alu repeat).

mtDNA (Mitochondrial DNA)

Small circular DNA found in mitochondria, approximately $16,000\,bp$ long, which is maternally inherited and mutates 20 times faster than nuclear DNA.

Heteroplasmy

The presence of more than one type of mitochondrial DNA genome within a single cell or individual.