Genetics and Inheritance

DNA, cell division,

Genome

All the genetic information of a human (height, weight, diseases, eye colour, etc.)

DNA

carries genetic information (Genome is stored in DNA)

DNA is the genetic blueprint which codes for, and determines, the characteristics of an organism.

This includes the physical, behavioural and physiological features of the organism.

Nucleotide

A structural unit of DNA, composed of a sugar, phosphate, and nitrogenous base.

Nitrogenus bases

the pairs of complementary nitrogenous bases to form the rungs of the DNA ladder.

(Adenine + Thymine, Guanine + Cytosine)

Backbone of DNA includes:

Phosphate and sugar (five-sided)

Hydrogen bond

A weak bond joining the nitrogenous bases

Autosome

normal body cells (not sex cells)

Gamete

A reproductive cell of an animal or plant (sperm and egg cells)

Homologous

Matching pair of chromosomes in our body cells.

Non-homologous

The non-matching chromosomes that determine gender (sex cells)

Diploid

It is the number of chromosomes in an autosome. It contains two sets of complete chromosomes. (23 from each parent, 46 in total - humans)

Haploid

Number of chromosomes in a sex cell (23 for humans). Haploid number is half the diploid number.

Chromosome

A thread like structure located inside the nucleus of cells that carries genetic information in the form of DNA. Chromosomes are also DNA coiled up before cell division.

Sister chromatid

Identical copies of a chromosome, joined together by a centromere, which is formed during DNA replication prior to cell division.

Centromere

A specialized region on a chromosome that serves as the attachment point for spindle fibres during cell division

Spindle fibres

Protein structures that form a framework during cell division

Nondisjunction

Incorrect distribution of chromosomes

Karyotype

A laboratory produced micrograph of a person's chromosomes isolated from an individual cell's nucleus

Trisomy

A zygote with 3 copies of a chromosome

Monosomy

A zygote that is missing a chromosome

Zygote

A fertilised egg that will develop into a foetus

Mitosis

The type of cell division involved in growth, development, repair of tissue and asexual reproduction.

Parent Cell

The cell that splits into two to create two daughter cells

Daughter Cell

One of two cells that is genetically identical to a parent cell

Spindles

The fibers that the chromosomes attach to during mitosis