Cell reproduction and the Continuity of Life: DNA Flashcards
Test review
What is the nucleus?
Cell’s control centre that is surrounded by the nuclear membrane. Contains chromatin which is made up of genes, which are made up of DNA molecules.
What is a gene?
Segment of DNA located on a chromosome. Each one codes for a specific protein which has some function in or creates some structure in our body. Different ones have different locations on chromosomes.
What is a chromosome?
Coiled up and condensed chromatin and associated proteins.
What is chromatin?
DNA when it exists as long threads, before coiling up into a chromosomes.
What is a DNA double helix?
The twisted ladder shape of a DNA molecule.
What is the diploid (2n) number?
46 chromosomes in humans. Found in body/somatic cells.
What is the haploid (n) number?
23 chromosomes in humans. Always half of the diploid number, found in sex cells/gametes.
What are autosomes?
22 pairs of body chromosomes that do not directly determine gender.
What are sex chromosomes?
1 pair of chromosomes that directly determine gender (XX or XY).
What are gametes?
Sex cells, eggs (Oocytes) and sperm (spermatocytes).
What is fertilization?
Fusion of the genetic material of male and female gametes.
What is a zygote?
Single cell formed from fertilization.
What are homologous chromosomes?
Chromosome pairs similar in size and shape. Have same centromere and banding pattern, but they are not identical even though they have similar genetic content. Humans have 23 homologous pairs, though males only have 22 (Sex chromosome pair is not homologous in them).
What is synapsis?
Process by which homologous chromosomes pair up in prophase 1.
What is a tetrad?
Group of 4 chromatids from 2 chromosomes.
