The cell cycle and cell divison Flashcards
What’s a chromatid?
One of the two identical copies of a chromosome, joined at the centromere prior to cell division.
What’s a centromere?
Specialised region of a chromosome where two chromatids join and to which the microtubules of the spindle attach at cell division.
What’s the structure of chromosomes?
- DNA
- Protein called histone
- DNA molecule double helix
- Sections run long its length called genes
- Chromosomes become visable when chromatin condenses prior cell division after DNA replicated and made exact copy of itself
- -2 copies= sister chromatids
- lie paprellel
- joined together by centromere
How many body cells do humans have?
46 chromosomes
What does diploid mean?
Having two complete set of chromosomes.
What does haploid mean?
Having one compete set of chromosomes
What does homologous mean?
Identical in size and shape and they carry the same gene loci, with genes for the same characterists. One chromosome of each pairs of sex chromosomes, such as the y and x in male mammals are different sizes and are not humongous pairs.
What’s the haploid symbol?
n
How many homologous pairs of chromosomes do human cells have?
23
What’s the diploid symbol?
2n
What’s the name given to the number of complete sets of chromosomes?
Ploidy level
What’s the name given to organisms with more than two compete sets of chromosomes?
Polyploid
What’s mitosis?
A type of cell division in which the two daughter cells have the same number of chromosomes and are genetically identical with each other and the parent cell.
What are the 4 stages of mitosis?
1) Prophase
2) metaphase
3) anaphase
4) telophase
The division of the cytoplasm to form two daughter cells- What’s this called?
Cytokinesis
