IMMS Flashcards
How many chromosomes are in a normal human somatic cell?
46
What separates the p and q arms in a chromosome?
the centromere
How many daughter cells are produced in mitosis?
2
Describe a cell’s position in the cell cycle if it is in G0?
It is not in the cell cycle
What replicates in the synthesis phase of the cell cycle?
DNA and the centrosome
What happens during prophase?
- Chromatin condenses into chromosomes
- Nuclear membrane starts to break down
- Centrosomes move to opposite poles of the cell and nucleate microtubules
What happens during prometaphase?
- The nuclear membrane breaks down and the chromosomes are released into the cytoplasm
- Chromatids attatch to microtubules
What happens during metaphase?
Chromosomes line up along equatorial plane of cell (metaphase plate forms)
What happens during anaphase?
Microtubules shorten and pull the identical chromatids apart towards opposite poles of the cell
What happens during telophase?
- Nuclear membrane reforms
- Chromosomes unfold into chromatin
- Cytokinesis begins
Which chromosomal disease is trisomy 21?
Down syndrome
How many daughter cells are produced in meiosis?
4
When can crossing over occur in meiosis?
prophase 1
spermatogonia are formed from the division of what type of cells?
Primordial germ cells
How many days does it take for spermatozoa to mature?
60-65
What does non-disjunction result in?
an abnormal number of chromosomes
When does germline mosaicism occur?
when precursor germline cells to ova or spermatozoa are a mixture of two or more genetically different cell lines
What is a somatic cell?
any cell apart from a reproductive cell
What is the word for programmed cell death?
apoptosis
What is a geneotype?
The genetic constitution of an individual
What is a polymorphism?
frequent hereditary variation at a locus
What does hemizygous mean?
Only one allele
What would the karyotype of a male with Down syndrome be?
47XY+21
What is an autosomal recessive disease?
Disease that manifests in the homozygous state