Lecture 4 and 5 Flashcards
What are sex cells and what are their charateristics?
They are called gamates and have half the number of chromosomes
During fertilization two gamates fuse into one new cell what is that cell called?
Zygot
What are chromosome pairs called?
Homologus chromosomes or homologs since they both code for the same genes just have different expression of them, fort example both can code for hair color but one of the chromosome code for brown hair and one for blonde hair
Wha does haploid and diploid mean?
Haploid half number of chromosome, diploid a set of pair of all chromosomes, twice the number
How is the sex determined by the chromosomes?
Women have at least 2 x chromosomes and men only 1, y chromosome does not determine sex.
What is karyotyping?
Lining up after certain elements suich as size or shape condensed sister chromatids often after meosis or mitosis to visually examine them.
What is the end product of mitosis?
As long as no mutations, 2 daughter cells copies of the maternal cell
What is the end product of meisis I?
After meosis I there is half the number of chromosomes since the homologous pairs segregate forming singular pairs of chromosomes. There is first an duplication so there is two pairs of the sister chromatids, there is a reshuffling and exchange of genetic material at the chiasma then the sister chromatids segregate and form 2 new cells such as mitosis but the daughter cells are not copies of the maternal cell.
What is the end product of meosis II?
There is another cell division resulting in gamates with the number of chromosomes maintained, the chromosomes instead segregate into sister chromatids.
What does the recombination frequence tell us?
How far away the genes are to each other. Linked genes (on the same chromosome) have a lower recombination frequence then independent genes(on different chromosomes) but it can never be greater then 50%
Describe the DNA structure
It’s a polymer made out of monomeres which are the nucleotides adenine that binds to thymine with two hydrogen bonds and guanine that bind to cytosine with three bonds. In RNA instead of thymine there is uracil. The structure of the DNA is two polar anti parallell strands, there is major and minor groves of the DNA helix.
What affects the DNA structure?
hydrophobic effects, wander wals bonds and electrostatic forces as well as the hydrobonds and the covalent bonds.
What affect DNA denaturation(melting point)?
Anything that afects the hydrogen bonds so pH, salt concentration, lenght of the DNA and how many GC bonds there are (since they have three hydrogen bondsthe structure will be more stable and have a higher TM)
Describe how the human genome is divided?
Into nuclea genome and ribosomal genome. The nuclear genome is only 25% genes and of that 90% non coding DNA. The rest of the 75% are exhagenic DNA which is the space between two genes.
What are the ratio and function of repetetive DNA?
It’s about 40-60% repetitive DNA and they function such as CpG islands and telomeres.
