| what is the process of autoradiography? | 1) chromsome |
| What are homologous chromosomes? | same structure and loci positions |
| What is another name for a chromosome? | chromatid |
| What determines child's sex? | the Y chromosomes from the sperm, if present child will be male |
| what are heterosomes? | chromosomes that determine sex |
| what are autosomes? | chromosomes that don't determine sex (in body cells) |
| what is the difference in chromosome structure in eukaryotes and prokaryotes? (5 each) | pros:
genophore and plasmid
not membrane bound
not protein bound
compact (no introns)
horizontal gene transfer of plasmids with sex pili
euks:
linear chromosomes
membrane bound
bound with histone proteins
compact for better storage |
| what is the order of organisation for DNA? (7) | 1) DNA
2) Nucleosome
3) Chromatosomes ( linked with H1 histone)
4)Solenoid
5) 30 nm fibre
6) chromatin
7) chromosome |
| which organells have DNA? | chloroplast and mitochondria =can do self replication |
| what are karotypes? How are they seen? what can be found out with them? | number and type of chromosomes seen by:
harvesting cells from fetus / WBC
induced cells (condensed DNA)
fetus gender
chromosome abnormalities |
| what is autoradiography used for? | imaging technique that uses radioactive sources to measure DNA length because in mitosis DNA is too compacted to be accurate |
| how does down syndrome affect the chromosomes?
how does it happen? | Trisomy of chromsome 21 (3 copies) caused by no separation of chromosomes in mitosis (non-disjunction) |
| what is amniocentesis? what are the problems surrounding it? | used to detect chromosomal abnormalities in fetus
collected from anmniotic fluid at 16 weeks
0.5% risk of miscarriage |
| what is chorionic villi sampling? problems? | used to detect chromosomal abnormalities
from placental tissue at 11 weeks
1% chance of miscarriage |
| what are chromosomes? | single double stranded DNA molecule |
| what is the process of autoradiography? (6) (hint: AgBr and RA) | 1) cells grown in radioactive thymidine and is mixed with the DNA
2) cells are lysed to isolate chromosomes and embedded on a slide
3) placed in RA sensitive mixture of AgBr (silver bromide)
4) radiation from thymidine changes Ag+ = insoluble Ag
5) excess AgBr is washed away = leaving Ag (small black dots)
6) film develops to show chromosomal DNA |
| What are the other discoveries with autoradiography about DNA? (3) | DNA replication forms a replication bubble
pro replication as a single origin of replication
DNA replication is bidirectional and independent |
