Chromosomes & Genes Flashcards
1
Q
what are the 4 steps of DNA condensation in eukaryotes ?
A
- Chromatin formation
- Filament formation
- Scaffold formation
- Metaphase chromosome formation
2
Q
condensation stage 1 : chomatin formation
A
- Coild of DNA are wrapped around histones
- structure resemles beads on a string (nucleosome)
3
Q
condensation stage 2:
Filament formation
A
- nuceosome chromatic structure contains DNA that is only visible witha low-salt buffer
- structure transitions into ribbon like (FILAMENT)
4
Q
condensation stage 2:
Filament formation
A
- nuceosome chromatic structure contains DNA that is only visible witha low-salt buffer
- structure transitions into ribbon like (FILAMENT)
5
Q
Condensation Stage 3: Scaffold Formation
A
- 30nm filament is further looped and anchrored around the chromosome scaffold at specific points
- structure: loosly condensed loops
5
Q
Condensation Stage 3: Scaffold Formation
A
- 30nm filament is further looped and anchrored around the chromosome scaffold at specific points
- structure: loosly condensed loops
6
Q
Condensation Stage 4:
Metaphase Chromosome
A
- compact phase of DNA is only vivisible during mitosis
- at metaphase compact chromosomes line up at equator of the cell and become visible under microscope
7
Q
Condensation Stage 4:
Metaphase Chromosome
A
- compact phase of DNA is only vivisible during mitosis
- at metaphase compact chromosomes line up at equator of the cell and become visible under microscope
8
Q
how many individual chromosomes do humans contain ?
A
46
9
Q
what is a gene ?
A
A segment of DNA that contains the instructions for making a particular protein
9
Q
what is a gene ?
A
A segment of DNA that contains the instructions for making a particular protein
10
Q
what is the display of the 46 human chromosomes at mitosis called ?
A
human karyotype
11
Q
across how many autosomes are genes distributed ?
A
- 22 autosome
& - 2 sex chromosomes
