Chapter 4a - Chromosomal Basis of Heredity Flashcards
no. of chromosomes in prokaryotes
single chromosome + plasmids
no. of chromosomes in eukaryotes
many chromosomes
shape of chromosomes in prokaryotes
circular chromosome
shape of chromosomes in eukaryotes
linear chromosomes
component of chromosomes in prokaryotes
DNA
component of chromosomes in eukaryotes
chromatin, a nucleoprotein (DNA coiled around histone proteins)
location of chromosomes in prokaryotes
cytoplasm
location of chromosomes in eukaryotes
nucleus
duplication of chromosomes in prokaryotes
copies its chromosomes and divides immediately afterwards
duplication of chromosomes in eukaryotes
- copies chromosome
- cell grows
- goes through mitosis to organize chromosomes into 2 equal groups
chromosomes in eukaryotes during cell division
condensed and visible
at the beginning of mitosis, eukaryotic chromosomes can be seen to consist of what
two threads (sister chromatids) joined by a centromere
specific region of the eukaryotic chromosome where the kinetochore attach and pull the chromosomes during both mitosis and meiosis
centromere
complex of DNA and proteins to which the spindle fibers attach
kinetochore
Centromeric positions
- metacentric
- submetacentric
- acrocentric
- telocentric
centromere is median
metacentric
centromere is submedian
submetacentric
centromere is subterminal
acrocentric
centromere is terminal
telocentric
parts of chromosome
- p (upper)
- q (bottom)
ends of chromosome
GT rich repetitive sequences
shortens with age
telomere length
role of telomere
protects end of chromosome from deterioration
cell aging
senescence
cell death
apoptosis
telomere and cancer
do not shorten
sequence of telomere
TTAGGG (500-3000 times)
- constant for each cell in the body (except sex cells)
- constant throughout the life of an individual
- constant for all members of a species
chromosome number
Cell Division stages
- Interphase
- Prophase
- Metaphase
- Anaphase
- Telophase
- Cytokinesis
3 stages of Interphase
- G1 phase
- S phase
- G2 phase