Chapter 3- Only Forgeting Cards Flashcards
Another word for chromosome
Coloured body given in 1880
When do sister chromatids separate?
Anaphase of mitosis
Anaphase II of meiosis
Cell cycle in order
G1 S phase G2 Mitosis Cytokenesis
Linear DNA with 1 arm in ?
G1 phase
S phase
Anaphase of mitosis
Anaphase of meiosis
Describe chromosomes at interphase
Can be highly condensed and more extended because not all are paired up
Have v specific location
What is the constricted portion of each chromosome
Centromere
What is a constricted (central portion) of each chromosome
This section contains alpha satellite of nucleotide sequence of 171 repetitive
Centromere is always vondensed
Constitutive heterchromatin
Functions of centromere
Hold sisters
Bind to various proteins to facilitate cell division
Attach to kinetechors during M phase
Explain telomere region
Non coding regions of chromosome at the end Short repeated sequence Include specialized proteins Forms a capped end structure Repeat TTAGGGTTAGGGTTAGGG
Function of telomeres
Binds with telomere binding proteins
Protect chromosome
Allow cells to distinguish chromosome ends from broken DNA
Prevent chromosome from fussing with one another
Attachment of DNA to nuclear scaffold
What happens when cell shortens and reach a critical point
Cellular seescense by apoptosis
What is a telomerase
An RNA containing enzyme (riboneucleo protein)
It adds more nucleotide to the 3’ end of telomere
Contain RNA components and enzyme
What is the function of RNA compartment in telomerase
- template for synthesis of its DNA complement- reverse transcription
- acts as a guide to attach to the telomere region
What is the function of enzyme compartment in telomerase
Catalyst
Where is telomerase present in
- primordial germ cells
- cancer cells
- stem cells x although they do shorten over time
- one celled organism
Mutations in DNA can be spontaneous due to - - - —
Repressors
What causes mutations
Ionizing radiation
oxidative
Physical, chemical mitogen
4 types of structure mutation
Duplication - double
Translocation - exchange btw non homologous , in meisois, occurs btw homologous
Inversion - flipped
Deletion
Affects of translation
- chromosome imbalance
- gene fussion activating harmless genes to oncogenes
Human disease related to translation
Chronic myelogenic leukaemia
Explain Chronic myelogenic leukaemia
Reciprocal translation btw 9 and 22 gene
C - ABL - BCR - fussion gene - Philadelphia
Leads to cont stimulation of WBC
2 way translocation
Reciprocal
Ploidy of
Human ——- —
Mouse— — - -
Drosophila————
2n=46
2n=40
2n=80
How are karyotypes observed
Isolating mitotic cells and staining the chromosome
Karyotypes are also called
Painting bodies
Single stranded DNA tagged with fluorescence that hybridizes with DNA in chromosome therefore they will also light up
What lead to evolution , explain
Duplication
There is 98% similarities in non coding seq of humans and chimps
Mutation is number of chromosome is called
Non disjuntion
How does non - disjunction occur
When chromosomes fail to separate in meiosis I and II, gametes end up with more or less chromosome affecting the zygote
In 10,000, 800 chromosomally abnormal leads to 750 spontaneous miscarriage
If more then one chromosome duplicates, it leads to miscarriage
Down syndrome
Usually lethal other then 21 chromosome trisomy
Hay flick lucite
No. Of times a normal cell divides before cell division stops
What is the Chromosome difference btw humans and chimps
A fussion of no. 2 chromosomes in chimps
Humans have lot of duplications in non coding regions
If X and Y undergo non disjunction
Not fatal
3rd in inactive
May be infertile
Tellings of karyotypes
Sex determination in human through presence or absence of Y chromosome
No. Of chromosome in any given organism
Chromosome aberration ( weather there are abnormal no. )
Structural mutations
Cant detect Point mutation
Disorders associated with number mutations
1- Turner syndrome
45 chromosome instead of 46- lack X chromosome
2- kleinfelter syndrome
47 chromosome instead of 46 - gain X chromosome
3- Down syndrome
Trisomy in chromosome number #21
Autosome
4- Edward syndrome
Trisomy in chromosome number 18
Function of satellite DNA
Highly repetitive short DNA sequence
Ensure stability and protection of centromere region
