Chromosomes & Telomeres

Front 1

Who came up with the theory of genes being on Chromosomes?
when?

Back 1

Walter Sutton
Theodor Bovary
1902

Front 2

Procaryote stats?

Back 2

1n* haploid
vegetative

Front 3

Eucaryote stats?

Back 3

2n diploid somatic
1n haploid germ cell

Front 4

Who proved the Gene on Chromosomes theory?

When?

Back 4

1910
Thomas Hunt Morgan

Front 5

fill in the blanks

Back 5

Front 6

How much does an organisms chromosome count vary?
how many pairs do humans have?
how many pairs does a potato have?
drosphilia?

Back 6

-A lot (4-24...)
-23
-24
-4

Front 7

how much does human chromosome size vary?
what are some chromosome sizes?
X?
Y?

Back 7

Chr. 1 - 247 mb (mb= 10^6 bp)
Chr. 21 - 47 mb
X Chr. - 155 mb
Y Chr. - 56 mb

Front 8

What are these?

Back 8

Front 9

What makes up the structure of chromosmes?

Back 9

Condensed Nucleoprotein Complex
 (DNA & Protein)

Front 10

What's Condensed Nucleoprotein Complex?

Back 10

DNA & protein are always bound together, should be what we refer to, rather than just DNA

Front 11

What's an abundant example of a nucleoprotein?

Back 11

Histones (small, abundant)

Wide variety of non-histone proteins:
transcription DNA --> RNA
replication DNA --> DNA

Front 12

Are histones basic or acidic?
Who discovered them? When?

Back 12

Basic (Lys+, Arg+)
Albrecht Kossel (1884)

Front 13

1) What is this?
2) What process is this showing?

Back 13

2) condensation - first order

Front 14

What are the types of histones?
Which is the linker histone?

Back 14

H2A 13.9 kD
H2B 13.8 kD
H3 15.3 kD
H4 11.3 kD
H1 17-28 kD (LINKER)

Front 15

*What is an example of histone conservation?

Back 15

High level amino acid similarity (homology)

Cow Vs Garden Pea
H4 2% difference
H1 75% difference

Front 16

Catalysis or Regulation:

Replication = DNA >>> ?

Transcription = DNA >>> ?

Back 16

Rep: DNA >>> DNA
Trans: DNA >>> RNA

Front 17

What process is this?
What order?
What formation?

Back 17

Chromosome Condensation
2nd order
Solenoid formation (old telephone cord) 25nm

Front 18

What is this process?
What order?
What model is it?
What evidence supports this model?

Back 18

-Chromosome condensation
-3rd order
-Radial Loop Model
  Topoisomerase I & II (twists DNA after looping it)
  supercoiling
-no evidence

Front 19

Which model of chromosome condensation is believed?
What enzymes/proteins are used?

Back 19

 Axial glue model
  -Topoisomerase II: introduces super coil similar to what was theorized in Radial loop model, uses 2 stranded cut.
  -SCM2 (condensin)

Front 20

How do Topoisomerase I & II differ?
what process are they part of?

Back 20

Topo I: releives super coils, 1 stranded cut
Topo II: introduces super coils, 2 stranded cut

chromosome condensation

Front 21

What is heterochromatin?
What are the types?

Back 21

-DNA wound so tight becomes inactive
-Facultative

Front 22

What are these?
how do they differ?

Back 22

Front 23

Back 23

Front 24

what's a kinetochore?

Back 24

Protein/Riboprotein discs
Spindle microtubule attachment

Front 25

What is the primary constriction on a chromosome?

Back 25

Centromere
DNA ~220 bp

Front 26

Back 26

Front 27

What are telomeres?
Why are they important?

Back 27

-Chromosome ends
  Repeated sequences (50-70)
  Lengths vary within & between species
-Protect chromosome ends
-Distinguish ends from broken DNA
-Mechanism for “counting” cell divisions (Mitotic Clock)

Front 28

***
what is this?
when does this happen?
why?

Back 28

-Chromosome Shortening
-Shortens with cell division

-End Replication Problem
 problem with linear DNA

-Each round >>> 30-200 bp unreplicated at 3’
end
  Loss of chromosome sequence
  Telomeres protect coding sequence

Front 29

What type of replication is done by DNA?

Back 29

bidirectional

Front 30

What is DNAP?
What replication is used?
what does it require?

Back 30

DNA polymerase:
>enzyme that synthesizes DNA molecules from their nucleotide building blocks.
>essential for DNA replication
>function in pairs while copying 1 double-stranded DNA molecule into 2 double-stranded DNAs (semiconservative DNA replication).

-undirectional

-requires RNA primer (can't replace w/ DNA)

Front 31

Which DNA end is bp lost in a cell division?
how many?

Back 31

3' end
30-200 bp

Front 32

How are telomeres synthesized?
Which protein is used?

Back 32

Telomerase
TERT
Guide RNA (TERC)

Front 33

what does TERT stand for?
what process is it used in?
what does it do?

Back 33

-Telomerase reverse transcriptase
(protein)
-Telomere Synthesis
-catalytic subunit of the enzyme telomerase, which, together with the telomerase RNA component (TERC), comprises the most important unit of the telomerase complex.

Front 34

what does TERC stand for?
what process is it used in?
what does it do?

Back 34

-Telomerase RNA component
-Telomere synthesis
-RNA component that serves as a template for the telomere repeat. (guide DNA)

Front 35

who discovered telomere synthesis?
what did they receive?
when?

Back 35

Elizabeth Blackburn
  Carol Greider
  Jack Szostak

 Nobel Prize
2009

Front 36

***
what is this?

Back 36

telomere structure

Front 37

Which genes express telomerase?

Back 37

-Germ cells
-Early embryonic cells
-Some stem cells
-NOT somatic cells


Front 38

what happens to a somatic cell's telomeres?
what's the exception?

Back 38

-Telomeres lose sequence with cell divisions
-Cell on average get 50-60 divisions (hayflick limit)
- cellular senescence (aging)

EXCEPTION: Cancer cells (80-90%)
*Immortalization (1st step in tumoragenesis)

Front 39

Do telomeres cause cancer?
who studied this?

Back 39

-no; Connection but not cause
Immortalization only
No characteristics of cancer cells
-Chromsome instability, loss contact inhibition, serum independent growth, no loss chk. pnt control
-Not tumoragenic in mice
-University of Texas study (Shay & Wright,1998)

Front 40

Back 40

Front 41

what affects telomere length?

Back 41

Cellular aging
  Chronic stress
  Elevated cortisol?
  Increased oxidative stress?

Front 42

How many telomere bp's do human lose per year on average?

Back 42

Human telomere shortening (31-63 bp/yr)

Front 43

how long are human telomeres on average?
in comparison to other primates? mice?

Back 43

5-15 kb; 10 kb ave

Human – other primates (> 23 kb)
Human – mouse (~38 kb)

kb = 7.5 x 10^5 bp

Front 44

what's a hayflick limit?

Back 44

amount a cell can divide before telomeres are critically short
(50 +/- 10 divisions)

Front 45

What are some immune cells with active telomerase?

Back 45

-lymphocytes (white blood cells)
T cells / B cells
-macrophages
-cytocines (trigger inflammatory response, so you want number to be low)

Front 46

loss of telomere sequence activates what?
what happens if it does not activate?

Back 46

p53
(activates p21, which mediates cell cycle)

this process then starts either damage repair or apoptosis
-if cell cycle arrest does not occur then damaged cell continues to replicate, maybe leading to cancer :< (no active P53 = tumors)

Front 47

which gender starts out with more telomeres?

Back 47

women