Lecture 10 + 11 (12) Flashcards Preview

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Flashcards in Lecture 10 + 11 (12) Deck (48):
1

What is the Position effect?

Due to translocations gene expression may come under the control of different regulatory sequences

2

Neurofibromatosis is...
How was it mapped

-genetic disease with numerous fibrous tumours of the skin and nervous system
-was mapped using translocation break points

3

Abnormal meiotic configurations can result from

Tranlocations

4

Translocations involve the movement of genetic material between...

nonhomologous chromosomes and within the same chromosome

5

What are the 2 types of translocations

reciprocal and nonreciprocal

6

how does genetic material move in Nonreciprocal translocation

genetic material moves from 1 chromosome to another without any reciprocal exchange

7

Translocation in meiosis __% of gametes of the segregation pattern are viable

50%

8

What are the 3 types of segregation patterns resulting from translocation in meiosis, and what one(s) produce viable gametes
-these are reciprocal or nonreciprocal translocations

-alternate segregation = viable gametes
-adjacent 1 (horizontal) = non viable
-adjacent 2 (vertical) RARE = non viable
are reciprocal translocations

9

A heterozygote with a reciprocal translocation has 1 or both normal and or translocated chromosome

1 normal and 1 translocated chromosome

10

What happens to the recombinants when a translocation heterozygote is testcrossed?
Why is this?

-the recombinants do NOT survive
-they carry unbalanced genomes (duplications and deletions make them nonviable)

11

In a translocation heterozygote testcross what are the viable progeny

progeny with parental genotypes only

12

Genes on translocated chromosomes (that are normally on seperate homologous chromosomes) act as though they are linked, what is this called?

Pseudolinkage

13

What happens in a Robertsonian translocation (x3)

-the short arm of 1 acrocentric chromosome is exchanged with the long arm of another
-Generates 2 metacentric chromosomes, 1 with 2 long arms and 1 with 2 short arms
-the short arm often fails to segregate and is lost
(see pic)

14

Translocation of chromosome 21 (x2) = Familial Down Syndrome

-The long arm of chromosome 21 is attached to the chromosome 14
-The carrier is phenotypically normal but is at risk of producing Down's syndrome children
-4% of ppl with down syndrome have this translocation familial type

15

Of these what ones are aborted and what one(s) result in down syndrome?
Trisomy 21
Trisomy 14
monosomy 21
monosomy 12

Trisomy 21 = Down Syndrome
Trisomy 14 = aborted
monosomy 21 = aborted
monosomy 12 = aborted

16

Chimps, gorillas and orangutan have 48 chromosomes and humans have 46 , what casued this difference

Translocation and loss of a chromosome

17

What is special about Chromosome 2 (in humans) (x3)

-is a large metacentric chromosome
-G-banding patterns
-this matches the banding patterns found on 2 acrocentric chromosomes in apes

18

Colchicine (x2)

Inhibits spindle formation
makes polyploid plants

19

Meiotic paring in autotriploid results in

Trivalent OR Bivalent+Univalent

20

In autopolyploidy mutations can occur with/without mutations

with out

21

Bread =
cotton =
banana =

Bread = allopolyploid
cotton = allopolyploid
banana = autopolyploid

22

non-disjunction

failure of homologous chromosomes to separate in mitosis or meiosis

23

non-disjunction is the most common cause of _____ in meiosis and mitosis, but _____ is more common

Aneuploidy
meiosis is more common

24

Without _____ nondisjunction at meiosis 1 increases

crossing over

25

Meiotic nondisjunction at 1st division results in what gametes

x2 Trisomic
x2 monosomic

26

Meiotic nondisjunction at 2nd division results in what gametes

x1 trisomic
x1 monosomic
x2 normal n

27

Aneuploidy mutations are almost always lethal except in

Sex chromosomes
because the extra X chromosomes are inactivated and the Y chromosome carries few genes

28

Klinefelter syndrome...

Human aneuploidy: have x2 X-chromosomes + Y -chromosome
Man is feminine: small testes, osteoporisis, brest development, tall, female pubic hair, impared IQ, loose chest hair

29

Incidence of Down syndrome in USA

1 in 700

30

Down Syndrome mainly arises from

Maternal nondisjunction

31

Female are born with the primary oocytes suspended in the

diplotene substage of prophase 1 of meiosis
-meiosis resumes at each menstural period, the chromosomes must remain in the bivalent for many decades
-spindle may break down over time

32

Most frequent chromosomal abnormality is...

aneuploidy in sex chromosomes

33

in chloroplast a whole stack of Thylakoids =

Granum

34

Mit diameter

0.5-1 um

35

cp diameter

4-6 um

36

matrix in mit or cp. stroma in mit or cp

matric in mit
stroma in cp

37

Endosymbiosis

cell living inside another host cell

38

Mit and cp both have a ____ origin

endosymbiosis

39

An anaerobic eukaryotic cell engulfed an aerobic ____ through endocytosis to make present day animal cell (with mit)
Then engulfed a photosynthesizing eubacterial cell _____, to make present day plant cell with mit an cp

probacterium (eubacterrial cell)
cyanobacterium

40

Protist=

single cell eukaryote

41

human mit genome = ___ bp

16, 569

42

Human mtDNA:
_rRNA
__tRNA
__ proteins

2 rRNA
22 tRNA
13 proteins

43

Heavy chain of mitDNA strands has more __ while Light strand has more___

G heavy, C light

44

What is the d-loop

origin of replication for he heavy strand, shows variation

45

mitDNA is highly economic...

no introns, all mRNA is translated, only has a few noncoding nucleotides, compared to yeast which has introns and noncoding sequences

46

poky mutaion occurs in

Cytoplasm in of mit, fungi have poky ie slow growth phenotype, poky mutation of rRNA

47

Heteroplasmy

the existance of 2 different types of mtDNA

48

cytoplasmic segregation

process by which 1 type of mtDNA comes to dominate tissue