Chromosome number

Question 1

A change in chromosome number

Answer 1

Aneuploidy

Question 2

What does aneuploidy usually arise from?

Answer 2

Non-disjunction

Question 3

What is mongolism?

Answer 3

An antiquated term for Down’s Syndrome

Question 4

Down’s syndrome is aneuploidy of

Answer 4

Chromosome 21

Question 5

What is the mutation in Down’s Syndrome?

Answer 5

Trisomy 21

Question 6

How common is Down’s Syndrome?

Answer 6

Fairly common, about 1 in 800

Question 7

How was Down’s Syndrome diagnosed before chromosomal tests?

Answer 7

Single palmar crease, but already present in about 3% of population anyway

Question 8

What environmental factor is known to greatly increase the risk of Down’s Syndrome?

Answer 8

The age of the mother

Question 9

What are the characteristics of Klinefelter?

Answer 9

Male, but with female traits

Question 10

Klinefelter karyotype:

Answer 10

XXY up too 6XY

Question 11

What is a “supermale?”

Answer 11

XYY; supposed association with criminal behavior, many are unaware of having this

Question 12

What does XO karyotype result in?

Answer 12

Turner Syndrome

Question 13

What are the characteristics of Turner syndrome?

Answer 13

Sterile female, vast majority of cases spontaneously abort

Question 14

What is the “superfemale” karyotype?

Answer 14

XXX up to 8X

Question 15

How debilitating are trisomies generally?

Answer 15

Very, chromosome 21 is smallest, and sex chromosomes controlled by lyonisation, so effect is not as big

Question 16

Trisomy 18

Answer 16

Edward’s Syndome, die within weeks of birth

Question 17

What happens in trisomies of large chromosomes?

Answer 17

Presumably die early in development; thought that most pregnancies spontaneously abort due to trisomies

Question 18

How does gynandromorphy occur in insects and birds?

Answer 18

Non-disjunction of X chromosome; some cells XX some XO (XO is male in insects)

Question 19

What are possible ploidies?

Answer 19

Almost anything, but generally an even multiple

Question 20

How is ploidy used for sex determination in bees?

Answer 20

Males are haploid (i.e. unfertilised eggs) females are diploid (fertile)

Question 21

What is typical plant ploidy?

Answer 21

Polyploidy

Question 22

What is autopolyploidy?

Answer 22

Form of polyploidisation, gives rise to new plant ploidies by multiplying number of sets within a species

Question 23

What is allopolyploidy?

Answer 23

Form of polyploidisation, gives rise to new plant ploidies by hybridising species and mixing their chromosome sets

Question 24

How does plant ploidy affect size?

Answer 24

More sets, larger size, generally

Question 25

How has plant polyploidisation been relevant to crops?

Answer 25

Hexaploid bread wheat arose thro a series of hybridisations of primitive agricultural wheats with wild wheats

Question 26

What is Einkorn?

Answer 26

One of the oldest agricultural wheats, AA diploid, still used today by peasants

Question 27

What is Emmer wheat?

Answer 27

Old agricultural wheat, AA BB tetraploid, still used today

Question 28

What is a modern example of artificial hybridisation of bread wheat?

Answer 28

Triticale

Question 29

What is triticale?

Answer 29

An amphidiploid of Emmer wheat and Rye, AA BB RR, widely used as a wheat or dry and cold growing conditions

Question 30

How are seedless crops made?

Answer 30

Adding colchicine to cells in culture, causes polyploidisation, some crosses will produce sterile triploids

Question 31

What does polyploidy do in humans?

Answer 31

Death

Question 32

What is the general genetic evolutionary trend from chimps to humans?

Answer 32

Decaying gene families

Question 33

What are the major physical decays from lower primates to humans?

Answer 33

Jaw muscles, hair, taste and smell receptors, digestive enzymes (lots of decay here), "ability"

Question 34

What has grown in humans compared to other primates?

Answer 34

Brains 5x as big

Question 35

What chromosome is most heavily conserved across species?

Answer 35

X chromosome

Question 36

What is notable about hawaiian drosophila?

Answer 36

More species there than anywhere else on the world

Question 37

How does genomic complexity relate to organism complexity?

Answer 37

Not very much, human genome

Question 38

In what animals is polyploidisation still somewhat common?

Answer 38

Fish, accounts for vast range of phenotypic appearance