Bios 221: Human Chromosomes

Front 1

What do chromosomes consist of? 2

Back 1

histones (proteins)
DNA

Front 2

What is chromosome morphology based on?

Back 2

length and position of centromere

Front 3

Why can't chromosome morphology be studied in non-dividing cells?

Back 3

chromosomes remain elongated and entangled

Front 4

What designates the short arm of chromosome?

Back 4

p

Front 5

What designates the long arm of chromosome?

Back 5

q

Front 6

Metacentric?

Back 6

centromere is located in the center, both arms are equal length

Front 7

Submetacentric?

Back 7

centromere is located close to the center but is slightly displaced towards one end

Front 8

Acrocentric?

Back 8

centromere is a or almost near the end of the chromosome

Front 9

Telocentric?

Back 9

the centromere is at or almost near the end of chromosome

Front 10

Acentric?

Back 10

chromosomes lack a centromere

Front 11

Satellites?

Back 11

secondary constrictions

Front 12

How are chromosomes arranged in a karotype?

Back 12

by size, centromere position, banding pattern

Front 13

What cells can karotypes be generated from?

Back 13

white blood cells
cancer cells
connective tissue

Front 14

Why are white blood cells good for generating karotypes?

Back 14

they dont divide easily and are therefore induced to divide

Front 15

Why are cancer cells good for generating karotypes?

Back 15

actively dividing cells, easy to make karotype

Front 16

Why is connective tissue good for generating karotypes?

Back 16

easy to culture

Front 17

What does karotypes help recognize? 3

Back 17

abnormality in chromosome structure, abnormality in chromosome numbers, chromosome ploidy

Front 18

Banding?

Back 18

treatment of chromosomes by reageants that generate a characteristic of horizontal bands

Front 19

What are the different types of banding? 5

Back 19

G-banding, R-banding, Q-banding, T-banding, FISH banding

Front 20

G-banding: dark and light regions?

Back 20

-dark regions are heterochromatic (late replicating and AT rich)
-light regions are euchromatic, early replicating and GC rich

Front 21

R-banding: light and dark regions?

Back 21

reverse of G-banding
light regions are heterochromatic
dark regions are euchromatic

Front 22

Q banding: staining?

Back 22

quinacrine is used to obtain fluorescent staining

Front 23

T-banding: what does it visualize?

Back 23

telomeres

Front 24

What does FISH detect and what is it useful for?

Back 24

detection and analysis of abberrant karotype and complex chromosomal arrangements
-useful in diagnosis of certain types of cancers

Front 25

Chromosome deletion: what is it, what does it cause, how can it be discovered?

Back 25

-part of chromosome is lost
-causes severe congential anomalies and marekedly retarded mental and physical development
-may be discovered prenatally if karotype is performed for other reasons

Front 26

Chromosome Duplication: what is it, what does it result from?

Back 26

part of chromosome is dupilicated, 3 copies instead of 2
-results from unequal crossing over (recombination) that occurs between misaligned homologous chromosomes during meiosis

Front 27

What is chromosome inversion?

Back 27

a chromosome is clipped out, turned upside down and reinserted back into the chromosome

Front 28

Balanced inversion?

Back 28

genetic makeup remains the same, even though order of alleles has changed

Front 29

Unbalanced Inversion: what is it, what does it cause?

Back 29

genes have been deleted or duplicated
-causes problems and birth defects

Front 30

Paracentric Inversion?

Back 30

inverted area does not include the centromere, inversion in within the arm

Front 31

Pericentric Inversion?

Back 31

inverted area included the centromere

Front 32

Chromosome Translocation?

Back 32

rearrangement between nonhomologous chromosomes

Front 33

What are types of abnormalities in chromosome number? 3

Back 33

ploidy, euploidy, aneuploidy

Front 34

Ploidy?

Back 34

number of homologous sets of chromosomes

Front 35

Euploidy?

Back 35

each homologous pair is present as an exact integer multiple of the haploid number

Front 36

Aneuploidy?

Back 36

less or more than the normal diploid number chromosomes

Front 37

Types of Aneuploidy?

Back 37

Monosomy
Nullisomy
Trisomy

Front 38

Monosomy?

Back 38

loss of one chromosome from a chromosome pair, the entire chromosome or partial can be missing

Front 39

What defects result from Monosomy?

Back 39

Turners syndrome, Cri du chat

Front 40

Turners syndrome chromsomes?

Back 40

women have one X instead of 2

Front 41

Nullisomy?

Back 41

one entire chromosome pair is missing

Front 42

Trisomy?

Back 42

three chromosomes instead of 2

Front 43

Trisomy defects? 6

Back 43

down syndrome
edwards syndrome
patau syndrome
triple x syndrome
klinefelter syndrome
XYY syndrome

Front 44

Down syndrome chromsome defect?

Back 44

trisomy 21

Front 45

Edwards syndrome chromosome defect?

Back 45

trisomy 18

Front 46

Patau syndrome chromosome defect?

Back 46

trisomy 13

Front 47

Klinefelter syndrome sex chromosome defect?

Back 47

XXY

Front 48

How does trisomy arise?

Back 48

due to non-disjunction during meiosis 1 or 2