Chromosomal Interitance II

Question 1

what are the 2 types of large scale chromosomal alterations on ptype

Answer 1

abnormal chromosome number

alterations of chromosome structure

Question 2

describe abnormal chromosome number

Answer 2

caused by nondisjunction in meiosis I or II

one gamete receives 2 of same chromosome, other receives nothing

Question 3

what gametes are produced by nondisjunction in meiosis I

Answer 3

n+1, n+1, n-1, n-1

Question 4

what gametes are produced by nondisjunction in meiosis II

Answer 4

n, n, n+1, n-1

Question 5

define aneuploidy

Answer 5

fert of gametes that have nondisjunctin

results in trisomies(2n+1) and monosomies(2n-1)

Question 6

T/F: most alterations of chromosome number are viable

Answer 6

F

trisomies and monosomies are leading cause of pregnancy loss; viable ones have sever health probs

Question 7

why do some indiv live to survive at birth and beyond?

Answer 7

some aneuploidies upset genetic balance to a lesser degree but have syndrome

Question 8

Down syndrome/Trisomy 21

Answer 8

extra chromosome 21
1/830
inc risk w inc mother age

Question 9

Patau syndrome (trisomy 13)

Answer 9

extra chromosome 13
1/5000
eye probs, circulation probs, cleft palate
rarely live more than few months

Question 10

Edward’s Syndrome(Trisomy 18)

Answer 10

1/10000
almost every organ system affected
children do not live more than a few months

Question 11

Trisomy X (XXX)

Answer 11

1/1000
healthy fertile female
slightly taller than avg

Question 12

Klinefelter (XXY)

Answer 12

1/500-1000
small testes and sterile
breast enlargement

Question 13

Monosomy X (XO)

Answer 13

1/2500
only known viable monosomy in humans
sterile female
no female organ maturation

Question 14

XYY

Answer 14

1/1000
healthy fertile
taller than avg

Question 15

accessory chromosomes

Answer 15

not necessary for survival
present in some insects, fungi

core chromosomes are essential for cell metab; evolve slowly
accessory chromosomes evolve fast and high mutation rates

Question 16

Polyploidy

Answer 16

complete nondisjunction
organism has > 2 sets of each chromosome

causes smaller upset in genetic balance than missing 1 chromosome or having 1 extra chromosome
common in plants

inc metabolism of certain tissues (megakaryocytes that produce platelets, hepatocytes and TGCs provide nutrients and metabolites)

Question 17

Chromosome structure alterations

Answer 17

deletion- chromosomal segment removed
duplication- segment is repeated
inversion- reverses segment w/in chromosome
translocation- segment is moved from 1 chromosome to another

Question 18

disorders from structurally altered chromosome

Answer 18

cri du chat

myelogenous leukemia

Question 19

cri du chat

Answer 19

deletion from chromosome 5
small head, retarded, cries like cat
die in infancy or early childhood

Question 20

myelogenous keukemia

Answer 20

translocation of a larger section of chrom 22 to 9 and a small section of 9 to 22(reciprocal)
chrom 22 called philadelphia chrom
causes cancer by activating gene involved in cell cycle

Question 21

chromosomal structure and evol

Answer 21

chrom structure changes over time

chrom 2 between humans (fused) and chimps/gorillas/orangs

Question 22

inheritance patterns that are exceptions to mendelian inheritance

Answer 22

1) genomic imprinting

2) extranuclear genes

Question 23

Genomic imprinting

Answer 23

certain genes 🧬 have preference over whether the maternal or paternal allele is expressed
ex. in mice, a mouse inheriting a dwarf allele from mom and normal from dad will be normal but a mouse inheriting a dwarf from dad and normal from mom will be dwarf
most imprinted genes are important in embryonic dev
genes imprinted in germ line are not expressed early in dev

Question 24

extranuclear DNA

Answer 24

mito, chloro, plastids inherit maternal material

zygote cytoplasm was the egg’s

Question 25

first evidence of extranuclear DNA?

Answer 25

yellow and white patches on leaves of a green plant

ptype of offspring matched only to materal ptype