Developmental Malformations

Question 1

Every individual is said to be unique in every aspect and this is determined by the?

Answer 1

genes in the chromosomes

Question 2

is hereditary when the defect of one parent is transmitted in the gametes through the generations

Answer 2

defect

Question 3

simply imply that the individual is born with the defect and has no reference
to it being hereditary or no

Answer 3

congenital defects

Question 4

not all defects are hereditary

True or False

Answer 4

True

Question 5

all congenital defects have a genetic
origin

True or False?

Answer 5

False, Not All.

Question 6

not all hereditary defects are congenital, for some are made
manifest later in life of the individual
such as those inborn errors of
metabolism

True or false?

Answer 6

True

Question 7

showed that although some traits are transmitted to generation of offspring in an unchanged state, the physical expression of a trait differed
from genetic constitution

Answer 7

Mendel

Question 8

a unit of genetic information (gene) is transmitted unchanged from generation to generation

Answer 8

first law

Question 9

alternate forms of the gene must segregate during gamete formation and recombine independently in the offspring to provide a 1:2:1ratio

Answer 9

second law

Question 10

This alternate form of gene was later called? and its transmission outlined
the concepts of dominance and
recessivity

Answer 10

allele

Question 11

non-allelic traits do not segregate but assort randomly and recombine with a probability representing the product of their independent probabilities

Answer 11

Third law

Question 12

There are three modes of genetic defect transmission in animals and these includes;

Answer 12

✓ mutant genes of large effect
✓ change in number or morphological state
✓ additive effects of many genes of small effects but influenced by environmental factors

Question 13

is the most commonly reported genetic defects in domestic animal species, compared to humans where autosomal dominant inheritance was reported to account for most cases

Answer 13

autosomal recessive inheritance

Question 14

individual contains a pair of identical alleles of a given gene

Answer 14

homozygous

Question 15

if a heterozygote affected animal mates with a homozygote animal; each offspring has 50% risk of being
affected

Question 16

Assuming that both parents
are heterozygote affected, the risk
that the offspring produced are
affected increases to how many percent?

Answer 16

75%

Question 17

Cases reported in farm animals that are expressed by autosomal dominant inheritance include?

Answer 17

idiopathic epilepsy and familial convulsion in cattle

Question 18

male of the species carries the?

Answer 18

XY chromosomes

Question 19

the female of the species carry the

Answer 19

XX chromosomes

Question 20

If
the defect is X-linked, an affected
female (XX) is mated to anormal
male (XY), there is 50% chances that
the female offspring will carry the
defect, and 50% of the male will inherit the maternal X chromosomes
containingthe defect.

Question 21

an individual with possessing only one allele

Answer 21

hemizygous

Question 22

However, if the allele is recessive
to the normal allele, the affected female carrying the allele will not express the defect, but the male who has only one X chromosome been hemizygous for the trait and will not carry any normal allele and would express the defect

Question 23

diploid number of chromosomes in
somatic cells, e.g., in human the
diploid number is

Answer 23

46

Question 24

In gametes however, the haploid number is

Answer 24

23

Question 25

The karyotype for a species is writtenas the diploid number of chromosome and the sex chromosome, for instance 46,XY to denote a human male

Question 26

chromosomal abnormalities, there occur two types:

Answer 26

✓ numerical abnormality ✓ structural abnormality

Question 27

Abnormalities in the number of chromosomes are called?

Answer 27

heteroploidy

Question 28

When an individual is born and carries with its multiples of the haploid number of its chromosomes, the condition is called?

Answer 28

Polyploidy

Question 29

involves either an increase or decrease in the normal number of chromosomes without regard to completion of full haploid set

Answer 29

aneuploidy

Question 30

If there are three sex chromosomes instead of two (e.g.,XXY, or XYY), the condition is called

Answer 30

trisomy

Question 31

if only one sex chromosome occur (e.g., OX, OY), the condition is called

Answer 31

monosomy

Question 32

occur as a result of non disjunction of chromosomes during the anaphase stage in meiosis of germ cells or in mitosis at the zygote, and result to

Answer 32

heteroploidy

Question 33

the presence of two or more population of cells with different genotypes.

Answer 33

mosaicism

Question 34

In animals, particularly in fraternal twinning (male and female twin) in cattle, sheep and goats, there are chances that fetal sharing of circulation result to population of cells between twins, resulting to the presence of different genotypes in cell population of one twin. This condition is called?

Answer 34

chimerism

Question 35

example of chimerism

Answer 35

freemartin

Question 36

defects in sex chromosome number are called?

Answer 36

gonadal dysgenesis

Question 37

example of gonadal dysgenesis

Answer 37

✓ Turner’s syndrome (45, 0X) ✓ Klinefelter’s syndrome (47, XXY)

Question 38

parts of the chromosome exchange places with another and is called?

Answer 38

reciprocal translocation

Question 39

heteroploidy involves either?

Answer 39

polyploidy or aneuploidy

Question 40

For instance, in humans, the diploid number are ________ and in polyploidy, the number may be ______ or ______.

Answer 40

23N 69 (triploidy) and 92 (tetraploidy)

Question 41

in what phase in meiosis heteroploidy occur as a result of nondisjunction of chromosomes?

Answer 41

anaphase stage

Question 42

occur at the chromosome and be expressed in the individual

Answer 42

number of structural abnormalities

Question 43

a typical example of translocation was that observed is?

Answer 43

down syndrome in humans

Question 44

where a piece of the chromosome is missing

Answer 44

chromosomal deletion

Question 45

where two breaks occurs and a realignment result to a reversal of the order of the chromosome

Answer 45

inversion of chromosome

Question 46

one of the best-studied diseases due to polygenic inheritance

Answer 46

diabetes in humans

Question 47

is a defect where there is a deficiency of insulin

Answer 47

diabetes mellitus

Question 48

increased blood sugar levels

Answer 48

hyperglycemia

Question 49

although some malformations are clearly associated with abnormal genes, many are required in?

Answer 49

utero

Question 50

differentiating cells are destroyed or altered by agents

Answer 50

teratogens

Question 51

cells become committed to specific developmental pathways

Answer 51

early in embryogenesis

Question 52

can be acquired not only by deletion of critical primordial cells

Answer 52

congenital malformations

Question 53

agents that affect developing cells and tissue altering its structure, genetic constitution, or botj

Answer 53

teratogens

Question 54

teratogens causing a defect in DNA result to malformations, and may be heritable.

Answer 54

susceptibility to teratogenesis depends on the genotype of the developing fetus and the way they interact with teratogens

Question 55

the cells in the developing fetus are most susceptible to the adverse effects of teratogens during the stage of cellular differentiation, and organogenesis.

Answer 55

susceptibility to teratogenesis varies with the developmental stage of the fetus at the time of exposure

Question 56

some teratogens cause cell death, some cause excessive cell growth, and other cause specific gene damage that leads to the expression of the defect

Answer 56

teratogens act on specific ways on developing cells and tissues to initiate a sequence of abnormal developmental events

Question 57

the dose and the period of exposure . may determine the magnitude of the effect as malformation, death, or no effect at all

Answer 57

teratogenesis is dose dependent and cumulative

Question 58

Teratogen may be grouped under the following categories;

Answer 58

1. physical agents 2. chemical agents 3. biological agents

Question 59

physical agents includes;

Answer 59

✓ trauma ✓ ionizing radiation ✓ heat ✓ cold ✓ pressure

Question 60

chemical agents includes;

Answer 60

✓ drugs ✓ chemicals ✓ hormones ✓ vaccines ✓ toxins ✓ toxicants

Question 61

biological events includes;

Answer 61

✓ metazoan ✓ bacteria ✓ fungi ✓ protozoan including viruses

Question 62

are the agents often implicated in cases of congenital malformation

Answer 62

drugs, viruses and plant toxins

Question 63

plant toxins proven to cause malformations include?

Answer 63

✓ coniine and gamma coniceine from conium maculatum ✓ nicotine from nicotiana tabacum ✓ undefined alkaloid from veratrum californicum

Question 64

a drug released in the 60's to relieve nausea during pregnancy.

Answer 64

thalidomide

Question 65

a twin joined at some portions of the body, with both twins presenting complete parts

Answer 65

symmetrical conjoined twin

Question 66

symmetrical conjoined twins are also called what?

Answer 66

siamese twins

Question 67

two blastoderm developing from a single ovum joined at the thorax called?

Answer 67

thoracopagus

Question 68

two blastoderm developing from a single ovum joined at the ilium of pelvis

Answer 68

ileopagus

Question 69

two blastoderm developing from a single ovum joined at ischium of pelvis

Answer 69

ischiopagus

Question 70

twins joined in some portions of the body, but one twin may be incompletely developed

Answer 70

asymmetrical conjoined twins

Question 71

this malformation is a result of problems in placental circulation with compression of umbilical vessels of one the twins

Answer 71

asymmetrical conjoined twins

Question 72

the attached malformed part of the twin is called?

Answer 72

parasite

Question 73

a twin presented without body form and heart

Answer 73

acardius amorphous

Question 74

a conjoined twin presenting two distinct bodies, united to a common point, but one of the twins is incompletely developed

Answer 74

duplication of parts

Question 75

mechanical constriction of the BLASTULA and GASTRULA causes this malformation. Examples include;

Answer 75

✓ dicephalus monster ✓ dipygus monster

Question 76

malformation with two heads

Answer 76

dicephalus monster

Question 77

malformation with two hind parts

Answer 77

dipygus monster

Question 78

the basic defect is arrest in development of cells in the neural tube resulting;

Answer 78

✓ defect in neural tube formation ✓ incomplete closure and formation of the vertebral column ✓ abnormalities in the ventricular system of the brain

Question 79

Example of defects in neural tube and axial skeleton

Answer 79

✓ spina bifida ✓ anencephaly ✓ cranioschisis ✓ cephalocele ✓ hydrocephalus ✓ amyelia ✓ hydromyelia ✓ syringomyelia

Question 80

imperfect closure of vertebra

Answer 80

spina bifida

Question 81

failure of the brain to develop

Answer 81

anencephaly

Question 82

imperfect closure of the cranium

Answer 82

cranioschisis