Heredity and Disease

Question 1

What does DNA stand for?

Answer 1

deoxyribonucleic acid

Question 2

What is DNA made of?

Answer 2

backbone of deoxyribose sugars, phosphates, and 4 chemical bases (adenine, thymine, guanine and cytosine)

Question 3

What are genes made of?

Answer 3

sequences of A, T,G and C arranged in diff orders and diff lengths

Question 4

What does DNA synthesis?

Answer 4

RNA (ribonucleic acid) which = protein synthesis

Question 5

What are chromosomes

Answer 5

contain thousands of genes which codes for the synthesis of a particular protein

Question 6

What is karyotype?

Answer 6

the complete chromosomal compoisiton of the nucleus

Question 7

How to visualize karyotypes + why is it important to do so?

Answer 7

extracting chromosomes from the nucleus and photographing them under a microscope to detect abnormalities

Question 8

What is meoisis?

Answer 8

cells in ovaries and testis seperate to produce gametes that hae 23 chromosomes each so when the gametes unite during fertilization there are 23 chromosomes

Question 9

what is haploid?

Answer 9

gametes with half chromosomes (23)

Question 10

what are diploids

Answer 10

represents somatic cells that have 46 chromosomes in 23 pairs

Question 11

What is a locus?

Answer 11

where genes for a trait occupy a site on a chromosome

Question 12

What are alleles?

Answer 12

alternative forms of a gene (one ofthese alleles r located on each paired chromosomes)

Question 13

What is genome?

Answer 13

the complete set of DNA in a living things

Question 14

What are autosomal dominant disorders?

Answer 14

disease cuased by inheritign a single autosomal dominant allele (usualy transmitted by a parent who is het for trait)

50% chance if other parent is normal

appears in every gen of fam

Question 15

what are some autosomal dom disorders

Answer 15

huntington’s disease

neurodegenerative disorder

polydactyly

achodroplastia (achondroplastic dwarfism)

marfan syndrome

familian hypercholesterolemia

Question 16

what are autosomal recessive disorders?

Answer 16

only occurs when 2 allele is inherited from each parent (has to be homo for the trait)

If parents r both carriers child has 25% chance

Question 17

examples of autosomal recessive disorder?

Answer 17

cystic fibrosis

hemochromatosis

phenylketonuria

galactosemia

sickle cell anemia

Tay-Sachs

albinism

Question 18

What is a sex-linked inheritence?

Answer 18

affected allele is located on X chromosome so male with sexlinked trait will have it (female can be hetero so children will have 50%)

Question 19

Sex-linked traits are most common in…..

Answer 19

men >o<

Question 20

x-linked recessive diseases:

Answer 20

gene is located only on X chromosome so more likely for males

Duchenne muscular dystrophy

color blindness

hemophilia A

fragile x syndrome

Question 21

What are familial diseases?

Answer 21

disease that appear consistently in families but means of inheritance r understood

Question 22

What is down syndrome?

Answer 22

• aka mongolism
• extra autosomal chromosome (trisomy 21) bc no 21 chromosomes failed to seperate as gametes
• mild to severe intellectual developmental disorder
• occurs in 1 in 700 live births
• more often in infants born to women older than 35 y/o

Question 23

S/s of down syndrome

Answer 23

• mild to severe intellectual disorder
• heart defects
• small head w/ flat back skull
• eyes r slanted bc extra fold of skin
• small low-set ears
• small mouth with coarse tongue that often protrude
• nose is short and flat, short
• sex organs r underdeveloped
• more likely to get sick
  -small, weak muscles
• hand r short w/ stubby fingers and deep horinzontal crease across palm (simian line)
• exaggerated space between big and lttile toes

Question 24

What is turner’s syndrome

Answer 24

presence of only one x chromosome (appears female but no ovaries so is sterile, no boobs, short, stocky)
- most common disorder of gonadal dysgenesis in females

Question 25

What is Klinefelter's Syndrome?

Answer 25

extra x chromosomes (appears male but has small testes that didnt mature and dont produce sperm, has female traits after puberty) male hypogonadism (appearing in males after puberty with at least 2 X chromosones and 1 or more Y chromosomes (typically XXY)

Question 26

What is Pseudohermaphroditism?

Answer 26

have either testes or ovaries (nonfunctional) but rest of anatomy is mixed, known as intersex

Question 27

what is sex reversal?

Answer 27

in the first few weeks after conception sex glands r neutral if there is not enough testosterone ovaries develop and individual is anatomically female but has XY chromosomes

Question 28

What is amniocentesis?

Answer 28

small amt of amniotic fluid is withdrawn after 14th week of pregnancy to test the chromosomes in the fetal cells in the fluid can detect 200 genetic diseases before birth

Question 29

What is chorionic villus sampling

Answer 29

removing cells from the villi through the cervix (can test immediately for chromosomes)

Question 30

What is gene therapy?

Answer 30

procedure that involves identification, manipulation, and transfer of genetic material into a pt to replace or repair defective genes

Question 31

What are congenital disorders?

Answer 31

those present at birth or shortly after (not genetic or chromosomal abn) affected by inadequate oxygen, maternal infection, drugs, malnutrition, and radiation

Question 32

ex of congenital disorders?

Answer 32

• Congenital rubella • Cerebral palsy • Hydrocephalus • Spina bifida • Congenital heart diseases • Congenital disorders of the intestine • Cleft lip and cleft palate

Question 33

effect of thalidomide

Answer 33

used for morning sickness but affect fetuses by them borning without limbs or had flipperlike appendages

Question 34

What are genetic diseases?

Answer 34

- produced by abnormality in or a mutation of genetic code in a single gene - caused by several abn genes (producing the so-called polygenic diseases) - caused by abnormal presence or absence of an entire chromosome - alteration in structure of chromosomes - caused by mutations that pass from one gen to next, caused by mutagens that disrupt DNA code- includes certain chemicals, radiation and viruses)

Question 35

how to diagnose and treat down syndrome?

Answer 35

- severe r usually diagnosed prenatal via ultrasonography, blood tests and/ or amniocentesis or durign neonatal period, milder forms r diagnosed later, phyiscal s/s, presence of small white dots on riis, karyotype treatment - depends on severity, no cure, surgical correction of cardiac defects, antiobitioc therapy for susceptiblity to pulmonary disease, care at home or long-term care centers

Question 36

s/s of klinefelter syndrome?

Answer 36

- reduced levels of male hormone testosterone - puberty normal w/ regula sized penis but small testes and body hair is scant - infertility from azoospermia (rarely fertile if they have mosaic form that carries extra X chromosomes in only 1 cell line) - mild delay in language acquisition - increased risk of behavioral and learning disabilities - mild to more significant intellectual disabilites - mammary glands r enlarged - osteoporosis - chronic pulmonary disease - autoimmune disorder - venous disease - breast cancer - tooth decay

Question 37

how to diagnose and treat klinefelter syndrome?

Answer 37

diagnose - physical exam, serum and urine gonadotropin level determination, semen analysis, chromosomal smear analysis treat - long-term hormone replacement w/ testerone via injection or transdermal patch - supplemental calcium intake to prevent osteoporosis

Question 38

s/s of turner syndrome?

Answer 38

- ovarian r immautre or absent - short - low-set ears - swollen hands and feets - webbing neck - absence of sexual maturation - amenorrhea - sterility - dwarfisim - cardiac defects (coarctation of aorta and aortic dissection caused by CV disease) - kidney defects - ovaries slowly begin to disappear or dont have eggs - delayed speech and ambulation - normal intelligence