Heredity And Disease

Question 1

Deoxyribonucleic acid

Answer 1

DNA

Question 2

44 of the chromosomes are called what?

Answer 2

Autosomes

Question 3

What are the remaining two chromosomes called?

Answer 3

X and Y chromosomes

Question 4

The complete chromosomal composition of the nucleus

Answer 4

Karyotype

Question 5

What are alleles?

Answer 5

Alternative forms of a gene

Question 6

Hereditary diseases or disorders are generally the result of what?

Answer 6

Metabolic breakdown caused by a lack of direction from a missing or compromised gene or chromosomal segment.

Question 7

What is the most common genetic disorder states?

Answer 7

Hemochromatosis

Question 8

This allele is usually transmitted from a parent who is heterozygous for the trait.

Answer 8

Autosomal dominant

Question 9

An example of an autosomal dominant disorder which involves extra fingers or toes developing.

Answer 9

Polydactyly

Question 10

Another disorder resulting from one defective dominant allele. Cartilage formation in the fetus is abnormal. The long bones of the arms and legs are short, the trunk of the body normal in size, the head is large and forehead prominent.

Answer 10

Achondroplasia

Question 11

Results from the dysfunction of the gene that normally codes for the connective tissue to protein fibrillin which is necessary for maintenance of connective tissue’s in various organs, tendons, heart valves, and blood vessels. Causes skeletal changes, floppy heart valves, and ocular changes.

Answer 11

Marfan syndrome

Question 12

Caused by mutation in the gene encoding the receptor for low density lipoprotein (too many LDLs and body can’t remove cholesterol from blood). This inefficiency results in accelerated atherosclerosis and incidence of coronary heart disease.

Answer 12

Family hypercholesterolemia (FH)

Question 13

Manifest themselves only when a person is homozygous for the defective allele

Answer 13

Autosomal recessive diseases

Question 14

An inborn error of metabolism caused by autosomal recessive allele. Person’s lack a specific enzyme that converts phenylalanine to tyrosine. Results in higher levels of phenylalanine to build up in the blood and is toxic to the brain.

Answer 14

Phenylketonuria (PKU)

Question 15

Where are the signs and symptoms of phenylketonuria?

Answer 15

Patient has disorders of the nervous system, such as lack of balance, tremors, and hyperactivity, and may suffer convulsions. Person must avoid consuming phenylalanine.

Question 16

Another example of an inborn error of metabolism from autosomal recessive inheritance. Person lacks enzyme to convert galactose to glucose. Galactose accumulates in blood and interferes with development of brain, liver, and eyes.

Answer 16

Galactosemia

Question 17

What are the signs and symptoms of galactosemia?

Answer 17

If untreated, mental retardation develops. Liver becomes enlarged and cirrhotic, and ascites fluid accumulates in abdominal cavity. Intestinal distress results in vomiting and diarrhea.

Question 18

How do you treat galactosemia?

Answer 18

Consist of eliminating lactose from the diets or taking supplements to assist digestion and reduce symptoms.

Question 19

A severe anemia generally confined to the black population. And autosomal recessive disorder in which hemoglobin is abnormal, resulting in deformed red blood cells.

Answer 19

Sickle cell anemia

Question 20

What are the symptoms and signs of sickle cell anemia?

Answer 20

Improperly formed cells become lodged in capillaries and block circulation, causing infarcts, pain, and necrosis. Depletion of red blood cells results in severe anemia.

Question 21

And autosomal recessive condition that primarily affects families of eastern Jewish origin. Because of an absence of an enzyme, a lipid called GM2 ganglioside accumulates in cells, especially nerve cells of the brain.

Answer 21

Tay-Sachs

Question 22

What are the signs and symptoms of Tay-Sachs?

Answer 22

Symptoms appear by six months when no new skills are learned, convulsions occur, and blindness develops. Children usually died between two and four years of age.

Question 23

An autosomal recessive disorder that is easily recognized. The skin and hair color are very white and do not darken with age.

Answer 23

Albinism

Question 24

What are the symptoms and signs of albinism?

Answer 24

People have increased risk for skin cancer and exhibit visual problems such as nearsightedness and abnormally high sensitivity to light.

Question 25

Diseases that are generally result from defective genes on the X chromosome, because the Y chromosome is small and carries very few genes.

Answer 25

Sex-linked inheritance

Question 26

Why do males have a better chance of getting a sex linked disease then females?

Answer 26

Males only have one X-chromosome, so defective recessive gene is expressed. Females can be heterozygous and will only be a carrier.

Question 27

The inability to distinguish between certain colors, is a disorder of sex linked inheritance. Person is unable to distinguish reds and greens. Corrective lenses may offer treatment.

Answer 27

Color blindness

Question 28

People do not bleed more profusely or bleed faster than normal; they bleed for a longer period of time. Factor VIII is usually inactive in cases of this disease.

Answer 28

Hemophilia

Question 29

Can we treat hemophilia?

Answer 29

There have been significant advances in treating hemophilia in the last decade. New genetically engineered clotting proteins is now used for treatment in some types. Research is underway to develop gene therapy.

Question 30

A genetic condition associated with mental retardation is identified by thin, threadlike strands on the long arm of the X-chromosome.

Answer 30

Fragile X syndrome

Question 31

What are the signs and symptoms of fragile X syndrome?

Answer 31

Majority of patients are mildly to moderately retarded. Men and boys are socially engaging, but have unusual style of interacting. Avoid eye contact, and slapping or hand biting is common. Unusual speech with narrow face, and protruding ears.

Question 32

Some diseases appear in families, but the means of inheritance is not understood. Examples are families with high incidence of epilepsy, diabetes, cardiovascular problems, allergies, and familial polyposis.

Answer 32

Familial diseases

Question 33

Cause of these diseases does not seem to be a single gene but the effect of several genes working together

Answer 33

Multifactorial

Question 34

An example of a disorder caused by the presence of an extra autosomal chromosomes. Chromosome 21 is inherited in triplicate, a condition called trisomy 21.

Answer 34

Down syndrome

Question 35

What are the symptoms and signs of down syndrome?

Answer 35

I appear slanted because of extra fold of skin at the upper, medial corner of that I; Tonyas course and often protrudes; and nose is short and flat. Is usually short in stature. Life expectancy is short because of complications that accompanied the condition.

Question 36

Caused by deletion of part of the short arm of chromosome 5. Infants have abnormally small head with a deficiency of cerebral brain tissue.

Answer 36

Cri du chat syndrome (cat cry syndrome)

Question 37

What are the symptoms and signs of cri du chat syndrome?

Answer 37

Those born alive has a week, catlike cry. Eyes are spaced far apart and children exhibit mental retardation. Infant dies usually in first five or six years.

Question 38

One of the sex chromosomes is missing, resulting in a karyotype of 45, XO, indicating the presence of 45 chromosomes with only one X chromosome.

Answer 38

Turner syndrome

Question 39

What are the symptoms and signs of turner syndrome?

Answer 39

Person appears female, but ovaries do not develop. Thus, no ovulation or menstruation, and person is sterile. Person is short of stature and has stocky build. Heart problems frequently accompanied turner syndrome. Facial deformities are often present.

Question 40

An extra sex chromosome is present, resulting in a karyotype of 47, XXY, indicating the presence of 47 chromosomes, including two X and one Y chromosomes.

Answer 40

Klinefelter syndrome

Question 41

What are the symptoms and signs of Klinefelter syndrome?

Answer 41

Person appears to be male but has small testes and failed to mature and produce no sperm. At puberty, the breasts enlarge and female distribution of hair develops. There is little facial hair and general appearance is that of immature young adult. Person is tall and slender.

Question 42

A person with both testes and ovaries. Is referred to as sex reversal, in which the chromosome will sex is different from the anatomic sex. Person develops anatomically female but chromosomally male.

Answer 42

Hermaphrodite

Question 43

How can people get an early diagnosis of genetic diseases?

Answer 43

Amniocentesis after the 14th week of pregnancy. Chromosomes are examined and anabiotic fluid is examined for biochemical abnormalities.

Question 44

Are those diseases appearing at birth or shortly after, but they are not caused by genetic or chromosomal abnormality’s. Usually result from some failure in development during the embryonic stage, or first two months of pregnancy.

Answer 44

Congenital defects

Question 45

A gap between the left and right halves of the lip or upper palate.

Answer 45

Cleft lip and cleft palate

Question 46

Absence of a normal opening in an organ is called

Answer 46

Atresia

Question 47

A complete obstruction of the intestine, resulting in vomiting, dehydration, scanty stool production, and distention of the abdomen.

Answer 47

Intestinal atresia

Question 48

The pyloric sphincter are hyper trophies, closing the opening between the stomach and the beginning of the small intestine nine. Shows projectile vomiting, dehydration, constipation, and weight loss.

Answer 48

Pyloric stenosis

Question 49

Bile ducks are blocked, causing severe jaundice to develop. Liver and spleen become greatly enlarged.

Answer 49

Biliary atresia

Question 50

Review questions on page 106

Answer 50

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