Genetics

Question 1

What are Genes?

Answer 1

Genes are sections of the DNA that code for a specific trait. Genes specify which trait.

Question 2

What are Alleles?

Answer 2

Alleles are different forms of the same genes. Ex: if eye color is the gene: Alleles would be blue eyes, brown eyes, green eyes. Alleles specify what form the gene takes. Alleles can be dominant or recessive.

Question 3

What is a Genotype and its example?

Answer 3

Genotype is the exact pairing of Alleles for a trait. It is the genetic makeup of these traits. not concerned with expression, only pairing of alleles.
Examples are BB, Bb and bb. genotypes are not concerned with the expressions of the Alleles.

Question 4

What is a Phenotype and its example?

Answer 4

Phenotype is the physical appearance/expression of a trait such as how it looks or functions. E.g.: eye colour. Genotypes BB & Bb both give the same phenotype: Blue eyes.

Question 5

Genes are contained in ____________ which are in the ________________

Answer 5

chromosomes, cell nucleus

Question 6

A _____________ contains hundreds to thousands of genes.

Answer 6

chromosome

Question 7

Every normal human cell contains ______ pairs of chromosomes, for a total of _______chromosomes

Answer 7

23. 46

Question 8

A _______ is any gene-determined characteristic and is often determined by more than one gene

Answer 8

Trait

Question 9

Some traits are caused by _________ genes that are inherited or that are the result of a ____________

Answer 9

mutated genes, new gene mutation.

Question 10

Paired chromosomes __________ gametes will have single chromosomes ________ so their normal is __________

Answer 10

(diploid) - (haploid) - euploid

Question 11

Cells that have multiple copies of each chromosome are ___________ not compatible with life – which leads to spontaneous abortion or stillbirth.

Answer 11

polyploidy

Question 12

_____________ affects only 1 chromosome.

Answer 12

Aneuploidy

Question 13

What is trisomy of chromosome No. 21 called?

Answer 13

Down syndrome.

Question 14

Decreased intellectual abilities, low nasal bridge, protruding tongue, low-set ears, poor muscle tone – short stature are all characteristics of what?

Answer 14

Down Syndrome

Question 15

Mortality Rates of what disease is – 75% are spontaneously aborted, 20% will die before 10 years of age, and the life expectancy of the remainder is 60 years.

Answer 15

Down syndrome

Question 16

What disease is caused by 95% of mother’s chromosome nondisjunction (failure of chromosomes to separate)

Answer 16

Down syndrome

Question 17

What is the major predisposing factor of Down syndrome?

Answer 17

It increases considerably after the mother reaches 35 years of age

Question 18

Which disease has at least 2X chromosomes and 1Y?

Answer 18

Klinefelter’s Syndrome

Question 19

What disease has the following characteristics: moderate degree of mental impairment, usually has male appearance, and high pitched voice?

Answer 19

Klinefelter’s Syndrome

Question 20

which disease is often not diagnosed until adulthood?

Answer 20

Klinefelter’s Syndrome

Question 21

50% result from nondisjunction of X chromosomes in mother and increased risk with maternal age plus degree of physical and mental impairment increases with each extra X, what disease is this?

Answer 21

Klinefelter’s Syndrome

Question 22

What syndrome has this Mortality statistics – highly lethal in utero – 0.5% surviving to term – cardiovascular events – major risk factor due to narrowing of the aorta – 1 in 2500 born with Turner syndrome – but 1-2% of all conceptions have Turner syndrome – thought to be a factor in 10% of miscarriages

Answer 22

Turner’s syndrome

Question 23

What disease is the monosomy of the X chromosome, usually with no pairing of X or Y chromosomes?

Answer 23

Turner’s syndrome

Question 24

Characteristics of ___________ are medical and developmental problems, short height, failure of the ovaries to develop, and heart defects, and 75% are usually caused by a meiotic error in the father,

Answer 24

Turner’s syndrome

Question 25

Turner's syndrome is usually seen in Males or females only.

Answer 25

Female only

Question 26

Recessive alleles are symbolized by _____ letters while dominant alleles are symbolized by________ letters.

Answer 26

Lowercase..... Upper/Capital

Question 27

Copies of the same allele are _______ and two different alleles are called _________

Answer 27

Homozygote ...Heterozygote

Question 28

A recessive allele will produce a ________ if there is no dominant allele present?

Answer 28

Phenotype

Question 29

An inherited alteration of genetic material or Mistake in copying DNA – there is an alteration in genetic material – can also be the result of environmental factors is called?

Answer 29

Mutation

Question 30

Sickle-cell - error during DNA replication which places the wrong sequence of nucleotides in the wrong position. Non-oxygen-carrying sickle cells are produced instead of healthy red blood cells. when this happens what is it called?

Answer 30

SUBSTITUTION

Question 31

What is this called.....CF – DNA material is not copied - a genetic disease that occurs when a child inherits two defective copies of the gene responsible for cystic fibrosis, one from each parent. The gene causes the secretion of thick mucus, clogs lungs and some digestive organs

Answer 31

DELETION

Question 32

ENVIRONMENTAL Asbestos lung – asbestos fibers adhere to DNA & RNA and induce changes in shape causing deletion or substitution changes – can result in cancer in the lung

Question 33

Genetic diseases caused by ________ genes are autosomal dominant, autosomal recessive or X linked recessive.

Answer 33

Single

Question 34

A person can carry the disorder without presenting with symptoms but can potentially pass it on to their children if partnered with a person who is a carrier too.

Question 35

How many single gene disorders has been identified?

Answer 35

7000

Question 36

X linked recessive diseases are more oftwn seen in Male or female?

Answer 36

Female

Question 37

If the cells have 3 copies of each chromosome __________is present. Trisomy or polypoidy

Answer 37

Trisomy

Question 38

A ________ trait or disease occurs from several genes acting together.

Answer 38

Polygenic.

Question 39

Which diseases are chromosomal or single-gene? A) Turner's Syndrome B) Klinefelter's syndrome C) Down syndrome D) Huntington's disease E) Cystic Fibrosis

Answer 39

Turner's Syndrome → Chromosomal, Klinefelter's syndrome → Chromosomal, Down syndrome → Chromosomal, Huntington's disease → Single-gene, Cystic Fibrosis → Single-gene

Question 40

What is the difference between monosomy and trisomy?

Answer 40

Monosomy means that one of the chromosomes in the somatic cells has only one copy instead of the normal two copies. Trisomy means that one of the chromosomes in somatic cells has three copies.