Mechanics of Hereditary

Question 1

Epigenetics

Answer 1

above genetics, how nature v nurture interact

Question 2

When does human life begin?

Answer 2

it begins with the union of mother’s ovum (egg cell) and father’s sperm cell.

Question 3

How often is an egg cell released?

Answer 3

every 28 days

Question 4

All women’s ova are present at birth (around _____ in number) and only ____ # will mature and be released between puberty & menopause.

Answer 4

maybe a million, 400 mature

Question 5

How much sperm do males produce per month? per 3-4 days?

Answer 5

billions per month; 200-300 million every 3-4 days; this continues from puberty - death.

Question 6

_______ is largest cell in body; ______ is one of the smallest.

Answer 6

Ovum; sperm

Question 7

What are somatic cells?

Answer 7

body cells; contain 23 PAIRS of rod-like structures (chromosomes)

Question 8

What are sex cells? How do they differ from somatic cells?

Answer 8

ova and sperm; they contain 23 (instead of pairs) chromosomes each

Question 9

Of the 23 chromosomes in each sex cell, ____ determines the sex of the offspring

Answer 9

one (based on father)

Question 10

Describe the two types of sperm.

Answer 10

X and Y; X sperm are larger and stronger; Y sperm are smaller, weaker but faster

Question 11

What do XX and XY represent?

Answer 11

XX = female, XY = male; X chromosome necessary for life (no Y sole disorders)

Question 12

Define gene.

Answer 12

units of heredity

Question 13

Define Genotype.

Answer 13

actual genetic make up, all genes inherited from parents, fixed at conception

Question 14

Define Phenotype.

Answer 14

what you see, manifested characteristics, not fixed - interactions between genotype and environment as a person develops

Question 15

Each ____ cell of __ chromosomes include roughly ______ genes.

Answer 15

body cell; 46; 20,500

Question 16

Give examples of inherited genes.

Answer 16

skin pigmentation, eye color, some personality traits (shyness, activity level

Question 17

Define a dominant gene and give examples.

Answer 17

form of an allele whose chemical instructions are followed; curly hair, normal hair, dark hair, thick lips, cheek dimples, normal hearing/vision/color vision, farsightedness, A/B blood type, Rh positive blood

Question 18

Define a recessive gene and give examples.

Answer 18

allele whose instructions are ignored in the presence of a dominant allele; straight hair, baldness, blond hair, thin lips, no dimples, some types of deafness, nearsightedness, red-green blindness, O blood type, Rh-negative blood

Question 19

What happens if a person is a carrier of a single recessive gene for an abnormality?

Answer 19

The person may not know of the abnormality and it will not show up in offspring unless the other mate is also a carrier.

Question 20

Describe Huntington’s Chorea (disease)

Answer 20

caused by dominant trait; fatal disease that is a progressive degeneration of the nervous system; doesn’t manifest until 30-40/50 years of age

Question 21

Describe Sickle-Cell Anemia.

Answer 21

recessive trait; carried primarily by African-Americans (10% carry the gene); the blood cell is misshapen so it doesn’t carry oxygen normally

Question 22

Define Sickle-cell trait.

Answer 22

disorder in which individuals show mild anemia only when they are seriously deprived of oxygen; occurs in individuals who have one dominant allele for normal blood cells and one recessive sickle-cell allele; an example of incomplete dominance

Question 23

Define incomplete dominance and give an example.

Answer 23

situation in which one allele does not dominate another completely.

Question 24

Describe PKU.

Answer 24

phenylketonuria; inherited (recessive trait) disorder where liver enzyme needed to process bread, dairy, diet soda and fish is missing; if undetected and the foods are ingested, MR and brain seizures can occur; detected in newborns by blood or urine test

Question 25

Describe Tay-Sacks.

Answer 25

enzyme disorder where brain is unable to break down some fatty substances; symptoms start at 6 mo; child dies before 3-5 yo; detectable but not preventable.

Question 26

Describe Downs Syndrome.

Answer 26

two chromosome 21’s are given by mother (Trisomy 21), resulting in 3 chromo. 21’s instead of 2; 1 in 680 births; risk increases with parents age (mother especially); mother in late 20’s = 1/1000 births; late 40’s= 1/50 births

Question 27

Describe Turner Syndrome.

Answer 27

1 in 2.5K-5K females missing an X chrom (XO); 90% result in miscarriages; survivors underdeveloped secondary sex characteristics, short, problems with spatial relations; treatable with estrogen but infertile

Question 28

Describe Klinefelters Syndrome.

Answer 28

1 in 500 males presence of extra X (XXY); underdeveloped testicles, some breast development, high pitched voice, little facial hair, tall, passive, below normal intelligence many sterile, treatable with testosterone

Question 29

Describe XXY Syndrome.

Answer 29

Super males; 1 in 1K male births; taller, lower than avg intelligence, tend to be more aggressive; higher percentage in prison population but majority where jailed due to being caught (less intelligence) instead of aggression

Question 30

Describe Fragile X syndrome.

Answer 30

X chromo. is abnormally compressed or broken; more common in males; results in MR; no symptoms until puberty (10-15yo) - marked decline in intellectual functioning that worsens with age.

Question 31

Describe XXX syndrome.

Answer 31

1 in 500-1K female births; normal stature, delayed motor and language development