Module 10.1 : Hereditary

Question 1

genotype

Answer 1

• your DNA resulting in your genetic make up

Question 2

phenotype

Answer 2

• the physical representation of the gene

- what you look like

Question 3

allele

Answer 3

• variants of a particular gene due to the changes in the gene sequence
• 2 basic characteristics
  + dominant or recessive

Question 4

dominant allele

Answer 4

• affects the phenotype when present in one copy

Question 5

recessive allele

Answer 5

• must be present in 2 copies to be expressed

Question 6

pungent square

Answer 6

• map of statistical outcomes or risks of inheriting a disease or condition
• alleles from both parents
• dominant is BIG LETTER
• recessive is little letter

Question 7

chromosomes

Answer 7

• humans have 23 pairs of chromosomes
• or 46 singular chromosomes
  + 2 sex chromones
  + 44 autosomes
  - not sex hormones

Question 8

meiosis

Answer 8

• entail two divisions of the genetic material

- produces 4 haploid cells each carrying a new assortment of genes and chromosomes

Question 9

mode of inheritance

Answer 9

• depends on whether allele is dominant or recessive
• does the gene that determines that trait appear on a sex chromosome or an autosome
  + autosomal dominant
  + autosomal recessive
  + sex linked dominant
  + sex linked recessive

Question 10

genetic variability

Answer 10

• one person carries more than 8 million possible combinations
• possibility of 70 trillion genetically unique individuals

Question 11

homozygous

Answer 11

• an individual with 2 identical alleles for a gene

+ CC cc

Question 12

heterozygous

Answer 12

• an individual with 2 different alleles for the gene

+ Cc

Question 13

recessive

Answer 13

• recessive disorders tend to be more severe and produce symptoms at much earlier age

Question 14

dominant disorders

Answer 14

• with early presentations are not as common because these people are to sick to reproduce so allele vanishes from the population
• do not present to until adulthood remain in population because they can reproduce

Question 15

tourettes syndrome

Answer 15

• autosomal dominant

- many different symptoms

Question 16

cystic fibrosis

Answer 16

• autosomal recessive

Question 17

marfan syndrome

Answer 17

• autosomal dominant
• defect in an elastic connective tissue protein called fibrillin
• long limbs
• pectus excavatum caved in chest
• aortic dissection
• lens dislocation

Question 18

co dominant

Answer 18

• some alleles can be co dominant
  + AB blood type
  - antigen on surface of RBC

Question 19

uniparental disomy

Answer 19

• two copies of an allele from one parent
• it was discovered that a girl expressed cystic fibrosis even though mother was only carrier of recessive allele
• recieved both copies of recessive gene from mom

Question 20

x linked recessive

Answer 20

• a male inherits his Y chromosome from his father and his x chromosome from his mother
• femal inherits X chromosome from each parent so doesnt usually present with that

Question 21

x linked recessive traits

Answer 21

• x linked traits never passed from father to son
• father would pass Y not an X to produce son
• hemophilia A is an example of X linked trait
  + daughters carry it but males present it

Question 22

klinefelters syndrome

Answer 22

• males with and extra X chromosome passed on from their mother
• underdeveloped sexually - rudimentary tests and prostate
• long arms and legs, large hands and feet
• no pubic hair or facial hair may develop breast tissue
• 1 in 500-1000 births
• most men do not know until fertility is problem
• 47XXY

Question 23

Jacobs syndrome

Answer 23

• has been associated with violence or aggressive behaviour
• some inmates in jail however many guys with normal lives have XYY
• XYY

Question 24

variations of genes

Answer 24

• deletion - missing
• duplication - extra
• translocation - gen moved to another chromosome
• inversion - genes switched position on the chromosome arm

Question 25

Down syndrome

Answer 25

• most of the cases are due to maternal nondisjunction
  + nondisjunction occurs when the chromosomes do not separate in meiosis
  + (+1) or (-1) chromosomes
• increases maternal age increases the incidence of nondisjunction

Question 26

Down syndrome translocation

Answer 26

• individual with a translocation may not show signs - normal
• individual has an increase risk of having children with down syndrome
• T21 usually a random event and not inherited in the classic mosaic form
  + some normal some abnormal