Genetics

Question 1

Nondisjunction

Answer 1

Rare failure of the chromosomes to separate during any phase of meiosis; too many chromosomes in a gamete

Question 2

Down Syndrome

Answer 2

Result of nondisjunction; has three instead of two of the #21 chromosome

Question 3

Genotype

Answer 3

The genetic makeup of an organism (Aa)

Question 4

Phenotype

Answer 4

An organisms physical appearance; not always and indication of the genotype

Question 5

Homozygous

Answer 5

An organism that has inherited two matching alleles for a trait (AA)

Question 6

Heterozygous

Answer 6

An organism has two different alleles for a trait (Aa)

Question 7

Sex Linkage

Answer 7

Traits linked to sex; traits located on the X chromosome only

Question 8

Gene

Answer 8

A heritable trait

Question 9

Allele

Answer 9

Alternate versions of a gene (round nose, pointed nose)

Question 10

Chromosome

Answer 10

Fibers that house the cells DNA; each section houses a particular gene

Question 11

Pleiotropic Inheritance

Answer 11

One gene has the capacity to determine and influence multiple traits

Question 12

Polygenic Inheritance

Answer 12

Two or more genes determine a single character

Question 13

Multiple Alleles

Answer 13

Premise that most genes have more than two forms (not just dominant or recessive); spectrum of variation

Question 14

Codominance

Answer 14

When alleles are equally strong and unmasked by others; multiple phenotypes expressed

red flower+white flower= pink flower

Question 15

Number of autosomes in a human brain cell

Answer 15

44

Question 16

Autosomal Dominant

Answer 16

If at least one chromosome has the allele the individual will be affected; any chromosome besides XY (AA or Aa)

Question 17

Autosomal Recessive

Answer 17

Both chromosomes must have recessive allele for the individual to be affected; except XY chromosomes (Aa=carrier, aa= affected)

Question 18

Sex (X) linked recessive

Answer 18

Trait only carried on the X chromosome; recessive allele must be on X chromosome for expression