principles of genetics

Question 1

what are the 3 types of mendelian genetics

Answer 1

principles of dominance
principle of segregation
principle of independent assortment

Question 2

describe principle of dominance

Answer 2

when 2 forms of a trait exist one (dominant) can mask other (recessive)

Question 3

describe principle of segregation

Answer 3

• alleles are separated into gametes during meiosis
• parent can only pass 1 onto progeny

Question 4

describe principle of independent assortment

Answer 4

alleles at 1 locus segregate into gametes independently of alleles at other loci

Question 5

sexual reproduction produces …. …. ….

Answer 5

genetically diverse offspring

Question 6

describe sexual reproduction

Answer 6

• 2 genomes merge to form new genom
  
  • genetically distinct
• provides genetic diversity
• evolutionary advantage in changing envs
• sexual reproduction requires reproduction of genetic material to 1n - gametes
  
  • egg
  • sperm
• reduction happens during meiosis
  
  • 2n → 1n

Question 7

describe meiosis

Answer 7

• 1 round of DNA duplication
• 2 rounds of cell division
• gives rise to egg + sperm
• function:
  
  • reduction division - 23 chromosomes per gamete
  • assortment of genes
• variation in the individual comes from:
  
  • free assortment of maternal + paternal chromosome
  • presence of crossing over exchanges between homologous chromosomes - recombination
  • independent assortment of maternal and paternal homologues at meiosis generates a possible 8.4 million combinations

Question 8

what is the function of meiosis

Answer 8

reduction division
assortment of genes

Question 9

how many rounds of cell division in meiosis

Answer 9

2

Question 10

how many rounds of DNA replication in meiosis

Answer 10

1

Question 11

where does variation come from in meiosis

Answer 11

• free assortment of maternal + paternal chromosome
• presence of crossing over exchanges between homologous chromosomes - recombination
• independent assortment of maternal and paternal homologues at meiosis generates a possible 8.4 million combinations

Question 12

describe the mechanism of meiosis

Answer 12

• each homologue replicates to give 2 chromatids
• homologues pair
• random assignment of homologues to daughter cells
• exchange of material between non-sister chromatids
  
  • crossing- over
  • recombination

Question 13

describe crossing over

Answer 13

• swapping chromosomal segments between non-sister chromatids
• scrambling of genetic info
• genes that lie far enough apart on the same chromosome will segregate independently

Question 14

what are the 2 arms that chromosomes have

Answer 14

p + q

Question 15

what is the short arm in a chromosome designated

Answer 15

p

Question 16

what is the long arm in a chromosome designated

Answer 16

q

Question 17

each gene has a specific … on a chromosome

Answer 17

locus

Question 18

what are chromosomes further sub-divided into

Answer 18

bands + numbered

Question 19

genetic diversity = …… ……

Answer 19

different combinations

Question 20

what are alleles

Answer 20

different version of the same gene
different in their DNA base sequence

Question 21

what is the term used to describe the combination of alleles being unique

Answer 21

phenotype

Question 22

2 identical alleles =

Answer 22

homozygous

Question 23

2 different alleles =

Answer 23

heterozygous

Question 24

which allele dictates the phenotype

Answer 24

dominant

Question 25

what are the 3 modes of inheritance

Answer 25

autosomal dominant
autosomal recessive
sexx linked recessive

Question 26

where is the gene located on autosomal

Answer 26

on the autosome

Question 27

when is a recessive condition caused

Answer 27

condition caused only when 2 copies of abnormal allele are carried

Question 28

what does a deective X-linked gene affect

Answer 28

phenotype

Question 29

when is a dominant condition caused

Answer 29

condition caused by one copy of the abnormal allele