Lecture 7- Mendelian Genetics 2

Question 1

Number of human chromosomes

Answer 1

46 chromosomes
23 pairs

Question 2

Diploid cell

Answer 2

Diploid number of chromosomes 2n=46 (2 sets of chromosomes)

Question 3

Haploid cell

Answer 3

Haploid number of chromosomes n=23 (1 set of chromosomes

Question 4

Mitosis overview

Answer 4

Process by which cells are replicated for growth/ repair
Produces 2 diploid daughter cells

Question 5

Meiosis overview

Answer 5

Process by which gametes are produced
Produces 4 haploid daughter cells

Question 6

Meiosis I- overview

Answer 6

Reductional division- homologous pairs are separated, chromosome number halves

Question 7

Meiosis I- stages

Answer 7

Interplase I
Prophase I
Metaphase I
Anaphase I
Telophase & cytokinesis

Question 8

Meiosis I- interphase I

Answer 8

Chromosomes duplicate

Question 9

Meiosis I- prophase I

Answer 9

Homologous chromosomes pair and exchange segments

Question 10

Meiosis I- metaphase I

Answer 10

Tetrads line up

Question 11

Meiosis I- anaphase I

Answer 11

Pairs of homologous chromosomes split up

Question 12

Meiosis I- telophase and cytokinesis

Answer 12

Two haploid cells form, chromosomes are still double

Question 13

Meiosis II- overview

Answer 13

Equational division- sister chromatids are separated producing 4 haploid gametes

Question 14

Meiosis II- stages

Answer 14

Prophase II
Metaphase II
Anaphase II
Telophase II

Question 15

Crossing over

Answer 15

Produces recombinant chromosomes
Average 1-3 crossing over events per pair
Occurs in Prophase I
Pieces of maternal and paternal chromatids joined
produces new combinations of maternal and paternal alleles

Question 16

Random fertilisation

Answer 16

Adds to there genetic variation that arises from meiosis

Question 17

Law of segregation

Answer 17

When an organism makes gametes, each gamete receives just one gene copy, which is selected randomly

Question 18

Law of Independent Assortment

Answer 18

Alleles of two (or more) different genes get sorted into gametes independently of one another

Question 19

Non mendelian patterns of inheritance- degree of dominance

Answer 19

Alleles can show differing degrees of dominance and recessiveness

Question 20

Non mendelian patterns of inheritance- incomplete dominance

Answer 20

The phenotype of the heterozygote is intermediate between the phenotype of the dominant and recessive traits

Question 21

Incomplete dominance

Answer 21

Both alleles of a gene at a locus are partially expressed
Results in an intermediate or different phenotype

Question 22

Codominance

Answer 22

Both alleles for a trait are expresses in heterozygous offspring
Two dominant genes expressed at the same time

Question 23

Pleiotriopy

Answer 23

Most genes have multiple phenotypic effects

Question 24

Epistasis

Answer 24

Phenotypic expression of a gene at one locus affects another gene at a different locus

Question 25

Polygenic inheritance

Answer 25

One character influences by many genes
generally quantitative traits

Question 26

Non mendelian patterns of inheritance- mitochondrial inheritance

Answer 26

mtDNA is solely inherited through maternal line

Question 27

Non mendelian patterns of inheritance- linkage

Answer 27

Two genes that are close together physically
Unlikely to have crossing over between them
Inherited together

Question 28

Non mendelian patterns of inheritance- linkage disequilibrium

Answer 28

Two alleles that are not inherited separately