Genetics, chromosomes and genes- topic 5

Question 1

what is the study of genetics?

Answer 1

-the science of hereditary and how characteristics pass from parents to offspring

Question 2

what are genes?

Answer 2

-short sections of chromosomes in the nucleus which carry genetic material

Question 3

how are chromosomes organised?

Answer 3

-in homologus pairs

Question 4

what do the homologus chromosomes carry?

Answer 4

-they carry the same gene but in different forms

Question 5

what is an allele?

Answer 5

-different forms of the same gene

Question 6

what does homozygous mean?

Answer 6

-both alleles of a gene are the same

Question 7

what does heterozygous mean?

Answer 7

-the alleles of the same gene are different

Question 8

what is the gene locus?

Answer 8

-the position of the gene on the chromosome

Question 9

who was the founder of genetics?

Answer 9

-gregor mendel

Question 10

what is the study of monohybrid inheritance?

Answer 10

-the study of only one characteristic at a time

Question 11

what is pure breeding?

Answer 11

-interbreeding with organisms with a similar characteristic for many generations so that they always produced this characteristic in their offspring e.g.

Question 12

what is mendel’s first law of inheritance?

Answer 12

-the two alleles of each gene separate during meiosis with only one entering each gamete

Question 13

what is the outcome of each parent having a heterozygous genotype?

Answer 13

-75% will have the dominant phenotype
-25% will have the recessive phenotype

Question 14

what is the name of the cross that is used to study one characteristic at a time? what is the name for multiple being studied?

Answer 14

-monohybrid cross
-dihybrid cross

Question 15

what is the definition of the purpose of a monohybrid cross?

Answer 15

-the inheritance study of the alleles of a single gene at one gene locus

Question 16

what is the definition of a geneotype?

Answer 16

-the two alleles for a particular characteristic

Question 17

what is the definition of a phenotype?

Answer 17

-the outward appearance of an individual in terms of the trait

Question 18

what is the definition of a dominant allele?

Answer 18

-the dominant allele will override the non- dominant allele

Question 19

what is the definition of a recessive allele? when will the recessive allele show?

Answer 19

-the allele which will always be override by the dominant allele
-only when both alleles for a gene are recessive

Question 20

to get the ratio 1:1 in their offspring, what geneotypes must the parents have?

Answer 20

-one must be heterozygous and the other homozygous recessive