ORIGINS OF GENETIC VARIATION

Question 1

what does polyploidy mean? (1)

Answer 1

more than 2 sets of entire chromosomes

Question 2

what is chromosome translocation? (1)

Answer 2

a chromosome mutation in which a segment of one chromosome is transferred to another chromosome.

Question 3

what does trisomy mean? (1)

Answer 3

3 of a particular chromosome

Question 4

what genetic disorder has 3 x chromosomes? (1)

Answer 4

triple x syndrome.

Question 5

what genetic disorder has 2 x chromosomes and 1 y chromosome? (1)

Answer 5

klinfelter syndrome

Question 6

what genetic disorder has one x chromosome and one o chromosome? (1)

Answer 6

turner syndrome.

Question 7

what are the types of chromosome mutations? (4)

Answer 7

-deletion
-duplication
-inversion
-translocation

Question 8

what does aneuploidy mean? (1)

Answer 8

the wrong number of one or more chromosomes.

Question 9

what does polysomy mean? (1)

Answer 9

more than two of a particular chromosome.

Question 10

what does monosomy mean? (1)

Answer 10

only one of a particular chromosome.

Question 11

what is meant by crossing over? (2)

Answer 11

sections of chromosomes containing the same genes (but possibly different alleles) break off and reattach to their non-sister chromatid i.e. on the homologous chromosome.

Question 12

MEIOSIS
What processes lead to genetic variation? (4)

Answer 12

(before meiosis) - DNA replication (mutations)
(during meiosis) - independant assortment of chromosomes metaphases. assortment of chromosomes metaphase 2.
(after meiosis) - random fertilisation

Question 13

what is chromosome deletion? (1)

Answer 13

a chromosome mutation in which part of a chromosome is missing.

Question 14

what is chromosome duplication? (1)

Answer 14

the repetition of a region of the chromosome resulting in double the number of genes.

Question 15

what is chromosome inversion? (1)

Answer 15

the chromosomal rearrangement in which a segment of genetic material is broken away from the chromosome, inverted from end to end and reinserted into the chromosome at the same breakage site.

Question 16

what is the end product of meiosis? (1)

Answer 16

4 non-identical cells, each cell contains half the normal number of chromosomes generally haploid cells.

Question 17

what is the second phase of meiosis? (4)

Answer 17

prophase 2
metaphase 2
anaphase 2
telophase 2

Question 18

what does locus mean? (1)

Answer 18

the position of a gene on a chromosome

Question 19

what is DNA measured in? (1)

Answer 19

kilobases

Question 20

what is the product of meiosis? (1)

Answer 20

meiosis produces sex cells ,or gametes for sexual reproduction.

Question 21

what is the first phase of meiosis? (4)

Answer 21

prophase
metaphase
anaphase
telophase

Question 22

what does meiosis introduce? (1)

Answer 22

genetic variation

Question 23

what is the process of fertilisation? (1)

Answer 23

fertilisation is a random process (crossing over)

Question 24

what are multiple alleles? (1)

Answer 24

occur when there are more than two alleles of a single gene (ABO blood group)

Question 25

what are co dominant alleles? (1)

Answer 25

when present in the genotype, show their effect in the phenotype regardless of the allele on the gene

Question 26

what are recessive alleles? (1)

Answer 26

when present in the genotype, do not show their effect in the phenotype if a dominant allele is present. recessive alleles only show their effect in the homozygous condition.

Question 27

what is the genotype? (1)

Answer 27

the combination of alleles of a particular gene or genes present in a haploid gamete or diploid organism.

Question 28

what are dominant alleles? (1)

Answer 28

when present in the genotype, always show their effect in the phenotype.

Question 29

what is heterozygous? (1)

Answer 29

are diploid and have different alleles of a gene under consideration.

Question 30

what is dihybrid inheritance? (1)

Answer 30

the transfer from generation to generation of two different genes.

Question 31

what is homozygous? (1)

Answer 31

are diploid and have the same allele of a gene under consideration and both copies of a pair of homologous chromosomes.

Question 32

what are some examples of homogenic characteristics? (1)

Answer 32

blood groups

Question 33

what is monohybrid inheritance? (1)

Answer 33

inheritance of a characteristic controlled by a single gene.

Question 34

what is meant by polygenic? (1)

Answer 34

characteristics controlled by several genes.

Question 35

what are some examples of polygenic characteristics? (3)

Answer 35

height mass skin colour

Question 36

how do genes effect an organisms phenotype? (3)

Answer 36

-some characteristics are monogenic -some characteristics are polygenic -the different alleles an organism has at a single gene locus can determine a phenotype

Question 37

what is genetic variation? (1)

Answer 37

the small differences in DNA base sequences between individual organisms within a species population.

Question 38

what is he phenotype effected by? (2)

Answer 38

-genetic factors -environmental factors

Question 39

what is a phenotype? (1)

Answer 39

the observable characteristics of an organism.