Genetics 1 (definitions)

Question 1

Genetics

Answer 1

the study of inheritance; he way in which characteristics are passes from one generation to the next

Question 2

Traits

Answer 2

physical or chemical characteristics that a living organism possesses

Question 3

Chromosome

Answer 3

found in the nucleus, made of DNA and protein and contain genes along their length

Question 4

Gene

Answer 4

part of a chromosome, made of DNA and controls a single characteristic eg. Height in plants

Question 5

Homologous chromosomes

Answer 5

pairs of chromosomes that contain genes for the same characteristics at the same position on the chromosome

Question 6

Locus

Answer 6

position of gene on chromosome

Question 7

Allele

Answer 7

different forms of the same gene, occupy the same locus on homologous chromosomes

Question 8

Genotype

Answer 8

the type of genes present in the cell eg. Tt

Question 9

Phenotype

Answer 9

expression of the gene in the environment eg.tall

Question 10

Homozygous

Answer 10

2 alleles for a particular characteristic are the same eg. TT or tt

Question 11

Heterozygous

Answer 11

2 alleles for a particular characteristic are different eg. Tt

Question 12

Dominant

Answer 12

the allele that is always expressed in the phenotype

Question 13

what is the phenotype if the plant is Tt and the dominant is T

Answer 13

tall (T)

Question 14

Recessive

Answer 14

an allele which is not expressed in the phenotype when a dominant gene is present

Question 15

When is the recessive gene (t) ever seen in the phenotype

Answer 15

when it is only tt (no dominant allele)

Question 16

Haploid cells

Answer 16

have one set of chromosomes

Question 17

example of haploid cells in humans

Answer 17

gametes; sperm and egg cells

Question 18

what are gametes capable of

Answer 18

fusion

Question 19

Fertilisation

Answer 19

the fusion of a haploid egg and sperm to form a diplod zygote

Question 20

Diploid cells

Answer 20

have 2 sets of chromosomes