Week 2

Question 1

Model Species

Answer 1

Organism used to study biological phenomenon
Short life cycle
Cheap
Low junk DNA
Drosophila melanogaster
Escherichia coli
Arabidopsis thaliana

Question 2

Bacteriophage

Answer 2

a virus that parasitizes a bacterium by infecting it and reproducing inside it

Question 3

Blended inheritance

Answer 3

outdated theory that progeny inherits any characteristic as the average of the parents’ values of that characteristic

Question 4

Gene

Answer 4

a sequence of nucleotides in DNA or RNA that encodes the synthesis of a gene product, either RNA or protein

Question 5

Phenotype

Answer 5

composite observable characteristics or traits of an organism

Question 6

Alleles

Answer 6

one of two or more versions of a gene. An individual inherits two alleles for each gene, one from each parent

Question 7

Gametes sex cells

Answer 7

organism’s reproductive cells
haploid cells, and each cell carries only one copy of each chromosome
egg or sperm

Question 8

Linkage group

Answer 8

all of the genes on a single chromosome. They are inherited as a group; that is, during cell division they act and move as a unit rather than independently

Question 9

Chromosome

Answer 9

a DNA molecule with part or all of the genetic material of an organism

Question 10

Genome

Answer 10

genetic material of an organism

Question 11

Dominant

Answer 11

one variant of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome

Question 12

Recessive

Answer 12

masked or overriden variant of a gene

Question 13

Genotype

Answer 13

an organism’s complete set of heritable genes, or genes that can be passed down from parents to offspring

Question 14

Co-dominant

Answer 14

neither allele is recessive and the phenotypes of both alleles are expressed

Question 15

Partial dominance

Answer 15

production of an intermediate phenotype in individuals that are heterozygous for the gene concerned (i.e. the heterozygote shares a phenotype that is quantitatively intermediate between those of the corresponding homozygotes)

Question 16

Punnett squares

Answer 16

a square diagram that is used to predict the genotypes of a particular cross or breeding experiment

Question 17

Genotype ratio

Answer 17

the number of times a genotype would appear in the offspring after a test cross

Question 18

Phenotype ratio

Answer 18

the relative number of offspring manifesting a particular trait or combination of traits

Question 19

Pedigree chart

Answer 19

a diagram that shows the occurrence and appearance of phenotypes of a particular gene or organism and its ancestors from one generation to the next

Question 20

Homozygotes

Answer 20

an individual having two identical alleles of a particular gene or genes and so breeding true for the corresponding characteristic

Question 21

Heterozygotes

Answer 21

an individual having two different alleles of a particular gene or genes, and so giving rise to varying offspring

Question 22

Somatic Cells

Answer 22

any cell of the body except sperm and egg cells
diploid
mutations can affect the individual but will not be passed down

Question 23

Mitosis

Answer 23

part of the cell cycle when replicated chromosomes are separated into two new nuclei
gives rise to genetically identical cells in which the number of chromosomes is maintained

Question 24

Meiosis

Answer 24

special type of cell division in sexually-reproducing organisms used to produce the gametes, such as sperm or egg cells
two rounds of division that ultimately result in four cells with only one copy of each chromosome

Question 25

Recombination

Answer 25

exchange of genetic material between different organisms which leads to production of offspring with combinations of traits that differ from those found in either parent

Question 26

Haploid

Answer 26

having the number of sets of chromosomes normally found in a gamete having exactly half the number of sets of chromosomes found in a somatic cell

Question 27

Diploid

Answer 27

cells have two homologous copies of each chromosome

Question 28

Triploid

Answer 28

3 sets of chromosomes

Question 29

Tetraploid

Answer 29

4 sets of chromosomes

Question 30

Polyploid

Answer 30

state where all cells have multiple sets of chromosomes beyond the basic set, usually 3 or more

Question 31

Aneuploidy

Answer 31

state where one or more individual chromosomes of a normal set are absent or present in more than their usual number of copies Down's syndrome

Question 32

Trisomy

Answer 32

a type of polysomy in which there are three instances of a particular chromosome, instead of the normal two. A trisomy is a type of aneuploidy

Question 33

Nondisjunction

Answer 33

failure of homologous chromosomes or sister chromatids to separate properly during cell division.

Question 34

Karotype

Answer 34

process by which photographs of chromosomes are taken in order to determine the chromosome complement of an individual, including the number of chromosomes and any abnormalities

Question 35

Sex-linked genes

Answer 35

a trait in which a gene is located on a sex chromosome. In humans, the term generally refers to traits that are influenced by genes on the X chromosome. This is because the X chromosome is large and contains many more genes than the smaller Y chromosome