Chapter 3

Question 1

who was William Bateson—

Answer 1

discovered and promoted Mendel’s findings about genetics (Bateson coined that term)

Question 2

what are structural genes—

Answer 2

genes that contain the information to make a protein

may be quite similar across different (but related) species

Question 3

what are regulatory genes—

Answer 3

guide the expression of the structural genes, without coding for a protein themselves

Question 4

what is genotype—

Answer 4

the genetic makeup of an individual, can refer to the entire genetic complement or more narrowly to the alleles present at the specific locus on 2 homologous chromosomes

Question 5

what is phenotype—

Answer 5

an observable or measurable feature of an organism, they can be anatomical, biochemical or behavioural

Question 6

how are genotypes and phenotypes related

Answer 6

in some cases the relationship between the genotype and phenotype is direct: the phenotype is the direct product of the underlying alleles. In other cases, the genotype interacts with factors in the environment to produce a phenotype. In phenotypes that are the result of complex gene-environment interactions, it can be difficult to figure out the contributions each makes to the variation we observes. 2 contrasting examples of the relationship between genotype and phenotype is humans are the ABO blood type system and obesity

Question 7

what is recessive—

Answer 7

in a diploid organism, an allele that is expressed when present in 2 copies (homozygous) in order to be expressed

Question 8

what is dominant—

Answer 8

in a diploid organism, an allele that is expressed when present on only one of a pair of homologous chromosomes

Question 9

what is co-dominant—

Answer 9

in a diploid organism, 2 different alleles of a gene that are both expressed in a heterozygous individual

Question 10

what is blending inheritance

Answer 10

discredited 19th century idea that genetic factors from parents averaged out or blended together when they were passed on to offspring
Darwin supported this

Question 11

what is particulate inheritance—

Answer 11

the concept of heredity based on the transmission of genes (alleles) according to Mendelian principles

Question 12

what did mendel focus on

Answer 12

what Mendel proved 
Mendel’s experiment focused on 7 traits of the peas
seed coat (round or wrinkled)
seed colour (green or yellow)
pod shape (full or constricted)
pod colour (green or yellow)
flower colour (violet or white)
stem form (axial or terminal)
stem size (tall or dwarf)

Question 13

what are the 4 The Mendelian insights

Answer 13

1. hereditary characteristic are controlled by participate unit factors that exist in pairs in individual organisms
2. when an individual has 2 different unit factors responsible for a characteristic, only one is expressed and is said to be dominant to the other, which is said to be recessive
3. during the formation of gates, the paired unit factors separate, or segregate, randomly so that each sex cell receives one or the other with equal likelihood
4. during gamete formation, segregation pairs of unit factors assort independently of each other
   this is known as Mendel’s law of independent assortment— the two alleles of a gene found on each of a pair of chromosomes segregate independently of now another into sex cells
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Question 14

what is Mendel’s law of independent assortment

Answer 14

Mendel’s law of independent assortment— genes found on different chromosomes and sorted into sex cells independently of one another

Question 15

what is linkage—

Answer 15

genes that are found in the same chromosome are said to be linked, the closer together 2 genes are on a chromosome, the greater the linkage and the less likely they are to be separated during closing over

Question 16

what are point mutation—

Answer 16

a change in the base sequence of a gene that results from the chage of a single base to a different base

Question 17

what is sickle cell disease—

Answer 17

an autoimmune recessive disease cause by a point mutation in an allele that codes for one of the polypeptide chains of the hemoglobin protein

Question 18

what is autosomal recessive disease—

Answer 18

a disease caused by a recessive allele; one spy of the allele must be inherited from each parent for the disease to develop