Ch.14: Mendel & the Gene

Question 1

is considered the father of Genetics
Discovered the basic principles of heredity by breeding garden peas in carefully planned experiments
Described basic principals of heredity with no knowledge of DNA or the process of Meiosis

Answer 1

Gregor mendel

Question 2

Advantages of pea plants for genetic study:

Answer 2

There are many heritable features, or characters (such as flower color);
And character variants (such as purple or white flowers) called traits
Mating of plants can be controlled
Controlled breeding can be achieved by dusting one plant with pollen from another

Question 3

plants that produce offspring of the same variety when they self-pollinate

Answer 3

true breeding

Question 4

Mendel mated two contrasting, true-breeding varieties, a process called

Answer 4

hybridization

Question 5

Mendel discovered a ratio of about ____ ____ ____, purple to white flowers, in the F2 generation

Answer 5

three to one

Question 6

purple flower is _______ _____ while the white flower is the ____ _____

Answer 6

dominant trait

recessive trait

Question 7

What Mendel called a “heritable factor” is what we now call a _____

Answer 7

gene

Question 8

Mendel’s four concept

Answer 8

1. The first concept is that differing versions of genes account for variations in inherited characters
2. The second concept is that for each character an organism inherits two alleles
   one from each parent transferred via the gametes
3. if the two alleles differ, then one (the dominant allele) determines the organism’s appearance
4. law of segregation

Question 9

These alternative versions of a gene are now called

Answer 9

alleles

Question 10

two alleles for a heritable character separate during gamete formation and end up in different gametes

Answer 10

law of segregation

Question 11

Letters are used to represent characters
A capital letter represents the dominant allele, and a lowercase letter represents the recessive allele
A parent can be Homozygous for either allele
or
Heterozygous, having different alleles

Answer 11

punnet square

Question 12

physical appearance

Answer 12

phenotype

Question 13

genetic makeup

Answer 13

genotype

Question 14

The F1 offspring produced in this cross were _________, individuals that are heterozygous for one character

Answer 14

monohybrids

Question 15

A cross between such heterozygotes is called a

Answer 15

monohybrid cross

Question 16

Crossing two true-breeding parents differing in two characters produces _______ in the F1 generation, heterozygous for both characters
A XXXXXx cross can determine whether two characters are transmitted to offspring as a package or independently

Answer 16

dihybrids

Question 17

Using a dihybrid cross, Mendel developed the ______ ______ _____ _____ ___.
Each pair of alleles segregates independently of other alleles during gamete formation
“Strictly speaking, this law applies only to genes on different chromosomes”
Genes located near each other on the same chromosome usually are inherited together

Answer 17

law of independent assortment

Question 18

Deviations from simple Mendelian patterns occurs in the following situations:

Answer 18

When alleles are not completely dominant or recessive
When a gene has more than two alleles
Human Blood types
When a gene produces multiple phenotypes
Pleiotrophy
When a character is determined by more than one gene.
Epistasis

Question 19

occurs when phenotypes of the heterozygote and dominant homozygote are identical

Answer 19

complete dominance

Question 20

the phenotype of heterozygotes is somewhere between the phenotypes of the two homozygotes

Answer 20

incomplete dominance

Question 21

two dominant alleles affect the phenotype in separate, distinguishable ways

Answer 21

codominance

Question 22

Most genes have multiple phenotypic effects Called ________. responsible for the multiple symptoms of certain hereditary diseases, such as cystic fibrosis and sickle-cell disease

Answer 22

pleiotropy

Question 23

a gene at one locus alters the phenotypic expression of a second gene
Two genes for one trait

Answer 23

epistasis

Question 24

Another departure from Mendelian genetics arises when the phenotype for a character depends on ________ as well as genotype

Answer 24

environment

Question 25

why are Humans are not good subjects for genetic research

Answer 25

Generation time is too long
– Parents produce relatively few offspring
– Breeding experiments are unethical

Question 26

a family tree that describes the interrelationships of parents and children across generations
Inheritance patterns of particular traits can be traced and described using XXXXX
XXXXX are also very useful to animal and plant breeders that are seeking certain, desirable traits

Answer 26

pedigrees

Question 27

Recessively inherited disorders show up only in individuals

Answer 27

homozygous for the allele

Question 28

are heterozygous individuals who carry the recessive allele but are phenotypically normal (i.e., pigmented)

Answer 28

carriers

Question 29

the liquid that bathes the fetus is removed and tested

Answer 29

amniocentesis

Question 30

a sample of the placenta is removed and tested

Answer 30

chorionic villus sampling