Lecture 24 - Mendelian genetics

Question 1

• Define and compare the Genotype and Phenotype of an organism

Answer 1

Genotype:
the genetic makeup of a cell or organism

Phenotype:
an individual’s observable characteristics (i.e., height, eye color,
weight, color blindness, etc.)

Question 2

Define and compare genes and alleles

Answer 2

Gene:
sequence of DNA nucleotides that codes for a protein or functional
RNA

Alleles:
the different forms of a gene, corresponds to differences in DNA
sequences

Question 3

• Describe how an organism’s genotype influences its phenotype

Answer 3

Different DNA sequence codes for different Amino Acid, codes for different protein, different protein has different function (may be associated with disease).

Question 4

• Define and compare homozygous and heterozygous

Answer 4

An individual that inherits the same allele of a particular gene from both
parents are homozygous for the trait encoded by that gene

An individual that inherits different alleles of a particular gene from the
parents are heterozygous for the trait encoded by that gene

Question 5

• Define transmission genetics

Answer 5

• Transmission genetics: the manner in
which genetic differences among individuals
are passed down from generation to
generation

Question 6

Describe and compare the theory of Blending Inheritance with Mendel’s
Modern Transmission Genetics

Answer 6

Blending inheritance:

• traits in offspring are a blend of parents traits.
• This offers no means for natural selection.

Mendal:
- Discovered genes are transmitted not traits.

Question 7

• Define a true-breeding organism

Answer 7

true-breeding plants
for each trait: the physical
appearance of the offspring in each successive generation is identical to the previous one.

Question 8

• Describe the process of controlled pea plant mating

Answer 8

• Anthers of female parent are exposed and cut off.
• Mature pollen is collected from another flower and deposited on the stigma of the female parent.
• After fertilization, cloth bag tied around flower to prevent stray pollen from entering.

Question 9

• Describe Mendel’s pea plant cross using Yellow vs Green seeds and how this
trait (and the others he observed, Table 16.1) was passed down to F1 and F2
generations.

Answer 9

• in the F1 generation the phenotype was dominant.

- in the F2 generation the recessive phenotype reappeared with a 3:1 ratio of dominant to recessive phenotypes.

Question 10

• Describe Mendel’s Principle of Segregation

Answer 10

?

Question 11

During which phase of Meiosis is

segregation taking place?

Answer 11

Anaphase 1