DNA Discoveries
Erwin Chargaff discovered the nitrogenous base pair rules. (A,C,T,G)
What are those rules?
A=T
C=G
What does recessive mean?
Lowercase
a
will only show up if there are two recessive alleles
What does dominant mean?
Upper case letters
The trait will always show
What does the inside of the punnett square represent?
The possible genotypes and phenotypes of an offspring.
Where is DNA located?
The nucleus
Who is the "Father of Genetics"/ punnett sqaures, who used peas?
Gregor Mendel
Give an example of a homozygous dominant genotype...
The same letters
AA
What does heterozygous mean?
Give an example of a heterozygous genotype....
Having two different alleles for a trait
Aa
What does the outside of the punnett square represent?
The parents genotypes
What was the first mammal to be cloned?
Bonus points for the name!!!!
Dolly the sheep
What process did Charles Darwin discover?
Natural Selection
What does Heredity mean?
Passing down of traits from parent to offspring
What does Phenotype mean? Give an example...
The physical appearance of someone traits
EX: Brown hair
In corn, smooth kernels (K) are dominant to wrinkled kernels (k).
A farmer crosses two corn plants that are heterozygous for kernel texture.
What are the odds that the offspring will have smooth kernels?
The cross results in one KK (smooth kerneled), two Kk (smooth kerneled), and one kk (wrinkled kerneled) offspring.
3/4 or 75%
What are the 3 components of a nucleotide?
Deoxyribose sugar
Phosphate group
Nitrogenous Base Pair
Who took Photo 51? (the x-ray of DNA)
Maurice Wilkins and Rosalind Franklin
What does allele mean?
one of two or more alternative forms of a gene
What does genotype mean? Give an example...
The letters that represent the trait.
AA, Aa, aa
In horses, black coloring (B) is dominant, and chestnut coloring (b) is recessive.
A homozygous black horse crosses with a chestnut horse.
What percentage of offspring are expected to be chestnut?
The cross results in only Bb (black) offspring. It does not produce any bb (chestnut) offspring.
0/4 bb = 0% chestnut offspring
What is the shape of DNA called?
What does antiparallel mean?
Double Helix
2 strands running in opposite directions
Who got credit for discovering the double helix structure of DNA?
James Watson and Francis Crick
What does genotype mean?
What is the full name of DNA?
Deoxyribonucleic Acid
In rabbits, brown fur (B) is dominant to white fur (b) and short fur (H) is dominant to long fur (h).
A brown, long-furred rabbit (Bbhh) is crossed with a white, short-furred rabbit (bbHh).
What percentage of the offspring will be brown with long fur?
...don't forget to FOIL
4 of the possible 16 genotypes will be brown with long fur (Bbhh).
4/16 Bbhh = 1/4 = 25%
How long is DNA?
A) 2 feet B) 6 inches
C) 6 feet D) 2 inches
C) 6 feet
when fully stretched out !!!