All categories

3 years ago

After observing the F2F2 generation, what conclusion did Mendel come to?

1 answer:

6 0

In his experiment mendel first crossed tall and short peas plant and noticed that the F1 plants were all tall. in the second experiment he crossed the the F1 plants and noticed that short plants reappeared in the rate of 25% in F2 generation. in his third experiment he crossed he crossed F2 plants and noticed that when he crossed some tall plants with the shot plants the F3 generation contained short plant in frequency of 50%. after this observations mendel concluded that there were genes that could be only expressed in homozygous state but not in heterozygous state. these genes were later referred to as recessive alleles wheres the genes that prevented the expression of recessive genes were later referred to as dominant genes.

You might be interested in

Water vapor in the air can be high or low, depending on your location. Water vapor is a _____.

Marizza181 [45]

variable gas hope this helps

4 0

3 years ago

Read 2 more answers

An additional gene, gene W, was also examined. A test cross was made between true-breeding EEWW flies and EEWW flies. The result

Debora [2.8K]

This question is incorrect but here is the correct question below;

An additional gene,gene W was also examined. a test cross was made between true breeding EEWW flies and eeww flies. The resulting F₁ generation was then crossed with eeww flies. 100 offspring in the F₂ generation were examined and it was discovered that the E and W genes were not linked.

Which is the correct genotype of the F₂ offspring if the genes were linked and if the genes were not linked?

a) Linked: 50% EeWw and 50% eeww; not linked: 25% EeWw, 25% Eeww, 25% eeWw and 25% eeww.

b) Linked: 25% Eeww, 50% eeWw; not linked:parental genotypes EeWw and eeww.

c) Linked genotypes (EeWw and eeww) and recombinant genotype ( Eeww & eeWw) in the F₂ generation are nearly the same irrespective of their linkage.

d) Linked: mostly with parental genotypes, Eeww and eeWw; unlinked: 25% EeWw and eeww with 75% Eeww and eeWw.

Answer:

a) Linked: 50% EeWw and 50% eeww; not linked: 25% EeWw, 25% Eeww, 25% eeWw and 25% eeww.

Explanation:

a test cross was made between true breeding EEWW flies and eeww flies

If EEWW self crossed, we have the following ( EW, EW, EW, EW)

Also, for eeww, we have ( ew, ew, ew, ew)

EW EW EW EW

ew EWew EWew EWew EWew

All offspring are (EWew)

The question goes further by saying "The resulting F₁ generation was then crossed with eeww flies".

And we are asked to find the correct genotype of the F₂ offspring if the genes were linked and if the genes were not linked

∴

To determine the offsprings of the linked genes we need to go by the definition and understand what linked genes are: Linked genes are genes that are physically close together on the same chromosomes. Effect of recombinantion on linked genes, results in gene swaps which occur in chromosomes that are homologous.

Having said that; If EWew × eeww

we have; EW & ew × ew & ew

EW ew

ew EeWw eeww

offspring that

are linked in ⇒ EeWw EeWw & eeww eeww

F₂ will be

$\frac{1}{2}$ = 50% of EeWw of the total 100 offspring in the F₂ cross

$\frac{1}{2}$ = 50% of eeww of the total 100 offspring in the F₂ cross

∴ Linked genes = 50% EeWw and 50% eeww.

For unlinked genes; If EWew × eeww

if rearrangement occurs in EWew and EWew self crossed, we have ( EW,Ew,eW,ew) as the traits needed for the unlinked gene F₂ crossing.

Also ewew will be (ew, ew, ew, ew).

EW Ew eW ew

ew EeWw Eeww eeWw eeww

We have the following results for the unlinked genes

$\frac{1}{4}$ = EeWw 25% of the total 100 offspring in the F₂ cross

$\frac{1}{4}$ = Eeww 25% of the total 100 offspring in the F₂ cross

$\frac{1}{4}$ = eeWw 25% of the total 100 offspring in the F₂ cross

$\frac{1}{4}$ = eeww 25% of the total 100 offspring in the F₂ cross

∴ not linked: 25% EeWw, 25% Eeww, 25% eeWw and 25% eeww.

3 0

2 years ago

Describe a characteristic of both an Emperor Penguin and Galapagos Penguin that evolved differently due to their different envir

nevsk [136]

Answer: The size.

Explanation: On the one hand the Emperor Penguin is bigger reaching up to 48 Inches (120cm) of height and 100 Lb in weight, on the other hand the Galápagos Penguin is much smaller. For example a large adult usually goes up to 21 Inches (53cm) and 5 Lb of weight.

This is directly related to the temperature of the environment in which each one develops, because a body exchanges heat in two dimensions through the surface. So, it's easier for a big creature to maintain core temperature stable.

This is really important in environments like the Arctic where temperature goes below zero and the opposite happen in the Equator where there is a tropical weather all the time.

8 0

3 years ago

What is the quotient?<br><br><br> StartFraction 5 Superscript negative 6 Over 5 cubed EndFraction

Sedaia [141]

Answer:

1/(5⁹) or 5⁻⁹

Explanation:

This is a Mathematics question rather than a Biology question.

The given fraction is:

$\frac{5^{-6}}{5^3}$

This fraction can be rewritten as:

$\frac{1}{5^6*5^3}=\frac{1}{5^9}=5^{-9}$

Therefore, the quotient of the given fraction is 1/(5⁹) or 5⁻⁹

7 0

3 years ago

Read 2 more answers

Why is it important for DNA to be organized? Please put it in your own words.

Reptile [31]

Answer:

Chromosomes are made up of DNA(deoxyribosenucleicacid) which is a protein complex called chromatin that is organized into subunits called nucleosomes. The way in which eukaryotes compact and arrange their chromatin also helps regulate gene expression.

Explanation:

7 0

2 years ago