In watermelons, bitter fruit (B) is dominant over sweet fruit (b), and yellow spots (S) are dominant over no spots (s). The gene
s for the two characteristics assort independently. A homozygous plant that has bitter fruit and yellow spots is crossed with a homozygous plant that has sweet fruit and no spots. The F1are intercrossed to produce the F2.
a) What will the phenotypic ratio be in the F2 generation?
b) If an F1 plant is backcrossed with the bitter, yellow spotted parent what phenotypes and proportions are expected in the offspring?
c) If an F1 plant is backcrossed with the sweet, nonspotted parent what phenotypes and proportions are expected in the offspring?
a) What will the phenotypic ratio be in the F2 generation?
b) If an F1 plant is backcrossed with the bitter, yellow spotted parent what phenotypes and proportions are expected in the offspring?
c) If an F1 plant is backcrossed with the sweet, nonspotted parent what phenotypes and proportions are expected in the offspring?
1 answer:
Answer:
A) 9:3:3:1
B) All bitter fruit, yellow spotted offsprings
C) Phenotypes are bitter yellow spotted (4), bitter no spot (4), sweet yellow spot (4), and sweet no spot (4). 1:1:1:1
Explanation:
This is a typical dihybrid cross involving two genes, one coding for fruit taste and the other for spot color. The allele for bitter taste (B) and yellow spot (S) is dominant over the allele for sweet taste (b) and no spot (s) respectively.
Hence, a heterozygous F1 resulting from a cross between an homozygous dominant (bitter fruit, yellow spot) and homozygous recessive (sweet fruit, no spot) will have a BbSs genotype. The heterozygous F1 offsprings are self-crossed and produce gametes BS, Bs, bS, bs. (See punnet square). The F2 offsprings will have the following phenotypes: Bitter fruit, yellow spot (9)
Bitter fruit, no spot (3)
Sweet fruit, yellow spot (3)
Sweet fruit, no spot (1)
Back cross between a F1 offspring (BbSs) and homozygous dominant parent (BBSS) will produce all bitter fruit, yellow spot offsprings (see attached image). BBSS (4), BBSs (4), BbSS (4), and BbSs (4) are the offsprings' genotypes.
For the back cross between a F1 offspring (BbSs) and a homozygous recessive (bbss) parent, the Phenotypes with their proportions are as follows:
Bitter fruit, yellow spot (BbSs, 4)
Bitter fruit, no spot (Bbss, 4)
Sweet fruit, yellow spot (bbSs, 4)
Sweet fruit, no spot (bbss, 4).
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Answer:
1. Electrons
2. thru the circuit from the negative power terminal to the positive power terminal
3. Current
4. Voltage
5. resistance
6. Amps
7. Volts
8. Ohms
9. The voltage is decreased by the electrical resistance.
10. It doesn't work. The electricity can't go backwards thru an LED.
11. The current will decrease.
12. 0.75 amps
13. The current increase
14. an inverse relationship
Explanation:
1. Electrons are what move through a circuit. These electrons are called mobile electrons. Unlike protons and neutrons, they are not confined in the nucleus and are free to move about.
2. Electrons tend to move towards the positive. When an electron moves to a stable atom,the atom would have too much electrons, making it negatively charged. This then would cause a chain reaction of passing on electrons to keep stable.
10.
3 to 8:
Collectively, the flow of electric current is dependent on four things: Voltage, current, resistance, and power.
Voltage is the like the driving force of current. It is the measure of the potential energy or electric potential difference between two points. The unit of voltage is volts, named after Alessandro Volta. You can think of volts as electrical pressure. The higher the voltage, the higher the pressure on the flow of charge.
Current is the "flow" of electrons. It could have another meaning though, in electronics, we refer to current as the volume of the flow of electrons. Current is measured in AMPERES or amps named after Andre M. Ampere. Current is a measure of rate, or the rate of the amount of electrons that flow through a certain point in a circuit, at a given time.
Resistance on the other hand is the opposing force. As electrons move along a circuit, there is bound to be friction. This friction opposes the movement of the electrons, which we call resistance. Resistance uses the unit ohms or the symbol Ω.
These three are all related. The flow of current is affected by how much voltage there is available or pressure available for the movement of the electrons, and at the same time, it is also affected to how much resistance there is in the circuit. And that is where Ohm's Law comes in.
9 and 11-14:
Ohm's Law describes the relationship between current, voltage and resistance. It can be summarized into this formula:
Where:
V = voltage
I = Current
R = Resistance
9. When electricity is met with an electrical component, the resistance through that part of the circuit increases. However, the resistance does not change the potential difference between the two points, but rather, it changes the amount of current that flows through. This means that it does not affect the voltage.
11. But on the other hand, for this scenario, the resistance was increased from 10 Ohms to 15 Ohms. Current and resistance have an indirect relationship. This means that as one goes up, the other goes down. As the resistance increases, the less current is able to flow through and thus the current will decrease.
12. Using Ohm's Law we can solve this:
The following is our given:
V = 9 V
R = 12 Ω
We plug that in our formula:
13. As mentioned earlier, current and resistance have an indirect relationship. So when you have this scenario where the resistance chages from 20 Ω to 12Ω, you see that there is a decrease in resistance. This means that more current can flow through this circuit. So this means that the current increases.
14. was already explained above.
Hope this helps even just a little bit! Good Luck!