Biology Help?

Question

1. Why are absereved results sometimes different from expected results?

2. What laws of genetics did Mendel explain?

3. You mate a red-flowered plant with a white-flowered palnt. You expect all the offsprings to be red, but you find that half of them are white. Why??

4. Being an albino is a recessive trait in which no color is prouced in the skin or eyes. Could an albino chlid be produced by two normally-pigmented parents? Why??

Answer 1

1.
a) Small sample size.
A random event is a random event -- flip your coin 5 times, and you may come up with all heads. Flip it 5 million times, and you'll get a better idea of what's happening.
b) Observer error
c) Deliberate fudging of the data by the observer
d) The experiment may have been badly designed
e) There's something going on that the observer didn't know about, and so didn't take into account.

2.
a) Mendel's First Law - the law of segregation; during gamete formation each member of the allelic pair separates from the other member to form the genetic constitution of the gamete
b) Mendel's Second Law - the law of independent assortment; during gamete formation the segregation of the alleles of one allelic pair is independent of the segregation of the alleles of another allelic pair

3. Red is the dominant trait, and your particular red-flowered plant is heterozygous for it. Say R is red, and r is white.
Your initial red plant is Rr. Half of the offspring will be Rr (red) and the other half will be rr (white).

4. Yes, if both parents are heterozygous for albinism. Say M is for normal pigment, and m is for albinism. With both parents Mm, the parents will have normal pigment. The children they could produce would be:
MM - normal pigmentation
Mm - normal pigmentation
Mm - normal pigmentation
mm - albino
Chances are one in four that a child born to this couple will be albino.

Answer 2

Ok, I just did this in Bio, so I know what I'm talking about.

1. The observed results of genetic crosses are different from expected results because biology isn't always precise. For instance, if you flip a coin four times, you expect a 1 heads :1 tails ratio. But, sometimes, you can get heads four times. Its the luck of the draw. However, the larger the numbers you deal with (400 instead of 4), the numbers tend to be more accurate.

2. Okay, Mendel explain 2 laws: Law of Segregation and the Law of Independant Assortment.
Segregation says that factors (genes) occur in pairs. Each parent passes on 1 of two facotrs to offspring at random. Each offspring receives 1 factor from each parent at random and factors can be dominant or recessive.
Independant Assortment says that the inheritance of a pair of alleles of one gene (like AA, Aa, or aa), do not affect the inheritance of another pair of alleles of another gene (like BB, Bb, and bb) So, you don't get Ab or Ba, etc.

3.Okay, just because a flower is red, doesn't mean its genotype has to be RR. Because red(R) is dominant and white(r) is recessibe, Rr (heterozygous red) will still be a red flower. So, if you do a punnett square with Rr crossed with rr (white), you will find that half will be white and half will be red.

4. Yes, because if each parent was like the red flower in the other example (heterozygous), a punnett square (Rr crossed with Rr) will show a 3 normal: 1 albino ratio.

Answer 3

rececissve and dominant genes
because white is dominant?? ot because 1/4 of the chances are that the flower will be white and it happens all for times
yes only if they both have an albino recessive gene

Answer 4

!recessivity
2.Mendel first,principle of genetics states that the sex cell of a plant or animal my contain one factor(allele)for different traits but not both factors needed to express the traits.
2the second p of g. states that characteristics are inherited independently from other (characteristics)
3. the third states that each inherited (characteristic is determined by two heredity factors/genes, one from each parent which determine whether a gene will be dominant o recessive.

Answer 5

1. because of recessive traits
2. law of segregation, concept of unit characters, law of dominance, law of independent assortment
3. Incomplete dominance
4. Yes, because normally pigmented parents could be heterozygous, (Pp), so they could both donate the recessive p

Answer 6

What he said.