Biology 2013ers MARATHONN (2 Viewers)

[Menomaths]

Incomplete dominance isn't in the course

 

[bedpotato]

............................. Enzyme 1 ................ Enzyme 2 .............. Enzyme 3
Starting substance ----------> Ornithine ----------> Citrulline ----------> Arginine

If the gene responsible for producing Enzyme 1 was mutated, which amino acid(s) would have to be added to the fungus' growth medium? Explain your answer. [3]

(Beadle and Tatum)

 

[Spiritual Bean]

............................. Enzyme 1 ................ Enzyme 2 .............. Enzyme 3
Starting substance ----------> Ornithine ----------> Citrulline ----------> Arginine

If the gene responsible for producing Enzyme 1 was mutated, which amino acid(s) would have to be added to the fungus' growth medium? Explain your answer. [3]

(Beadle and Tatum)

well...

 

[bangladesh]

Guys can someone explain question 15 MC from 2008 paper? Does anyone know if the bos ended up doing something about the question? I actually cannot make sense of it as i believe that D could also be right.

Cheers.

 

[bedpotato]

well...

why don't you answer it? lol

 

[bedpotato]

Guys can someone explain question 15 MC from 2008 paper? Does anyone know if the bos ended up doing something about the question? I actually cannot make sense of it as i believe that D could also be right.

Cheers.

It's sex-linked. Males can't be carriers, they either have it or they don't. So 3 is normal.

 

[superSAIyan2]

Guys can someone explain question 15 MC from 2008 paper? Does anyone know if the bos ended up doing something about the question? I actually cannot make sense of it as i believe that D could also be right.

Cheers.

Its an X-linked disease. Any non-affected male is normal. You cant have a male carrier

 

[bangladesh]

It's sex-linked. Males can't be carriers, they either have it or they don't. So 3 is normal.

But he can still pass it on if he's affected?

 

[bedpotato]

But he can still pass it on if he's affected?

But he's not affected. For 3 and the mother to pass it on to their children, the mother has to be a carrier.

X^RY x X^RX^r

This can result in: X^rY

 

[bangladesh]

nvm nvm. I understand now. My bad

THank you so much for the explanation.

 

[bedpotato]

Yes. I understand why C is right, what I'm saying is that D could also be right. I'm asking for the reason as to why D is wrong.

I already did. If you look at the pedigree, 3 isn't shaded --> he's unaffected. Males can't be carriers of sex-linked diseases.

 

[Menomaths]

Yes. I understand why C is right, what I'm saying is that D could also be right. I'm asking for the reason as to why D is wrong.

For a male to be a carrier he HAS TO BE AFFECTED since he can't mask the recessive gene. Look at person 3, he's a male, and he's not affected. If he's not affected HE CAN'T BE A CARRIER. D is saying person 3 is a carrier while being a male, while being normal. That can't be true.

Not e-shouting, just emphasizing the main point

 

[bangladesh]

For a male to be a carrier he HAS TO BE AFFECTED since he can't mask the recessive gene. Look at person 3, he's a male, and he's not affected. If he's not affected HE CAN'T BE A CARRIER. D is saying person 3 is a carrier while being a male, while being normal. That can't be true.

Yes yes. For some stupid reason i assumed that both genes could come from the father, my bad.

 

[fionarykim]

............................. Enzyme 1 ................ Enzyme 2 .............. Enzyme 3
Starting substance ----------> Ornithine ----------> Citrulline ----------> Arginine

If the gene responsible for producing Enzyme 1 was mutated, which amino acid(s) would have to be added to the fungus' growth medium? Explain your answer. [3]

(Beadle and Tatum)

would the answer be ornithine?
because since enzyme 1 was mutated, accordin to Beadle and taytums one gene one polypeptite hypothesis, without that enzyme ornithine would not be produced. this would break the chain and hence the fungus growth is inhibited. As long as ornithine is added to the medium, the rest of chain can continue and hence produce the growth.

explanation sounds too dodgy haha
How could a change in a polypeptide affect cell activity

 

[bedpotato]

would the answer be ornithine (1)?
because since enzyme 1 was mutated, accordin to Beadle and taytums one gene one polypeptite hypothesis, without that enzyme ornithine would not be produced. this would break the chain and hence the fungus growth is inhibited. (2) As long as ornithine is added to the medium, the rest of chain can continue and hence produce the growth. (3)
explanation sounds too dodgy haha
How could a change in a polypeptide affect cell activity

haha

A change in polypeptide will result in a change in the protein produced. As most enzymes are proteins, this will disrupt cell activity as the enzyme needed for a particular reaction has been altered and substrate molecules can no longer bind to the enzyme active site. (not sure if this is right anymore)

Gregor Mendel and Charles Darwin made their respective contributions to genetics and evolutionary theory at about the same time. Darwin's The Origin of Specieswas published in 1859, while Mendel's paper outlining his work with pea plants was published in 1866.

Compare the responses of the scientific community to the publishing of Darwin's and of Mendel's work and propose reasons for significant differences in their responses. [3]

 

[Memomaths]

 

[HeroicPandas]

Question: What are the differences between a neutrophil and a macrophage? (3 marks)

 

[hamstar]

Question: What are the differences between a neutrophil and a macrophage? (3 marks)

Dam!!!! Never heard of that before. Is it even in the course????

 

[Menomaths]

Dam!!!! Never heard of that before. Is it even in the course????

Nope, we don't need to know them afaik

 

[hamstar]

haha

A change in polypeptide will result in a change in the protein produced. As most enzymes are proteins, this will disrupt cell activity as the enzyme needed for a particular reaction has been altered and substrate molecules can no longer bind to the enzyme active site. (not sure if this is right anymore)

That answer seems to make sense