VCE Biology Question Thread

[vox nihili]

For Exam 1 of 2007, question 7, why can't alternative B also be correct? Thanks!

Because glycolysis occurs in the cytoplasm.

[anat0my]

Because glycolysis occurs in the cytoplasm.

The title states that it's aerobic respiration?

[katiesaliba]

The title states that it's aerobic respiration?

Aerobic respiration still encompasses anaerobic respiration, as for aerobic respiration to occur, glycolysis needs to happen

[RazzMeTazz]

How do antiviral drugs work and why are antibiotics ineffective against virus'?

Thanks!

[RazzMeTazz]

Would blood clotting be considered first line of defense ?

[shivaji]

Would blood clotting be considered first line of defense ?

2nd line

[shivaji]

When the temperature goes below optimum, the enzyme reaction slows down (and can even cease.) Is this because the active site of the enzyme has changed conformation or is it because collisions between enzyme and substrate is low?

Thanks

[Reus]

When the temperature goes below optimum, the enzyme reaction slows down (and can even cease.) Is this because the active site of the enzyme has changed conformation or is it because collisions between enzyme and substrate is low?

Thanks

Fewer collisions between the enzyme and substrate molecules

[katiesaliba]

When the temperature goes below optimum, the enzyme reaction slows down (and can even cease.) Is this because the active site of the enzyme has changed conformation or is it because collisions between enzyme and substrate is low?

Thanks

The tertiary conformation of enzymes only changes (where temperature is concerned) when  temperature is increased above optimum. So, your latter reasoning is correct-the rate decreases due to a loss of average kinetic energy in substrates, which reduces the number of successful and thus prevents enzyme-substrate complexes from forming as frequently

[theBRENDAN97]

What

[theBRENDAN97]

What did we need to know about rational drug design?

[RazzMeTazz]

When Th cells bind to specific MHC class 2 - antigen complexes and release cytokines to stimulate clonal selection of the B lymphocytes do they only stimulate clonal selection of the B lymphocyte which is presenting antigens on its MHC class 2 markers to them? and no other ones?  

[katiesaliba]

When Th cells bind to specific MHC class 2 - antigen complexes and release cytokines to stimulate clonal selection of the B lymphocytes do they only stimulate clonal selection of the B lymphocyte which is presenting antigens on its MHC class 2 markers to them? and no other ones?

Yes, because there's only one B-lymphocyte that will possess complementary immunoglobulins to the antigen concerned

[katiesaliba]

Could someone please explain the attached question to me. The answer is C

Also, do we need to know the functions of plant hormones, or was that removed from the study design?

Thanks

[grannysmith]

Could someone please explain the attached question to me. The answer is C

Also, do we need to know the functions of plant hormones, or was that removed from the study design?

Thanks

It shows crossing over between homologous chromosomes in meiosis. Testes would contain germline cells undergoing meiosis to produce gametes.