Saturday, January 31, 2009

Grade 11 Biology

This is a place where you can ask questions, or send me good links to check out. I need to moderate all comments, so your words may not show up right away. I'll get answers up as soon as I can.

11 comments:

Anonymous said...

how do we the scale bar for the cell parts in our microjourny?

Jake said...

how do we create a scale bar for the organells in owr microjourney

Ms.Bearse said...

Jake (and Anonymous),
you need to know the approximate size for each organelle. I realize that not all mitochondria, for example, are the same size. You need to understand the relative size of the organelles, to perhaps rank them by size.

For the microjourney, make your best size estimate based on internet/book research. Draw a scale bar that matches the size of the organelle picture. Put the size that you found from your research on top of that line.

Hope that helped you.

Anonymous said...

Dear Ms. Bearse,
I am confused with Cellular Respiration. All the steps producing ATP and breaking down glucose confuse me. Glycolysis, Pyruvate Oxidation, Krebs Cycle and the Electron Transport Chain. Wow. It is intense. Could you possibly explain to me the important things? Will we need to know all in great detail? Thanks for all your help.

Ms.Bearse said...

I've posted a note about photosynthesis and cellular respiration on the website. I gave out copies in class too. That is what you will need to know.

glycolisys turns glucose to pyruvate in the cytoplasm of the cell. Pyruvate goes to the mitochondria where it will go through Kreb's cycle if there is enough oxygen for that to happen. Next comes the electron transport chain that allows the controlled release of the energy through lots of steps in the reaction.

keep studying :)

Rosie said...

Hi Ms. Bearse!
It's been awhile since I've posted on here but I have a lovely homework question in biology for you. (I'm in Prentice's IB class).

How could you determine if the products of cellular respiration have less chemical potential energy than the reactants? Where did the energy that was released during cellular respiration come from?

It is number 5 on page 64 in the textbook. Thanks so much!
-R

Ms.Bearse said...

It has to do with the chemical bonds in the products and reactants. Carbon-hydrogen bonds contain potential energy. There are lots of them in glucose, there are fewer in pyruvate and alcohol, and there are none in water and carbon dioxide. Maybe you can work that information into your answer. Have you studied enthalpy of formation in chemistry? That would help you understand the potential energy in the bonds.

Anonymous said...

can an artificial cell reach equilibrium?

Ms.Bearse said...

that depends on the permeability of the membrane, and what is inside and outside the cell.

Anonymous said...

Sorry to bother you but I am slightly confused on a question in the Chapter 4 review.
2. Explain why, under normal circumstances, an individual can carry only two alleles of a gene.

Is it due to the fact that humans are diploid organisms and each allele for that trait is located on one of the homologous chromosomes?
Thank you so much!

Ms.Bearse said...

That's true. The only case where you could have 3 alleles would be if there was nondisjunction that happened during meiosis, and the resulting offspring had trisomy of a chromosome.