What Are Some Fundamental Concepts in Biology?

[nemzy]

1) what is diff between osmolarity and molarity?

is osmolarity the difference of molarity in a cell and the outside?

2) are both enzymes and substrates pH specific?

i know that enzymes are, but are substrates pH specific too?

3) increassing enzyme concentration increases the enzymatic reaction if substrate concentration is held constant right?

4) I know that yeast cells can undergo both respiration and fermentation, does that mean yeast cells have mitochondria too?

5) In a mitotic phase, i know that 90% of the time the cell is in prophase, but what about the other 10%? Are metaphase, anaphase, and telephase happening in equal proportions?

6) how is optical density diff than absorbance?

 

[iansmith]

1) what is diff between osmolarity and molarity?

is osmolarity the difference of molarity in a cell and the outside?

osmolarity is equal to the molarity times the number of particles per molecule whereas the molarity is the number of moles per litre of a molecule.

2) are both enzymes and substrates pH specific?

i know that enzymes are, but are substrates pH specific too?

I will depend on the substrate. Protein configuration is affected by pH. The enzyme recognize a certain configuration. the enzyme might be active at a pH but the configuration of the protein is incorrect.

3) increassing enzyme concentration increases the enzymatic reaction if substrate concentration is held constant right?

Yes but the enzyme reaction will plateau past a given concentration of enzyme for a given substrate concentration. There only so much substrate for a a certain number of enzyme

4) I know that yeast cells can undergo both respiration and fermentation, does that mean yeast cells have mitochondria too?

Yes, yeast have mitochondria. Every eucaryotes type cells have mitochondria. It is one of the key feature.

5) In a mitotic phase, i know that 90% of the time the cell is in prophase, but what about the other 10%? Are metaphase, anaphase, and telephase happening in equal proportions?

It is not equally divided and it will change depending on the species but in general the anaphase and telophase are the shortest steps but my memory might be play trick on me.

6) how is optical density diff than absorbance?

In biology it is not consider the same. You take absorbance reading but you express it as an optical density (OD) after you remove the absorbance of the blank. My old supervisor told me once and did not pay enough attention. In biology always express it as OD when talking about culture growth.

 

[ravenprp]

1) Osmolarity and molarity are both measures of concentration, but they differ in how they measure the concentration of solutes in a solution. Osmolarity takes into account the total number of solute particles (both ions and molecules) in a given volume of solution, while molarity only measures the concentration of the solute molecules. So, osmolarity is affected by the number of ions present in a solution, while molarity is not. In a cell, osmolarity takes into account the intracellular and extracellular concentrations of solutes, while molarity only considers the concentration of solutes within the cell.

2) Enzymes are pH specific, as the pH of the environment can affect their structure and function. However, substrates may not necessarily be pH specific. Some substrates may require a specific pH for optimal activity, while others may not be affected by pH changes.

3) Yes, increasing the concentration of enzymes will increase the rate of enzymatic reaction, as long as the substrate concentration is held constant. This is because more enzymes are available to bind with the substrate and catalyze the reaction.

4) Yes, yeast cells do have mitochondria. While they are known for their ability to undergo fermentation, they are also capable of undergoing cellular respiration in the presence of oxygen. Mitochondria are responsible for the production of ATP through cellular respiration.

5) The other phases of mitosis (metaphase, anaphase, and telophase) do not occur in equal proportions. Prophase is typically the longest phase, followed by metaphase, anaphase, and telophase. The length of each phase can vary depending on the cell type and stage of development.

6) Optical density and absorbance are related, but they are not the same thing. Optical density measures the amount of light that is transmitted through a sample, while absorbance measures the amount of light that is absorbed by a sample. Absorbance is directly proportional to the concentration of a substance in a solution, while optical density is not always directly proportional to concentration.