Question

unit 11 biomolecules & cells test review
explain how temperature is affecting the enzyme activity in the graph below
what is happening at low temperature?
where is the temperature optimal?
what is happening at high temperatures?
what structures do all cells, regardless of type, have in common?
1.
2.
3.
4.
what evidence supports the endosymbiotic theory?
1.
2.
3.
4.
what organelles resulted from the endosymbiotic theory?

Explanation:

1. For the enzyme - activity vs temperature graph:

• At low temperatures, enzyme activity is low because the kinetic energy of the enzyme and substrate molecules is low, reducing the frequency of effective collisions.
• The temperature is optimal at the peak of the curve, where the enzyme has the highest activity due to the ideal balance of molecular motion and enzyme - substrate interactions.
• At high temperatures, enzyme activity decreases as the enzyme may denature, losing its three - dimensional structure and active - site functionality.

1. All cells, regardless of type, have the following in common:

• Cell membrane: It encloses the cell and regulates the movement of substances in and out.
• Cytoplasm: The gel - like substance within the cell where many metabolic reactions occur.
• Ribosomes: They are involved in protein synthesis.
• Genetic material (DNA or RNA): Carries the hereditary information.

1. Evidence for the endosymbiotic theory:

• Mitochondria and chloroplasts have their own circular DNA, similar to prokaryotic DNA.
• They have their own ribosomes that are more similar to prokaryotic ribosomes in size and structure.
• They reproduce by binary fission, similar to prokaryotic cells.
• They have a double - membrane structure, which could be a result of the engulfment process.

1. Organelles resulting from the endosymbiotic theory are mitochondria (originated from aerobic prokaryotes) and chloroplasts (originated from photosynthetic prokaryotes).

Answer:

1. For the enzyme - activity vs temperature:

• At low temperatures: Enzyme activity is low due to low molecular kinetic energy.
• Optimal temperature: At the peak of the curve where enzyme activity is highest.
• At high temperatures: Enzyme activity decreases due to denaturation.

1. Common cell structures:

• 1. Cell membrane
• 2. Cytoplasm
• 3. Ribosomes
• 4. Genetic material (DNA or RNA)

1. Evidence for endosymbiotic theory:

• 1. Own circular DNA
• 2. Prokaryote - like ribosomes
• 3. Binary fission reproduction
• 4. Double - membrane structure

1. Organelles from endosymbiotic theory:

• Mitochondria
• Chloroplasts