Practical #2

If an enzyme is boiled, will its activity increase, decrease or stop completely? Why does this happen?

The enzyme's activity will stop completely because boiling it will cause the enzyme to denature, destroying its active site.

What is the fewest number of catalase molecules needed to break down 10 molecules of hydrogen peroxide?

1

The _______ ______ is the energy needed to start a chemical reaction.

Activation Energy

What term refers to the energy investment that is required to start a chemical reaction?

Activation Energy

The part of the enzyme where the substrate attaches is called the ______ _____.

Active Site

Archimedes eats a large steak at the Outfront. Although his stomach pH is 2, pepsin, the enzyme that digests proteins, is active. Why is pepsin able to function in this acidic environment?

All enzymes have an optimal pH and temperature at which they work. Pepsin's optimal pH is 2.

What is the process of cell division called in bacteria (prokaryotes)?

Binary Fission

Identify the enzyme(s) in the reaction below. Catechol Oxidase Catechol ------------------------------------------------> Benzoquinone

Catechol Oxidase

Prophase

Chromosomes condense, nuclear envelope fragments, mitotic spindle forms

Telophase

Chromosomes uncoil, nuclear envelope reforms, mitotic spindle disappears

When an animal cell is placed in a hypertonic solution, ____ occurs.

Crenation

List the term that describes what happens to an enzyme when exposed to an unfavorable environment.

Denatured

When an enzyme is exposed to an unfavorable (increased) temperature or pH, the enzyme loses its three-dimensional shape and is said to become ______________.

Denatured

The movement of solute particles across the cell membrane is called ___________.

Diffusion or Simple Diffusion

What molecules regulate chemical reactions in living organisms?

Enzymes

How do enzymes accelerate the rate of chemical reactions?

Enzymes lower the energy of activation

What term do we use to describe a plant cell placed in isotonic solution?

Flaccid

Give one reason why eukaryotic cells need to go through the process of cell division.

Growth

How does increasing temperature affect the rate of diffusion?

Increased temperature increases the rate of diffusion.

Define lysis and describe the osmotic condition that would cause an animal cell to lyse. Explain why plant cells never lyse.

Lysis is when an animal cell bursts. It occurs when an animal cell is placed in a hypotonic solution for an extended period of time. Plant cells do not lyse because their cell walls prevent them from bursting.

What is the product in this reaction? Amylase Starch ---------------> Maltose

Maltose

Mitotic spindle fibers are made of ______________.

Microtubules

Would you predict that all cells in the adult human body divide at the same rate?

No. Depending on the cell type and location, different cells divide at different rates. Some cells, like skin, hair and those lining the gastrointestinal tract, are replaced quickly as they wear out. Other cells, such as skeletal muscle and neurons, stop dividing completely at a certain stage.

Why does it take only 1 catalase molecule to break down 10 molecules of hydrogen peroxide?

Only one catalase enzyme is required to break down 10 molecules of hydrogen peroxide. Enzymes catalyze a reaction without being used up or altered in the process, so after the catalase enzyme is done breaking down one hydrogen peroxide molecule, it can be used to break down the second hydrogen peroxide and so on...

Give one example of how you can affect the rate of diffusion.

Permeability can affect the rate of diffusion because if a substance is not permeable through a membrane than it will not be able to diffuse through it. So the more permeable a substance is than the faster it can diffuse.

Metaphase

Sister chromatids align at the equator of the cell

Anaphase

Sister chromatids are pulled apart to opposite ends of the cell

What will happen to a plant cell when placed in a hypertonic solution?

Plasmolysis

Name the stage of the cell cycle or mitosis during which the mitotic spindle forms.

Prophase

Name the enzyme used to solidify milk in the experiment to test the affect of temperature on enzyme activity.

Rennin

In what parts of the plant body would you expect cell division to be most likely to occur?

Roots and Shoots (new bud formation)

Name the stage of the cell cycle or mitosis during which chromosomes replicate (be specific).

S phase (synthesis)

Name the solute in a salt water solution.

Salt

A dialysis membrane separates solutions A and B. Solution A is a 30% sucrose solution, while solution B is a 10 % sucrose solution. Which solution is hypertonic?

Solution A

Solution A = 50% protein; Solution B= 30% protein. Which of these solutions is hypotonic?

Solution B

When an enzyme is boiled the enzyme's activity:

Stops Completely

What happens in the active site of an enzyme?

Substrates bind by an induced fit and products are formed.

In a sugar and water solution, which is the solute?

Sugar

During which stage of cell division do the chromosomes replicate?

Synthesis phase

List two factors that can affect the amount of product formed in an enzymatic reaction.

Temperature and pH

In lab, a dialysis bag is filled with distilled water and placed in a beaker of sucrose. What will happen to the weight of the bag after 40 minutes?

The weight of the bag will decrease as water leaves the bag and enters the beaker.

In lab, a dialysis bag is filled with sucrose and placed in a beaker of distilled water. What will happen to the weight of the bag after 40 minutes?

The weight of the bag will increase as water enters the bag and leaves the beaker.

Mitotic divisions begin with a "parent cell". How do the resulting daughter cells compare to the parent cell?

They are exactly the same size and are genetically identical

Cell membranes are selectively permeable. What does this mean?

This means that the cell membrane will allow some substances in or out of the cell, but not other substances.

True or False: If a selectively permeable membrane separates two isotonic solutions, osmosis will occur.

True. Osmosis constantly occurs between the cell and its environment. In an isotonic solution, the amount of water entering the cell is equal to the amount of water leaving the cell.

What term do we use to describe a plant cell placed in hypotonic solution?

Turgid

Which of the following showed the greatest enzymatic activity in the catalase experiment (with the potato and hydrogen peroxide)?

Water (pH 7)

Which of the following temperatures showed the least enzymatic activity in the milk experiment?

boiled (100 degrees Celcius)

What is the process of cytokinesis in plant cells called?

cell plate formation

What is the process of cytokinesis called in animal cells?

cleavage furrowing

when the stomata are open, water is lost from the leaf in a process known as _________________

transpiration

What is the mitotic spindle composed of?

microtubules

The ability of the cell membrane to allow some substances to pass more easily than others is known as __________ ____________.

selective permeability