BIO119 Module 1: Cell Structure

Questions and Answers

What is the primary purpose of centrifugation in cell fractionation?

To separate organelles based on their buoyant density

What is the purpose of using marker enzymes in subcellular fractionation?

To identify specific organelles

Which of the following is NOT a step in subcellular fractionation?

Microscopy of cellular structures

What is the result of incomplete homogenization in subcellular fractionation?

Incomplete breakage of cellular membranes Signup and view all the answers

Which of the following is a limitation of using centrifugation in subcellular fractionation?

It can cause damage to organelles Signup and view all the answers

What is the purpose of extraction in subcellular fractionation?

To solubilize membranes and release proteins Signup and view all the answers

Which of the following is NOT a type of centrifugation used in subcellular fractionation?

Electrophoresis Signup and view all the answers

What is the result of using a low speed centrifugation step in subcellular fractionation?

Removal of large cellular debris Signup and view all the answers

What type of proteins are attracted to the positive functional groups in anion exchange chromatography?

Proteins with net negative charge Signup and view all the answers

What is the main purpose of using DEAE resin in anion exchange chromatography?

To attract proteins with net negative charge Signup and view all the answers

In size exclusion chromatography, what happens to large proteins that cannot fit into the pores of the beads?

They are washed off the column quickly Signup and view all the answers

What is the purpose of using a ligand in affinity chromatography?

To bind specifically to proteins of interest Signup and view all the answers

How are bound proteins eluted from the column in affinity chromatography?

By adding a solution containing the ligand Signup and view all the answers

What is the application of affinity chromatography in the medical field?

To eliminate undesirable substances from blood Signup and view all the answers

What type of proteins move quickly down the column in anion exchange chromatography?

Proteins with net positive charge Signup and view all the answers

What can be purchased with pores of a specific size range to accommodate proteins of a certain size?

Size exclusion chromatography beads Signup and view all the answers

What is the composition of the stationary phase in Cation Exchange Chromatography?

Microscopic polymer beads with negatively charged functional groups Signup and view all the answers

What happens to proteins with a net positive charge in Cation Exchange Chromatography?

They interact strongly with the column's negative functional groups Signup and view all the answers

What is the role of the Na+ ions in Cation Exchange Chromatography?

To exchange with positively charged proteins Signup and view all the answers

Why do proteins with a large net positive charge remain stuck to the column?

Because they interact strongly with the stationary phase Signup and view all the answers

How can proteins with a large net positive charge be eluted from the column?

By increasing the pH of the buffer Signup and view all the answers

What is the application of Cation Exchange Chromatography in water treatment?

Softening of hard water Signup and view all the answers

What is the difference between Cation and Anion Exchange Chromatography?

Cation exchange uses negatively charged beads, while Anion exchange uses positively charged beads Signup and view all the answers

What is the name 'Cation Exchange' referring to in Cation Exchange Chromatography?

The exchange of positively charged proteins for cations Signup and view all the answers

Study Notes

Biochemistry

Biochemistry is the application of chemistry to the study of biological processes at the cellular and molecular level.

Introduction to Cell Structure

The cell is the most basic unit of life.
Animal and plant cells have variations in their structures.
The module reviews various organelles within cells.

Learning Outcomes

Define terms associated with cells.
Describe the organelles found in all kinds of cells.
Outline the function of each organelle.
Outline the method used for fractionation and separation of cell components.
Differentiate between the features of eukaryotic and prokaryotic cells.

Definitions

Genome: the entire genetic complement of an organism, including all organic bases contained within the DNA, organized into 23 pairs or 46 chromosomes.
Co-enzyme: an organic non-protein compound that binds with an enzyme to catalyze a reaction, can be reused several times.
Pili: protein structures that extend from the bacterial cell envelope, function to attach cells to surfaces.

Chromatography

Size Exclusion Chromatography:
- Stationary phase composed of microscopic cross-linked polymer beads with pores of a specific size range.
- Small proteins fit into the pores, while large proteins don't, resulting in separation based on size.
Affinity Chromatography:
- Stationary phase composed of polymer beads with a ligand cross-linked to the beads.
- Proteins that bind to the ligand stick to the stationary phase, while others are washed off.
- Bound proteins can be eluted using a solution containing the ligand.
- Application: elimination of undesirable substances from blood.
Ion Exchange Chromatography:
- Cation Exchange Chromatography:
  - Stationary phase composed of microscopic polymer beads with negatively charged functional groups.
  - Proteins with a net positive charge are attracted to the beads, while those with a net negative charge are not.
  - Application: softening of hard water, demineralisation of water, and the separation and determination of anions.
- Anion Exchange Chromatography:
  - Bead surface covered with positively charged groups.

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Description

Introduction to cell structure, focusing on the cell as the basic unit of life, including a brief overview of its components and functions.