Bio 11.1 Exercise 5A (Using Scientific Models to Study a Property of the Cell Membrane) | Flashcards

1. Technological viewpoint

2. Scientific viewpoint

Models are defined in two (2) ways. What are this?

Technological viewpoint

What viewpoint is this?

It may be anything used as a guide in testing a new design. (e.g. small-scale version of a bridge or airplane.

Scientific viewpoint

What viewpoint is this?

May be a design or structure representative of some system.

Scientific viewpoint

What viewpoint is this?

It aims to synthesize a structure-function relation based on universally accepted knowledge and understanding.

Scientific viewpoint definition

Which definition of a model is generally useful in biology?

1. May simplify the study of some technology-limited system which are either too small or too large

2. To better visualize, understand, and analyze concepts, principles and systems.

3. Can clearly recognize some properties of and processes in the cell

4. Represents a broad concept and thus may act as a springboard for further investigation of more specific problems

5. Can help formulate hypothesis

6. Provides a logical framework of analysis

What are the several uses of a model?

Tangible (concerete structure) or intangible (use of words)

Models could be ________ or _________.

Osmosis

Movement of solvent molecules (i.e. water) across the cell membranes that caused the changes in the cell size and shape.

Diffusion

The movement of substances from an area of high concentration to low concentration across a semi-permeable membrane.

Osmotic concentration

Refers to the numbers of dissolved particles., such as molecules and ions.

moles per liter (mol/L)

Osmotic concentration is expressed as _____.

• hyper-

• hypo-

• isoosmotic

Medium to which cells are exposed to can be described as __________________.

Hyperosmotic or hypertonic

A medium is ________ relative to a cell if it has a higher osmotic concentration than the cell

Hypoosmotic or hypotonic

A medium is __________ relative to a cell if it has a lower osmotic concentration.

Isoosmotic or isotonic

A medium is ___ if one has the same osmotic concentration as the cell.

An artificial membrane (dialyzing membrane)

In Exerc 5A, what was used as a model?

Artificial membrane

Has microscopic pores that allow the passage of substances

Dialyzing membranes of variable pore sizes

Can be sourced from laboratory suppliers in the form of dialysis tubings.

1. DM has a specific pore size (could allow semi-permeability)

2. Conditions to ensure movement of substance concentration gradients

3. Detection of movement

Why was the dialyzing membrane chosen as the model?

• Soak it in distilled H₂O for 2-3 mins

• Tightly seal first one end with a string and open the other end by rubbing it against your thumb and index finger.

How do you open the tubing of the dialyzing membrane (DM)?

• Set-up 1: Distilled H₂O + 60% glucose sol’n

• Set-up 2: Distilled H₂O + 10% NaCl sol’n

• Set-up 3: Distilled H₂O + 1% boiled starch sol’n

• Set-up 4: 10% NaCl sol’n + 60% glucose sol’n

• Set-up 5: Distilled H₂O, 2 drops HCl + Distilled H₂O

What was the content of the beakers and DM Bag in Exerc 5A Act. #1?

I2KI solution
- yellow (absent)
- blue/black (present)

What chemical indicator do you use when testing for starch? What color should appear if starch is present/absent?

Benedict’s solution
- Blue (absent)
- Green, yellow, orange, red graduated from not much glucose (green) present to a lot present (red)

What chemical indicator do you use when testing for reducing sugars (e.g. glucose)? What color should appear if reducing sugar (e.g. glucose) is present/absent?

Silver nitrate (AgNO₃)
- Clear (absent)
- Cloudy white precipitate (present)

What chemical indicator do you use when testing for sodium chloride? What color should appear if sodium chloride is present/absent?

Copper (II) sulfate

What is the main ingredient of the Benedict’s reagent?

Reducing or non-reducing.
Their ability to act as a reducing agent.

Sugars are classified as ______ based on ______________________.

Reducing agent

Donates electrons during a redox rxn and is itself oxidized.

A reducing sugar

Is glucose a reducing or non-reducing sugar?

Red precipitate

Copper (I) oxide is seen as _________.

Starch

Is a coiled polymer of glucose

Iodine interacts with this coiled molecules and becomes bluish black. Other non-coiled carbohydrates do not react with iodine.

What is the basis for the test I2KI sol’n?

pH meter

What was used in detecting the pH of a solution?

Para hindi mag-burst (matapon).

Why should the DM bag appear flaccid

Electronic balance

What was the apparatus used to take the weight of the DM Bag