L.O: students will review laboratory techniques and the four required labs.

First lab safety:

You should know what to do in a lab…and……

You should know what NOT to do!

You will have ONE question on lab techniques and lab safety!

Are you being safe?

Be able to explain why any one of these kids is not being safe”!

Are you being safe?

Measurements: when one makes an observation using

numbers & a measuring instrument.

There will be one measurement question on the regents!

Example: what is the exact measurement of this worm?

9.0 centimeters

Example 2: how much water is in the graduated cylinder?

13.0 mL.

Example 3: how much water is in the graduated cylinder?

24.0 mL

Now answer 1-6.

Microscopes:• You should know the

basic parts of a microscope.

• There may be one question.

Microscopes are use to make small objects look bigger.

Objects under a microscope are always upside down and backwards. e

Because objects are upside down and backwards, one has to move a slide the OPPOSITE of where

one wants to move an object.

If i want to move the organism this way

I must move the slide this way

When wet-mounting a specimen on a slide, the cover-slip must be lowered at an angle to prevent air bubbles.

To stain a specimen, place a paper towel at one side of the slip cover. Add the dye stain at the opposite end. Capillary action will “pull”

the dye through, staining the specimen.

A microscope’s field of view is the diameter of the microscope’s circle. Knowing the field of view can be used to determine the size of microorganisms.

If this microscope’s field of view under low power is 1000um, what is the size of the

organism?

1000um

If this microscope’s field of view under low power is 1000um, what is the size of the organism?

~200um

1000um

Now answer 7-14.

And now the four required labs.

We did a diffusion through a membrane lab

We did a making connections lab

We did a relationships & biodiversity lab

We did a beaks of finches lab

First the diffusion through a membrane lab>>>

The goal of the lab is to model how a cell uses diffusion to maintain homeostasis.

What we did: 1. We put starch and glucose inside a piece of plastic called dialysis tubing.

2. We tied both ends tight with string.

3. We place several drops of iodine starch indicator into a cup of water.

We placed the dialysis tube in cup to see what happens:

Our predictions:• The Glucose will

DIFFUSE OUT of the dialysis tube because the molecules are small.

• The Iodine will DIFFUSE INTO the tube because the molecules are small.

• The starch will stay inside the tube because the molecules are big.

• We used indicators to determine our results.

Results:

The starch molecules were too large to diffuse out. Inside dialysis tube turned blue-black (purple-black) because the starch indicator (iodine) diffused into tube & change the

starches’ color.

A sample of the liquid from outside the tubing turned glucose indicator orange because the small glucose

diffuse out.

Indicators:

Indicators are used to determine if a substance (ex. Starch or glucose) is present (is there).

Starch indicator (iodine) turns purple-black if Starch is present (is there).

Glucose indicator turns orange if glucose is present (is there).

Diffusion: the movement of molecules from areas of high concentration to areas of low concentration without

using energy.

Diffusion: the movement of molecules from areas of high concentration to areas

of low concentration without using energy.

More sugar 97%

Less sugar

Lesssugar

More sugar

Cell has 94%

water inside

Cell has 97%

water insidesurrounding

Area has 96% water

Surrounding has92% water

Diffusion: molecules move from high concentration to low concentration

without using energy.

More sugar 97%

Less sugar

Lesssugar

More sugar

Cell has 94%

water inside

Cell has 97%

water insidesurrounding

Area has 96% water

Surrounding has92% water

Diffusion: molecules move from high concentration to low concentration

without using energy.

Cell has 6% salt inside

Cell has 100% water insidesurrounding

Area has 100% water

Surrounding has6% water

Diffusion molecules move from areas of high concentration to areas of low concentration.

Diffusion molecules move from areas of high concentration to areas of low concentration.

Why will easy for molecule B diffuse into the cell but hard for molecule A?

Another part of the diffusion through a membrane dealt with red onion cells.

What you did: we looked at slices of red onions, then….

Salt water was added to the onion slices.

Saltwater

First we saw view A: normal red onion cells.After the salt solution: the onion cells shriveled.

Then we put distilled (zero salt) water on the shriveled cells… they swelled

Remember: salt solutions cause cells to shrivel. Distilled water causes cells to

swell.

Remember: salt solutions cause cells to shrivel. Distilled water causes cells to

swell.

surrounding Area has 100% water

Surrounding has6% water

Now the beaks of finches lab:

Darwin’s finches

Know how to read and use this chart:

The outer circle has the names and drawings of the bills.

The next two circles describe the type of the bills each species has.

The inner circle shows the type of the food each species eats.

This is another finch chart that has appeared on previous regents exams.

Now answer 15-23.

Gel electrophoresis:

Gel electrophoresis is a method of analyzing DNA (also RNA & proteins)

The DNA (or RNA & proteins) are cut using enzymes…

The DNA (or RNA & proteins) samples are put into wells on the gel and an electric current is

run. The electricity makes the DNA bands more

The DNA (or RNA & proteins) samples are put into wells on the gel and an electric current is

run. The electricity makes the DNA bands more

Uses of gel electrophoresis:

1. Evolutionary relationships: if organisms are related.

Bands of DNA

2. Gel electrophoresis can be used to determine paternity

Who the parent or who the relative is.

3. Gel electrophoresis can be used for genetic testing. For genetic disorders

4. To solve crimes using DNA

Gel electrophoresis separates the DNA bands by size. The smallest move fastest through the gel.

Bands of DNA

The DNA results from gel electrophoresis is often used to make claudogram trees!

Gel electrophoresis is 99% or more accurate…. It is how we know humans are related to the other great apes.

Gel electrophoresis is 99% or more accurate…. It is how we know humans are related to the other great apes

It is how we know if someone is guilty or innocent of a crime….

It is how we know who the “baby daddy” is on Maury or Jerry Springer!

You ARE the

father!

In the Relationships and Biodiversity lab we were looking for which plant was related to Botana

Curus, a hypothetical cancer treatment.

The plants has similar appearance, seeds & microscope slides…

We used gel electrophoresis (DNA & Amino acids) to determine which plant was related to Botana Curus.

We used gel electrophoresis (DNA & Amino acids) to determine which plant was related to Botana Curus.

Remember: DNA (gel electrophoresis) & amino acids are the most accurate way to identify or determine relationships.

Which the most closely related to A, according the the DNA bands?

Which the most closely related to A, according the the DNA bands?

Which organisms are the most closely related according to their amino acids?

Now answer: 24- 46.

Paper chromatography:

Chromatography: a method of separating different molecules in a mixture.

Chromatography: a method of separating different molecules in a mixture.

The final mandatory lab is the making connections lab

The human body is like a machine with many complicated systems.

All the systems must work together to maintain homeostasis.

All of our organ systems work together to maintain our homeostasis.

Examples:

• Our muscular system moves our body. It gets Oxygen from our respiratory system in order to produce ATP. The circulatory system brings the oxygen to the muscles. Our excretory system sweats to keep the muscles cool (from over heating).

Which activity uses more energy?

Walking? Arguing with a friend?

When we’re very active. All of our systems speed-up to keep up with the increased activity.

Why does running cause more exhaled air than sitting?

Sample regents question

Sample regents question

Sample regents question

Sample regents question

Sample regents question

Now complete all the remaining questions.