Biology Lab

Metric System

Used in science for measurements based on powers of tens. Its is decimal based, standardized, and consistent.

Decimal based

Units scaled by multiples of 10

Standardized

Same prefixes across different types of measurements

Base unit for length

Meter m (ruler)

Base unit for mass

Gram g (Scale)

Base unit for volume

Liter l (graduated cylinder, micropipette)

Base unit for temperature

Celsius C (thermometer)

Base unit for time

Seconds s (stop watch, timer)

deci- d

-1

Centi- c

-2

Milli- m

-3

micro- u

-6

nano- n

-9

kilo K

3

mega M

6

Scientific notation

way of writing numbers in a shorter form using exponents

Meniscus

lowest margin of the water level

Celcius formula

C=(F-32)/1.8

Microscopy

fundamental technique that allows for the observation of structures too small to be seen with the naked eye

Visible light

Stereo microscope and compound light microscope

Beam of electrons

Electron microscope

40x-100x

Compound light microscope

10x-50x

Stereo microscope

1,000,000x or more

Electron microscope

200 nm

Compound light microscope

500 um

Stereo microscope

.1 nm

Electron microscope

2D

Compound light and TEM

3D

Stereo microscope and SEM

Thin, transparent specimens

Compound light microscope

Larger, opaque specimens

Stereo microscope

Very small, ultra thin, or coated specimens

Electron microscope

Simple specimens

Compound light microscope

Minimal prep

Stereo microscope

Complex specimens, must be fixed and dead

Electron microscope

Low cost and portable

Compound light microscope

Moderate cost and portable

Stereo microscope

Very expensive and stationary

Electron microscope

Compound light microscope

best for viewing small, transparent, or stained specimens like cells and thin tissues

Stereo microscope aka dissecting scope

best for examining larger, 3D objects like insects, leaves, or tools at low magnification

Electron Microscope

ideal for extremely high resolution imaging of viruses, organelles, and nanostructures- requires complex prep and expensive equipment

Magnification

making an object appear larger than it is

Resolution

ability to see objects clearly enough to tell two distinct objects apart

Eyepiece (Ocular lens)

the lens you look through, 10x magnification

Neck

connects the eyepiece to the objective lenses

Arm

supports the neck and connects it to the base

Revolving nosepiece (Turret)

holds multiple objective lenses and allows rotation to change magnification

Objective Lenses

Usually 3 or 4 lenses (4x, 10x, 40x, 100x) that provide levels of magnification

Stage

Flat platform where the slide is placed

Stage clips

holds the slide in place on the stage

Stage adjustment knob

Moves the stage forward, backward, left, or right

Diaphragm (Iris or disc)

adjusts the amount of light that reaches the specimen

Condenser

Focuses light onto the specimen for clearer viewing

Coarse adjustment knob

moves the stage up and down for general focusing

Fine adjustment knob

fine tunes the focus for detailed viewing

Light source (illuminator)

provides the light

Base

the bottom support structure of the microscope

Light dimmer knob

adjusts the brightness

Total magnification

ocular lens multiplied by the objective lens magnification

Scanning lens

x4

low power lens

x10

high and dry lens, blue

x40

oil immersion lens

x100

Field of view

what you can see when looking through the ocular lens. Diameter of the circle.

FOV formula

FOV=objective lens you measured x field of view you measure/ objective lens you want

Wet mount

simple and commonly used technique in biology labs to observe living microorganisms, cells, or tissues in a liquid medium.

Plasma membrane aka cell membrane

a selectively permeable barrier that surrounds every cell. Composed of a phospholipid bilayer with embedded proteins, carbs, and cholesterol.

Phospholipid

Polar hydrophillic head and nonpolar hydrophobic tails

Hydrophobic tails are

fatty acid chains

where is betacyanin found in beets

the central vacuole

High temperature can

increase fluidity, denature proteins, disrupt membranes, increase permeability

what do phospholipids do when temps rise

gain kinetic energy and move more freely

Low temperatures can

decrease fluidity, reduce transport, and cause cold shock

what do phospholipids do in low temps

pack tightly

Organic solvents disrupt

the phospholipid bilayer

which is more nonpolar ethanol or acetone

acetone

Changes away from optimum pH can

denature membrane proteins, change the charge and polarity of phospholipid head groups

What happens to the membrane at low pH

excess H disrupts hydrogen bonding and electrostatic interactions leading to membrane destabilization

what happens to the membrane at high pH

OH can interfere but less dramatic than acidic

reagent for protein

biuret

reagent for carbs

iodine

lipids

sterols, paper towel, water

Protein subunit

amino acids

carbs

monosaccharides

regent for monosaccharides

benedicts

Lipids subunit

fatty acids, glycerol, phosphate functional group

Dehydration synthesis

water molecule is removed between 2 subunits joining them together

degradation hydrolysis

breaking the bond between subunits by adding water

controls

known solutions used to validate our experiments

positive control

contains the variable you are testing, elicits a known postive result

negative control

does not contain the variable you are testing and elicits a known negative response

draw amino acid

H, Amino group H2N, carboxyl group, R group

Draw nucleotide

phosphate group, pentose sugar, nitrogeneous base

The Biuret test

detects proteins in a solution. Contains copper sulfate in an alkaline solution. When peptide bonds are present the copper ions turn violet

The iodine test

detects the presence of starch, will turn blueish black

Benedicts test

detects simple sugars. Changes redish orange in responde to copper oxide

Starch

polycaccharide that can be broken into maltose and glucose by the enzyme amylase

Sudan test

sudan is nonpolar so it dissolves nonpolar molecules, creating a red layer

Water solubility

water is polar so it will not dissolve non polar molecules, it will create 2 separate layers of insoluble fats or oils

emulsifier

a way to mix insoluble materials within polar water. It contains a polar and non polar side, polar side interacts with water nonpolar interacts with fat or oil.