biology exam

How much protein do you need to add to the 800 µL buffer to make a 1:5 dilution?

1 part sample required and 4 parts dilution taken (diluent should be 4 times amount of sample taken) 4 parts buffer = 800 ul 1 part protein -> 800/4 = 200 ul 200 ul protein needed

Why is it dangerous to wear contact lenses in the lab?

1. the plastic used in contact lenses is permeable to some of the vapors found in the laboratory 2. the vapors can trap behind the lenses and can cause extensive irritation 3. the lenses can prevent tears from removing the irritant

How do you make a 10X serial dilution from a 10M, 5M, or 1M stock respectively? How much diluent and stock solution would you add to each of the tubes?

10M -> 1 part stock solution, 9 parts diluent 15M -> 1 part stock solution, 9 parts diluent 1M -> 1 part stock solution, 9 parts diluent Each dilution will be 10% as concentrated as the preceding stock.

How much original protein sample do you need to add to a 500 ul buffer, 600 ul buffer, and 800 µl buffer to make a 1:5 dilution, respectively?

500 ul -> 500/4 = 125 ul 600 ul -> 600/4 = 150 ul 800 ul -> 800/4 = 200 ul

Lipids

Commonly found in foods with a lot of fat like butter, whole milk, and cheese Phospholipids and steroids and hormones are also lipids that can be in our bodies insoluble in water but soluble in organic solvents like natural oil composed of glycerol molecule binded to a long hydrocarbon chain

Proteins

Meat, eggs, nuts, soy are natural sources for proteins that help build muscle mass Antibodies and enzymes are examples of proteins that are in our bodies provide as much energy density as carbohydrates composed of long chains of amino acid residues sequence of amino acids determines each proteins 3D structure and function

Never use a CO2 based extinguisher on a person. Do you know the reason why?

Never use a CO2 fire extinguisher on a person, as it is extremely cold.

what's the volume range of the P20, P200, and P1000, respectively?

P20 -> 2-20 ul P200 -> 20-200 ul P1000 -> 200-1000 ul

What is the main risk of going outside of the volume range of a pipette?

The pipettes are only calibrated to those volumes so when you go over the volume range you may pick up the wrong amount and ruin the pipette.

Why/when do you press the plunger all the way down to the second stop?

When you are expelling the liquid so that the entire amount of liquid you took in is expelled (correct amount is put where it needs to be).

What is the difference between micro- and macro- molecules?

a micromolecule refers to a molecule of relatively small size and low molecular weight as opposed to a macromolecule, which is large and with greater molecular weight.

What is the first thing you should do if there is a fire in the lab?

a small fire - attempt to smother it out of control - fire extinguished - ensure safety -fire alarm - press the circuit breaker - fire blankets

electron microscopes

accelerated electron beam, higher resolution transmission and scanning

interpupillary distance adjustment

adjust distance between eyepieces

binary fission

asexual reproduction by a separation of the body into two new bodies organism duplicates its genetic material, or DNA, and then divides into two parts (cytokinesis), with each new organism receiving one copy of DNA

Know the relative cell sizes among bacteria cells and eukaryotic cells.

bacteria cells = 0.1 - 5 μm diameter; very small so can move and remove waste quick eukaryotic cells = 10 - 100 μm diameter

Why samples are stored at 4°C

bacteria growth is reduced

plants

cell wall, chloroplasts, large central vacuole, special plastids

animals

centrosomes, lysosomes

iodine-starch test

chemical reaction that used to test for the presence of starch or for iodine. The combination of starch and iodine is intensely "blue-black". The interaction between starch and triiodide is the basis for iodometry.

aperture (iris) diaphragm

controls diameter of circle of light, helps w contrast

concentric X-Y knob

controls position of slide (travel of stage)

working distance

distance from objective lens to sample low working dist = high magnification

contrast

expressed as a ratio in adjusting areas of scene

Why/when do you press the plunger to the first stop?

first stop: the first stop when drawing liquid in It's because if you go past the first stop, you'll draw in a higher volume of liquid than intended.

condenser lens (adjustment knob)

focus light from lamp

Understand what Fluorescent microscopy is used for.

helps to visualize structures ex: endothelial cell from bovine pulmonary artery - label with 3 different fluorescent stains nucleus - blue microtubules of cytoskeleton - green mitochondria - red illuminates specimen with light of specific wavelength to be absorbed it causes specimen to emit light with longer wavelength! use proteins (red/yellow) - tagged to specific structures

depth of field

how far through sample you can see (how fat the slide is) high magnification = low depth of field

field of view =

how large of view you are looking at in the sample high magnification = low field of view (small area)

What should you NOT do if a person's clothes suddenly catch fire?

if you clothing catches fire, do not run or take other action that will fan the flames immediately drop down and roll on the floor to extinguish the flames

numerical aperture

indication of how well light is collected and focused through an object to see a clear image high num aperture- can see finer details = high magnification

biuret test, also known as Piotrowski's test,

is a chemical testused for detecting the presence of peptide bonds. In the presence of peptides, a copper(II) ion forms mauve-colored coordination complexes in an alkaline solution.

Like lipids, the chemical Sudan IV

is not soluble in water; it is, however, soluble in lipids. In this test dark red Sudan IV is added to a solution along with ethanol to dissolve any possible lipids. If lipids are present the Sudan IV will stain them reddish-orange (positive test).

Streaking plates

isolation into a pure culture of the organisms (mostly bacteria), from a mixed population

light (LMs)

low power//insepection- SIMPLE high power- 10x objective lenses are 4x, 10x,40x, 100x total magnification= ocular lens x objective lens

resolving power

measure of clarity of image, can separate 2 points very close to each other and its still clear (can see details)

both

plasma mem, cytoplasm, nucleus, ribosomes, mitochondria, peroxisomes, some vacuoles

Know the difference between a polymer, monomer, and oligomer.

polymer: long, repeating chains of molecules monomer: a molecule that can be bonded to other identical molecules to form a polymer. oligomer: a polymer whose molecules consist of relatively few repeating units.

What is Aseptic technique and different sterilization methods?

prevent contamination by infectious agents

carbohydrates

rains, fruits, and vegetables are all natural sources of carbohydrates for energy. These foods consist of both soluble and insoluble carbohydrates. The insoluble part is known as fiber, which is mostly cellulose. carbs all sugars- complex carbs are sugar polymers

diopter adjustment

suit eyesight of user

Benedict's Test

test for simple carbohydrates. The Benedict's test identifies reducing sugars (monosaccharide's and some disaccharides), which have free ketone or aldehyde functional groups. Benedict's solution can be used to test for the presence of glucose in urine.

Generation time (def)

time it takes for a population of bacteria to double in number population doubles every generation time

How do you calculate total magnification of a high power/compound microscope?

total magnification = (ocular lens power) x (objective lens power)

If the original concentration of BHL sample is 0.35 mg/ml, can you estimate the concentration of BHL in the 1:50 dilutions? What if the original concentration is different?

If you have the dilution factor, you can divide the original concentration by that dilution factor. So, for 1:50, you just divide the starting concentration by 50: .35/50 = .007 mg/ml. And it goes the other way around also.

magnification

LMs can magnify upto around 1000 times how much larger object appears compared to real size

What are macromolecules comprised of?

Macromolecules are large molecules composed of thousands of covalently connected atoms. Carbohydrates, lipids, proteins, and nucleic acids are all macromolecules. Macromolecules are formed by many monomers linking together, forming a polymer.

Nucleic Acids

Main information carrying molecules of the cell direct process of protein synthesis make up DNA and RNA composed of nucleotides (nitrogen containing aromatic base attached to pentose sugar which is attached to a phosphate group