Lab practical 1 Flashcards
Also called steroscopic microscopes
Dissecting microscopes
includes both scanning and transmission
electron microscopes
also called light microscopes
compound microscopes
are used to view the surface of relatively larger specimens at lower power typically no more than 10x,
dissecting microscopes
functions like elaborate magnifying glasses and would be used to observe the gross anatomy of a living, preserved, or dissected specimen at greater detail
dissecting microscopes
scientific instruments that use a beam of highly energetic electrons to examine objects on a very fine scale (up to several 100,000x
electron microscopes
What type of microscope do we use in lab
compound microscopes
Describe how the compound microscope works
compound microscopes are limited by the physics to 500x or 1000x magnification, it consists of two lenses and associated hardware that make viewing of specimen easier
the lower lens of the compound microscope is called
objective lens
the uppermost lens of the compound microscope is called
the ocular lens
the part through which the person looks through is
the uppermost lens which is the ocular lens
are mounted on a turret, allowing rapid changing
the lower lens which are the objective lens
name the power listed on the objective lenses scope
4x scanning power, 10x low power, 40x high power
hols the ocular and objective lenses in place
the body tube
most microbiological specimens are mounted on glass
slides
glass slides with cover slips are placed on
the stage
holds the slide firmly on the stage
usually clips or clamps
what two objects are located beneath the stage
a light source and a condenser lens
why is the compound microscope called light microscope
because it has a light source
why must the specimen be sliced thin
the specimen must be sliced then enough so that light can pass through the specimen to be viewed
focuses on light through a hole in the stage
condenser
what does the condenser include
an iris
varies the amount of light passing through a specimen
the iris
what happens to the light as it passes through the specimen
the goes through the objective and ocular lens and through the eye of the observer
this image is calculated by multiplying the magnification of the ocular by the magnification of the objective
the total magnification
what happens to light as it passes through any object (glass, air, specimens, etc.),
it bends
the bending of light is called
refraction
is a measurement of the extent that the substance bends light
the refractive index of a substance
distortion of the image
excessive refraction
at magnifications of less than 500x
the distortion is minimal
we will not view specimens at any total magnification greater than
400x
when magnifications are high what becomes the problem
the distortion becomes so great the image details are lost
helps to remedy the distortion problem by eliminating the air gaps between the specimen and the objective lens
oil immersion lens
the 4th objective lens is
the oil immersion lens
topmost series of lenses through which an object is viewed
ocular lens or eyepiece
what is the magnifying power of the ocular lens on your microscope
10
holds the nosepiece at one end and eyepiece at the other end; conducts light rays
body tube
supports upper parts and provides carrying handle
arm
objectives
objective lens, scanning, low, and high power
hold 4x lens used to view the whole slide
scanning power objective lens
Holds 10x lens used to view objects in greater detail
low-power objective
holds 40x lens used to view the objective in even greater detail
high- power objective
holds 100x lens and is used in conduction with oil to view objects with the greatest magnification
oil immersion objective lens
what lens are you never suppose to use
the oil immersion objective lens if your compound/light microscope has one
knob used to bring object into approximate focus; used only with low-power objective
coarse-adjustment knob
knob used to bring object into final focus
fine-adjustment knob
controls amount of illumination used to view the object
diaphragm or diaphragm control lever
an attached lamp that directs a beam of light up through the object
light source
the flat surface of the microscope that rests on the table
base
holds and supports microscope slides
stage
aids in the accurate position of the slide
mechanical stage
what structures are present to move the stage
the mechanical stage control knobs
should you ever use something other than the mechanical stage control knobs
NO, you should never use anything to move the stage it will cause damage to the stage
two knobs that are usually located below the stage. one knob controls forward/reverse and the other controls right/left
mechanical stage control knob
what is the first rule for microscope use
the lowest power objective should be in position booth at the beginning and end of microscope use
what is the second rule for microscope use
use only lens paper for cleaning the lens
what is the third rule for microscope use
do not tilt the microscope when viewing a wet mount
what is the fourth rule for microscope use
keep the stage clean and dry to prevent rust and corrosion
what is the fifth rule for microscope use
do not remove parts of the microscope
what is the sixth rule for microscope use
keep the microscope dust-free by covering it after use
what is the 7th rule for microscope use
report any malfunctioning when you notice it. This will benefit you and those who use the microscope after you
what is the should you always do before the 1st rule for focusing the microscope
always start with lowest power objective lens on you microscope or the scanning lens with the compound microscope
what is the first thing you do after making sure you at the lowest power objective lens when focusing the microscope
turn the nosepiece so that the lowest power lens is in straight alinement over the stage
what is the second rule of focusing the microscope
alway begin with focusing with lowest power objective
what is the 3rd rule of focusing the microscope
with the coarse-adjustment knob, lower the stage until it stops
what is the 4th rule of focusing the microscope
place slide on the stage and stabilize it with the clips
that is the 5th rule of focusing the microscope
again be sure the lowest power is in place
look grin the side
decrease the distance between the stage and the objective lens until the lens comes to an automatic stop or is no closer than 3mm above the slide
Why would it be a bad idea for the slide and objective lens to come into contact
you could break the slide or damage the lens
what is the 6th rule of focusing the microscope
while looking in to the eyepiece, rotate the diaphragm lever to give the maximum amount of light
what is the 7th rule of focusing the microscope
slowly increase the distance between the stage and the objective lens, using the coarse adjustment knob until the object comes into view or focus
what is the 8th rule of focusing the microscope
once the object is seen, you may need to adjust the amount of light. to increase or decrease the contrast rotate the diaphragm slightly
what is the 9th rule of focusing the microscope
use the fine-adjustment know to sharpen the focus if necessary
what is the 10th rule of focusing the microscope
practice having both eyes open when looking through the eyepiece, as it greatly reduces eyestrain
define inversion
the act of inverting something or a reversal of the normal
define parfocal
once the object is in focus with lowest power in our case scanning power, it should be nearly in focus with the higher power
How do you go from scanning power to high power
- bring the object into focus
- Make sure that the object is center in the field of the lowest objective
- move to the higher objective (lower power 10x) by turning th nosepiece until you hear or feel it click into place
- Do not change the focus
- if any adjustment is needed use only the fine-adjustment knob
- remember always use fine-adjustment for higher powers
- repeat steps 2 and 4`
- when you finish your observation rotate the nosepiece until the lowest power objective clicks into place
How is total magnification calculated
by multiplying the magnification of the ocular lens (eyepiece) by the magnification of the objective lens
power of objective x power of ocular =
total magnification
what is the power of ocular
10
4x10 =
scanning 4 x 10 power of ocular = 40
10 x 10 =
low 10 x 10 power of ocular = 100
40 x 10 =
high 10 x 10 power of ocular = 400
How do properly put up your microscope?
- Remove any slides on the stage.
- Make sure the scanning objective is locked in place.
- Returned all slides to the correct slot in the slide tray.
- If you made any wet mounts, make sure to clean the slide and cover slip and return them to the tray
- If you break any slides or cover slips, throw them away into the trash labeled GLASS ONLY
- Center the mechanical stage
- Lower the mechanical stage or raise the nosepiece
- Turn off the scope (light source)
- Wrap and tie the cord using the plastic ties provided with the cord. DON’T WRAP CORD AROUND ANY PART OF THE MICROSCOPE
- Place dust cover over microscope
- Carry microscope with two hands and by the base. Store with the number that corresponds to the number on the desk
- Make sure cord is on the shelf not hanging
- Make sure arm is facing out. when do properly the # on the microscope base that correspondss with your station number can be seeen
what is biochemistry
the study of the chemistry of life
all living organisms consists of
organic compounds called carbon
molecules are made of smaller subunits called
monomers
what are known as the building blocks
monomers
monomers or building blocks line together to form
larger molecules called polymers
name the four class biological molecules are divided into macromolecules
- lipids which includes fats, waxes, and oils
- carbohydrates which are compromised of sugars that form starch and cellulose
- Proteins which are composed of amino acids
- Nucleic acids which include DNA and RNA
includes fasts, oils, steroids, waxes
lipids
lipids are the main components of the
plasma membrane of all living cells
the lipids found in plants are
oils
the lipids found in animals are
fats
are solids at room tempreature
oils are liquids
Lipids are _______, ________
non-polar, hydrophobic, they do not dissolve in water
when doing the lipid experiment using the full pipette of water and the full pipette full of vegetable oil to the same tube. What property of lipids explain the results you obtained
non-polar, hydrophobic, because lipids do not dissolve in water
is there anyway you can dissolve the oil in water
through use of detergent, soap and or dishwashing liquid
what is Sudan IV used to identify
the presence of a fat or oil
Using sudan IV what color was the lipid layer
hot pink
what color was the water layer
cloudy white
Sudan IV indicates the presence of what macromolecule
lipids
What property does Sudan IV have in order to react with this macromolecule?
neutral and hydrophobic
can be simple sugars or polymers made up of many sugar units
carbohydrates
carbohydrates are organic molecules
made of carbon, hydrogen and oxygen
simplest sugars are
monosaccharides
maonosaccharides are comprised of
one sugar unit
most common monosaccharide is
glucose
what is the function of glucose
serves as the immediate source of energy
the primary form of sugar stored in the human body
glucose
the main sugar found in most fruits
frutose
What is the molecular molecule for glucose and fructose
C6H12O6
how are glucose and fructose different
Fructose and glucose have the same molecular formula but differ structurally
CH2OH
I
H / C ------------O
I / I \ H
C H \ I
I \OH H / C
OH I I I
C \_\_\_\_\_ C OH
I I
H OHGLUCOSE
C6H12O6
CH2OH O CH2OH
I
I
Frutose
C6H12O6
What is the difference between glucose and fructose?
different structures or structural formulas
how many carbon atoms do glucose and fructose have
6
What is the molecular formula for glucose
C6H12O6
What is the molecular formula for fructose?
C6H12O6
Can be bonded together to form
monosaccharides
what contains two sugar units linked by a glycosidic bond
disaccharides
table sugar
sucrose
in seeds
maltose
milk sugar
lactose
is a disaccharide that consists that consists of glucose unit bonded to a fructose unit
common table sugar
sucrose is made of what two monosaccharides?
glucose and fructose
what is the molecular formula of sucrose
C12 H22 O11
what molecule must be lost in order to produce sucrose
one molecule of H2O must be lost
The joining of two monosaccharides to produce a disaccharide occurs through a
dehydration reactions
a indicator for monosaccharides
Benedict’s solution
what is the positive indicator for monosaccharaides
orange
would you expect to see the same results in the Benedicts solution for sucrose as the sample
no because there is a difference in structure and structural formula
when using Benedict’s soution for sucrose what color do you observe
blue
what does the results tell you about Benedict’s solution as an indicator?
it allows the you to detect the difference between a monosaccaride and disaccharide
If more than two sugar units are joined by a glycosidic bond, the carbohydrate is called a
polysaccharide
what are some examples of polysaccharides
glycogen, starch, and cellulose
the polysaccharide found in animals
glycogen
the polysaccharide found only in plants and cellulose
starch
is a polysaccharide only in the cell walls of plants
starch
the principal polysaccharide used by plants to store glucose for later use as energy
starch
often stores starch in seeds or other specialized organs
plants
common sources of starch include rice, beans, wheat, corn potatoes etc.
plants often store starch in seeds or other specialized organs
What happens when humans eat starch
an enzyme that occurs in saliva and in the intestines called amylase breaks the bonds via hydrolysis reactions between the repeating glucose units this allowing sugar to be stored into the blood stream.
an enzyme that occurs in saliva and in the intestines called amylase breaks the bonds via hydrolysis reactions between the repeating glucose units this allowing sugar to be stored into the blood stream.
what happens when humans eat starch
the enzyme that occurs in saliva and in the intestines is called
amylase
the function of the enzyme amylase
breaks the bonds via hydrolysis reactions between the repeating glucose units, this allows sugar to be stored into the blood stream
what allows sugar to be stored into the bloodstream
the enzyme amylase breaks the bonds via hydrolysis reactions between the repeating glucose units
What happens once absorbed into the bloodstream
the human body distributes glucose to the areas where it is needed for energy or stores it as its own special polymer - glycogen
name another polymer of glucose
glycogen
The polysaccharide used by animals to store energy
Glycogen
Bonded to together to form glycogen molecules
Excess glucose
The animals stores in the liver and muscles tissues as an “instant” source of energy
Excess glucose is bonded together to form glycogen molecules
Both starch and glycogen are
Polymers of glucose
What structural differences do you observe between starch and sucrose
Starch has long chains
what monomer units do you observe in starch?
glucose
the most common test for a polysaccharide is
Lugol’s test
In the Lugol’s test what color is for the presence of starch
blue-black
dropping a very small drop of Lugol’s on paper is what color and why
brown because lugol’s is an indicator of polusaccaharide which paper is made out of
macromolecules with a diverse range of functions
proteins
proteins exist as
enzymes, antibodies, hormones, and transport proteins
Proteins are made up of
amino acids linked by peptide bonds
how many amino acids occur in nature
20
Proteins are also known as
polypeptides
H O
+ I II
H3N–C–C-O H3N—-C—-CO O ——> H3N
TRY TO REMEMBER THE 1ST IS AN AMINO ACID 1 THE SECOND IS AMINO ACID 2 AND THE THIRD IS A DIPEPTIDE
The biuret test is a positive indicator of the number of
peptide bonds in proteins
In the biuret test what is the color in the presence of proteins
pink to purple
why are proteins known as polypeptides
amino acids are linked by peptide bonds and there are many
what color does the bieuret solution turn in the presence of a great number of peptide bonds?
violet
comprised of DNA and RNA
nucleic acids
the genetic material of life
DNA and RNA
adds red coloration to lipids
Sudan IV
an indicator of the presence of monosaccharides
BENEDICT’S SOLUTION
an indicator of the presence of polysaccharides
lugol’s test
an indicator for the presence of polypeptides
biuret test
common feature found in all cells
the plasma membrance
