Bio 123 Lab Exam 1

Null Hypothesis

a hypothesis that says there is no statistical significance between the two variables

Alternative Hypothesis

an opposing theory to your null hypothesis

what axis does the independent variable stay on?

x-axis

what axis does the dependent variable stay on?

y-axis

independent variable

the variable that is manipulated

dependent variable

response to the variable that is measured

how should you hold the microscope?

the arm and the base

what is the microscope used for?

viewing life closer than the naked eye can see

how many lenses does the compound light microscope have?

2

what do you use to switch lenses?

the nosepiece

what is the magnification of the ocular lens?

10x

What is the field of view

the circle of light visible when looking through the microscope

what objective lense do you start viewing the slide with?

4x

how do you calculate total magnification?

total magnification=objective lens x ocular lens

can you use oil with a 40x?

no

What are the organic molecules?

lipids, carbohydrates, proteins, and nucleic acids

what is the monomer of a polysaccaride?

monosaccaride

what kind of molecule was Biuret’s reagent a color indicator for?

protein

Amino Group

NH2

Sudan IV used to test for which type of molecule?

lipids/fats

Which color indicator would have a positive test for starch?

lugals reagent

Carbonyl group

C=O

A positive Ninhydrin test for proline would be what color?

yellow

Two cell types:

Eukaryotic and Prokaryotic cells

magnification

how big the specimen looks

resolution

the ability to distinguish between two objects

lower total magnification=

larger field of view with less fine detail

higher total magnification:

smaller field of view with more fine detail

what is magnification determined by?

the objective lens

what is the light adjusted by?

the rheostat and the iris diaphram

what is focus determined by?

course and fine adjustment knobs

what moves the stage back and forth and left and right?

the mechanical stage knobs

what is cytoplasmic streaming?

when a substance moves around with the cytoplasm, like chloroplasts

4 key biomolecules

carbohydrates, fats, proteins, and nucleic acids

What do each key biomolecules contain?

carbon, oxygen, hydrogen

What will we use to identify the presence or absence of certain molecules?

indicatiors

What is an indicator?

a special chemical that changes color in the presence of a specific chemical substance

What do we use to compare our experiment to?

control group; for this experiment H2O

What are Carbohydrates made up of?

Carbon, Hydrogen, and Oxygen (ex is CnH2nOn)

What is the simplest unit of a carbohydrate?

monomer aka monosaccharide, ex. glucose, fructose

What is a more complex carbohydrate?

disaccharide aka two monosaccharides joined together; ex. sucrose and lactose

What is the most complex carbohydrate?

polysaccharides aka three or more monosaccharides linked together; ex. starch, cellulose, glycogen, chitin

What are reducing sugars?

Contain a free carbonyl group (aldehyde or ketone); all monosaccharides and some disaccharides

What does Benedicts reagent show?

tests for the presence of reducing sugars; requires heat to react, + result = green-yellow (medium concentration of reducing sugars) and red-orange (high concentration of reducing sugars); - result means no color change

Lugol’s reagent

tests for the presence of non-reducing sugars (starch); some disaccharides and all polysaccharides will react; negative looks brown; positive will look black

How do lipids differ from carbs?

hydrophobic, non-polar; contains carbon, hydrogen, and oxygen however there is far less oxygen causing the ratio to be different

What is Sudan IV test?

tests for the presence of lipids, fat soluble only; results red floating droplets

What is the basic units of proteins?

amino acids; two amino acids bind together with a peptide bond; C, N, O, H

Biuret test:

tests for the presence of protein (peptide bonds); positive reaction: purple in color change; negative reaction: no color change

Ninhydrin test:

tests for the presence of free amino acids; positive result: purple color change shows presence of amino acid other than proline while yellow color change show proline only)

Nucleic Acids

subunit is a nucleotide; 3 parts; phosphate group, pentose sugar, and nitrogenous base

prokaryotic cells

generally unicellular, small, more simple; no membrane bound organelles, nucleoid region, circular DNA (plasmid), can be photosynthetic, reproduce via binary fission

eukaryotic cells

can be unicellular (protists) or multicellular, generally much larger, more complex, membrane bound organelles, nucleus, linear chromosomal DNA, reproduce through mitosis, can be photosynthetic

What type of DNA do prokaryotes have?

circular DNA

What type of DNA do eukaryotes have?

linear DNA

What type of organelles do prokaryotes have?

ribosomes and no membrane bound organelles; nucleoid and DNA in cytoplasm

What type of organelles do eukaryotes have?

ribosomes and membrane bound organelles; nucleus with DNA stored separate from the cytoplasm as linear chromosomes

autotroph

make their own food (most often using energy from the sun)

Heterotroph

consume autotrophs for food

what are the three types of prokaryotic shapes?

coccus, round; bacillus, rod or pill shaped; spirillum, helical or spiral shaped

gram negative

has lipopolysaccharide layer; has outer membrane; has thin peptidoglycan layer

gram positive

has thick peptidoglycan layer

What do both gram positive and gram negative possess?

a cytoplasmic membrane and a peptidoglycan layer

Why did we select the basic stains of crystal violet and safranin?

positively charged chromatophore; attracted to the negative charge of bacterial cell wall; positive will turn purple and negative will turn pink

Gram Iodine’s purpose

acts as a mordant and reacts with the crystal violet to form the crystal violet iodine complex (makes gram positive bacteria stay purple)

Ethanol’s purpose

dehydrates the thick peptidoglycan of gram positive bacteria and will dissolve the lipopolysaccharide layer of gram negative bacteria

What is cyanobacteria?

photosynthetic prokaryote, contains chlorophyll A, NO chloroplasts, contain a thylakoid membrane where photosynthesis occurs, linear filaments, aka “blue-green algae”

What is the purpose of a streak plate?

decreasing bacterial concentrations enough to proliferate into discrete colonies after the incubation period

What is the purpose of a spread plate?

creates uniform surface of bacterial growth

photoautotrophs

photo- light, auto-self, troph-food (plants and many protists)

heterotrophs

hetero-different, troph-food (animal and many protists)

structures of photoautotrophs:

contain plastids (chloroplasts-chlorophyl & synthetic material and tonoplasts-central vacuole), cell wall, can be multicellular or single celled

structures of heterotrophs:

no chloroplasts, no tonoplasts, can be multi or unicellular, and animal cells do not have a cell wall but many protists do

STOP: draw and label a photoautotroph

yes go do it there’s 11 things

chloroplast

chloro- green, plast- shape/form; contains thylakoids and is the site for photosynthesis (produce sugar)

chromoplast

chromo- color, plast- shape/form; contains accessory pigments that capture light which are used in photosynthesis but DO NOT complete photosynthesis

leucoplast

leuco-white, plast- shape/form; contain starch and other useful molecules, cellular tupperware

tonoplast

aka-central vacuole, tono-tension, plast- form/shape; contains water, critical in ion regulation, maintain osmotic homeostasis

STOP and draw and label a heterotroph

yes do it there are 10 things

what are the two membrane flavors of membrane types

1. semi permeable

2. selectively permeable

semi permeable membrane

pore size is fixed/inanimate (think dialysis bag in experiment)

selectively permeable membrane

poor size can change and is only present in living organisms (it can “select” its pore size)

two types of cellular transport and type of membrane they occur in:

semipermeable membrane can have active and passive transport along its membrane

active transports

requires energy (normally ATP) to move against a concentration gradient

passive transport

requires no energy and moves with the gradient, subdivided into osmosis and diffusion

osmosis

a special type of diffusion where water molecules pass through a semipermeable membrane from low concentration of a solute to high concentration of a solute until equilibrium is reached

diffusion

molecules passively move from an area of high concentration to an area of low concentration until equilibrium is reached

what is hypotonic for an animal cell?

too much water inside the cell therefore causing it to lyse (burst)

what is hypertonic for an animal cell?

too much water outside the cell causing it to crenate (shrivel)

what is isotonic for an animal cell?

equal amounts of water inside and outside the cell

what do animal cells prefer their pressure to be at?

isotonic

what do plant cells prefer their pressure to be at?

hypotonic

what happens to a plant cell when it is hypertonic?

it is plasmolyzed (shriveled)

what do you call a plant cell when it is hypotonic?

turgid pressure, plant cells prefer this state

what do you call a plant cell when it is isotonic?

flaccid

What influences the rate of diffusion?

1. size of the molecule

2. permeability of the membrane

3. temperature

4. viscosity of the solvent

5. distance

nucleus

stores genetic information/control center for the cell

Nucleolus

help produce/create the cells ribosomes

Centrioles

organization of microtubules

cyclosis

movement of material within a cell that follows the flow of the cytoplasm