Bio Lab Flashcards
Prokaryotic Cell
-evolved first,
-lacks a nucleus and other membrane-bound organelles,
-the nucleoid region contains the DNA,
-contains ribosomes and various internal membranes
-bacteria, archaea
-some have a cell wall and use flagella for motility
-unicellular
Eukaryotic Cell
-has a nucleus surrounded by a nuclear membrane,
-has membrane-bound organelles
-larger cellular organelles are easily identified under a microscope
-multicellular for plants and animals and fungi, unicellular for protists
Nitrogen Fixation & who does it?
converting nitrogen from the atmosphere into forms useable by plants
bacteria
Decomposers & who does it?
break down dead matter which returns organic materials to the system to be used by other organisms
bacteria
Photosynthetic vs Chemosynthetic Bacteria
use light as their energy source (similar to photosynthesis in plants), many do not use water as an electron source and lack chloroplasts (in contrast to plants)
obtain their energy from the oxidation of inorganic substances (remember: oxidation means electron loss)
Bacilli
rod-shaped bacteria
Cocci
small spherical bacteria
Spirilla
bacterium that uses milk sugar (lactose) and converts milk to yogurt
Cyanobacteria and its 2 forms
aka blue-green algae
photosynthetic, possess chlorophyll a, produce oxygen as a by-product
some capable of nitrogen fixation
two forms: gloeocapsa (unicellular), oscillatoria (colonial)
Gloeocapsa
unicellular form of cyanobacteria
appearance: green, cocci (small bubbles)
gelatinous sheath
Oscillatoria
colonial form of cyanobacteria
appearance: bacilli (long rods)
photosynthesize
Lactobacillus
Present in yogurt
Consumes lactose and converts milk to yogurt
Rod-shaped chains
List the steps in scientific inquiry as used in Biology 101
- observation
- hypothesis
- experiment
Yeast
cocci shaped
saccharomyces
fungus kingdom
saccharomyces
easily viewed fungus in yeast
anaerobic resp in Yeast
in the presence of O2 it oxidizes sugar into carbon dioxide, cause gas bubbles to form in rising bread dough
ferments sugar like glucose and sucrose into ethyl alcohol
Describe and distinguish between objective and subjective observations
objective: observations which can be verified-repeated and consistently interpreted by different observers
subjective: (more common) observer-specific, not interpreted the same to all
Describe the difference between plant and animal cells and relate the differences in structure to differences in function
animal: centrosomes, lysosomes
plant: central vacuole, chloroplasts, cell wall, plasmodesmata
Describe correct microscope use including position of stage, scope, and objectives
- turn on microscope/light
- adjust ocular lenses to eye width
- adjust objectives to lowest magnification
- turn coarse focus down all the way
- slowly turn up coarse focus which raises stage until you can see the edge of a slide and then adjust fine focus
- repeat for higher objective magnifications
Describe plant pigments that can be separated by chromatography
chlorophyll a, chlorophyll b, xanthophylls, beta-carotene
Describe the major component reactions of photosynthesis, listing their inputs (reactants) and outputs (products)
H20+CO2+light–>C6H12O6+O2
Explain where in the cell each of the photosynthetic reactions takes place
chloroplasts
thylakoids: light rxns (absorption of light)
stroma: dark rxns (Calvin Cycle/formation of carbohydrates)
Describe a method for separating plant pigments including the theory behind it
paper chromatography: the more polar pigments (assuming the plant cells are polar) will stay near the plant pigment and the more nonpolar pigments will travel further away with the solvent, creating a chromatogram
Describe a method to determine photosynthetic rate
Rf: reference front: between [0,1]. distance a compound moves in chromatography relative to the solvent front, reflects the affinity a substance has for the solvent
Predict how factors such as temperature, light intensity, or other variables affect photosynthesis
factors of photosynthesis:
temperature: indirect relationship, should be moderate for best results
light intensity: direct relationship
CO2 concentration: direct relationship
Photosynthesis
the conversion of solar/light energy to chemical energy
inputs: water, carbon dioxide, light, chloroplasts
outputs: carbohydrates+ oxygen; used to power respiration
Photoreceptors
pigments which absorb light energy
thylakoid membrane
The photosynthetic membrane within a chloroplast that contains light gathering pigment molecules and electron transport chains.
LIGHT DEPENDENT
stroma
where the carbohydrate formation or synthesis reaction takes place; fluid in the chloroplasts that surrounds the thylakoid membrane, LIGHT INDEPENDENT
rate of photosynthesis
change in %T/ change in time
Chlorophylls
Greenish pigments in all photosynthetic plant tissues and capture light for photosynthesis
Chlorophyll a
blue green occurs in all photosynthetic eukaryotes and cyanobacteria, photosynthetic pigment
Accessory pigments
pigments that capture additional light energy which is then transferred to chlorophyll a
think: (a)ccessory: chlorophyll a
ex: chlorophyll b
Chlorophyll B
Olive green
Catenoids
yellow red or orange pigments.
as accessory pigments in photosynthesis and as coloring in reproductive parts (flowers and fruits) to enhance pollination and fruit dispersal
carotene
yellow-orange pigment
Xanthophyll
yellow pigment
Carotenoids
red/yellow/orange pigments which function as: accessory pigments in photosynthesis and as coloring in reproductive parts
usually 4 _____ are present in leaves
Rf value and equation
Rf=
distance a substance travels from origin/distance solvent travels from origin
Answer between 0.01 and 0.99
Rf Value
- different colored bands show various pigment affinities fro the moving solvent
-disstance a compound moves during chromatography relative to the solvent front and reflects the relative affinity a substance has for a solvent
-polar or non polar molecuels exist
polar: absorb the paper and do not move
non-polar: travel with solvent
Chromatogram
complete array of colored bands in chromatography
Hill Reaction
the light-dependent transfer of electrons by chloroplasts in photosynthesis that results in the cleavage of water molecules and liberation of oxygen
2NADP+ + 2H2O –> 2NADPH + O2 + 2H+
- 2 DPIP +2 H2O +Light -> 2DPIPH2 +O2
-DPIP (blue) +e- -> DPIP (colorless)
More about Hill
Water is oxidized and carbon dioxide is reduced
Reduction vs Oxidation
Reduction: gain of electrons
Oxidation: loss of electrons
Reducing potential
ability to be alternately being reduced and oxidized
DPIP
replaced some of the NADP+ molecules to be reduced and change color from blue to colorless (a higher e- affinity than NADP+, intercepts electrons)
What is the purpose of deveining the leaves? Why put the spinach leaves under a lamp before they are blended with sucrose?
To separate the part containing chloroplast with the excess parts that don’t.
Why is the blender chilled?
To keep the chloroplast preserved
What is the point of blending the leaves in short bursts rather than blending for 30 seconds?
So we don’t generate too much heat that would kill the chloroplasts.
Why is cheesecloth used and what does it separate?
Separates the “chunks” of random waste that would hinder the transmittance later in the experiment.
What does the solution look like after boiling? What do you think has happened to the chloroplasts?
After boiling, the chloroplasts became denatured and could no longer function properly. Could not longer carry out photosynthesis.
Why is the phosphate buffer added to each tube?
To balance the pH of the reaction so it can go through photosynthesis
Why is it important to add the chloroplasts last? What would happen if they weren’t added last?
So the chloroplast wouldn’t start reacting before it was timed.
Why does the calibration tube contain chloroplasts and not DPIP?
gives a baseline before reading each measurement, the DPIP absorbs 605nm which gives data for a rate of photosynthesis compared to the constant
What kind of an effect would fingerprints have on your results?
decrease the rate of photosynthesis, prevents transmittance
What is the purpose of inverting the test tubes?
So the majority of the contents would be found in the middle where the spectrophotometer will be reading the transmittance of the solution.
What would happen if the light was shown directly on the test tubes?
they would heat up too much, chloroplasts could denature
Why is it necessary to read each tube quickly?
the chloroplast will continue to reaction and the transmittance reading will fluctuate. Reading it immediately gives the most accurate data.
What is the purpose of calibrating the spectrophotometer before each time interval?
Resets everything to 100% transmittance so we can accurately separate the different tested variables. If it wasn’t calibrated then the spectrophotometer would “add’ all the test tube contents together rather than reading them as separate entries.
spectrophotometer
- Turn on power button and let warm up for 10 minutes.
- Select wavelength
-605 nm for photosynthesis - Keep sample holder empty and lid closed
- fill one test tube with solution and wipe with Kimwipe
- Slide test tube into holder and close lid
- Press measure blank ket for 100%
- Remove test tube and fill next one
- Insert sample into sample compartment and close lid to read and record value
- repeat for all tubes, inverting, and wiping them before
Which tubes are controls and what is the variable controlled in each?
dark tube (light), boiled chloroplast tube (presence of chloroplasts)
% bacteria killed
(#unwashed-#washed/ #unwashed col)x100
