Bio Lab Exam 1 Flashcards
In what kinds of organisms does photosynthesis occur?
Plants, algae, and SOME bacteria
What is the equation for photosynthesis?
6CO₂ + 6H₂O → C₆H₁₂O₆ (glucose) + 6O₂
Where does photosynthesis occur?
Chloroplasts (usually, except for cyanobacteria/blue-green algae or other photosynthetic bacteria)
What two processes make up photosynthesis?
- Light Reactions
- Calvin Cycle
What happens in light reactions (photosynthesis)?
- Light energy converted to chemical energy (ATP, NADPH)
- Involves splitting of water molecules into oxygen
What wavelengths encompass the visible light spectrum?
380 nm - 760 nm
What is the role of photosynthetic pigments?
- Found in chloroplasts
- Can absorb photons of light and use in photosynthesis
Name some photosynthetic pigments.
- Chlorophyll a (main), b, c, d
- Carotenoids (Carotene & Xanthophylls)
What color is chlorophyll?
Green
What color are carotenoids?
Yellow, Orange, and Red
What is the calvin cycle?
- Energy from ATP and NADPH is used to convert CO₂ into organic molecules (such as glucose)
- Does not need light (dark reactions)
Which color has the longest/largest wavelength?
Red (760 nm)
Which color has the shortest wavelength?
Violet (380 nm)
What is the role of the sodium bicarbonate in the photosynthesis lab?
Source of CO₂ for photosynthesis
What is the equation for the rate of photosynthesis?
mL O₂ / time (hour)
What was the effect of increased light wattage on the rate of photosynthesis?
↑ Light Intensity = ↑ Rate of Photosynthesis
Would the rate of photosynthesis increase indefinitely?
No, because the CO₂ will be depleted eventually.
What is paper chromatography?
Using a specific type of paper as well as a solvent to separate different solutes/pigments in a solution and analyze their qualities.
What affects how far a pigment can move in paper chromatography?
- Molecular Weight (heavy pigments don’t move as far)
- Solubility in Solvent (more soluble = moves farther)
- Affinity for Paper (higher affinity doesn’t move as far)
What is the equation for Rf?
Pigment Distance / Solvent Distance
What color is chlorophyll a?
blue-ish green
What color is chlorophyll b?
yellowish green
What color is β-carotene?
yellowish orange
What color is xanthophyll?
yellow
Why is photosynthesis important?
- Produces O₂
- Regulates CO₂
- Produces food/energy
What was measured to calculate cell respiration and photosynthesis?
Oxygen
What is oxidation? (NOT redox)
Release of electrons & energy from a substance (such as glucose oxidation)
What is cellular respiration?
The collective chemical reactions and steps involved in oxidation
What is glycolysis?
- Glucose is converted into pyruvate
- Makes NADH
- Anaerobic process
- Produces 2 ATP
- STEP 1 - glucose to glucose 6-phosphate (adds O group) | committed/irreversible step (uses ATP) | hexokinase (hence 6-phosphate)
- STEP 2 - glucose 6-phosphate to fructose 6-phosphate | reversible step (equilibrium) | phosphoglucose isomerase
- STEP 3 - fructose 6-phosphate to fructose 1, 6-biphosphate (adds phosphate) | committed/irreversible step (uses ATP) | phosphofructokinase (pfk)
What is fermentation/anaerobic respiration?
- When pyruvate (converted from glucose through glycolysis) is converted to a different end product and excreted
- Anaerobic
- Does not yield much ATP (only 2)
What are some end products of fermentation?
- Ethyl Alcohol
- CO₂
TCA cycle, Citric Acid cycle, Krebs cycle
- Some energy is converted to ATP (only 2)
- Most is stored in electron carriers (NAD, FAD)
- CO₂ comes off
- NADH produced
- 2 ATP produced
- FADH₂ produced
- Many intermediates
- Aerobic
Electron Transport Chain (ETC)
- Redox chain
- H⁺ protons create a gradient, can only enter through ATP synthase
- Chemiosmosis - diffusion of H⁺ ions across ATP synthase (creates ATP)
- Produces 32 ATP
- Aerobic
Endotherms
- Maintain a constant body temperature
- Birds and mammals
- Does not fluctuate with environment
Ectotherms
- Cannot maintain a constant internal body temperature
- Fluctuates with environment’s temperature
Explain seed dormancy
- Energy metabolized very slowly
- Cannot use photosynthesis but can use cellular respiration
- Cannot germinate until conditions are favorable
- As seeds germinate, cell resp rates increase
What is the equation for cellular respiration?
C₆H₁₂O₆ (glucose) + 6O₂ → 6CO₂ + 6H₂O + energy (heat + ATP)
What is metabolism?
The collection of life-sustaining chemical reactions in one’s body
What was the role of KOH in the cellular respiration experiment?
To react with and remove the CO₂ from the environment so that only O₂ is measured
What is the equation for the rate of oxygen consumption?
mL oxygen consumed / hour
What is the equation for metabolic rate?
Rate of oxygen consumption (mL oxygen / hour) / mass of organism
How does temperature affect respiration in organisms?
- Endotherms: inverse relationship (↑ temp ↓ resp and vice versa)
- Ectotherms: direct relationship (↑ temp ↑ resp and vice versa)
Why would water move into the respirometer pipettes?
Pressure difference (as O₂ decreases, water moves in since pressure decreases)
Scientific Method
- Observation
- Question
- Hypothesis (possible explanation)
- Prediction (if, then statement)
- Experiment
- Analysis
- Conclusion
What must a hypothesis be?
- Specific
- Written as a Statement
- Testable
- Falsifiable
Diffusion
Moving from high conc. to low conc.
Gradient
Difference in concentration, pressure, or temperature
Osmosis
Special kind of diffusion that involves movement of a solvent (like water)
Tonicity
- Measure ability of solution to cause water to move
- Hypertonic
- Hypotonic
- Isotonic
Hypertonic
Greater concentration compared to the other side of the membrane
Hypotonic
Lower concentration compared to the other side of the membrane
Isotonic
Same concentration on both sides of membrane
Turgor Pressure
Resistance of water movement by cell wall
Plasmolysis
Separation of plasma membrane from cell wall
What is the equation for percent change in mass?
Change in mass (current - initial) / Mass (initial) * 100%
Dialysis
Diffusion of solute
Factors that affect diffusion
- Molecular Weight
- Molarity
- Temperature
- Concentration Gradient
What is a monosaccharide made of?
- Carbonyl group
- 2 or more hydroxyl groups
- Hexoses (like glucose) are the most important in biology
What is the reaction used to form larger molecules from small molecules?
Dehydration Synthesis
What are reducing sugars?
Sugars capable of reducing (can donate an electron) due to carbonyl group (C=O)
How does a reducing disaccharide work?
One of the rings of the 2 monosaccharides can break apart to form C=O (carbonyl)
Benedict’s Assay
- Tests positive for reducing sugars
- Positive results are green, yellow, orange, or red
- Originally a blue solution
- Must heat solutions in water
Barfoed’s Assay
- Tests positive for monosaccharides
- Positive results are green or red/violet
- Originally a blue solution
- Must heat solutions in water
- Similar to Benedict’s Assay but with 4.5 pH (acidic)
Iodine Test/Assay
- Tests positive for presence of a starch
- Control is yellow-ish
- Positive result is black or purple/blue
Biuret Test/Assay
- Tests positive for peptide bonds (proteins, usually)
- Positive result is violet or purple
- Originally blue solution
Miscibility Assay
- Tests NEGATIVE (no mixing) for lipids
Sudan Black (or Red) Test
- Mixes with and stains lipids
- Does not mix with or stain water or water-soluble compounds
- Positive test for lipids
