WorksheetsBiology Unit 2: Energy Flow & Cycling of Matter Assessment
Total questions: 29
Worksheet time: 15mins
Name
Class
Date
1.
A student observes that a plant placed in a dark closet for several days begins to wilt and turn yellow. Which biological process is most directly affected, and why?
a)
Photosynthesis decreases because light energy is unavailable for the light-dependent reactions
b)
Cellular respiration stops because no glucose is being produced
c)
Transpiration increases to compensate for the lack of photosynthesis
d)
The Calvin cycle continues but produces less glucose due to reduced CO₂
2.
If the light-dependent reactions of photosynthesis were completely blocked while the Calvin cycle machinery remained intact, what would be the immediate consequence?
a)
Oxygen production would increase
b)
Glucose production would continue at normal rates
c)
The Calvin cycle would stop due to lack of ATP and NADPH
d)
CO₂ uptake would increase to compensate
3.
During intense exercise, muscle cells switch from aerobic to anaerobic respiration. What is the primary reason this metabolic shift occurs?
a)
The body prefers lactic acid as an energy source
b)
Glucose becomes unavailable in muscle tissue
c)
Oxygen supply cannot meet the increased demand
d)
Mitochondria stop functioning during exercise
4.
A researcher measures ATP production in cells under different conditions. Which scenario would yield the highest ATP output per glucose molecule?
a)
Anaerobic fermentation in yeast cells
b)
Complete aerobic respiration with functional electron transport chain
c)
Calvin cycle coupled with glycolysis
d)
Glycolysis only in the presence of oxygen
5.
In a forest ecosystem, if decomposers were suddenly eliminated, which consequence would occur first?
a)
Primary producers would immediately die
b)
Nutrient cycling would be disrupted, affecting plant growth
c)
All consumers would switch to photosynthesis
d)
Energy flow would reverse direction
6.
An ecologist studying energy transfer finds that a hawk population requires 1000 kg of biomass from small birds to maintain their population. Based on the 10% rule, approximately how much plant biomass is needed to support this food chain?
a)
100,000 kg
b)
10,000,000 kg
c)
10,000 kg
d)
1,000,000 kg
7.
Why do ecosystems require a constant input of energy from the sun, while matter can be recycled indefinitely?
a)
Matter is more stable than energy in biological systems
b)
The sun provides both energy and matter to ecosystems
c)
Energy is converted to heat and lost at each trophic transfer
d)
Energy can only flow in one direction through living systems
8.
A student notices that both plants and animals have mitochondria. What does this suggest about cellular energy requirements?
a)
Both plants and animals require ATP for cellular work beyond photosynthesis
b)
Plants use mitochondria only during nighttime
c)
Only animals need ATP for cellular processes
d)
Mitochondria in plants serve a completely different function
9.
During photosynthesis, the oxygen released comes directly from which reactant?
a)
Water (H₂O)
b)
Carbon dioxide (CO₂)
c)
Chlorophyll molecules
d)
Glucose (C₆H₁₂O₆)
10.
If atmospheric CO₂ levels suddenly doubled, what would be the most likely immediate effect on the Calvin cycle (Light Independent)?
a)
The cycle would reverse direction
b)
The rate would increase due to higher substrate availability
c)
The rate would decrease due to enzyme saturation
d)
No change would occur since light is the limiting factor
11.
A cell biologist observes that a particular cell type has an unusually high number of mitochondria. What can be inferred about this cell's function?
a)
It stores large amounts of glucose
b)
It specializes in protein synthesis only
c)
It primarily performs photosynthesis
d)
It has high energy demands requiring substantial ATP production
12.
In the carbon cycle, what role do cellular respiration and photosynthesis play in maintaining atmospheric balance?
a)
Both processes only remove CO₂ from the atmosphere
b)
They have no effect on atmospheric CO₂ levels
c)
Both processes only add CO₂ to the atmosphere
d)
Photosynthesis removes CO₂ while respiration adds CO₂
13.
A farmer notices that crops grown in soil with abundant decomposer organisms grow better than those in sterilized soil. What explains this observation?
a)
Decomposers directly transfer energy to plant roots
b)
Decomposers release nutrients from organic matter that plants can absorb
c)
Decomposers perform photosynthesis for the plants
d)
Decomposers prevent all plant diseases
14.
Which statement best explains why food chains rarely exceed four or five trophic levels?
a)
Competition becomes too intense at higher levels
b)
Genetic diversity decreases at higher trophic levels
c)
Predators become too large to find adequate shelter
d)
Energy loss at each transfer makes higher levels unsustainable
15.
A student compares the chemical equations for photosynthesis and cellular respiration. What relationship do they represent?
a)
They are identical processes occurring in different organelles
b)
They are unrelated processes that occur independently
c)
They are reverse processes that complement each other in the carbon cycle
d)
They both produce the same products but use different reactants
16.
If a protein contains 200 amino acids, what elements must have been present during its synthesis?
a)
All elements found in living organisms
b)
Only carbon and hydrogen
c)
Carbon, hydrogen, oxygen, and nitrogen
d)
Carbon, hydrogen, and oxygen only
17.
A nutritionist explains that carbohydrates provide 'quick energy' while lipids provide 'long-term energy storage.' What molecular property explains this difference?
a)
Carbohydrates have more chemical bonds than lipids
b)
Lipids contain more oxygen atoms per molecule
c)
Carbohydrates are more readily accessible for cellular respiration
d)
Lipids are more easily broken down than carbohydrates
18.
DNA and RNA are both nucleic acids, but they have different functions. What structural difference allows DNA to store genetic information long-term?
a)
DNA contains different elements than RNA
b)
DNA contains more phosphate groups
c)
DNA molecules are smaller than RNA molecules
d)
DNA has a double-stranded structure that provides stability
19.
A researcher studying enzyme function discovers that high temperatures denature the protein. What does this suggest about protein structure and function?
a)
Protein shape is critical for proper function
b)
Temperature has no effect on biological molecules
c)
Proteins function better at high temperatures
d)
Only enzymes are affected by temperature changes
20.
In a controlled experiment, scientists remove all decomposers from a small ecosystem. What would be the most significant long-term consequence?
a)
Accumulation of dead organic matter and nutrient depletion
b)
Improved plant growth due to reduced competition
c)
Enhanced energy flow to higher trophic levels
d)
Increased oxygen production
21.
A plant geneticist creates a mutant plant that can perform the Calvin cycle but has defective chlorophyll molecules. What would be the most likely outcome when this plant is exposed to sunlight?
a)
The plant would perform cellular respiration instead of photosynthesis
b)
The plant would be unable to produce glucose due to lack of ATP and NADPH
c)
The plant would produce oxygen but no glucose
d)
The plant would produce glucose normally since the Calvin cycle is intact
22.
In a laboratory experiment, researchers provide muscle cells with glucose but remove all oxygen from the environment. After 30 minutes, which metabolic byproduct would accumulate in the highest concentration?
a)
ATP from oxidative phosphorylation
b)
Lactic acid from anaerobic respiration
c)
Carbon dioxide from aerobic respiration
d)
Ethanol from fermentation
23.
An ecosystem ecologist notices that a particular lake has very few fish despite abundant phytoplankton. Chemical analysis reveals high levels of organic matter but low oxygen levels. What process is most likely responsible for this oxygen depletion?
a)
Evaporation of dissolved gases
b)
Nitrogen fixation by aquatic plants
c)
Cellular respiration by decomposer bacteria breaking down organic matter
d)
Excessive photosynthesis by phytoplankton
24.
A biochemist studying cellular energetics discovers that blocking electron transport in mitochondria prevents ATP synthesis but allows glycolysis to continue. What does this reveal about cellular energy production?
a)
Glycolysis produces more ATP than the electron transport chain
b)
Most cellular ATP comes from processes requiring oxygen
c)
Fermentation is more efficient than aerobic respiration
d)
The Calvin cycle can substitute for electron transport
25.
In a controlled greenhouse experiment, plants are grown under different colored lights. Plants under green light show significantly reduced growth compared to those under red and blue light. What does this suggest about photosynthetic efficiency?
a)
Chlorophyll molecules cannot absorb green light wavelengths effectively
b)
Green light provides too much energy and damages chloroplasts
c)
Green light inhibits the Calvin cycle reactions
d)
Plants reflect green light because it's harmful to cellular processes
26.
A marine biologist studying coral bleaching finds that stressed corals expel their symbiotic algae. What would be the immediate metabolic consequence for the coral animal?
a)
Reduced access to glucose produced by algal photosynthesis
b)
Increased oxygen production from enhanced photosynthesis
c)
Improved nitrogen fixation capabilities
d)
Enhanced cellular respiration due to reduced competition
27.
An environmental scientist measures carbon dioxide levels in a forest throughout a 24-hour period. CO₂ levels are lowest at midday and highest just before dawn. What biological processes best explain this pattern?
a)
Both photosynthesis and respiration stop at night
b)
Decomposition rates vary with temperature throughout the day
c)
Photosynthesis peaks at midday while respiration is constant throughout the day
d)
Respiration only occurs in darkness while photosynthesis only occurs in light
28.
A cell biologist compares ATP yield from glucose metabolism in different cell types. Muscle cells produce 32 ATP per glucose while some bacteria produce only 2 ATP per glucose. What cellular structure most likely accounts for this difference?
a)
Mitochondria enabling aerobic respiration in muscle cells
b)
More efficient ribosomes in muscle cells
c)
Larger cell size allowing more metabolic reactions
d)
Presence of chloroplasts in muscle cells
29.
In a food web study, researchers find that removing a single plant species causes the collapse of three different herbivore populations. What ecological principle does this best demonstrate?
a)
The 10% rule of energy transfer between trophic levels
b)
The inefficiency of energy transfer in food chains
c)
The role of decomposers in nutrient cycling
d)
The importance of keystone species in ecosystem stability
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