Complete Solutions
Course
Biol 1104
1. Q: Explain the process of cellular respiration and write the overall chemical equation.
A:
Cellular respiration is the process by which cells convert glucose and oxygen into energy (ATP),
carbon dioxide, and water. It occurs in three main stages: glycolysis, the Krebs cycle, and the
electron transport chain.
Equation:
C6H12O6+6O2→6CO2+6H2O+ATP\text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2 \
rightarrow 6\text{CO}_2 + 6\text{H}_2\text{O} + \text{ATP}C6H12O6+6O2→6CO2+6H2
O+ATP
2. Q: What are the differences between prokaryotic and eukaryotic cells?
A:
Feature Prokaryotic Cells Eukaryotic Cells
Nucleus No (nucleoid region) Yes
Organelles Few (no membrane-bound) Many (membrane-bound)
Size Smaller (~1–10 μm) Larger (~10–100 μm)
DNA Structure Circular DNA Linear chromosomes
3. Q: Describe the role of enzymes in biological reactions.
A:
Enzymes act as catalysts that lower the activation energy of reactions, speeding up the reaction
rate without being consumed. They are specific to substrates and work by binding to the
substrate at the active site.
4. Q: What is the function of the mitochondria in a cell?
A:
Mitochondria are the “powerhouses” of the cell, producing ATP through aerobic respiration.
They also regulate cellular metabolism and apoptosis.
,5. Q: Outline the phases of mitosis.
A:
Prophase: Chromosomes condense, spindle fibers form, nuclear envelope breaks down.
Metaphase: Chromosomes align at the metaphase plate.
Anaphase: Sister chromatids separate to opposite poles.
Telophase: Nuclear envelopes reform around separated chromatids; chromosomes
decondense.
6. Q: Explain the difference between DNA and RNA.
A:
Feature DNA RNA
Sugar Deoxyribose Ribose
Strands Double-stranded Single-stranded
Bases A, T, C, G A, U, C, G
Function Genetic information storage Protein synthesis and regulation
7. Q: What is osmosis and how does it affect cells in hypertonic and hypotonic solutions?
A:
Osmosis is the diffusion of water across a selectively permeable membrane.
Hypertonic: Water leaves the cell; cell shrinks (crenation in animal cells).
Hypotonic: Water enters the cell; cell swells and may burst (lysis).
8. Q: Define gene and allele.
A:
Gene: A segment of DNA that codes for a specific protein or trait.
Allele: Different versions of a gene that can result in varying traits.
, 9. Q: What is photosynthesis and where does it occur?
A:
Photosynthesis is the process plants use to convert light energy into chemical energy stored in
glucose. It occurs in the chloroplasts, mainly in the thylakoid membranes.
Equation:
6CO2+6H2O+light energy→C6H12O6+6O26\text{CO}_2 + 6\text{H}_2\text{O} + \text{light
energy} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_26CO2+6H2
O+light energy→C6H12O6+6O2
10. Q: How does natural selection lead to evolution?
A:
Natural selection favors individuals with traits that increase survival and reproduction in a given
environment. Over generations, these advantageous traits become more common, leading to
changes in the population’s genetic makeup—evolution.
11. Q: What are the four major types of biological macromolecules? Name one function for
each.
A:
Carbohydrates: Provide energy (e.g., glucose).
Lipids: Store energy and make up cell membranes (e.g., phospholipids).
Proteins: Catalyze reactions and provide structure (e.g., enzymes).
Nucleic Acids: Store and transmit genetic information (DNA and RNA).
12. Q: Explain the fluid mosaic model of the plasma membrane.
A:
The plasma membrane is a fluid structure with a mosaic of proteins embedded in or attached to a
phospholipid bilayer, allowing flexibility and selective permeability.
13. Q: What is the difference between aerobic and anaerobic respiration?
A:
Aerobic respiration: Uses oxygen, produces more ATP (about 36–38 ATP per glucose).