AT 250 QUIZ 1 | Questions and
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## **[DOMAIN 1: BIOLOGY - 100 Questions]**
### **Cell Biology (Questions 1-20)**
* *1.** Which structural feature distinguishes prokaryotic cells from eukaryotic cells?
- A) Presence of ribosomes
- B) Presence of a membrane-bound nucleus **[CORRECT]**
- C) Presence of cytoplasm
- D) Presence of DNA
* *Rationale:** Prokaryotes (bacteria, archaea) lack membrane-bound organelles, most notably
the nucleus. Both cell types have ribosomes, cytoplasm, and DNA. The defining feature of
eukaryotes is the presence of a true nucleus enclosed by a nuclear envelope with nuclear
pores.
---
* *2.** Which organelle is responsible for cellular respiration and ATP production?
- A) Golgi apparatus
- B) Rough endoplasmic reticulum
- C) Mitochondria **[CORRECT]**
- D) Lysosomes
,* *Rationale:** Mitochondria are the "powerhouses" of the cell, containing the electron transport
chain and ATP synthase. They have double membranes (outer smooth, inner folded into cristae)
and their own DNA, supporting the endosymbiotic theory.
---
* *3.** According to the fluid mosaic model, what is the primary structural component of the cell
membrane?
- A) Cholesterol
- B) Phospholipid bilayer **[CORRECT]**
- C) Protein layer
- D) Carbohydrate coat
* *Rationale:** The fluid mosaic model describes the plasma membrane as a phospholipid
bilayer with embedded proteins. Phospholipids have hydrophilic heads and hydrophobic tails,
creating a semipermeable barrier. Proteins float within this bilayer, and cholesterol modulates
fluidity.
---
* *4.** Which transport mechanism requires ATP and moves substances against their
concentration gradient?
- A) Simple diffusion
- B) Facilitated diffusion
- C) Osmosis
- D) Active transport **[CORRECT]**
* *Rationale:** Active transport requires energy (ATP) to move molecules from low to high
concentration. The sodium-potassium pump (Na⁺/K⁺-ATPase) is the classic example,
maintaining electrochemical gradients. Passive transport (diffusion, facilitated diffusion,
osmosis) moves substances down concentration gradients without energy input.
---
* *5.** Which cytoskeletal element is composed of tubulin and forms the mitotic spindle?
- A) Microfilaments (actin)
- B) Intermediate filaments
- C) Microtubules **[CORRECT]**
- D) Myosin fibers
* *Rationale:** Microtubules are hollow tubes of α-tubulin and β-tubulin polymers. They form
centrioles, cilia, flagella, and the mitotic spindle. Microfilaments (actin) are involved in muscle
contraction and cell movement. Intermediate filaments provide structural support.
,---
* *6.** During which phase of the cell cycle does DNA replication occur?
- A) G₁ phase
- B) S phase **[CORRECT]**
- C) G₂ phase
- D) M phase
* *Rationale:** The cell cycle consists of interphase (G₁, S, G₂) and mitosis (M). DNA synthesis
(replication) occurs during the S (synthesis) phase. G₁ involves cell growth, G₂ involves
preparation for division, and M phase includes mitosis and cytokinesis.
---
* *7.** In which stage of mitosis do sister chromatids separate and move to opposite poles?
- A) Prophase
- B) Metaphase
- C) Anaphase **[CORRECT]**
- D) Telophase
* *Rationale:** Anaphase is characterized by the separation of sister chromatids at the
centromere, pulled by spindle fibers toward opposite poles. Prophase involves chromosome
condensation; metaphase aligns chromosomes at the metaphase plate; telophase involves
nuclear envelope reformation.
---
* *8.** What is the primary purpose of meiosis?
- A) Growth and tissue repair
- B) Production of genetically identical daughter cells
- C) Reduction of chromosome number by half and genetic recombination **[CORRECT]**
- D) Protein synthesis
* *Rationale:** Meiosis produces haploid gametes (n) from diploid cells (2n), reducing
chromosome number. It includes crossing over (prophase I) and independent assortment,
creating genetic diversity. Mitosis produces identical diploid cells for growth and repair.
---
* *9.** Which organelle contains hydrolytic enzymes for intracellular digestion?
- A) Peroxisomes
- B) Lysosomes **[CORRECT]**
- C) Golgi apparatus
- D) Mitochondria
, * *Rationale:** Lysosomes contain acid hydrolases that break down macromolecules, worn
organelles (autophagy), and foreign particles. They maintain an acidic pH (~4.5-5.0).
Peroxisomes contain catalase for breaking down hydrogen peroxide.
---
* *10.** What is the function of the smooth endoplasmic reticulum (SER)?
- A) Protein synthesis
- B) Lipid synthesis and detoxification **[CORRECT]**
- C) Modification and packaging of proteins
- D) Storage of genetic material
* *Rationale:** The SER lacks ribosomes and synthesizes lipids, phospholipids, and steroids. It
also detoxifies drugs and poisons (especially in liver cells). The rough ER has ribosomes for
protein synthesis. The Golgi modifies, sorts, and packages proteins.
---
* *11.** Which structure is found in plant cells but NOT in animal cells?
- A) Mitochondria
- B) Cell membrane
- C) Central vacuole and cell wall **[CORRECT]**
- D) Ribosomes
* *Rationale:** Plant cells have a large central vacuole (for storage and turgor pressure), a cell
wall (cellulose), and chloroplasts. Both plant and animal cells have mitochondria, cell
membranes, ribosomes, and nuclei. Centrioles are typically absent in higher plant cells.
---
* *12.** What type of transport involves the cell membrane engulfing external material?
- A) Exocytosis
- B) Endocytosis **[CORRECT]**
- C) Diffusion
- D) Active transport
* *Rationale:** Endocytosis brings material into the cell via vesicle formation (phagocytosis for
solids, pinocytosis for liquids). Exocytosis releases materials from vesicles. Both require energy.
Diffusion is passive movement across the membrane.
---
**13.** Which protein maintains cell shape and enables muscle contraction?
D
Answers | Solved 100% Correct |
Data Analytics Fundamentals |
Pass Guaranteed - A+ Graded
## **[DOMAIN 1: BIOLOGY - 100 Questions]**
### **Cell Biology (Questions 1-20)**
* *1.** Which structural feature distinguishes prokaryotic cells from eukaryotic cells?
- A) Presence of ribosomes
- B) Presence of a membrane-bound nucleus **[CORRECT]**
- C) Presence of cytoplasm
- D) Presence of DNA
* *Rationale:** Prokaryotes (bacteria, archaea) lack membrane-bound organelles, most notably
the nucleus. Both cell types have ribosomes, cytoplasm, and DNA. The defining feature of
eukaryotes is the presence of a true nucleus enclosed by a nuclear envelope with nuclear
pores.
---
* *2.** Which organelle is responsible for cellular respiration and ATP production?
- A) Golgi apparatus
- B) Rough endoplasmic reticulum
- C) Mitochondria **[CORRECT]**
- D) Lysosomes
,* *Rationale:** Mitochondria are the "powerhouses" of the cell, containing the electron transport
chain and ATP synthase. They have double membranes (outer smooth, inner folded into cristae)
and their own DNA, supporting the endosymbiotic theory.
---
* *3.** According to the fluid mosaic model, what is the primary structural component of the cell
membrane?
- A) Cholesterol
- B) Phospholipid bilayer **[CORRECT]**
- C) Protein layer
- D) Carbohydrate coat
* *Rationale:** The fluid mosaic model describes the plasma membrane as a phospholipid
bilayer with embedded proteins. Phospholipids have hydrophilic heads and hydrophobic tails,
creating a semipermeable barrier. Proteins float within this bilayer, and cholesterol modulates
fluidity.
---
* *4.** Which transport mechanism requires ATP and moves substances against their
concentration gradient?
- A) Simple diffusion
- B) Facilitated diffusion
- C) Osmosis
- D) Active transport **[CORRECT]**
* *Rationale:** Active transport requires energy (ATP) to move molecules from low to high
concentration. The sodium-potassium pump (Na⁺/K⁺-ATPase) is the classic example,
maintaining electrochemical gradients. Passive transport (diffusion, facilitated diffusion,
osmosis) moves substances down concentration gradients without energy input.
---
* *5.** Which cytoskeletal element is composed of tubulin and forms the mitotic spindle?
- A) Microfilaments (actin)
- B) Intermediate filaments
- C) Microtubules **[CORRECT]**
- D) Myosin fibers
* *Rationale:** Microtubules are hollow tubes of α-tubulin and β-tubulin polymers. They form
centrioles, cilia, flagella, and the mitotic spindle. Microfilaments (actin) are involved in muscle
contraction and cell movement. Intermediate filaments provide structural support.
,---
* *6.** During which phase of the cell cycle does DNA replication occur?
- A) G₁ phase
- B) S phase **[CORRECT]**
- C) G₂ phase
- D) M phase
* *Rationale:** The cell cycle consists of interphase (G₁, S, G₂) and mitosis (M). DNA synthesis
(replication) occurs during the S (synthesis) phase. G₁ involves cell growth, G₂ involves
preparation for division, and M phase includes mitosis and cytokinesis.
---
* *7.** In which stage of mitosis do sister chromatids separate and move to opposite poles?
- A) Prophase
- B) Metaphase
- C) Anaphase **[CORRECT]**
- D) Telophase
* *Rationale:** Anaphase is characterized by the separation of sister chromatids at the
centromere, pulled by spindle fibers toward opposite poles. Prophase involves chromosome
condensation; metaphase aligns chromosomes at the metaphase plate; telophase involves
nuclear envelope reformation.
---
* *8.** What is the primary purpose of meiosis?
- A) Growth and tissue repair
- B) Production of genetically identical daughter cells
- C) Reduction of chromosome number by half and genetic recombination **[CORRECT]**
- D) Protein synthesis
* *Rationale:** Meiosis produces haploid gametes (n) from diploid cells (2n), reducing
chromosome number. It includes crossing over (prophase I) and independent assortment,
creating genetic diversity. Mitosis produces identical diploid cells for growth and repair.
---
* *9.** Which organelle contains hydrolytic enzymes for intracellular digestion?
- A) Peroxisomes
- B) Lysosomes **[CORRECT]**
- C) Golgi apparatus
- D) Mitochondria
, * *Rationale:** Lysosomes contain acid hydrolases that break down macromolecules, worn
organelles (autophagy), and foreign particles. They maintain an acidic pH (~4.5-5.0).
Peroxisomes contain catalase for breaking down hydrogen peroxide.
---
* *10.** What is the function of the smooth endoplasmic reticulum (SER)?
- A) Protein synthesis
- B) Lipid synthesis and detoxification **[CORRECT]**
- C) Modification and packaging of proteins
- D) Storage of genetic material
* *Rationale:** The SER lacks ribosomes and synthesizes lipids, phospholipids, and steroids. It
also detoxifies drugs and poisons (especially in liver cells). The rough ER has ribosomes for
protein synthesis. The Golgi modifies, sorts, and packages proteins.
---
* *11.** Which structure is found in plant cells but NOT in animal cells?
- A) Mitochondria
- B) Cell membrane
- C) Central vacuole and cell wall **[CORRECT]**
- D) Ribosomes
* *Rationale:** Plant cells have a large central vacuole (for storage and turgor pressure), a cell
wall (cellulose), and chloroplasts. Both plant and animal cells have mitochondria, cell
membranes, ribosomes, and nuclei. Centrioles are typically absent in higher plant cells.
---
* *12.** What type of transport involves the cell membrane engulfing external material?
- A) Exocytosis
- B) Endocytosis **[CORRECT]**
- C) Diffusion
- D) Active transport
* *Rationale:** Endocytosis brings material into the cell via vesicle formation (phagocytosis for
solids, pinocytosis for liquids). Exocytosis releases materials from vesicles. Both require energy.
Diffusion is passive movement across the membrane.
---
**13.** Which protein maintains cell shape and enables muscle contraction?
