Biology Chapter: Cells as Building Blocks

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Questions and Answers

What fundamental characteristic do all cells share?

They have a rigid cell wall.

They are visible to the naked eye.

DNA directs the synthesis of proteins. (correct)

They contain organelles.

Which type of microscope allows for the observation of living cells?

Light microscope (correct)

Confocal microscope

Fluorescence microscope

Electron microscope

Which of the following is a defining feature of prokaryotic cells?

Have complex compartments

Lack membrane-bound organelles (correct)

Larger size than eukaryotic cells

Contain a membrane-bound nucleus

What is the primary function of organelles in eukaryotic cells?

To compartmentalize cellular processes Signup and view all the answers

What structure do prokaryotic cells utilize for movement?

Flagella Signup and view all the answers

Which component is NOT typically found in eukaryotic cells?

Nucleoid region Signup and view all the answers

What is a major difference in size between prokaryotic and eukaryotic cells?

Prokaryotic cells are smaller, typically 1-10 μm. Signup and view all the answers

Which of the following statements about fluorescence microscopy is correct?

It requires specimen preparation to visualize specific structures. Signup and view all the answers

What is the primary function of chloroplasts in plant cells?

Photosynthesis Signup and view all the answers

Which structure is involved in maintaining cell shape and facilitating movement within the cytoplasm?

Cytoskeleton Signup and view all the answers

What do thylakoids within chloroplasts contain that is essential for photosynthesis?

Chlorophyll Signup and view all the answers

According to the endosymbiotic theory, chloroplasts originated from which type of organism?

Cyanobacteria Signup and view all the answers

Which of the following structures is absent in plant cells but present in animal cells?

Centrioles Signup and view all the answers

What role do intermediate filaments play in the cell?

Structural support Signup and view all the answers

Which statements accurately describe vacuoles in plant cells?

They store water and organic compounds Signup and view all the answers

What is the primary function of tight junctions in animal cells?

Creating a watertight seal Signup and view all the answers

What is the fundamental structure of membranes?

Phospholipid bilayer Signup and view all the answers

Which type of protein is integrated into the phospholipid bilayer?

Transmembrane proteins Signup and view all the answers

How do integral proteins reach the plasma membrane after synthesis?

Vesicular transport Signup and view all the answers

What is described as the diffusion of water across a semi-permeable membrane?

Osmosis Signup and view all the answers

What kind of molecules are primarily transported through channel proteins?

Small polar molecules and ions Signup and view all the answers

In which direction does water move during osmosis?

From hypotonic to hypertonic Signup and view all the answers

Which is NOT a function of membrane proteins?

DNA replication Signup and view all the answers

Which process involves the shape change of a protein to facilitate molecule transport?

Facilitated diffusion Signup and view all the answers

What is the primary requirement for active transport across membranes?

It requires a protein transporter pump and ATP. Signup and view all the answers

What occurs during ATP hydrolysis?

Energy is released by removing a phosphate group from ATP. Signup and view all the answers

Which process is responsible for transporting large molecules out of the cell?

Exocytosis Signup and view all the answers

In which cellular location does glycolysis occur?

Cytoplasm Signup and view all the answers

What is produced during the first phase of glycolysis?

2 molecules of pyruvate Signup and view all the answers

What is the primary purpose of oxidative phosphorylation in aerobic respiration?

To generate ATP from ADP Signup and view all the answers

What is one of the products of the citric acid cycle from each pyruvate?

1 FADH₂ Signup and view all the answers

What role does oxygen play in oxidative phosphorylation?

It acts as the final electron acceptor Signup and view all the answers

Which of the following accurately describes ATP?

It is the primary energy-supplying molecule in cells. Signup and view all the answers

How many ATP molecules are generated during the metabolism of 2 pyruvate?

2 ATP Signup and view all the answers

How many NADH molecules are produced during glycolysis?

2 NADH Signup and view all the answers

What differentiates fermentation from aerobic respiration?

The final electron acceptor Signup and view all the answers

Which type of fermentation occurs in muscle cells during an oxygen shortage?

Lactic acid fermentation Signup and view all the answers

What is one product of alcohol fermentation carried out by yeast?

Ethanol Signup and view all the answers

What energy-producing process occurs primarily in the inner mitochondrial membrane?

Oxidative phosphorylation Signup and view all the answers

Which reactants are necessary for photosynthesis to occur?

Carbon dioxide, water, and sunlight Signup and view all the answers

What is the primary function of the plasma membrane in eukaryotic cells?

To regulate the passage of substances in and out of the cell Signup and view all the answers

Which structure forms sites of contact between adjacent eukaryotic cells?

Cell junctions Signup and view all the answers

What role do nuclear pores play in eukaryotic cells?

They facilitate the movement of large or polar molecules in and out of the nucleus. Signup and view all the answers

Which component of the endomembrane system is involved in the synthesis and modification of proteins?

Rough endoplasmic reticulum Signup and view all the answers

What is the primary function of the cytoskeleton in eukaryotic cells?

Maintaining cell shape and facilitating movement Signup and view all the answers

What is the composition of the cytoplasm in eukaryotic cells?

Organelles suspended in aqueous solution called cytosol Signup and view all the answers

What does the structure of the rough endoplasmic reticulum predominantly contribute to?

Protein synthesis and modification Signup and view all the answers

Which of the following is NOT a feature of eukaryotic cells?

Absence of organelles Signup and view all the answers

Study Notes

Cells as Building Blocks

Cells are the basic building blocks of the body
Each cell type has specific functions

Fundamental Characteristics of Cells

DNA directs protein synthesis through transcription and translation
Cells are too small to be seen with the naked eye
All cells have a plasma membrane

How Cells Are Studied

Microscopy is crucial for studying cells due to their small size
- Light Microscopes: Use visible light to view living organisms; may require staining for cellular components
- Fluorescence Microscopes: Use specific wavelengths (colors) and complicated specimen prep to visualize subcellular structures
- Electron Microscopes: Use electron beams for higher magnification and resolution, but cannot view live cells

Comparing Prokaryotic and Eukaryotic Cells

Prokaryotic Cells:
- Domains: Bacteria and Archaea
- Simpler structure, lacking a nucleus and membrane-bound organelles
- Key features include: plasma membrane, cytoplasm, DNA, ribosomes, cell walls (peptidoglycan in bacteria), sometimes capsules, and flagella for movement
Eukaryotic Cells:
- Domains: Animals, plants, fungi, protists
- More complex, containing a membrane-bound nucleus and organelles (e.g., mitochondria, chloroplasts)
- Larger than prokaryotic cells (10-100 µm)
- Specialized organelles facilitate complex functions

Key Components of Eukaryotic Cells

Plasma Membrane: Phospholipid bilayer with embedded proteins; regulates substance passage; contains cholesterol and carbohydrates for support and recognition
Cytoplasm: Cell's internal fluid; contains organelles suspended in cytosol (fluid portion); many metabolic reactions occur here
Endomembrane System: Includes the nuclear envelope, ER, Golgi apparatus, vesicles, and plasma membrane; involved in protein production, modification, packaging, and transport
Nucleus: Control center; contains DNA organized into chromosomes; directs transcription and protein synthesis; contains nuclear envelope with pores for molecule passage.
Endoplasmic Reticulum (ER): Extensive network of membranes; Rough ER is studded with ribosomes, synthesizing and modifying proteins; Smooth ER is involved in lipid synthesis and detoxification
Golgi Apparatus: Modifies, sorts, and packages proteins and lipids for distribution within the cell or secretion outside the cell.
Lysosomes: Contain digestive enzymes in animal cells to break down cellular waste, old organelles, and foreign invaders; function depends on the endomembrane system.
Transport Vesicles: Transport proteins and other cargo through the cell; vesicles bud from membranes and move to a target compartment, releasing their contents.
Mitochondria: Powerhouses of the cell; generate ATP (energy) through cellular respiration; contain DNA and ribosomes; multiple per cell, with folded inner membranes (cristae)
Chloroplasts (Plant Cells): Responsible for photosynthesis; convert light energy into chemical energy (glucose); have their own DNA and ribosomes; similar to mitochondria.

Cellular Energy and Respiration

ATP: Primary energy-supplying molecule in cells
- Conversion from ADP involves adding a phosphate group
Glycolysis: First step in glucose breakdown; occurs in the cytoplasm of all cells; produces 2 pyruvate, 2 ATP, 2 NADH; crucial for cells without oxygen
Citric Acid Cycle (Krebs Cycle): Occurs in the mitochondrial matrix; produces molecules for the electron transport chain.
Oxidative Phosphorylation: Uses the movement of H+ ions to generate ATP. Oxygen is the final electron acceptor.
Fermentation: ATP production in the absence of oxygen; often results in lactic acid or alcohol as a by-product

Photosynthesis

Definition: Process used by plants, algae, and some bacteria to convert solar energy into glucose.
Key Components: Sunlight, water (H2O), and carbon dioxide (CO2) are reactants; glucose (C6H12O6)and oxygen (O2) are products
Chloroplasts: Organelles where photosynthesis occurs
Contains chlorophyll - absorbs blue and red light
Thylakoid membranes: Site of light-dependent reactions; water is split, O2 is released, and energy is captured to produce ATP and NADPH.
Stroma: Site of the Calvin Cycle; CO2 is incorporated into organic molecules during the light-independent reactions.

Differences Between Plant And Animal Cells

Plant cells have rigid cell walls (cellulose), chloroplasts, and a large central vacuole. Animal cells have centrioles and lysosomes but lack cell walls and chloroplasts.

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Description

Explore the fundamental characteristics of cells, their structures, and functions in this comprehensive quiz. Learn about cell types, microscopy techniques, and the differences between prokaryotic and eukaryotic cells. This quiz is perfect for anyone looking to enhance their understanding of cellular biology.