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Questions and Answers
What is the basic unit of structure and function in living organisms?
What is the basic unit of structure and function in living organisms?
The cell
Who are credited with developing the cell theory in 1839?
Who are credited with developing the cell theory in 1839?
Matthias Jakob Schleiden and Theodor Schwann
From what Latin word is the term 'cell' derived from?
From what Latin word is the term 'cell' derived from?
Cellula
Who is credited with initiating the study of disease on a cellular level?
Who is credited with initiating the study of disease on a cellular level?
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What is the function of muscle cells?
What is the function of muscle cells?
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What is the function of pancreatic acinar cells?
What is the function of pancreatic acinar cells?
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What is the function of mucous gland cells?
What is the function of mucous gland cells?
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Which types of cells are responsible for the secretion of steroids?
Which types of cells are responsible for the secretion of steroids?
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What is the function of cells in the kidney?
What is the function of cells in the kidney?
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What is the function of macrophages?
What is the function of macrophages?
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What is the function of cells in the intestine?
What is the function of cells in the intestine?
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Prokaryotic cells have a nucleus.
Prokaryotic cells have a nucleus.
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Eukaryotic cells have a membrane-bound nucleus.
Eukaryotic cells have a membrane-bound nucleus.
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Prokaryotic cells are multi-celled.
Prokaryotic cells are multi-celled.
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Prokaryotic cells have organelles.
Prokaryotic cells have organelles.
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Prokaryotic cells have single circular chromosomes.
Prokaryotic cells have single circular chromosomes.
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Eukaryotic cells have multiple linear chromosomes.
Eukaryotic cells have multiple linear chromosomes.
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Prokaryotic cells have nucleosomes.
Prokaryotic cells have nucleosomes.
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Prokaryotic cells are typically smaller than eukaryotic cells.
Prokaryotic cells are typically smaller than eukaryotic cells.
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Eukaryotic cells are typically larger than prokaryotic cells.
Eukaryotic cells are typically larger than prokaryotic cells.
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The cell membrane is a single layer of phospholipids.
The cell membrane is a single layer of phospholipids.
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What is the main function of the cell membrane?
What is the main function of the cell membrane?
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What is the name given to the model that describes the structure of the cell membrane?
What is the name given to the model that describes the structure of the cell membrane?
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Which of the following is NOT a component of the cell's membrane system?
Which of the following is NOT a component of the cell's membrane system?
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Cytoplasm is primarily composed of water.
Cytoplasm is primarily composed of water.
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The osmotic pressure within cells is different from the extracellular fluid.
The osmotic pressure within cells is different from the extracellular fluid.
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Cytoplasm consists of 80% protein.
Cytoplasm consists of 80% protein.
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Cytoplasm contains organelles.
Cytoplasm contains organelles.
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Cytoplasm is only found in eukaryotic cells.
Cytoplasm is only found in eukaryotic cells.
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What is the main function of the nucleus within a cell?
What is the main function of the nucleus within a cell?
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What is the name of the double membrane that surrounds the nucleus?
What is the name of the double membrane that surrounds the nucleus?
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What are the small pores in the nuclear envelope called?
What are the small pores in the nuclear envelope called?
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What type of proteins stabilize the nuclear lamina?
What type of proteins stabilize the nuclear lamina?
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What is the name of the structure within the nucleus where ribosomal RNA (rRNA) is produced?
What is the name of the structure within the nucleus where ribosomal RNA (rRNA) is produced?
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DNA is a single helix molecule.
DNA is a single helix molecule.
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DNA is composed of 4 deoxyribonucleotides.
DNA is composed of 4 deoxyribonucleotides.
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Complementary base pairing in DNA is held together by disulfide bonds.
Complementary base pairing in DNA is held together by disulfide bonds.
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Chromatin is composed only of DNA.
Chromatin is composed only of DNA.
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Ribosomes are involved in protein synthesis.
Ribosomes are involved in protein synthesis.
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The central dogma of molecular biology describes the flow of genetic information from DNA to RNA to protein.
The central dogma of molecular biology describes the flow of genetic information from DNA to RNA to protein.
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The nucleus is the site of translation.
The nucleus is the site of translation.
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The number of ribosomes in a cell reflects the amount of protein synthesis occurring.
The number of ribosomes in a cell reflects the amount of protein synthesis occurring.
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What is the main function of mitochondria?
What is the main function of mitochondria?
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Mitochondria have their own DNA distinct from the cell's nuclear DNA.
Mitochondria have their own DNA distinct from the cell's nuclear DNA.
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The number of mitochondria in a cell does not vary depending on the cell's metabolic activity.
The number of mitochondria in a cell does not vary depending on the cell's metabolic activity.
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The endoplasmic reticulum (ER) is a network of interconnecting membranes within the cell.
The endoplasmic reticulum (ER) is a network of interconnecting membranes within the cell.
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Rough ER is characterized by the presence of ribosomes on its surface.
Rough ER is characterized by the presence of ribosomes on its surface.
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Smooth ER is involved in the synthesis of lipids and the processing of proteins.
Smooth ER is involved in the synthesis of lipids and the processing of proteins.
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What is the main function of the Golgi apparatus?
What is the main function of the Golgi apparatus?
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What type of enzymes do lysosomes contain?
What type of enzymes do lysosomes contain?
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Lysosomes are formed by budding from the endoplasmic reticulum.
Lysosomes are formed by budding from the endoplasmic reticulum.
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Lysosomes are sometimes called "suicide bags."
Lysosomes are sometimes called "suicide bags."
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Peroxisomes are involved in the breakdown of fatty acids and detoxification of harmful substances.
Peroxisomes are involved in the breakdown of fatty acids and detoxification of harmful substances.
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The cytoskeleton is a network of filaments and microtubules that provides structural support and facilitates movement within the cell.
The cytoskeleton is a network of filaments and microtubules that provides structural support and facilitates movement within the cell.
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Centrioles are involved in the separation of chromosomes during cell division.
Centrioles are involved in the separation of chromosomes during cell division.
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Cilia are short, numerous structures, while flagella are long, few structures.
Cilia are short, numerous structures, while flagella are long, few structures.
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Cilia and flagella are composed of microtubules.
Cilia and flagella are composed of microtubules.
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Cilia and flagella are found in higher plants.
Cilia and flagella are found in higher plants.
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Cilia are essential for the locomotion of single-celled eukaryotes.
Cilia are essential for the locomotion of single-celled eukaryotes.
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Cilia function to move materials past an immobile cell.
Cilia function to move materials past an immobile cell.
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The respiratory tract is lined with cilia that trap inhaled dust, smog, and other potentially harmful microorganisms.
The respiratory tract is lined with cilia that trap inhaled dust, smog, and other potentially harmful microorganisms.
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Cilia and flagella move by sliding microtubules past each other.
Cilia and flagella move by sliding microtubules past each other.
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Epithelial cells line the inside cavities of the body.
Epithelial cells line the inside cavities of the body.
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Epithelial cells are functional units of secretory glands.
Epithelial cells are functional units of secretory glands.
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Microvilli function to decrease surface area for absorption.
Microvilli function to decrease surface area for absorption.
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Cell junctions are specialized areas that allow for adhesion and communication between epithelial cells.
Cell junctions are specialized areas that allow for adhesion and communication between epithelial cells.
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Desmosomes function as communication channels.
Desmosomes function as communication channels.
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Gap junctions function as communication channels.
Gap junctions function as communication channels.
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A centriole is part of a chromosome.
A centriole is part of a chromosome.
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The rough endoplasmic reticulum is studded with microtubular structures.
The rough endoplasmic reticulum is studded with microtubular structures.
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The rough endoplasmic reticulum is only found in prokaryotic cells.
The rough endoplasmic reticulum is only found in prokaryotic cells.
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Lysosomes are formed by budding from the rough endoplasmic reticulum.
Lysosomes are formed by budding from the rough endoplasmic reticulum.
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Peroxisomes synthesize membrane components such as fatty acids and phospholipids.
Peroxisomes synthesize membrane components such as fatty acids and phospholipids.
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The Golgi apparatus is the energy supplier for the cell and contains its own DNA.
The Golgi apparatus is the energy supplier for the cell and contains its own DNA.
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The ribosome is an enzyme-filled organelle for breaking down waste in the cell.
The ribosome is an enzyme-filled organelle for breaking down waste in the cell.
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The cell membrane is composed of a single layer of lipids.
The cell membrane is composed of a single layer of lipids.
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The nuclear envelope does have infoldings to form cristae.
The nuclear envelope does have infoldings to form cristae.
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The cell membrane is the energy supplier for the cell.
The cell membrane is the energy supplier for the cell.
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Study Notes
Cell Structure and Function
- Cells are the basic unit of structure and function in living organisms.
- The cell theory was developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann.
- Robert Hooke named cells in 1665, deriving from the Latin word "cellula" (small room).
- Rudolf Virchow further developed the cell theory, linking cell structure with disease.
Eukaryotic Cell Structure
- Eukaryotic cells are 10-100 µm in size.
- They have a membrane-bound nucleus and organelles.
- Their DNA is organized into multiple linear chromosomes wound on nucleosomes.
Prokaryotic Cell Structure
- Prokaryotic cells are 1-10 µm in size.
- They lack a nucleus and membrane-bound organelles.
- Their DNA is a single circular chromosome without nucleosomes.
Cell (Plasma) Membrane
- The cell membrane is 6-10 nm thick.
- It acts as a boundary to contain cell contents and maintain integrity.
- It's a lipid bilayer composed of phospholipids and cholesterol.
- Embedded proteins are also present, forming a "fluid mosaic" membrane.
- The membrane system includes the plasma membrane, endoplasmic reticulum, Golgi complex, and lysosomes.
Cytoplasm
- Cytoplasm makes up about 70% of a cell.
- It's composed of water, salts, and inorganic molecules.
- Concentrations of potassium, magnesium, and phosphate are similar to extracellular fluid.
- About 8% of cytoplasm is protein.
- It contains membrane bound structures called organelles, filaments and granules.
- Metabolic pathways like glycolysis and the HMP occur.
Organelles
- Nucleus: Stores genetic material (DNA), coordinates cell activities (growth, metabolism, protein synthesis, reproduction). Contains chromatin, nucleolus.
- Mitochondria: Convert food energy (potential energy) into ATP (adenosine triphosphate). Number correlates to metabolic activity. Have an outer and inner membrane, intermembrane space, and cristae.
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Endoplasmic Reticulum (ER): A network of flattened sheets or elongated tubules and cisternal spaces (lumen).
- Proteins responsible for reactions that occur within the cytoplasm. Biosynthesis and transport of proteins and lipids.
- Smooth ER: Synthesis of lipids, steroid hormones, and carbohydrate metabolism.
- Rough ER: Protein production. Ribosomes are attached.
- Ribosomes: Involved in protein synthesis, using mRNA transferred from DNA. Free or attached to ER.
- Golgi Apparatus: Modifies, sorts, and packages macromolecules from the ER for export or other functions. Creates lysosomes, and modifies proteins (e.g., glycosylation).
- Lysosomes: Spherical bodies containing hydrolytic enzymes, involved in intracellular digestion of food particles and worn-out cell parts.
- Peroxisomes: Contain enzymes for removing toxic substances and breaking down fatty acids. Resemble lysosomes, but smaller.
- Vacuole: Various functions, such as storage and fluid balance (plant cells).
- Cytoskeleton: Internal scaffold made of filaments and microtubules, maintaining cell shape, offering protection, supporting intracellular movement, and cell division. Includes microfilaments, microtubules, intermediate filaments with different components such as centrioles.
Cilia and Flagella
- Both are motile appendages constructed from microtubules.
- Cilia are short, numerous; flagella longer and fewer.
- Essential for locomotion in single-celled organisms and moving fluids in multicellular organisms (like in the respiratory tract of animals).
Epithelial Cells
- Epithelium lines the outside of the body (e.g., skin) and inside cavities (e.g., respiratory and digestive tracts).
- Forms functional units of secretory glands.
Epithelial Cells Specialization
- Possess surface projections (cilia, microvilli) increasing surface area.
- Display specialized secretory adaptations from well developed ER and Golgi apparatus.
- Show cell junctions which allow for adhesion and communication.
Cell Junctions
- Specialized regions between cells that allow for adherence, communication and other functions.
Key Terms
- ATP: Adenosine triphosphate, energy currency of the cell.
- DNA: Deoxyribonucleic acid, genetic material.
- mRNA: Messenger ribonucleic acid, carries genetic information from DNA to ribosomes for protein synthesis.
- tRNA: Transfer ribonucleic acid, brings amino acids to ribosomes.
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Description
Test your knowledge on the fundamental concepts of cell structure and function, including cell theory, differences between eukaryotic and prokaryotic cells, and the components of the cell membrane. This quiz covers essential details that are crucial for understanding biology at a cellular level.
