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Questions and Answers
What is a key feature of prokaryotic cells?
What is a key feature of prokaryotic cells?
Prokaryotic DNA is associated with proteins called histones.
Prokaryotic DNA is associated with proteins called histones.
False
What is the region where prokaryotic DNA is located called?
What is the region where prokaryotic DNA is located called?
nucleoid region
Prokaryotic cells are thought to have evolved from __________ cells.
Prokaryotic cells are thought to have evolved from __________ cells.
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Match the following characteristics with prokaryotic or eukaryotic cells:
Match the following characteristics with prokaryotic or eukaryotic cells:
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Which of the following statements regarding cells is true?
Which of the following statements regarding cells is true?
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Cells can originate from non-living materials.
Cells can originate from non-living materials.
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What are the two main types of microscopes mentioned?
What are the two main types of microscopes mentioned?
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The magnification of light microscopes can reach up to _______.
The magnification of light microscopes can reach up to _______.
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Match the following measurement units with their equivalent sizes:
Match the following measurement units with their equivalent sizes:
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Which type of microscopy allows viewing details using ultraviolet or violet-blue light?
Which type of microscopy allows viewing details using ultraviolet or violet-blue light?
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Immunofluorescence is used to detect the presence of cellular structures without the need for antibodies.
Immunofluorescence is used to detect the presence of cellular structures without the need for antibodies.
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What advantage does an electron microscope have over a light microscope?
What advantage does an electron microscope have over a light microscope?
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All cells can live independently.
All cells can live independently.
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What are the common structures found in all cells?
What are the common structures found in all cells?
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The plasma membrane is primarily composed of _______ that form a bilayer.
The plasma membrane is primarily composed of _______ that form a bilayer.
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What is the universal genetic code made up of?
What is the universal genetic code made up of?
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What is the role of the hydrophilic heads of lipids in the plasma membrane?
What is the role of the hydrophilic heads of lipids in the plasma membrane?
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Phase-contrast microscopy requires staining of the specimen to reveal details.
Phase-contrast microscopy requires staining of the specimen to reveal details.
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What is the effect of short fatty acids or unsaturated fatty acids on membrane fluidity?
What is the effect of short fatty acids or unsaturated fatty acids on membrane fluidity?
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Match the following types of microscopy with their respective features:
Match the following types of microscopy with their respective features:
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What allows cells to carry out specific functions?
What allows cells to carry out specific functions?
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All cells in an organism express the same genes.
All cells in an organism express the same genes.
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What is the primary function of pancreatic cells in terms of gene expression?
What is the primary function of pancreatic cells in terms of gene expression?
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Eukaryotic cells have ____________ organelles, while prokaryotic cells lack them.
Eukaryotic cells have ____________ organelles, while prokaryotic cells lack them.
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Match the following cell types with their characteristics:
Match the following cell types with their characteristics:
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Which statement correctly describes the cytoplasm of eukaryotic cells?
Which statement correctly describes the cytoplasm of eukaryotic cells?
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Endosymbiosis explains the development of all organelles in eukaryotic cells.
Endosymbiosis explains the development of all organelles in eukaryotic cells.
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What is one evolutionary mechanism that supports the origins of eukaryotic cells?
What is one evolutionary mechanism that supports the origins of eukaryotic cells?
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What process do prokaryotic cells use to divide?
What process do prokaryotic cells use to divide?
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Eukaryotic cells lack a nuclear membrane.
Eukaryotic cells lack a nuclear membrane.
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What is the role of mitochondria in a cell?
What is the role of mitochondria in a cell?
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Chloroplasts are responsible for __________ in plant cells.
Chloroplasts are responsible for __________ in plant cells.
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What is the primary function of the cell wall in prokaryotic cells?
What is the primary function of the cell wall in prokaryotic cells?
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Match the organelle with its primary function:
Match the organelle with its primary function:
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The nucleoid region contains DNA that is associated with histone proteins.
The nucleoid region contains DNA that is associated with histone proteins.
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Which structure separates the interior material of organelles from the cytoplasm?
Which structure separates the interior material of organelles from the cytoplasm?
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Bacteria can reproduce at a rate of more than 1 million new cells in fewer than 8 hours.
Bacteria can reproduce at a rate of more than 1 million new cells in fewer than 8 hours.
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What type of reproduction do prokaryotic cells undergo?
What type of reproduction do prokaryotic cells undergo?
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The plasma membrane is described as __________ because it controls the entry and exit of substances.
The plasma membrane is described as __________ because it controls the entry and exit of substances.
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What are two types of cells in terms of structure?
What are two types of cells in terms of structure?
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Match the following structures to their functions in prokaryotic cells:
Match the following structures to their functions in prokaryotic cells:
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Which of the following statements about plasmids is true?
Which of the following statements about plasmids is true?
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Cytoplasm is involved in protein synthesis in prokaryotic cells.
Cytoplasm is involved in protein synthesis in prokaryotic cells.
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What is the role of the flagellum in prokaryotic cells?
What is the role of the flagellum in prokaryotic cells?
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The __________ region of a prokaryotic cell is where the naked DNA is located.
The __________ region of a prokaryotic cell is where the naked DNA is located.
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What is a key characteristic of 70S ribosomes in prokaryotic cells compared to eukaryotic ribosomes?
What is a key characteristic of 70S ribosomes in prokaryotic cells compared to eukaryotic ribosomes?
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Study Notes
Cell Theory
- All living organisms are composed of cells.
- Human bodies are made of different types of cells, each with a unique function.
- Cells are highly complex structures.
- Cells are produced from pre-existing cells.
- Cell growth is a result of cell division.
- Viruses are made of simpler subunits, but not composed of cells.
- Genetic code is universal (the 64 codons).
Cells as Basic Units of Life
- Cells are the basic and smallest unit of life for all living organisms.
- Cells are the fundamental building blocks to construct an organism.
Cell Structure
- Cells contain numerous structures.
- Examples include:
- Nucleus, Plasma membrane, Cytoplasm, Mitochondria, Ribosomes, Golgi apparatus, Endoplasmic reticulum, Lysosome etc.
Microscopes
- Microscopes have high magnification and resolution.
- Light microscopes pass light through specimens
- Electron microscopes pass electrons through specimens, providing a higher magnification (over 100,000x).
- Light microscopes are inexpensive and simple to operate, suitable for studying living and dead specimens.
- Electron microscopes are expensive and complex to operate, used to study dead and fixed specimens.
- Calculating magnification and actual size of specimens can be calculated using scale bars from images.
Relative Sizes of Cell Structures
- Molecules are measured in nanometres (nm).
- Cell membranes are measured in nanometres to micrometres.
- Viruses, bacteria, organelles, and cells are measured in micrometres.
Advanced Microscopy techniques
- Scanning electron microscope (SEM) scans the cell surface
- Transmission electron microscope (TEM) passes electrons through a thin section of the specimen
- Freeze-fracture is used for samples suitable for EM.
- Cryogenic electron microscopy uses computer enhancements to create 3D images of cell protein structures.
- Artefacts are structural features in EM images that don't belong to the original sample cells.
Light Microscopy
- Fluorescent stains, used in UV or Violet-blue light, allow visualization of cellular components.
- Immunofluorescence uses dyed antibodies which bind to specific targeted molecules.
Common Structures in all Cells
- All organisms have DNA
- Cytoplasm (mostly water)
- Plasma membrane
Arrangement and Properties of Plasma Membrane
- Plasma membrane forms a bilayer with hydrophobic tails inside and hydrophilic heads outside.
- Hydrophobic interactions and interaction with water stabilize the membrane.
- Membrane fluidity is critical for proper functioning.
- Short fatty acid chains make the cell membrane more fluid.
Prokaryotic Cells
- Prokaryotic cells are simpler in structure, lacking a nucleus or other membrane-bound organelles.
- The region where DNA is stored in a prokaryotic cell is called the nucleoid.
- Eukaryotic cells evolved from prokaryotic cells.
- Prokaryotic DNA is naked DNA (not associated with proteins).
- Prokaryotic cells are primarily unicellular.
- Common components of prokaryotic cells include (e.g.) cell wall, cell membrane, cytoplasm, and ribosomes.
Prokaryotic Cellular Structure
- Cell Wall protects the cell
- Plasma membrane is a barrier
- Cytoplasm contains metabolic enzymes
- Pili structures involved in attachment
- Flagella are used for motility
- Ribosomes synthesize proteins
- Nucleoid region contains the naked DNA.
- Capsules protect the cell.
- Plasmids are small, circular DNA molecules
Binary Fission
- Binary fission is the asexual reproduction process in prokaryotic cells.
- It results in two genetically identical daughter cells
- It's a fast process (greater than 1 million new cells in less than 8 hours).
Eukaryotic Cells
- Eukaryotic cells contain a nucleus and membrane-bound organelles.
- They are more complex and larger than prokaryotic cells.
- The cell contains numerous specialized structures and organelles.
Eukaryotic Organelles
- Mitochondria are responsible for aerobic respiration.
- Chloroplasts are involved in photosynthesis.
- Endoplasmic Reticulum, Golgi Apparatus, Nucleus, etc
- Nuclei contain DNA.
- Plasma membranes form the outer barrier.
- Cell walls are present in plant cells.
Unicellular Organisms
- Unicellular organisms have cell membranes, important for maintaining homeostasis.
- Vacuoles isolate and store materials.
- Cilia or flagella allow for movement in response to changes in the environment.
- Ribosomes and other cellular components facilitate cellular functions.
Different Types of Eukaryotic Cells
- Differences include presence of cell walls in plants and fungi or the presence or absence of chloroplasts.
Atypical Eukaryotes
- Some eukaryotic cells have unique structures, such as fungal hyphae or the multinucleated cells in human skeletal muscle.
Endosymbiotic theory:
- This theory explains the origin of mitochondria and chloroplasts.
- It proposes that these organelles were once free-living prokaryotic cells that were engulfed by a larger cell.
- The engulfed prokaryotic cells established a mutually beneficial relationship with the host cell and evolved into organelles.
Cell Specialization and Multicellularity
- Multicellular organisms exhibit cellular specialization of various functions and division of labor.
- Cells differentiate during development, forming tissues, organs, and organ systems
- Example of cell types include nerve cells, muscle cells, blood cells, etc.
Multicellular Organisms and Differentiation
- Cells arise from existing cells.
- Zygotes differentiate into various cell types through gene expression.
- Differentiation creates various cell types for specific functions.
Cells to Organism organisation
- Cell ⇒ Tissues ⇒ Organs ⇒ Organ Systems ⇒ Organism.
- This organisation is for specific function and co-ordination
Summary of Cell Structures and Functions
- Cells are the basic unit of all living organisms, with variation in structure and function.
- Prokaryotic cells lack a nucleus and membrane-bound organelles, while eukaryotic cells contain a nucleus and other organelles.
- The structure and function of organelles are crucial to cell survival and the maintenance of larger organisms.
- Differentiation allows for cell specialization and function in multicellular organisms.
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Description
Explore the fundamental concepts of cell theory, the diverse structures of cells, and the tools used to study them. This quiz covers everything from the basic unit of life to the types of microscopes that reveal cellular details. Test your knowledge of cell organization and functions!
