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Questions and Answers
What is the function of microtubules in the cytoskeleton?
What is the function of microtubules in the cytoskeleton?
Provides structural support to structures like the nucleus and plasma membrane.
Which statement is true about exocytosis?
Which statement is true about exocytosis?
Osmosis is the diffusion of _____ across a selectively permeable membrane.
Osmosis is the diffusion of _____ across a selectively permeable membrane.
water
Phagocytosis is the process of cell eating infectious pathogens.
Phagocytosis is the process of cell eating infectious pathogens.
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What are the four stages in the cell cycle?
What are the four stages in the cell cycle?
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What is cytokinesis?
What is cytokinesis?
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What is interphase?
What is interphase?
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Who was the first person to use the term 'cell'?
Who was the first person to use the term 'cell'?
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Matthias Schleiden concluded that all plant tissues are primarily composed of cells. Is this statement true or false?
Matthias Schleiden concluded that all plant tissues are primarily composed of cells. Is this statement true or false?
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Which of the following statements about Eukaryotic cells are true?
Which of the following statements about Eukaryotic cells are true?
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Prokaryotes usually divide by ______.
Prokaryotes usually divide by ______.
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Match the following components with their functions:
Match the following components with their functions:
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What is the function of the mitochondria?
What is the function of the mitochondria?
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The fluid inside lysosomes is much more acidic, at about pH 4.8, than the normal pH of about __.
The fluid inside lysosomes is much more acidic, at about pH 4.8, than the normal pH of about __.
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Which organelle is responsible for modifying, packaging, and sorting materials that arrive from the endoplasmic reticulum in transport vesicles?
Which organelle is responsible for modifying, packaging, and sorting materials that arrive from the endoplasmic reticulum in transport vesicles?
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Prokaryotes consist of single cell nuclei and contain DNA and multiple cellular chromosomes.
Prokaryotes consist of single cell nuclei and contain DNA and multiple cellular chromosomes.
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Study Notes
Historical Notes
- Robert Hooke discovered the term "cell" in 1665, referring to the small empty chambers in cork structure.
- He was the first to identify cells from plant tissue.
Cell Theory
- A cell is the basic structural and functional unit of living organisms.
- The activity of an organism depends on the collective activities of its cells.
- According to the principle of complementarity, the activities of cells are dictated by their structure, which determines function.
Eukaryotic vs. Prokaryotic Cell
- Eukaryotes have a membrane-bound nucleus and membrane-bound organelles, whereas prokaryotes lack these features.
- Eukaryotes contain mitochondria, endoplasmic reticulum, and Golgi complex, whereas prokaryotes do not.
- Eukaryotes divide by mitosis, whereas prokaryotes divide by binary fission.
Molecular Composition of Cell
- Water accounts for about 70-75% of the cell weight.
- Organic compounds (nucleic acids, proteins, carbohydrates, and lipids) account for 25-30% of the cell weight.
- Inorganic compounds make up the remaining cell weight.
Cell Membrane Transport
- Plasma membrane, also known as cell membrane or cytoplasmic membrane, is a selectively permeable boundary of the cell.
- It is composed of a phospholipid bilayer with cholesterol, proteins, and carbohydrates.
Cell Life Cycle
- Cell division involves mitosis.
- Genetic material is replicated and separated into two daughter cells.
Organelles
1. Plasma Membrane
- Acts as a physical barrier to movement into and out of the cell.
- Regulates material movement and cell communication.
2. Nucleus
- Control center of the cell, containing DNA that serves as a blueprint for protein synthesis.
- The nucleus is enclosed within a double membrane called the nuclear envelope.
3. Cytoplasm
- Provides support for organelles and serves as a viscous fluid medium.
- Contains inclusions, such as glycogen granules, pigments, and mucous membranes.
4. Mitochondria
- Responsible for providing ATP through oxidative phosphorylation.
- Structured as double-membrane-bound organelles containing a circular strand of DNA.
5. Lysosomes
- Responsible for the production of energy in the form of ATP.
- Contain digestive enzymes that break down and recycle cellular waste.
6. Endoplasmic Reticulum
- Divided into rough endoplasmic reticulum (with ribosomes) and smooth endoplasmic reticulum.
- Involved in protein synthesis, modification, and transport.
7. Golgi Apparatus
- Series of elongated, flattened sac-like membranous structures.
- Modifies, packages, and sorts materials, that arrive from the endoplasmic reticulum in transport vesicles.
8. Peroxisomes
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Small, spherical membrane-bound organelles formed from the endoplasmic reticulum.
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Involved in the modification, transport, and storage of cellular materials.### Peroxisome
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Hydrogen peroxide is toxic to the cell and is the basis of the name of the peroxisome
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Peroxisome helps to disarm pre-radicals and has no protein synthesis
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Catalase helps to convert hydrogen peroxide into water and oxygen, neutralizing the toxicity of the cell
Smooth Endoplasmic Reticulum
- Involved in lipid metabolism, fat synthesis, breakdown, and detoxification of drugs and pesticides
- Structure: extensive interconnected membrane network lacking ribosomes
- Functions: detoxifying specific harmful substances either produced by the cell or taken into the cell
Prokaryotic Cell
- Eubacteria and Archaebacteria are the most abundant organisms on earth
- Eubacteria consists of single cell nuclei; lacks nucleus and contains DNA and single cellular chromosome
- Can be gram positive and gram negative
- Examples: Lactobacilli, Escherichia Coli, Aspergillus, Azospirillum
- Archaebacteria are considered as the ancient form of microorganisms
- Functions: maintains integral structural support and organization of cells
- Does not contain a membrane-bound nucleus
- Each cell is surrounded by a plasma membrane
- Has no subcellular organelles, only mesosomes
- Deoxyribonucleic acid (DNA) is condensed within the cytosol to form the nucleoid
Cytoskeleton
- Structure: organized network of protein filaments
- Functions: maintains integral structural support and organization of cells
- Microfilaments maintain cell shape and provide mechanical support to structures
- Intermediate filaments give mechanical support to structures and help in cell wall formation
- Microtubules provide structural support and help in DNA replication
- Helps in the distribution of the daughter cell
Cell Membrane Transport
- Passive transport process: does not require energy (ATP)
- Types of passive transport: diffusion, osmosis, and facilitated diffusion
- Diffusion: movement of a substance from an area of its higher concentration to an area of its lower concentration
- Simple diffusion: type of diffusion of dissolved solutes through the plasma membrane
- Facilitated diffusion: type of diffusion that requires a protein carrier
- Osmosis: diffusion of water point across a selectively permeable membrane
Active Transport Process
- Uses energy (ATP) provided by the cell
- Example: sodium-potassium pump
- The sodium-potassium pump binds three sodium ions and a molecule of ATP
- The splitting of ATP provides energy to change the shape of the channel
- The sodium ions are released to the outside of the membrane, and the new shape of the channel allows two potassium ions to bind
Endocytosis and Exocytosis
- Endocytosis: bulk movement of substance into the cell by vesicles forming at the plasma membrane
- Exocytosis: bulk movement of substance out of the cell by fusion of secretory vesicles with the plasma membrane
- Phagocytosis: process of cell eating, engulfing particulate matter
- Pinocytosis: process of cell drinking, engulfing fluid
Cell Division
- Cell division: the process by which one cell divides into two cells
- Mitosis: consists of four stages - prophase, metaphase, anaphase, and telophase
- The result is two daughter nuclei, each identical to the mother nucleus
- Prophase: chromatin condenses into chromosomes, and the nuclear envelope disappears
- Metaphase: chromosomes align at the center of the cell
- Anaphase: chromatids separate at the centromere and migrate to opposite poles
- Telophase: two new nuclei assume their normal structure, and cell division is completed
Cell Life Cycle
- Growth requires cell division
- Four stages in cell cycle: synthesis, gap 1 phase, gap 2 phase, and mitosis phase
- Interphase: the longer phase of the cell cycle where the cell is active and preparing for cell division
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Description
Learn about the historical notes of biochemistry, focusing on the discovery of cells and the contributions of Robert Hooke. This quiz is designed for medical laboratory science students.
