Podcast
Questions and Answers
Which process involves the movement of a cell by extending a pseudopodium?
Which process involves the movement of a cell by extending a pseudopodium?
What is the purpose of ciliary movement in the respiratory airways?
What is the purpose of ciliary movement in the respiratory airways?
What defines a hypertonic solution in relation to a cell?
What defines a hypertonic solution in relation to a cell?
Which mechanism allows a cell to take in solid particles?
Which mechanism allows a cell to take in solid particles?
Signup and view all the answers
Which type of transport requires the use of ATP to move substances against their concentration gradient?
Which type of transport requires the use of ATP to move substances against their concentration gradient?
Signup and view all the answers
What structure beneath the cell membrane is associated with the formation of cilia?
What structure beneath the cell membrane is associated with the formation of cilia?
Signup and view all the answers
Which type of membrane transport results in the formation of vesicles for uptake of fluids?
Which type of membrane transport results in the formation of vesicles for uptake of fluids?
Signup and view all the answers
In secondary active transport, how is the energy for transporting a secondary substance provided?
In secondary active transport, how is the energy for transporting a secondary substance provided?
Signup and view all the answers
What is the main role of exocytosis in cellular function?
What is the main role of exocytosis in cellular function?
Signup and view all the answers
What is a characteristic feature of carrier-mediated transport?
What is a characteristic feature of carrier-mediated transport?
Signup and view all the answers
Which component is primarily responsible for forming the selectively permeable membrane of a cell?
Which component is primarily responsible for forming the selectively permeable membrane of a cell?
Signup and view all the answers
What function does the Golgi apparatus serve within the cell?
What function does the Golgi apparatus serve within the cell?
Signup and view all the answers
Which type of lipid is primarily responsible for energy storage in fat cells?
Which type of lipid is primarily responsible for energy storage in fat cells?
Signup and view all the answers
What is the primary role of integral proteins in the cell membrane?
What is the primary role of integral proteins in the cell membrane?
Signup and view all the answers
What is the primary composition of the cytoplasm?
What is the primary composition of the cytoplasm?
Signup and view all the answers
Which organelle is known as the 'powerhouse of the cell' for its role in energy extraction?
Which organelle is known as the 'powerhouse of the cell' for its role in energy extraction?
Signup and view all the answers
What roles do the carbohydrates on the cell membrane typically serve?
What roles do the carbohydrates on the cell membrane typically serve?
Signup and view all the answers
What distinguishes peroxisomes from lysosomes?
What distinguishes peroxisomes from lysosomes?
Signup and view all the answers
Which of the following structures are responsible for maintaining the cell's shape?
Which of the following structures are responsible for maintaining the cell's shape?
Signup and view all the answers
In what way does the lipid bilayer affect the permeability of the cell membrane?
In what way does the lipid bilayer affect the permeability of the cell membrane?
Signup and view all the answers
Study Notes
General Physiology with Family Planning
- Course title: General Physiology with Family Planning
- Institution: De La Salle Medical and Health Sciences Institute, College of Dentistry
- Instructor: David Pablo S. Fernandez Jr., DMD
- Year: 2022
Cell Physiology
- Understanding organ functions depends on understanding cell organization
- The cell has two major parts: nucleus and cytoplasm
- The nucleus is separated from the cytoplasm by a nuclear membrane
- The cytoplasm is separated from surrounding fluids by a cell membrane (or plasma membrane)
Protoplasm
- Protoplasm includes the cytoplasm and the nucleus
- The five basic substances that make up protoplasm are:
- Water
- Protein
- Lipids
- Electrolytes
- Carbohydrates
Water
- Water is the principal fluid medium in most cells (70-85%)
- Chemical reactions occur within the water or at the surface of suspended particles/membranes
Ions
- Ions, including potassium, magnesium, phosphate, sulfate, and bicarbonate, are inorganic chemicals essential for cellular reactions
- Sodium, calcium, and chloride are present in smaller quantities
- Ions at the cell membrane are crucial for transmitting electrochemical impulses in nerve and muscle fibers
Lipids
- Lipids are a diverse group of substances, soluble in fat solvents
- Phospholipids and cholesterol make up about 2% of total cell mass
- Lipids are largely insoluble in water
- They are vital components of plasma membranes and intracellular membranes
- Lipids create separation between cell compartments
- Triglycerides (neutral fat) account for about 95% of mass in fat cells
- Stored triglycerides are energy-giving nutrients
Carbohydrates
- Carbohydrates have a minor structural role in the cell (approximately 1% of total cell mass)
- In muscle cells, carbohydrate content can increase to 3%, and in the liver it can reach 6%.
- A small amount of carbohydrates is stored as glycogen, which quickly releases energy to cells
Physical Structure of Cells
- Membranous structures of cells include:
- Cell membrane
- Cytoplasm
- Intracellular organelles
Membranous Structures of Cells
-
Most organelles are enclosed by membranes made of lipids and proteins
-
These membranes include:
- Cell membrane
- Nuclear membrane
- Golgi apparatus membrane
- Endoplasmic reticulum membrane
- Mitochondrial membranes
- Lysosomal membranes
-
Lipids of membranes prevent the passage of water into different cellular compartments
-
Water is insoluble within the lipid layer
Cell Membrane
- The cell membrane is a thin, pliable, elastic structure (7.5 to 10 nm thick)
- It is composed of:
- Proteins (55%)
- Phospholipids (25%)
- Cholesterol (13%)
- Other lipids (4%)
- Carbohydrates (3%)
Lipid Bilayer of the Cell Membrane
- The cell membrane's structure is a lipid bilayer, a thin, double layer of lipids
- Each layer is a single molecule thick and continuous across the entire cell's surface
- Phospholipids make up the bilayer
- One end of the phospholipid is water-soluble (hydrophilic)
- The other end of the phospholipid is only soluble in fats (hydrophobic)
Phospholipid Bilayer
- The middle lipid layer is impermeable to water-soluble substances (e.g., ions, glucose, urea)
- Fat-soluble substances (e.g., oxygen, carbon dioxide, alcohol) can readily pass through
- Cholesterol molecules are highly fat-soluble and influence membrane permeability
Membrane Proteins
- Membrane proteins are globular masses within the lipid layer
- Most membrane proteins are glycoproteins
- Integral and peripheral proteins are the two types of proteins found in cell membranes
Integral Proteins
- Integral proteins extend fully through the membrane
- Some act as channels/pores for water and ions to pass between extracellular and intracellular fluids
- Others are carrier proteins that assist substances unable to pass through the lipid layer across the membrane
- Some function as enzymes
- Some act as receptors for water-soluble hormones that cannot penetrate the lipid layer
- Interact with ligands to cause changes in the receptor structure
- Induce interaction among receptors and proteins in the cytoplasm
- Relay extracellular information to the cell interior
Peripheral Proteins
- Peripheral proteins are attached only to one surface of the membrane
- They are often attached to integral proteins
- They function as enzymes or controllers of substances passing through membrane pores
Membrane Carbohydrates
- Carbohydrates are often part of glycoproteins or glycolipids
- Most integral proteins are glycoproteins
- About one-tenth of lipid-molecule proteins are glycolipids
- The glyco component protrudes outward from the cell's surface
- Many carbohydrates have a negative charge, repelling other negatively charged substances
- The glycocalyx is a loose carbohydrate coat on the cell's surface
- The glycocalyx in some cells attaches to the glycocalyx in other cells, binding them together
- Acts as receptor substances for binding hormones
- Involved in immune reactions
Cytoplasm
- The cytoplasm contains minute and large particles and organelles
- The clear portion of cytoplasm is called cytosol (includes dissolved proteins, glucose, and electrolytes)
- 5 important cytoplasmic organelles are: endoplamsic reticulum, Golgi apparatus, mitochondria, lysosomes, and peroxisomes
Organelles
- Endoplasmic reticulum
- Golgi apparatus
- Mitochondria
- Lysosomes
- Peroxisomes
Endoplasmic Reticulum (ER)
- Network of interconnected tubular and flat vesicles
- Walls are constructed of lipid bilayer membranes
- Contains large amounts of proteins
- Total surface area is 20-30 times greater than the cell membrane area
- Space inside the tubules and vesicles is filled with endoplasmic matrix (watery medium, different from the cytosol outside the ER)
- Vast surface area and attached enzyme systems provide machinery for the cell's metabolic processes
- Granular ER has ribosomes on its surface, which synthesize proteins
- Some proteins are released directly into the cytosol
- Agranular ER (SER) lacks ribosomes; synthesizes lipids and cholesterol
- Lipids are rapidly incorporated into the SER
- SER expands, then produces secretory vesicles, which migrate to the Golgi apparatus to continue processing
Golgi Apparatus
- Composed of 4+ stacked layers of thin, enclosed vesicles, located near the nucleus
- Important in secretory cells, processing substances that are extruded from the cell
- Small ER vesicles detach, fuse with the Golgi apparatus and continue processing
- Substances processed in the Golgi apparatus form lysosomes, secretory vesicles, and other cytoplasmic components
Lysosomes
- Vesicular organelles that form by breaking off from the Golgi apparatus
- They are the cell's intracellular digestive system
- They digest damaged cell structures, food particles, and unwanted substances like bacteria
- Various cell types have different quantities and sizes of lysosomes
- Lysosomes have a lipid bilayer membrane and granules (aggregates of hydrolases – enzymes capable of splitting organic molecules into smaller parts)
- The membrane of lysosomes prevents the release of hydrolytic enzymes, preventing unwanted digestion
- Conditions can cause membrane damage and release hydrolytic enzymes
Peroxisomes
- Similar to lysosomes, but different in two ways:
- Thought to be a product of self replication rather than Golgi production
- Contains oxidases (rather than hydrolases)
- Several oxidases combine oxygen with hydrogen ions to form hydrogen peroxide.
- Hydrogen peroxide is a powerful oxidizer working with catalases
- Peroxisomes contain oxidases responsible for oxidizing substances harmful to cells, such as alcohol. Often found in the liver.
Mitochondria
- "Powerhouses" of the cell present throughout the cytoplasm
- The quantity of mitochondria in a cell correlates to the cell's energy needs (ranging from hundreds to thousands)
- The cell membrane has two parts (inner, outer)
- Infoldings in the inner membrane create compartments containing the matrix.
- Matrix contains enzymes essential for extracting energy from nutrients, crucial to ATP synthesis.
- Mitochondria produce energy by breaking down nutrients
- Mitochondria are self-replicating organelles (one, two, or three more can be created depending on energy demands)
Cell Cytoskeleton
- Cytoskeleton: Network of protein fibers supporting the cell
- It keeps organelles in place, and changes the cell's shape
- Three types of proteins:
- Microtubules
- Microfilaments
- Intermediate filaments
Microtubules
- Formed by protein subunits, critical in cell division
- Support the cytoplasm
- Form components of organelles, such as cilia and flagella
Microfilaments
- Small fibrils that support and change the cell's shape
- Some microfilaments enable cell movement
- Example: Microfilaments in muscle cells enable contraction
Intermediate Filaments
- Smaller in diameter than microtubules but larger than microfilaments
- Provide mechanical support to cells
Centrosome
- Specialized zone of cytoplasm near the nucleus
- Site of microtubule formation
- Contains two centrioles that are perpendicular and each has nine triplets (three parallel microtubules)
Cilia, Flagella, and Microvilli
- Cilia: Cylindrical structures extending from the cell, occurring in specific locations such as the respiratory airways or uterine tubes and other mucous membranes.
- Flagella: Longer than cilia, occurring on a single cell (usually sperm)
- Microvilli: Specialized extensions of the cell membrane supported by microfilaments, increasing the surface area of cells for absorption (e.g., small intestine), but they do not move cells
- Cilia movement is essential for clearing mucus and particles in respiratory airways as well as for ovum movement in the uterine tubes during reproduction.
Locomotion of Cells
- Ameboid movement
- Cilia and Ciliary movement
Ameboid Movement
- Movement of the full cell, in relation to its surroundings
- Name derived from movement exhibited by amoebas
- Locomotion beings with protrusion of pseudopodium, a temporary extension from one end of the cell
- Pseudopodium are extended to secure itself in the environment
- The rest of the cell is then pulled toward the pseudopodium, moving the cell
- Common in white blood cells, fibroblasts, and embryonic cells
Ciliary Movement
- Whip-like movement of cilia on the cell surface
- Only found in two places in the human body: respiratory airways and uterine tubes
- Cilia cause mucus movement in the nasal cavity, clearing it towards the pharynx at ~1 cm/min
- In uterine tubes they move fluid to aid in ovum movement towards the uterus.
Movement through the Cell Membrane
- Selectively permeable membranes: Allowing certain molecules but not others
- Passive transport: Does not require energy (diffusion, osmosis, facilitated diffusion)
- Active transport: Requires energy (active transport, secondary active transport, endocytosis, exocytosis)
Diffusion
- Movement of a solute from higher to lower concentration areas
- Molecules are evenly distributed across the solution until the concentration is equal on both sides
Osmosis
- Diffusion of water across a selectively permeable membrane
- Water moves from higher to lower water concentration areas
- Predicting water movement across membranes depends on the water concentration difference
Osmotic Pressure
- Force required to prevent water movement across a selectively permeable membrane
- Measures water movement tendency across a membrane
Osmosis Examples: Hypotonic, Isotonic, Hypertonic
- Hypotonic: Higher water concentration outside the cell, causing water to move into the cell (potentially causing cell lysis)
- Isotonic: Equal water and solute concentrations inside and outside the cell, no net water movement (cells maintain shape)
- Hypertonic: Higher solute concentration outside the cell, causing water to move out of the cell (potential for cell shrinkage)
Carrier-Mediated Transport
- Movement of large water-soluble molecules or charged particles across the membrane (not by simple diffusion)
- Specific molecules bind to carrier molecules on one side of the membrane
- The carrier molecule changes shape and releases the molecule to the other side of the membrane
- Types of carrier-mediated transport:
- Facilitated diffusion
- Active transport
- Secondary active transport
Facilitated Diffusion
- Carrier-mediated transport from an area of higher concentration to an area of lower concentration
- Metabolic energy requirements are not needed
- Example: glucose transport
Active Transport
- Carrier-mediated transport from an area of lower concentration to an area of higher concentration; going against a gradient
- Requires energy (usually ATP) to function
- Example: Na+-K+ pump
Secondary Active Transport
- A carrier-mediated transport process facilitated by actively transported substances (like sodium)
- The diffusion of that substance creates an electrochemical gradient that provides energy to allow the secondary substance "riding" on the gradient to passively be moved, as well.
- Cotransport: diffusing substance moves in the same direction as the substance being transported
- Countertransport: diffusing substance moves in the opposite direction as the substance being transported
Endocytosis and Exocytosis
- Endocytosis: Uptake of material using vesicles
- Exocytosis: Elimination of material from the cell via vesicles
- Two types of endocytosis
- Receptor-mediated Endocytosis: Specific molecules bind to receptors on the cell membrane triggering uptake into the cell.
- Phagocytosis: Uptake of solid particles.
- Pinocytosis: Uptake of liquid material (often with receptor proteins and molecules involved).
- Receptor-mediated Endocytosis: Specific molecules bind to receptors on the cell membrane triggering uptake into the cell.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz covers essential concepts in General Physiology, focusing on cell organization, protoplasm, and the role of water and ions in cellular functions. Ideal for students studying within the field of health sciences. Test your understanding of basic physiological principles and their applications in family planning.
