Cell Structure and Function

Cell Structure

• Cell Membrane: Semi-permeable membrane that separates the cell from its environment, regulates what enters and leaves the cell.
• Cytoplasm: Gel-like substance inside the cell membrane, where metabolic processes take place.
• Nucleus: Control center of the cell, contains DNA.
• Mitochondria: Powerhouses of the cell, responsible for generating energy through cellular respiration.
• Endoplasmic Reticulum (ER): Network of membranous tubules and cisternae, involved in protein synthesis, transport, and storage.
• Ribosomes: Small organelles found throughout the cytoplasm, responsible for protein synthesis.
• Lysosomes: Membrane-bound sacs that contain digestive enzymes, break down and recycle cellular waste and foreign substances.

Cell Types

• Prokaryotic Cells: Lack a true nucleus, typically small and simple, found in bacteria.
• Eukaryotic Cells: Have a true nucleus, typically larger and more complex, found in plants, animals, fungi, and protists.

Cell Functions

• Metabolism: Conversion of energy and nutrients into the components that make up living organisms.
• Growth and Development: Increase in size and complexity of cells, tissues, and organs.
• Response to Stimuli: Ability of cells to react to changes in their environment.
• Reproduction: Production of new cells, essential for growth, repair, and replacement of cells.

Cell Division

• Mitosis: Process of cell division that results in two daughter cells with the same number of chromosomes as the parent cell.
• Meiosis: Process of cell division that results in four daughter cells with half the number of chromosomes as the parent cell, occurs in sex cells.

Cell Transport

• Passive Transport: Movement of molecules from an area of high concentration to an area of low concentration, without energy input.
• Active Transport: Movement of molecules from an area of low concentration to an area of high concentration, requires energy input.

Cell Signaling

• Signal Transduction: Process by which cells respond to signals from their environment, involves a series of molecular interactions.
• Hormone Signaling: Long-distance signaling between cells, involves the release of hormones into the bloodstream.

Cell Structure

• Cell membrane is semi-permeable, regulating what enters and leaves the cell, and is composed of a phospholipid bilayer with embedded proteins.
• Cytoplasm is a gel-like substance inside the cell membrane where metabolic processes, such as glycolysis, take place, and is composed of water, salts, sugars, and amino acids.
• Nucleus is the control center of the cell, containing most of the cell's genetic material in the form of DNA, and is surrounded by a double membrane called the nuclear envelope.
• Mitochondria are the powerhouses of the cell, generating energy through cellular respiration, which involves the breakdown of glucose and other organic molecules to produce ATP.
• Endoplasmic Reticulum (ER) is a network of membranous tubules and cisternae, involved in protein synthesis, transport, and storage, and is connected to the nucleus and Golgi apparatus.
• Ribosomes are small organelles found throughout the cytoplasm, responsible for protein synthesis, translating mRNA into a polypeptide chain.
• Lysosomes are membrane-bound sacs that contain digestive enzymes, breaking down and recycling cellular waste and foreign substances, and maintaining cellular homeostasis.

Cell Types

• Prokaryotic cells lack a true nucleus, are typically small and simple, and are found in bacteria, with a single circular chromosome.
• Eukaryotic cells have a true nucleus, are typically larger and more complex, and are found in plants, animals, fungi, and protists, with linear chromosomes.

Cell Functions

• Metabolism is the conversion of energy and nutrients into the components that make up living organisms, involving anabolic and catabolic reactions.
• Growth and development involve the increase in size and complexity of cells, tissues, and organs, through the process of cell division and differentiation.
• Response to stimuli involves the ability of cells to react to changes in their environment, such as light, temperature, and touch, through signal transduction pathways.
• Reproduction is the production of new cells, essential for growth, repair, and replacement of cells, and involves the processes of mitosis and meiosis.

Cell Division

• Mitosis is the process of cell division that results in two daughter cells with the same number of chromosomes as the parent cell, involving interphase, prophase, metaphase, anaphase, and telophase.
• Meiosis is the process of cell division that results in four daughter cells with half the number of chromosomes as the parent cell, occurring in sex cells, and involving two successive cell divisions.

Cell Transport

• Passive transport involves the movement of molecules from an area of high concentration to an area of low concentration, without energy input, through processes such as diffusion, osmosis, and facilitated diffusion.
• Active transport involves the movement of molecules from an area of low concentration to an area of high concentration, requiring energy input, through processes such as carrier proteins and pumps.

Cell Signaling

• Signal transduction is the process by which cells respond to signals from their environment, involving a series of molecular interactions, and resulting in a response, such as gene expression or protein activation.
• Hormone signaling involves the release of hormones into the bloodstream, which then travel to target cells, binding to receptors, and triggering a response, such as growth and development.