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What is a selectively permeable membrane?
A membrane that allows certain substances to pass while restricting others, essential for maintaining cell homeostasis.
What is the fluid-mosaic model?
A dynamic model of the cell membrane where lipids and proteins are arranged to allow fluidity and functionality, affecting membrane behavior.
What are the key components of the plasma membrane?
Key elements including lipids (forming the barrier), proteins (facilitating transport and signaling), and carbohydrates (for cell recognition and communication).
What is cell homeostasis?
Cell homeostasis is the process by which a cell maintains a stable internal environment, which is crucial for its survival and proper functioning.
Passive Transport
Movement of substances across membranes without the use of cellular energy (ATP), including diffusion, facilitated diffusion, and osmosis.
Active Transport
Requires energy input to move substances against their concentration gradient, including primary and secondary active transport.
Exocytosis
Process by which cells expel materials in vesicles that fuse with the plasma membrane, important for secretion of hormones and waste.
Endocytosis
Process of taking materials into the cell by engulfing them in a vesicle; includes phagocytosis, pinocytosis, and receptor-mediated endocytosis.
Tonicity
Refers to the ability of a solution to influence the movement of water across a semipermeable membrane based on solute concentration.
Isotonic Solution
Equal concentration of solutes inside and outside the cell, leading to no net water movement.
Hypotonic Solution
Lower solute concentration outside the cell, causing water to move into the cell and potentially leading to swelling.
Hypertonic Solution
Higher solute concentration outside the cell, causing water to move out, leading to cell shrinkage.
What is the nucleus?
Contains the cell’s genetic material (DNA) and regulates gene expression.
What are mitochondria?
The site of ATP (energy) production.
What are ribosomes?
Complexes where protein synthesis occurs.
What is the Golgi Complex?
Modifies, sorts, and packages proteins and lipids for transport out of the cell.
What are lysosomes?
Contains enzymes for digestion of macromolecules and waste processing.
What is the cytoskeleton?
Network of protein filaments that provides structural support and facilitates movement.
What is the plasma membrane?
Semi-permeable membrane that controls what enters and exits the cell.
What are the main organelles of a cell?
Nucleus, mitochondria, ribosomes, Golgi Complex, lysosomes, cytoskeleton, and plasma membrane.
Describe the structure and function of the nucleus.
The nucleus is a membrane-bound organelle that contains the cell's genetic material (DNA) and regulates gene expression, similar to a library that stores information needed for functioning.
Describe the structure and function of mitochondria.
Mitochondria are double-membraned organelles with folded inner membranes, responsible for ATP production, akin to power plants generating energy for the city.
Describe the structure and function of ribosomes.
Ribosomes are tiny complexes made of RNA and proteins that can be free-floating or bound to the endoplasmic reticulum, serving as factories for protein synthesis, much like construction sites building proteins.
Describe the structure and function of the Golgi Complex.
The Golgi Complex is a series of stacked membranes that modifies, sorts, and packages proteins and lipids, acting like a post office that dispatches finalized products to their destinations.
Describe the structure and function of lysosomes.
Lysosomes are membrane-bound vesicles containing enzymes, functioning as the cell’s waste disposal system, similar to a recycling center processing materials.
Describe the structure and function of the cytoskeleton.
The cytoskeleton is a network of protein filaments and tubules that provides structure and aids in cell movement, comparable to the scaffolding of a building that supports its structure.
Describe the structure and function of the plasma membrane.
The plasma membrane is a semi-permeable lipid bilayer that controls what enters and exits the cell, similar to a security gate regulating access to a facility.
What are the similarities between lipids and carbohydrates?
Both are essential macromolecules that provide energy for biological processes.
What is the primary difference between carbohydrates and lipids regarding energy usage?
Carbohydrates provide quick energy, while lipids serve as a long-term energy storage source.
What roles do lipids play in cellular structure?
Lipids are fundamental components of cellular membranes, regulating the passage of substances in and out of the cell.
What is the importance of lipid insulation?
Lipids provide thermal insulation to maintain body temperature and protect vital organs from mechanical shock.
What types of molecules can efficiently traverse the lipid bilayer?
Typically, small nonpolar molecules can pass through easily, while larger or polar molecules may require transport mechanisms.
What are steroid hormones?
A type of lipid that regulates a wide variety of physiological functions, including metabolism and immune responses.
How do lipids assist in cellular signaling?
Certain lipids are involved in cellular signaling pathways, influencing various biological processes.
What is a lipid bilayer?
A double layer of lipids that forms cell membranes, crucial for creating a barrier between the internal and external environments.
What is the G1 Phase?
The first phase of the cell cycle lasting 6-12 hours, focusing on cell growth, organelle duplication, and preparation for DNA synthesis.
What occurs during the S Phase?
The second phase of the cell cycle lasting 6-8 hours, where DNA is replicated, and the chromosome number temporarily doubles.
What happens in the G2 Phase?
The third phase lasting 3-4 hours, where final preparations for mitosis occur, ensuring all elements for division are in place.
What is the M Phase?
The final phase lasting about 1 hour, during which the cell divides to form two identical daughter cells.
What does the G1 Checkpoint assess?
The G1 Checkpoint assesses cell size, energy reserves, and DNA integrity before proceeding in the cell cycle.
What is checked at the G2 Checkpoint?
The G2 Checkpoint checks for DNA damage and ensures DNA replication is complete before mitosis.
What is the purpose of the M Checkpoint?
The M Checkpoint ensures proper chromosome alignment and spindle fiber attachment before anaphase.
What is the role of DNA Polymerase?
DNA Polymerase synthesizes new DNA strands during DNA replication.
What does DNA Ligase do?
DNA Ligase joins Okazaki fragments, forming continuous DNA strands during replication.
What is the function of Helicase?
Helicase unwinds the DNA double helix, allowing replication to occur.
What are the phases of the cell cycle?
The cell cycle consists of G1, S, G2, and M phases.
What occurs during mitosis?
Mitosis is the process of cell division that includes prophase, metaphase, anaphase, and telophase, resulting in two identical daughter cells.
What is assessed at the G1 Checkpoint?
The G1 Checkpoint assesses cell size, energy reserves, and DNA integrity.
What is regulated at the G2 Checkpoint?
The G2 Checkpoint ensures that DNA replication is complete and checks for DNA damage.
What is the significance of the M Checkpoint?
The M Checkpoint ensures proper chromosome alignment and attachment of spindle fibers before anaphase.
What is the process of DNA replication?
DNA replication involves unwinding the double helix, synthesizing new strands using DNA polymerase, and joining fragments with DNA ligase.
What happens in prophase during mitosis?
In prophase, the chromatin condenses into visible chromosomes, and the nuclear envelope begins to break down.
What occurs during metaphase?
During metaphase, chromosomes align along the metaphase plate, and spindle fibers attach to the centromeres.
What is anaphase?
Anaphase is the stage where sister chromatids are pulled apart to opposite poles of the cell.
What changes happen during telophase?
During telophase, chromosomes begin to de-condense, nuclear envelopes reform around each set of chromosomes, resulting in two nuclei.
What is Anabolism?
Anabolism refers to the metabolic pathway that builds larger, complex molecules from smaller, simpler units, requiring energy input often derived from ATP.
What is Catabolism?
Catabolism is the metabolic pathway that breaks down larger molecules into smaller units, releasing energy in the process.
How do Anabolism and Catabolism interact?
Anabolism and catabolism work together to maintain homeostasis in the body, with anabolism building and storing energy, and catabolism breaking down molecules to release energy.
What is Metabolism?
Metabolism encompasses all the biochemical reactions in the body, including both anabolic and catabolic pathways.
How does food intake influence cellular energy dynamics?
Food intake supplies the necessary substrates for metabolic pathways, directly influencing energy production and consumption within cells.
What are the two main types of cells?
The two main types of cells are prokaryotic and eukaryotic cells. Prokaryotic cells lack a nucleus and membrane-bound organelles, while eukaryotic cells have a nucleus and various organelles.
List examples of prokaryotic organisms.
Examples of prokaryotic organisms include bacteria (like E. coli and Streptococcus) and archaea (such as Halobacterium and Methanogens).
List examples of eukaryotic organisms.
Examples of eukaryotic organisms include animals (like humans), plants (such as oak trees), fungi (like mushrooms), and protists (such as amoebas).
How do cells differ from viruses?
Cells are the basic units of life capable of metabolism and reproduction, while viruses are non-living entities that require a host cell to replicate and do not carry out metabolic processes on their own.
What is the cell theory?
Cell theory states that all living organisms are composed of cells, the cell is the basic unit of life, and all cells arise from pre-existing cells.
Describe the modern tenets of cell theory.
Modern tenets of cell theory include that cells contain hereditary information (DNA) that is passed during cell division and that all cells are essentially similar in composition and metabolic activities.
What is cell biology?
Cell biology is the study of cells, their physiological properties, their structure, the organelles they contain, interactions with their environment, and the processes they partake in.
How has cell biology impacted our understanding of cellular activities?
Cell biology has greatly enhanced our comprehension of fundamental processes such as cell division, metabolism, and cellular communication, leading to advances in medicine, genetics, and biotechnology.
What is the role of the cell membrane?
The cell membrane regulates the movement of substances in and out of the cell, providing structural support and protection.
What are the major components of the cell membrane?
Major components of the cell membrane include a phospholipid bilayer, embedded proteins (for transport and signaling), carbohydrates (for cell recognition), and cholesterol (to maintain fluidity).
