Results for "vacuole"

Cell theory organisms are composed of 1+ cells, which are the smallest unit of life, which come from pre-existing cells What do Prokaryotic Cells have? - Cell wall - Plasma Cell membrane -Flagella -Ribosomes -Nucleoid Cell Wall made of of carb protein complex, PEPTIOGLYCAN, allows for cell to hold shape Plasma Membrane Controls movement of materials in and out of cells, plays role in binary fission Cytoplasm -occupies interior, no compartmentalization, site of all chemical processes in the cell -Region where organelles can be found Capsule some, not all have this, made of polysaccharide, sticky and allows for attachment to surfaces Pili short hair growth on cell wall, used for attachment, joins bacteria cells to prep for DNA transfer Flagella longer than pili, used for movement Ribosomes where protein synthesis occurs, in big numbers in cells that require high protein content Nucleoid Region non-compartmentalization and has a single long thread of DNA, controls cells and reproduction Plasmids small circular DNA molecules, not connected to main loop Binary Fission the simple cell division, process where DNA is copied and the daughter chromosomes become attached to different regions on the membrane, cell elongates and divides into 2 identical daughter cells Microscope DOs -careful -proper carrying -using for intended purpose Microscope Don'ts -squinting -carrying with one hand -using coarse focus knob on high power -leaving at edge of lab bench Characteristics of Prokaryotic Cells -DNA is circular, not enclosed -Free DNA -Non-membrane bound organelles -70s ribosomes -Very small -Division by binary fission SURFACE AREA TO VOLUME RATIO does what? What does this do? Limits cell size, the bigger this ratio, the more efficient it is for the diffusion to take place in and out of the cell. Differentiation process whereby cells develop into specific cells as a result of the expression of certain genes but not others What are stem cells? Cells that retain their ability to divide into various types of cells. What type of tissue in plants contains stem cells? Meristematic tissue. Where are stem cells found in animals? In embryos. Cytosol Fluid portion of cytoplasm What is the endoplasmic reticulum? An extensive network of tubules and channels that extends almost everywhere from the nucleus to the plasma membrane. What is the function of the endoplasmic reticulum? Transports materials throughout the internal region of the cell. Rough ER has ribosomes on its surface and is therefore involved in protein development and transport. Smooth ER lacks ribosomes on its exterior but contains unique enzymes embedded on its surface. 6 functions of the smooth ER 1. production of membrane phospholipids and cellular lipids 2. Production of sex hormones such as testosterone and estrogen 3. Detoxification of drugs in the liver 4. Storage of calcium ions needed for contraction in muscle cells 5. Transportation of lipid-based compounds 6. Aid the liver in releasing glucose into the bloodstream when needed What are ribosomes? Structures that have no exterior membrane What is the primary function of ribosomes? Carry out protein synthesis What are ribosomes composed of? A type of RNA and a protein How many subunits do ribosomes have? Two subunits What are lysosomes? Intracellular digestive organelles that arise from the Golgi apparatus. What do lysosomes catalyze the breakdown of? Proteins, nucleic acids, lipids, and carbohydrates. Golgi apparatus Responsible for the collection, packaging, modification, and distribution of materials synthesized in the cell Two sides : cis and trans cisternae Golgi apparatus is composed of a stack of flattened sacs called this What shape are mitochondria? Rod-shaped What are mitochondria commonly referred to as? The cell's powerhouse Do mitochondria have their own DNA? Yes, it is similar to that of bacterial cells What type of membrane do mitochondria have? Double-membraned How is the outer membrane of mitochondria described? Smooth What are the folds in the inner membrane of mitochondria called? Cristae matrix Inside the mitochondria inner membrane is fluid called this What is the function of the cristae in mitochondria? The cristae provide a huge internal surface area for the chemical reactions in the mitochondria to occur. What type of ribosomes do mitochondria produce and contain? Mitochondria produce and contain their own ribosomes. What is the primary energy molecule produced by mitochondria? ATP (adenosine triphosphate). What is the nucleus? A compartmentalized region where DNA can be found. What is the nuclear envelope? A double membrane that covers the nucleus. What do the pores in the nuclear envelope allow? Communication with the cell's cytoplasm. What are chloroplasts? Organelles that can only be found in algae and plant cells. What type of membrane do chloroplasts have? Double-membraned. What unique genetic material do chloroplasts contain? Their own ribosomes and DNA in the form of a ring. What structures are found in the interior of chloroplasts? Grana, thylakoids, and the stroma. Granum made up of a stack of thylakoids Thylakoids flattened membrane sacs with components essential for the absorption of light Stroma similar to cytosol; contains many enzymes and chemicals essential to complete the process of photosynthesis What is a centrosome? A structure that consists of a pair of centrioles at right angles to one another. What is the function of centrioles in the centrosome? They are involved in assembling the microtubules necessary for providing structure and movement in the cell. Why are microtubules important for cells? They are necessary for cell division. In which types of cells are centrosomes found? Centrosomes are found in animal, fungal, and most protoctist cells, but not in higher plant cells. What are vacuoles? Storage organelles that usually arise from the Golgi apparatus. What substances do vacuoles store? Potential food, metabolic wastes and toxins, and water. How do vacuoles affect cell size? They allow cells to have a higher surface area to volume ratio even at larger sizes. What role do vacuoles play in plant cells? They allow the uptake of water to provide rigidity to the cell.

Vacuoles and Their Functions in Cells

structure cellulaire: lysosomes / vacuoles

Cell Organelles: Peroxisomes, Vacuoles, Golgi, Lysosomes, and ER

Vacuole

BIOLOGY | Vacuole, Blood Type

lysosomes, vacuoles, quick flashcards

cellulose cell wall, vacuole, chloroplast

Organelles in Cells: Lysosomes and Vacuoles

🧪 Lysosomes + Vacuoles + Cytoskeleton

Lysosomes, vacuoles and peroxisomes

endomembrane system Semi-autonomous organelles Protein sorting to organelles Systems biology of cells Cell Biology & Cell Theory Cell biology: The study of individual cells and their interactions. Cell Theory (Schleiden & Schwann, with contributions from Virchow): All living organisms are composed of one or more cells. Cells are the smallest units of life. New cells arise only from pre-existing cells through division (e.g., binary fission). Origins of Life: Four Overlapping Stages Stage 1: Formation of Organic Molecules Primitive Earth conditions favored spontaneous organic molecule formation. Hypotheses on the origin of organic molecules: Reducing Atmosphere Hypothesis: Earth's early atmosphere (rich in water vapor) facilitated molecule formation. Stanley Miller’s experiment simulated early conditions, producing amino acids and sugars. Extraterrestrial Hypothesis: Organic carbon (amino acids, nucleic acid bases) may have come from meteorites. Debate exists over survival after intense heating. Deep-Sea Vent Hypothesis: Molecules formed in the temperature gradient between hot vent water & cold ocean water. Supported by experimental evidence. Alkaline hydrothermal vents may have created pH gradients that allowed organic molecule formation. Stage 2: Formation of Polymers Early belief: Prebiotic synthesis of polymers was unlikely in aqueous solutions (water competes with polymerization). Experimental evidence: Clay surfaces facilitated the formation of nucleic acid polymers and polysaccharides. Stage 3: Formation of Boundaries Protobionts: Aggregates of prebiotically produced molecules enclosed by membranes. Characteristics of a protobiont: Boundary separating the internal & external environments. Polymers with information (e.g., genetic material, metabolic instructions). Catalytic functions (enzymatic activities). Self-replication. Liposomes: Vesicles surrounded by lipid bilayers. Can enclose RNA and divide. Stage 4: RNA World Hypothesis RNA was likely the first macromolecule in protobionts due to its ability to: Store information. Self-replicate. Catalyze reactions (ribozymes). Chemical Selection & Evolution: RNA mutations allowed faster replication & self-sufficient nucleotide synthesis. Eventually, RNA world was replaced by the DNA-RNA-protein world due to: DNA providing more stable information storage. Proteins offering greater catalytic efficiency and specialized functions. Microscopy Microscopy Parameters Resolution: Ability to distinguish two adjacent objects. Contrast: Difference between structures (enhanced by special dyes). Magnification: Ratio of image size to actual size. Types of Microscopes Light Microscope: Uses light; resolution = 0.2 micrometers. Electron Microscope: Uses electron beams; resolution = 2 nanometers (100x better than light microscopes). Light Microscopy Subtypes Bright Field: Standard; light passes directly through. Phase Contrast: Amplifies differences in light phase shifts. Differential Interference Contrast (DIC): Enhances contrast for internal structures. Electron Microscopy Subtypes Transmission Electron Microscopy (TEM): Thin slices stained with heavy metals. Some electrons scatter while others pass through to create an image. Scanning Electron Microscopy (SEM): Heavy metal-coated sample. Electron beam scans the surface, producing 3D images. Cell Structure & Function Determined by matter, energy, organization, and information. Genome: The complete set of genetic material. Prokaryotic vs. Eukaryotic Cells Feature Prokaryotic Cells Eukaryotic Cells Nucleus ❌ Absent ✅ Present Membrane-bound organelles ❌ None ✅ Yes Size Small (1-10 µm) Large (10-100 µm) Examples Bacteria, Archaea Plants, Animals, Fungi, Protists Prokaryotic Cell Structure Plasma Membrane: Lipid bilayer barrier. Cytoplasm: Internal fluid. Nucleoid Region: DNA storage (no nucleus). Ribosomes: Protein synthesis. Cell Wall: (Some) Provides structure & protection. Glycocalyx: Protection & hydration. Flagella: Movement. Pili: Attachment. Eukaryotic Cell Structure Nucleus: Contains DNA & controls cell functions. Organelles: Rough ER: Protein synthesis & sorting. Smooth ER: Lipid synthesis, detoxification. Golgi Apparatus: Protein modification & sorting. Mitochondria: ATP production (Powerhouse of the Cell™). Lysosomes: Digestive enzymes for breakdown & recycling. Peroxisomes: Breakdown of harmful substances. Cytoskeleton: Provides structure (microtubules, actin filaments, intermediate filaments). Plasma Membrane: Regulates transport & signaling. Endomembrane System Includes: Nucleus, ER, Golgi apparatus, lysosomes, vacuoles, and plasma membrane. Nuclear Envelope: Double membrane structure. Nuclear pores allow molecule transport. Golgi Apparatus: Modifies & sorts proteins/lipids. Packages proteins into vesicles for secretion (exocytosis). Lysosomes: Contain acid hydrolases for macromolecule breakdown. Perform autophagy (organelle recycling). Semi-Autonomous Organelles Mitochondria Function: ATP production (cellular respiration). Structure: Outer & inner membrane (inner folds = cristae for increased surface area). Mitochondrial matrix houses metabolic enzymes. Chloroplasts (Plants & Algae) Function: Photosynthesis (light energy → chemical energy). Structure: Outer & inner membrane. Thylakoid membrane (site of photosynthesis). Contains chlorophyll. Endosymbiosis Theory Mitochondria & chloroplasts evolved from free-living bacteria that were engulfed by an ancestral eukaryotic cell. Protein Sorting & Cell Organization Co-translational sorting: Proteins destined for ER, Golgi, lysosomes, vacuoles, or secretion. Post-translational sorting: Proteins sent to nucleus, mitochondria, chloroplasts, peroxisomes. Systems Biology Studies how cellular components interact to form a functional system

Lysosomes, Vacuoles

vacuole

vacuoles/vesicles

Ribosomes and Vacuoles

chloroplasts and vacuoles 2.1.1

4.4.c - Ribosomes + Endomembrane + Golgi + Lysosomes + Vacuoles

Cells and movement. Animals and plants are multicellular organisms. They consist of many cells that work together. The main parts of an animal cell are the nucleus, cell membrane, cytoplasms and mitochondria. Plant cells contain the same features as animal cells. They also have some additional ones. Chloroplasts, cell walls, and large central vacuoles. That the cell membrane controls the movement of substances in and out of the cell. It is found in plant and animal cells. Cytoplasm, is a jelly like substance where the chemical reactions happen. It is found in plant and animal cells. The nucleus carries genetic information and controls what happens inside the cell. And it was also found in plant or animal cells. Mitochondria is where respiration takes place, releasing energy for the cell. It's found in planting animal cells. Large central vacuole contains a liquid called cell sap which keeps the cell firm. It is contained in plant cells only. A cell wall is made of toss substance called cellulose, which supports the cell, its implant. Cells only. Chloroplasts contain the green pigment chlorophyll, which absorbs light. Energy. This is where photosynthesis is, in plant cells only.

Cell wall and vacuole