Eukaryotes Flashcards
The 3 principles of cell theory
All living organisms are composed of one or more cells
Cell - basic unit of structure and organization in organisms
Cells arise from pre-existing cells
Basic cell features
Plasma membrane - covering
Cytosol - found in cytoplasm
DNA - genetic material
Ribosomes - protein synthesis
Most important tool in studying the cell
Microscopes
Separates cell components based on size and density
Cell fractionation
Basic structural and functional unit of life
Cell
Cells that contain membrane-enclosed organelles, including a DNA-containing nucleus
Eukaryotic
Cells that lack organelles
Prokaryotic
Critical step in the evolution of eukaryotes
Fusion between 2 different prokaryotic cell with different function
Endosymbiosis
Prokaryotes example
Bacteria and Archaea
Eukaryotes example
Protists
Fungi
Animals
Plants
Aka cell membrane
Barrier of the cell to its surroundings
Allows passage
Plasma membrane
Refers to all cell components bounded by plasma mebrane
Cytoplasm
Plasma membrane composition
Double layer of phospholipids
Functions of membrane proteins
As enzymes Transport proteins As receptor sites Cell to cell recognition Cell adhesion Attachment to cytoskeleton
Contains most of the genes/DNA
Nucleus
Nucleus is enclose by
Nuclear envelope
- double membraned, separating it from cytoplasm
Essential in transport of proteins in nucleus
Pore complexes
DNA areangement structure
Chromosomes
Complex of DNA and protein (histone) that makes up the chromosome
Chromatin
Site of ribosomal RNA (rRNA) synthesis
Nucleolus
Complex machinery for protein synthesis
Ribosome
Endomembrane system
Nuclear envelope Endoplasmic reticulum Golgi apparatus Lysosome Vacuoles Plasma membrane
Little network within the cytoplasm
Endoplasmic Reticulum
Flattened sacs inside ER used as a reservoir for a liquid
Cisternae
Internal compartment of ER
ER lumen (cavity) Or cisternal space
Continuous with the nuclear envelope
ER membrane
Continuous with the nuclear envelope and bound with ribosomes
Rough ER
Lacks attached ribosomes
Smooth ER
Involves in:
Synthesis of lipids
Detoxification of drugs and poisons
Calcuim ion storage
Smooth ER
Secretes proteins created by ribosomes
Add carbs to proteins for glycoproteins
Synthesis of more membranes
Modification of proteins
Rough ER
Received, sorts, ships, and even manufacture macromolecules
Golgi apparatus
Membranous sacs containing digestive enzymes
Lysosomes
Process in which cells engulf another cell
Phagocytosis
Help remove or recycle damage parts of a cell
Lysosomes
“self devouring”
Autophagy
Importance of autophagy
Degradation of damaged organelles or proteins
Response to nutrient deprivation during starvation
Membranous sacs, larger than vesicles
Vacuoles
Functions of vacuoles
Digestion Storage Waste Disposal Water Balance Cell Growth Protection
Together with lysosome, funtion in autophagy
Food vacuoles
Help eliminate excess water from the cell
Contractile vacuoles
Up to 90% of the volume of plant cell
Plants vacuoles
Energy-converting organelles
Mitochondria
Chloroplasts
Sites of cellular respiration in nearly all eukaryotic cells
Mitochondria
Found in plants and algae, sites of photosynthesis
Chloroplasts
Convertion of sugar to energy in ATP
Cellular respiration
Conversion of light energy from the sun to the chemical energy of sugar molecules
Photosynthesis
Three compartments of chloroplast space
Intermembrane space
Stroma
Thylakoid space
Flattened membranous sac inside a chloroplast
Thylakoids
Stack of thylakoids
Interconnected
Grana
Fluid outside thylakoids
Contains chloroplast DNA and ribosomes
Stroma
Mitochondria and Chloroplasts evolutionary origin
Endosymbiosis
Evidence of Endosymbiosis
2 membranes
Circular DNA and ribosomes
Autonomous organelles
Membrane-bound organelle containing enzymes that catalyze the breakdown of long chain fatty acids and amino acids
Peroxisomes
Network of fibers extending throughout the cytoplasm
Cytoskeleton
Functions of cytoskeleton
Mechanical support to the cell and maintain its shape
Involved in various cell movement
Transmits signals
Three main kinds of fibers that make up the cytoskeleton according to size and protein structure
Microtubules
Microfilaments
Intermediate filaments
Thickest kind
Microtubules
Also called actin filaments
Thinnes kind
Microfilaments
Diameters in middle range
Intermediate filaments
Microtubule-organizinh center
Centrosome
Circular flow of cytoplasm within cells
Cytoplasmic streaming
Cellular extension
Causes the cell to crawl along a surface
Pseudopodia “false foot”
Locomotor appendages that protrude from cells
Cilia
Flagella
Shorter
More numerous
Move “like the oars of a crew boat”
Cilia
Longer
Less numerous
Whiplike movement
Flagella
Extracellular components
Most cells synthesize and secrete materials that are external to the plasma membrane
3 extracellular structures
Cell walls of plant
Extracellular matrix of animal cells
Intercellular junction
Relatively thin and flexible wall
Primary cell wall
Thin layer rich in sticky polysaccharides called pectins
Glues adjacent cells together
Middle lamella
Has strong and durable matrix that affords the cell protection and support
Secondary wall
Extracellular matrix is made of:
Glycoproteins such as collagen
Proteoglycans
Fibrobectin
Functions of ECM
Support
Adhesion
Movement
Regulation
Receptor proteins in the plasma membrane where ECM glycoproteins bind
Integrins
Span the plasma membrane and connect to microfilaments of the cytoskeleton
Integrins
Connect neighboring cells
Cell Junctions
Junction found in plants
Plasmodesmata
Junctions found in animals
Tight junctions
Desmosomes
Gap junctions
Cytoplasmic channels between adjacent plant cell walls
Plasmodesmata
Prevent leakage of extracellular fluid across a layer of epithelial cells
Tight junctions
Fasten cells together into sheets
Desmosomes (anchoring junctions)
Channels that allow molecules to flow between cells
Gap junctions