TEST 5 - CELLS Flashcards
Autotroph
Organisms that can make its own food
Heterotroph
Organisms that cannot make their own food.
Differentiate
- The ability of multicellular organisms to have cells that specialize in a certain function.
- Specialized Cells have switched on particular genes that correlate to these specific functions.
Cell Theory Principles
- All living things are made out of cells
> Multicellular
> Unicellular - Cells are the smallest units of life
> Carry out metabolic functions
> Cell components cannot survive alone - Cells come only from other cells
> Multiply by division
> Descended from simpler common ancestors
Functions of Life
Metabolism
Growth
Reproduction
Response
Homeostasis
Nutrition
Excretion
Ultrastructure
Detailed cell structures observable only under an electron microscope, such as organelles like ribosomes or the endoplasmic reticulum.
Micrograph: A photographic image captured using a microscope, often enhanced with color for clarity in presentations.
Light Microscope
- Magnifies up to 1,000x.
- Limited resolution due to the wavelength of visible light (400–700 nm).
- Can observe live specimens.
Electron Microscope
- Uses electron beams for higher magnification and resolution (up to 1,000,000x).
- Visualizes subcellular structures like organelles.
- Cannot be used on living specimens.
Staining
Techniques using dyes to highlight specific cell structures, such as methylene blue for DNA or fluorescent markers for proteins.
Cryogenic Microscopy
A method where proteins or molecules are frozen and imaged to create 3D models, ideal for studying their structure.
Freeze-Fracture Microscopy
A technique where frozen cells are fractured along membranes to visualize internal surfaces, such as transmembrane proteins
Cell Diversity
- Size: Ranges from microscopic bacteria to large egg cells.
- Shape: Adapted to function, e.g., nerve cells are elongated for signal transmission. (Coccus, Bacillus, Spirilla)
- Internal Organization: Variability in organelle presence and arrangement depending on the cell type.
Surface Area to Volume Ratio
- Determines the efficiency of material exchange.
- As a cell grows, its volume increases faster than its surface area, reducing efficiency.
- Smaller cells maintain faster diffusion, effective waste removal, and adequate nutrient absorption.
Emergent Properties
Complex functions arise when specialized cells work together in tissues, organs, and systems, enabling multicellular organisms to perform more than the sum of their parts.
Totipotent Stem Cells
Have the potential to develop into any cell type, including an entire organism, e.g., a fertilized egg.
Pluripotent Stem Cells
Can become almost any cell type in the body, e.g., embryonic stem cells.
Multipotent Stem Cells
Limited to forming specific types of cells, e.g., BLOOD, SKIN.
Unipotent Stem Cells
Specialized to form only one cell type, e.g., NERVE
Prokaryotic Cells
Simple, single-celled organisms without membrane-bound organelles, e.g., bacteria.
Prokaryotic - Slime Capsule
A protective polysaccharide layer that enhances survival in harsh conditions.
Prokaryotic - Cell Wall
Provides structure and protection, composed of peptidoglycan
Prokaryotic - Cytoplasm
Fluid containing enzymes for metabolic reactions.