Week 3 Flashcards
Cell theory
Cells are fundamental units of life
All living organisms are composed of cells
All cells come from pre existing cells
What limits cells
Surface area to volume ratio
Surface area decrease
Size increases
Volume of cell determines
Amount of metabolic activity
Surface area determines
Amount of substance that can enter from outside and amount of waste product that can exist
Why cells must maintain large surface area
In order to function
How irregular shaped cells maintain large ratio
Folds in cell membrane
Light microscope
Uses glass lense and visible light
Electron microscope
Uses electron beam and focused by magnets to illuminate a specimen
- specimens are preserved and stained so live cells can’t be visualised
Cell membrane
Semi permeable
Communication with other cells and receives signals
Bonds to other cells
Prokaryote structure
Cell membrane encloses cell
Nuceliod - where DNA is
Cytoplasm - liquid component and cytosol
Ribosomes - rna and proteins
Internal membrane
Allows bacteria to carry out photosynthesis
Nuclear envelope
Separates DNA transcription (in nucleus) from translation (in cytoplasm)
Cytoskeleton
Supports she’ll and maintains shape
Holds cell organelles in position
Moves organelles and other particles around
Microfilaments
Helps cell move
Determine and stabilise cell shape
Intermediate filaments
Fibrous keratin proteins
Anchors cells in place
Resists tension
Microtubules
Long, hollow
Form rigid internal skeleton
Acts as framework with motor proteins move along
Extracellular membrane
Fibrous macromolecules
Gel like medium
Plant cell wall - extracellular
Provides support to the cell and limits volume
Acts as barrier to infection
Contributes to form by controlling direction of cell expansion
ECM
Holds cell together
Contributes to physical properties
Filters materials passing between tissue
Tight junctions
Prevents substances from moving through cells
Desmosome
Prevents substances from moving through cells
Gap junctions
Channels that allow substances to pass
What determines membrane structure
It’s lipids and proteins and carbs
Membrane fluidity
Increased by lipid composition and temp
Integral membrane proteins
Particully embeddedd through bi layer
Transmembrane proteins
Extended through bi layer and have different function each side
Primary active transport
Direct hydrolysis of atp
Secondary active transport
Uses energy from ion concentration gradient or electrical gradient
Sodium potassium pump
Integral membrane protein that pumps na+ out of a cell and k+ in
Secondary active transport - uses
Uses this regained energy by letting ions move across the membrane with their concentration gradient
Phagocytosis
Cellular eating
Pinocytosis
Cellular drinking
Receptor endocytosis
Brings specific molecules to a cell via specific receptors
Autocrine signals
Affects same cells that realise
Paracrine signals
Difuse to and affect nearby cells
Juxtacrine signals
Requires contact between cells
Hormones
Travel to distant cells
DNA replication and transcription - place
Nucleus
RNA translation
Cytoplasm
ECM
Polycharride chains that help filter nutrients and move structures around
Integrin
Position cell in matrix, adhere cells to other cells
Cholesterol
Interspersed among phospholipid tails and influence the fluidity to fatty acids
Carbs
Attached to outer surfaces of proteins
Simple diffusion
Small non polar molecules
Channel diffusion
Allows polar substance through, substance opens the channel
Carrier diffusion
Bonds to molecules, changes shape to fit through channel then deposits molecule other side
How atp works
When bonds are broken between adenosine and phosphate energy is released
Primary active transport
Hydrolysis of atp
Secondary active transport
Doesn’t come directly from atp, comes from previously pumped ion
