Mod 1, IQ2: How do cells coordinate activities within their internal environment and the external environment? Flashcards
Module 1: Cells as the Basis of life
Permeability
The ability for a molecule to pass freely through the membrane
Two forms of transport
Passive: requires no energy input, down the concentration gradient
Active: requires energy (ATP), against the concentration gradient.
Diffusion
Particles in a solution move from an area of high concentration to an area of low concentration
Passive process
Simple and Facilitated
Simple diffusion vs Facilitated diffusion
Simple diffusion occurs when small molecules pass through the lipid bilayer of the cell membrane.
Facilitated diffusion depends on proteins to allow specific substances to pass through
Channel proteins
Fastest form of transport in facilitated diffusion
Works like a gate, can be open or closed which is determined by electrical or physical signals
Carrier proteins
Bind with a solute and change their shape to move the solute to the other side of the membrane.
Osmosis
The movement of water molecules from a region of high water concentration to a region of low water concentration through a selectively permeable membrane.
Active transport
Involves using energy in the form of ATP to transport particles across the cell membrane - always involves carrier proteins.
Endocytosis
The cell takes in new materials from outside the cell by forming vesicles from infolds of the cell membrane.
Three types of Endocytosis
Phagocytosis: engulfing a solid material
Pinocytosis: engulfing a liquid that contains dissolved molecules
Receptor mediated endocytosis: Engulfs specific substances determined by the receptors on the outside of the cell membrane
Exocytosis
Moving molecules from the inside of the cell into the extracellular fluid
Autotrophs
Make their own organic compounds from inorganic compounds found in their environment
Example: photosynthesis
Heterotrophs
Gain organic compounds by eating other organisms
Organic and Inorganic compounds
Organic: contain carbon and are quite complex
Inorganic: include water, oxygen, carbon dioxide, nitrogen and minerals
Photosynthesis
Converts solar energy into chemical energy (glucose)
Occurs in the chloroplast - chlorophyll is used to absorb solar energy
Photosynthesis formula
co2 + h2o –(Sunlight & Chlorophyll) –> c6h12o6 + o2
Cellular respiration
Converts chemical energy into ATP
Catalysts
An element of compound that speeds up a chemical reaction
Biological catalysts - enzymes
Factors that speed up biological processes are known as enzymes
Binds with substrates to speed them up
Example: Lactase (enzyme) breaks down lactose (substrate)
Enzyme-substrate complexes
Lock and key model
Induced fit model
Lock and key model
If the active site does not fit correctly into the substrate, then no reaction will occur and there ill be no catalyst
Induced fit model
When the substrate binds to the active site, the active site can change shape slightly to accommodate the substrate
Catabolic reactions
Break down substrates into two or more parts.
Releases energy and is used to break down large molecules into smaller ones (degradation).
Anabolic reactions
Build large molecules from smaller substrates.
Uses energy to build up large molecules from smaller ones (biosynthesis).