Please enable JavaScript.
Coggle requires JavaScript to display documents.
Cells as The Basis of Life - Coggle Diagram
Cells as The Basis of Life
IQ1 - What Distinguishes One Cell From Another
Technologies used to see cells
Microscopes
Light microscopes
Can view both living and non-living organisms
Produces images up to x1500
Resolution is 0.250um
Electron microscopes
Uses electron beam
Can see structures in more detail than light microscopy
Resolution is 0.25nm
Resolution - how close 2 objects can be, and still be seen separate
Magnification - How any times bigger and object is in an image than in real life
Drawing scaled biological drawings
3) Draw and label image
4) Determine scale bar using formula - actual size of specimen ÷ size of drawing
2) Choose a size that you will use to draw the specimen
5) Draw scale bar onto diagram
1) Determine actual size of the specimen
Calculating sizes of organisms
Magnification - image size ÷ actual image
Image size - actual image × magnification
Actual image - image size ÷ magnification
IQ1 - What Distinguishes One Cell From Another
Investigate different cellular structures
Eukaryotic
Can be unicellular or multicellular
Can be plant and animal cells
Membrane bound organelles
Larger (10-100um)
More complex form of organisms
Prokaryotic
No membrane bound organelles
Unicellular
Simplest form of organism on Earth
Smaller (1-5um)
No membrane bound nucleus
Most abundant form of life
Both can have cell wall and be unicellular
Cell - Basic unit of all living things
Cell Theory - all cells come from pre-existing cells
All organisms are made of cells
Investigate a variety of cell structures
Cell membrane - outer boundary of a cell. Controls what enters and exits the cell
Cytoplasm - jelly-like substance all other organelles are suspended in
Organelles - subcellular structures that have specific functions within the cell
DNA - carries hereditary information, directs cell activities
Ribosomes - responsible for the synthesis of proteins
Nucleus - contains DNA and is considered the control centre of the cell brain. It tells the organelles what to do
Endoplasmic reticulum
Mitochondria - powerhouse of the cell
IQ2 - How do cells coordinate activities
Investigate cell requirements
Organic compounds
Contain carbon and hydrogen
Nucleic Acids
DNA - stores info inside cell, main chemical making up the nucleus
RNA - found in small amounts in nucleus and lager amounts in cytoplasm, assists in creation /manufacturing of proteins
Proteins
(Insulin, enzymes) - form structural components in tissue, some have a functional role, amino acids are building blocks of proteins
Lipids
(oils, fats hormones) - energy storage, structural component of membranes, essential part of hormones
Carbohydrates
(glucose) - source of energy in plant and animal cells
Inorganic compounds
Oxygen - used by all living things during cellular respiration to release energy for cell function
Minerals - assist all chemical reactions, used in synthesis, essential for cell membrane function
Water - transport medium in cells and organisms, important solvent, medium in which chemical reactions take place
Nitrogen - essential nutrient for production of amino acids
Carbon dioxide - used during photosynthesis to create glucose, released as product of cellular respiration
Suitable forms of energy
Light energy
Photosynthesis uses energy from the sun to produce glucose
Chemical energy
All cells use glucose as primary source
ATP (Adenine triphosphate)
Is broken down glucose that is then stored after being released during cellular respiration
Removal of wastes
Oxygen and carbon dioxide are removed by diffusion
Water is removed by osmosis
Lipids and oils are broken down and absorbed by water, then removed by osmosis
Proteins and old cell parts are removed in vesicle by exocytosis
IQ2 - How Do Cells Coordinate Activities
Movement of Materials
Concentration gradient - movement of molecules from a high concentration to a low concentration
Passive transport
- movement of molecules without the expenditure of energy
Facilitated diffusion
Large polar molecules require a protein to pass through membrane
Fast process
Movement of solute molecules along the concentration gradient
Osmosis
Isotonic - fluids inside and outside cell are of equal solute concentration
Hypertonic - higher solute concentration surrounding the cell than inside (water moves out of cell)
Osmotic pressure - more water moving across membrane = higher pressure
Hypotonic - lower solute concentration surrounding the cell than inside (water moves into the cell)
Movement of water molecules from low concentration to high concentration
Simple diffusion
Involves solutes that the membrane is permeable to
Small molecules and water molecuoles
Movement of solute molecules along the concentration gradient
Slow process
Active transport
- movement of molecules against concentration gradient with the expenditure of energy
Endocytosis
Vesicle moves large molecules that cannot cross cell membrane into the cell
Cell membrane changes shape and surrounds and engulfs the vesicle
Molecules enter vesicle upon arriving to cell
Types of endocytosis
Phagocytosis - solid particles are engulfed by cell membrane
Pinocytosis - liquid containing dissolved molecules are engulfed by cell membrane
Receptor - type of pinocytosis in which the cell membrane engulfs specific substances that are bound to receptors
Exocytosis
Vesicle fuses with membrane
Membrane releases contents out of cell
Involves a membrane bound vesicle moving to cell membrane
Moves large molecules that cannot cross cell membrane out of the cell
Surface area to volume ratio
Small organisms have high SA:V ratio
A high SA:V allows the most efficient movement of substances into and out of the cell.
The surface area to volume ratio decreases as the size of an object increases
Larger SA:V ratio makes exchange of materials less efficient
IQ1 - What Distinguishes One Cell From Another
Fluid Mosaic Model
The membrane is composed of a phospholipid bilayer which eater finds very difficult to get through
Lipid - doesn't dissolve in water
Hydrocarbon tails are hydrophobic (hates water)
Phosphate head is hydrophilic (loves water)
Phospholipids are amphipathic - have a hydrophobic tail and hydrophilic head
Fluid mosaic - constantly moving
Semipermeable - selective about materials that enter and exit cell
Polar - attracted to water
Have protein channels for larger molecules (glycolipids)
IQ2 - Action of Enzymes
Speed up reactions by lowering activation energy required
Environmental factors affecting enzyme activity
pH
Temperature
Substrate concentration
Enzymes are protein molecules that control all metabolic reactions
Properties of enzyme
Folded over to create particular chemical shape
Surface of enzyme with specific shape is called the ACTIVE SITE
SUBSTRATES bind to ACTIVE SITE to form a substrate - enzyme complex
Products are released from ACTIVE SITE
MODELS of enzyme activity
Induced fit
Enzyme can alter shape to accommodate substrate
Key and Lock
Rigid - doesn't change
Denaturation - when the structure of an enzyme is permanently altered