Some organisms have a CELL WALL Plants cellulose
- Slides: 59
Some organisms have a CELL WALL • Plants (cellulose) • Algae (polysaccharide) • Fungi (chitin) • Prokaryotes(peptidoglycan)
What does the cell wall do? 1. Scaffolding - mechanical support and structure 2. Protection 3. Involved in Cell-cell communication 4. Maintenance of structure (turgor)
Movement across the cell membrane
Where is the water in your body?
Where are membranes located? 1. Cell membrane (double membrane) 2. Organelles (membrane -bound) can be single or double membrane) • Secret Universe • Introduction to cell membrane
What do membranes do? All cells live in an aqueous environment (surrounded by water, ions and molecules) • …they must control what gets in (nutrients) and out ( waste products and signalling molecules) • they need to communicate with each other… How is this achieved? . .
What do membranes do? 1. Protective barrier 2. Cell-Cell signalling 3. Transport of nutrients, products and waste products 4. Localisation of function within organelles Cell membrane function
Membranes are: 1. Semi-permeable: controls entry and exit of substances 2. Self-sealing 3. Flexible, mobile fluid mosaics
Let’s meet the components of the cell membrane
Phospholipid bilayer polar hydrophilic heads nonpolar hydrophobic tails polar hydrophilic heads
Substances can be hydrophilic or hydrophobic
Membrane Proteins Each membrane has its own unique set of proteins Proteins act as: • CHANNELS to get substances in or out of the cell or organelle • PUMPS to get substances in or out of the cell or organelle • RECEPTORS to allow the cell or organelle to respond to a stimulus
3. 4. 2 Explain the importance of the membrane proteins to transport across the membrane
Protein channels move substances from one side of membrane to the other
Protein pumps move substances from one side of membrane to the other
Protein receptors
Membranes have sugars (carbohydrates) attached to their surfaces • ‘Chemical identification cards’ • Used for cell communication • Used by the immune system to identify self or ‘non-self’ (invaders)
Blood cells have glycoproteins (blood type)
Let’s Review… Let's build a membrane from scratch… And now…let’s make a membrane!
Movement across the Cell Membrane
How do things get into and out of our cells? PASSIVE MECHANISMS These don’t require energy 1. Simple diffusion 2. Facilitated diffusion 3. Osmosis ACTIVE MECHANISMS These require energy to transport substances (often against their concentration gradient) 1. Protein pumps 2. Endocytosis/ exocytosis
3. 5. 4 State that the energy for diffusion comes from the kinetic energy of random movement of molecules and ions Particle theory states that all matter consists of many, very small particles, which are constantly moving, or in a continual state of motion. The degree to which the particles move is determined by the amount of energy they have and their relationship to other particles
3. 4. 2 Explain the importance of the membrane proteins to transport across the membrane
3. 5. 1: Diffusion: Definition • Diffusion is the net movement of particles from a region of their higher concentration to a region of their lower concentration down a concentration gradient, as a result of their random movement • Works for small particles
Simple Diffusion 2 nd Law of Thermodynamics governs biological systems: the universe tends towards disorder (entropy) Diffusion: movement of small, soluble particles from high low concentration
Diffusion Movement is from HIGH to LOW concentration • “passive transport” • no energy needed diffusion movement of water osmosis
3. 5. 3 substances move into and out of cells by diffusion through the cell membrane; this is a dynamic process (always happening) • Gas exchange in the lungs • Gas exchange in plants
Gas exchange between lungs and blood is via diffusion
Gas exchange in plants is via diffusion
3. 4. 2 Explain the importance of the membrane proteins to transport across the membrane
Facilitated Diffusion Facilitated diffusion is diffusion of specific molecules through protein channels in the cell membrane – no energy is required facilitated = with help open channel = fast transport high low
Factors affecting diffusion 1. Concentration gradient 2. Temperature 3. Surface area for diffusion 4. Distance for diffusion 5. (size of particle) 6. (charged or uncharged)
Factors affecting the rate of facilitated diffusion are the same as for simple diffusion 1. Concentration gradient 2. Temperature 3. Surface area for diffusion 4. Distance for diffusion
Osmosis • water diffuses through partially permeable membranes from higher to lower concentrations by osmosis • water moves in and out of cells by osmosis through the cell membrane
Osmosis: Definition • Osmosis is the net movement of water molecules from a region of higher water concentration [potential] (dilute solution) to a region of lower water concentration [potential] (concentrated solution), through a partially permeable membrane • Like other types of diffusion, osmosis is a dynamic process [achieves balance (equilibrium) but never stops]
Movement of water across membranes involves BOTH simple AND facilitated diffusion
Factors affecting osmosis 1. Concentration gradient 2. Temperature 3. Surface area for diffusion 4. Distance for diffusion
Comparing ‘water concentration’ of different solutions Direction of osmosis is determined by comparing total solute concentrations on either side of the membrane: • Hypertonic - more solute, less water • Hypotonic - less solute, more water • Isotonic - equal solute, equal water hypotonic hypertonic net movement of water
freshwater balanced saltwater
Osmosis is the diffusion of water across a semi-permeable membrane Facilitated diffusion of water from high concentration of water to low concentration of water across a semi-permeable membrane
Examples of Osmosis in Biology • Absorption of water by plant roots. • Re-absorption of water in the kidney. • Re-absorption of tissue fluid into blood capillaries. • Absorption of water in the GI tract
Water moves across a membrane from the hypotonic solution to the hypertonic solution • Animation of osmosis 1 • Animation of osmosis 2: why water balance matters
How do things get into and out of our cells? PASSIVE MECHANISMS These don’t require energy 1. Simple diffusion 2. Facilitated diffusion 3. Osmosis ACTIVE MECHANISMS These require energy to transport substances (often against their concentration gradient) 1. Protein pumps 2. Endocytosis/ exocytosis
Active transport 1: Protein pumps • Active transport uses • Animation energy (ATP) to • protein pumps in plants transport substances AGAINST a concentration gradient low into/out of the cell • The energy is used to change the shape of the ATP ‘protein pump’ and thus import/export specific molecule high
3. 6. 2 Discuss the importance of active transport as a process for movement across membranes: e. g. ion uptake by root hairs and uptake of glucose by epithelial cells of villi and kidney tubules
3. 6. 3 Explain how protein molecules move particles across a membrane during active transport
Transport summary simple diffusion facilitated diffusion active transport ATP
Active Mechanisms: Endocytosis and Exocytosis • A simple one. . . • Animation 2 Endocytosis/ exocytosis are import/export of materials by infolding/outfolding of the cell membrane
Cell responses 3. 7. 1 Explain the effects on plant tissues of immersing them in solutions of different concentrations by using the terms turgid, turgor pressure, plasmolysis and flaccid
3. 7. 3 Explain the importance of osmosis on animal cells and tissues
3. 7. 4 Explain how plants are supported by the turgor pressure within cells, in terms of water pressure acting against an inelastic cell wall
- Wine roots servian
- Middle lamella
- Cell wall vs cell membrane
- Which kingdom does not have a cell wall?
- Why do organisms interact with other organisms
- Unicellular/multicellular
- In unicellular organism
- Sound wall phonemic awareness
- Wall to wall chris brown
- One and a half brick wall
- Members used to carry wall loads over wall openings
- Fruit develops from ovary
- Storage of carbohydrates
- Stramenophiles
- Ascomycetes diagram
- Schulze's test for cellulose
- Cellulose starch glycogen
- Cellulose amylose amylopectin and glycogen
- Cellulose starch glycogen
- Cellulose plates in dinoflagellates
- Define permiation
- Simple saccharides
- Whats the difference between a monomer and a polymer
- Cellulose introduction
- Cellulose plant
- Cellulose tape swab
- Cellulose wafers dentistry
- Starch and liquid combinations
- Surfathix
- Living wall plants
- Vascular vs nonvascular plants
- Vascular vs nonvascular plants
- Classify non flowering plants with examples
- C3 plants vs c4 plants
- Animal-like protist
- Single cell organisms
- Cell division in multicellular organisms
- 8 vertices 12 edges 6 faces
- In some plants like grass monstera and banyan tree
- Sometimes you win some
- Sometimes you win some
- Countable and uncountable nouns ice cream
- Contact vs noncontact forces
- Some say the world will end in fire some say in ice
- Some say the world will end in fire some say in ice
- Some trust in chariots and some in horses song
- Meiosis
- Ispindle
- Emergent properties
- Which kingdoms have photosynthetic organisms? *
- Cell membrane function
- Eubacteria characteristics chart
- Prokaryotic cell of bacteria
- Cell membrane function
- Kingdom fungi cell wall
- Fungi spore
- Koh test positive result
- Ingestion
- Mitochondria vocabulary
- Cell wall function