Basics of Biology

1. Basics of Biology Chapter 4

2. Do Now • Name one difference between a plant cell and an animal cell • What is the purpose of a cell membrane? • What type of cells do we have? A) Prokaryotic B) Eukaryotic

3. Objective • SWBAT: Identifylevels of organization from cell to ecosystem • Describe the challenges that marine organisms face living in the sea • Describe the process of osmosis and determine what makes active transport different from passive transport.

4. Types of Organisms • All living organisms can be divided into two basic groups based on cellular composition: • Prokaryotic • Eukaryotic

5. Types of Organisms • Prokaryotic Organisms: • Lack a nucleus • Posses ribosomes • Contain a circular ring of DNA • Some may also have plasmids, extra pieces of DNA • Cell wall is normally present • May have a flagellum • Unicellular

8. Types of Organisms • Eukaryotic Organisms • Possess DNA enclosed inside a nucleus • Posses many specialized organelles (look at organelles in Fig. 4.8) • Eukaryotic organisms can be unicellular or multicellular

9. Levels of Organization in Living Organisms • Atom – fundamental unit of all matter • Molecule – two or more atoms chemically joined together

10. Levels of Organization in Living Organisms • Organelle – specialized features of cells • Cell – basic unit of life

11. Levels of Organization in Living Organisms • Tissue – group of cells functioning as a unit • Organ – many tissues arranged into a structure with a specific purpose in an organism

12. Levels of Organization in Living Organisms • Organ system – group of organs that work together • Whole organism (individual)

13. Interactions among individuals • Population- A group of organisms of the same species that occur together • Example

14. Interactions among individuals • Community- all the populations in a particular habitat • Example

15. Interactions among individuals • Ecosystem- A community of communities in a large area, together with their physical environment • Ecosystem

16. Challenges of life in the sea • Planktonic organisms (drifters) • Benthic organisms (bottom dwellers) • Nekton (strong swimmers) • Many adaptations are made to maintain internal body conditions • Homeostasis

17. Salinity • Enzymes and organic molecules are sensitive to ion concentration • Diffusion and Osmosis

18. Diffusion • In solution- ions & molecules move around like water molecules • Random movement spreads them out until they are evenly distributed. • Result: molecules move from areas of high concentration to low concentration

20. Diffusion and cells • Internal composition differs from external in the cell- substances will move into or out of the cell by diffusion • If more sodium in outside the cell – sodium will diffuse into the cell • Problem if organism is sensitive to sodium

21. Diffusion and Osmosis • Since marine organisms live in a very solute-rich environment, they have a tendency to gain solutes and lose water • This can result in the death of cells if the water loss/solute gain is significant • These organisms must find ways to deal with this diffusion and osmosis

22. Membrane barrier • Membrane blocks the passage of the common ions in seawater and many organic molecules. • Membrane allows exchange with many molecules such as O2 and CO2 • Selectively permeable – only some substances enter and leave

23. Osmosis • If the solutes are higher outside of the cell than inside of the cell, water will rush out of the cell. • Cell will shrink • http://www.youtube.com/watch?v=sdiJtDRJQEc • Discovery Ed simulation

24. Osmosis • The movement of water across a selectively permeable membrane • If the total concentration of solutes inside a cell is higher than the outside the cell, water will rush into the cell. • Cell will swell

25. Active Transport • Proteins in the cell membrane pump materials in the opposite direction to which they would move by diffusion. • Requires energy • What form is that energy in? • How often do we use active transport? • Over 1/3 of a cells total energy expenditure

26. Active Transport • What is needed to move molecules into or out of a cell against the gradient? • What are cell membranes made of? • What is imbedded in the cell membrane? • ATP has “trapped” energy from what process? • Active transport brings in materials to the cell and what else does it do? • Discovery ed Simply Science: Matter and Energy on the move active transport

27. Regulation of Salt and Water Balance • Some marine organisms do not actively maintain salt and water balance • Salinity changes with salinity of water – Osmoconformers

28. Osmoconformers • If an osmoconformer were placed in a freshwater environment, the would swell and burst. • Water would rush into the cell because water would move into the cell (low concentration) • Open ocean is where you find osmoconformers

29. Ways to adapt • Adjust solutes in your body to match solutes of water outside the body. • Total amount of dissolved material needs to be the same • Change the amount of one particular chemical to match changes in salinity outside • Sharks- increase/decrease urea in their blood • Danasliella-single celled marine alga – changes glycerol

30. Osmoregulation fresh vs marine

31. Osmoregulation • Marine birds, reptiles and plants have special cells or glands to get rid of extra salts. • Marine plants have cell wall to help regulate swelling caused by osmotic water gain

32. Vocab

33. Exit Ticket • What is the difference between osmosis and diffusion • How do marine fishes deal with the the water they constantly loose to the salty environment they live in? • What is a population? • What is a community?