basics of biology
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Basics of Biology. Chapter 4. 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 . Objective . SWBAT: Identify levels of organization from cell to ecosystem - PowerPoint PPT PresentationTRANSCRIPT
Basics of Biology
Chapter 4
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
Do Now
SWBAT: Identify levels 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.
Objective
All living organisms can be divided into two
basic groups based on cellular composition:
1. Prokaryotic2. Eukaryotic
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
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
Types of Organisms
Atom – fundamental unit of all matter
Molecule – two or more atoms chemically joined together
Levels of Organization in Living Organisms
Organelle – specialized features of cells
Cell – basic unit of life
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
Levels of Organization in Living Organisms
Organ system – group of organs that work
together
Whole organism (individual)
Levels of Organization in Living Organisms
Interactions among individuals
Population- A group of organisms of the same species that occur together
Example
Interactions among individuals
Community- all the populations in a particular habitat
Example
Interactions among individuals
Ecosystem- A community of communities in a large area, together with their physical environment
Ecosystem
Planktonic organisms (drifters) Benthic organisms (bottom dwellers) Nekton (strong swimmers)
Many adaptations are made to maintain internal body conditions Homeostasis
Challenges of life in the sea
Enzymes and organic molecules are sensitive
to ion concentration Diffusion and Osmosis
Salinity
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
Diffusion
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
Diffusion and cells
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
Diffusion and Osmosis
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
Membrane barrier
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
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
Osmosis
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
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
Active Transport
Some marine organisms do not actively
maintain salt and water balance Salinity changes with salinity of water –
Osmoconformers
Regulation of Salt and Water Balance
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
Osmoconformers
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
Ways to adapt
Osmoregulation fresh vs marine
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
Osmoregulation
Vocab
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?
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