2-1 Characteristics of Living Things

1.Made of one or more units called cells

2. Reproduce

3. Grow and Develop

4.Obtain and use energy

5. Respond to their environment

#1 Living things are made up of cells Cell – small self contained unit Can perform all the functions of life Cell – small self contained unit Can perform all the functions of life

Unicellular – organism made of one cell Multicellular – organism made of many cells Unicellular – organism made of one cell Multicellular – organism made of many cells

Cells are only found in living material or material that was once alive

#2 Living things Reproduce Produce organisms like themselves

Sexual reproduction – 2 cells formed from different individuals unite to form an organism

Asexual Reproduction – single

#3 – Living things grow and develop Are capable of growth at one stage of their life cycle at least Development – cycle of growth Are capable of growth at one stage of their life cycle at least Development – cycle of growth

Aging – comes at the end of development –Organism becomes less efficient at the process of life Aging – comes at the end of development –Organism becomes less efficient at the process of life

#4 – Living things obtain and use energy Energy from their environment or surroundings Energy to grow, develop, and reproduce Energy from their environment or surroundings Energy to grow, develop, and reproduce

Metabolism = Anabolism + Catabolism

Anabolism – putting together or synthesizing complex substances from simpler substances

Plants – photosynthesis Animals – take in energy  food Plants – photosynthesis Animals – take in energy  food

Catabolism – final breakdown of complex substances into simpler substances resulting in the release of energy

#5 – Living Things respond to their environment Slow – changes in metabolic processes Rapid – changes in behavior Slow – changes in metabolic processes Rapid – changes in behavior

Stimulus – anything that causes an organism to react Irritability – the ability of living things to react to stimuli Stimulus – anything that causes an organism to react Irritability – the ability of living things to react to stimuli

Living things respond to stimuli in a way that improves their chances for survival

Homeostasis Organisms ability to maintain constant or stable conditions that are necessary for life Process by which organisms respond to different stimuli Homeo – same Stasis – stopping/standing Organisms ability to maintain constant or stable conditions that are necessary for life Process by which organisms respond to different stimuli Homeo – same Stasis – stopping/standing

2-2 Biology: The Study of Life

Biology – the study of life Biologist – person who studies living things Biology – the study of life Biologist – person who studies living things

Branches of Biology Many divisions –Molecular biologist –Cell biologist –Zoologist (animals) –Botanist (plants) –Paleontologists –Ecologists –Global Ecologists Many divisions –Molecular biologist –Cell biologist –Zoologist (animals) –Botanist (plants) –Paleontologists –Ecologists –Global Ecologists

Questions at the …. Molecular level Cellular level Multicellular level Population level Global level Molecular level Cellular level Multicellular level Population level Global level

Tools of a Biologist

To study small organisms  microscopes –Produces a larger image To study small organisms  microscopes –Produces a larger image

Compound Light Microscope Most common Can observe living organisms Light passes through the organism Two types of lenses – Objectives – 2 –Ocular (eyepiece) Most common Can observe living organisms Light passes through the organism Two types of lenses – Objectives – 2 –Ocular (eyepiece)

Total Magnification = Ocular x Objective Total Magnification = Ocular x Objective

Limit of Resolution Beyond this point objects become blurry and detail is lost – will always exist Increase magnification – more and more detail until you reach the limit of resolution Beyond this point objects become blurry and detail is lost – will always exist Increase magnification – more and more detail until you reach the limit of resolution

Staining Colors some parts of the cell to make them clearly visible

Types of Microscopes Compound light microscope Electron microscope Compound light microscope Electron microscope

Electron Microscope

Can see smaller things than the compound Uses electromagnets to bend electrons Two types – SEM and TEM Can see smaller things than the compound Uses electromagnets to bend electrons Two types – SEM and TEM

TEM (Transmission) How it works – shine a beam of electrons at a sample and magnify the image onto a florescent screen (TV)

SEM – Scanning How it works – beam of electrons scans back and forth across the surface of a specimen Electrons bounce off the specimen are picked up by detectors and a 3-D image is formed How it works – beam of electrons scans back and forth across the surface of a specimen Electrons bounce off the specimen are picked up by detectors and a 3-D image is formed

Limitations of Electron Microscopes Specimens must be in a vacuum (no air) Thin slices Stained, dried out or dead Specimens must be in a vacuum (no air) Thin slices Stained, dried out or dead

Laboratory Techniques of a Biologist

Centrifugation Cell fractionation – cells blended in a blender Broken bits spun 20,000x a minute Cell fractionation – cells blended in a blender Broken bits spun 20,000x a minute

Heaviest parts sink Scientists remove the part they want Heaviest parts sink Scientists remove the part they want

Micromanipulation Microdissection – can be used to remove cell parts Can be used to insert material in a living cell Microdissection – can be used to remove cell parts Can be used to insert material in a living cell

Cell Cultures Used to produce large numbers of cells Cell is grown in a dish with nutrients Overtime many cells develop Used to produce large numbers of cells Cell is grown in a dish with nutrients Overtime many cells develop

The End