LIFE SCIENCE 1.2
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Transcript of LIFE SCIENCE 1.2
LIFE SCIENCE1.2
Microscopes allow us to see inside the
cell.
Because cells are very small, in order to measure them we need a new unit.The micrometer (mm)is one millionth of a meter.Cells can range from 1 to 1000 micrometers.It would take 17,000 bacterial cells to line up across a dime.
Light Microscopes bend light and magnify cells up 1000 times.
Cells can be treated with dyes to make more visible.Cameras and computers observe movement of cell parts.Can observe living cells.
Scanning Electron Microscopeand
Transmission Electron Microscope
SEM and TEM can view objects as small as 0.002 micrometers.Can see details inside the cell.
Use particles called electrons not light to produce an image.Can magnify objects up to 1 million times.Can not be used to study live specimens.
SEMTHE CELL SAMPLE IS COATED WITH A HEAVY METAL SUCH AS GOLD.A BEAM OF ELECTRONS IS RUN BACK AND FORTH OVER THE SURFACE.THE ELECTRONS BOUNCE OFF THE SURFACE AND ARE READ BY A DETECTOR WHICH PRODUCES A 3 D IMAGE OF THE SURFACE
SEM IMAGESButterfly Proboscis Pollen
TEM
THE CELL SAMPLE IS SLICED EXTREMELY THIN.ELECTRONS PASS THROUGH A SECTIO.IMAGES PRODUCED ARE 2 DIMENSIONAL.
TEMGolgi Bodies Mitochondrian
CELLS ARE DIVERSE
EVERY CELL HAS:
Cell membrane- separates the cell from its environment.
Cytoplasm – gelatin-like material inside the cell, carries on most of the work of the cell.
Two categories of CellsEukaryotic Cells
Prokaryotic Cells
Two categories of CellsProkaryote- pro: before; kary: nucleus
Genetic material contained in a membrane bound structure called a nucleus. Contain other membrane bound structures called organelles.
Usually multicellular organisms.
Eukaryote- eu: true; kary: nucleus
Genetic material contained in the cytoplasm does not have membrane bound organelles.
Usually unicellular organisms
Eukaryotic Cells are divided into 2 typesPlant Cells Animal Cells
ORGANELLES: any part of the cell that is enclosed by a membrane.
THESE ORGANELLES ARE ONLY FOUND IN PLANT CELLS.
Cell Wall Plant cells have a
cell wall. A tough outer
covering that lies just outside the cell membrane.
Supports and protects the cell.
Chloroplast All energy comes from
the sun. Chloroplasts help the
plant capture and use the sun’s energy.
Plants convert this energy into sugar and store the excess as starch.
THESE ORGANELLES ARE ONLY FOUND IN PLANT CELLS.
Cell Wall Chloroplast
These organelles are found in all eukaryotic cells…both Plant and
Animal
Mitochondria The powerhouse
of the cell. Releases energy
from sugar for use by the cell.
Endoplasmic Reticulum
A system of twisting and winding membranes, some contain Ribosomes which manufacture proteins.
The ER manufactures parts of the cell membrane.
Part of the cellular transportation system.
These organelles are found in all eukaryotic cells…both Plant and
Animal
MitochondriaEndoplasmic
Reticulum
These organelles are found in all eukaryotic cells…both Plant and
Animal
Ribosomes Found attached to
the endoplasmic reticulum and floating freely in the cytoplasm.
Manufacture proteins.
Golgi Apparatus ER breaks off and forms
Vesicles. Inside the vesicles are
products the cell has made for transport outside of the cell.
The Golgi Apparatus which looks like a stack of pancakes finishes the processing of the products.
These organelles are found in all eukaryotic cells…both Plant and
Animal
Ribosomes Golgi Apparatus
Organelles for storage recycling and waste
Vacuole Enclosed in a
membrane Found in plant and
fungus cells. Can store water,
waste and other materials.
Plant cells have one large central vacuole that helps support the plant.
Not found in animal cells.
Lysosome
Vesicles that contain chemicals to breakdown materials taken in by the cell as well as old cell parts.
Animals do not make their own food like plants do so must digest or breakdown the food.
Organelles for storage recycling and waste
Vacuole Lysosome