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.

SEM

THE 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 SECTION.IMAGES PRODUCED ARE 2 DIMENSIONAL.

TEM

Golgi 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 Cells

Eukaryotic CellsProkaryotic 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 types

Plant 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