C ELLS AND CELL THEORY © J Beauchemin 2006

C HARACTERISTICS OF L IVING T HINGS ….( A REVIEW ) are made up of cells (organization). respond to the environment. have the ability to reproduce. move. grow and develop. perform metabolic processes.

A LL LIVING THINGS ARE MADE UP OF CELLS …. The cell is the smallest unit of a living thing. If an organism is unicellular, all functions of life happen within that one cell. If an organism is multicellular, different cells have different jobs and they all work together.

C ELL THEORY - HOW IT CAME ABOUT 1660’s – Robert Hooke discovered the cell He looked at cork under the microscope (30x) He noticed little compartments, which he named after the little rooms that monks lived in…”Cells” 1670’s – Anton von Leeuwenhoek described microorganisms in pond water He looked at pond water under the microscope (300x) He noticed that the water was full of moving living things

CELL THEORY With the invention of the microscope and the contributions of many scientists, a very important question was answered in the1850’s. The question was: Where do cells come from?

CELL THEORY There are three concepts to the cell theory… 1. Every living thing is made up of one or more cells. 2. Cells carry out the functions needed to support life. 3. Cells come only from other living cells.

C ELLS AND O RGANELLES © J Beauchemin 2006

C ELL O RGANELLES Organelle= “little organ” Found only inside eukaryotic cells

C ELL M EMBRANE Boundary of the cell Made of a phospholipid bilayer- fatty, porous, made also of phosphorus BAG- CELL: ziploc

N UCLEUS Control center of the cell Contains DNA Surrounded by a double membrane Usually the easiest organelle to see under a microscope BAG CELL: CHESNUT

E NDOPLASMIC R ETICULUM A.k.a. “ER” Highway of the cell Rough ER: studded with ribosomes; it makes proteins Smooth ER: no ribosomes; it makes lipids (fats) BAG CELL: RAMAN NOODLES

R IBOSOME Where protein is made Found attached to rough ER or floating free Produced in a part of the nucleus called the nucleolus

G OLGI A PPARATUS ( BODY ) Looks like a stack of plates or ribbon candy Stores and packages proteins Molecules transported to and from the Golgi by vesicles BAG CELL: RIBBON CANDY

VESICLES Bud off from the Golgi bodies Hold and then move the protein molecule BAG CELL: ENVELOPE

L YSOSOMES Garbage disposal (or recycling) of the cell Contain digestive enzymes that break down wastes BAG CELL: SKITTLES

M ITOCHONDRIA “Powerhouse of the cell” Cellular respiration occurs here to release energy for the cell to use BAG CELL: CASHEW NUT

CYTOPLASM Gel-like material in a cell where all the organelles are Supports the organelles Gives cell shape BAG CELL: OIL OR JELLO

PLANT CELLS © J Beauchemin 2006

C ELL W ALL Found in plant and bacterial cells Rigid, protective barrier Located outside of the cell membrane Made of cellulose (fiber) BAG CELL: PAPER BAG

C HLOROPLAST Found only in plant cells Contains the green pigment chlorophyll Site of food (glucose) production BAG CELL: GREEN SKITTLES

V ACUOLES Large central vacuole usually in plant cells Many smaller vacuoles in animal cells Storage container for water, food, enzymes, wastes, pigments, etc BAG CELL: WATER BALLOON WHAT HAPPENS TO THE VACUOLE WHEN A PLANT DOESN’T GET ENOUGH WATER?

22 S IMILARITIES BETWEEN PLANT CELLS AND ANIMAL CELLS Both have a cell membrane surrounding the cytoplasm Both have a nucleus Both contain mitochondria

23 D IFFERENCES BETWEEN PLANT CELLS AND ANIMAL CELLS Animal cellsPlant cells Relatively smaller in size Irregular shape No cell wall Relatively larger in size Regular shape Cell wall present

24 Animal cellsPlant cells Vacuole small or absent Glycogen as food storage Nucleus at the center Large central vacuole Starch as food storage Nucleus near cell wall D IFFERENCES BETWEEN P LANT C ELLS AND A NIMAL C ELLS

Q UICK R EVIEW Which organelle is the control center of the cell? Nucleus Which organelle holds the cell together? Cell membrane Which organelles are not found in animal cells? Cell wall, central vacuole, chloroplasts Which organelle helps plant cells make food? Chloroplasts What does E.R. stand for? Endoplasmic reticulum