Introduction to cells

Quickflart! 10/11

• What is a good one – sentence definition of a cell?

Introduction to Cells

What is a cell?

…membrane bound structure, it is the smallest unit of life.

Important people who helped discover cells

1) Robert Hooke – looked at cork cells named the 1665structure “cell”

2) Anton von Leeuwenhoeklooked at pond water, was

1st to look at living cells!1700

Microscopes

Only been around for about 250 years.

Several types: Light microscopeElectron microscope

(SEM & TEM)

Light microscope

Euglena under light microscope

Electron Microscope

Euglena under SEM (Scanning Electron Microscope)

What are the 3 parts to the Cell Theory?

1) All living things are made of at least 1 cell.

2) Cells are the basic unit of structure & function of life.

3) Cells only come from other living cells.

Are there differences between cells?

1) Different shapes

2) Different sizes

3) Different internal organization

Quackstort! 10/15

• Write the three parts of the cell theory. • Use your notes if you can’t remember. • Smile.

• Table of Contents - Write: Prokaryotes & Eukaryotes

Different cell shapes

How is the internal organization different?

Cells are either Prokaryotic or Eukaryotic!!

Prokaryote

• No nucleus

• Has DNA & circular chromosome

• No membrane-bound organelles

• Can only be unicellular

• Ex: bacteria

Typical prokaryote

Eukaryote

• Has nucleus • Has DNA & rod shaped chromosomes• Has many membrane-bound

organelles• Can be unicellular or multicellular• Ex: fungus, plants, my dog, Mr. R

Typical Eukaryote (animal cell)

Typical Eukaryote (plant cell)

Microfilament MicrotubuleCytoskeleton{

Mitochondrion

Plasma Membrane

Vesicle

Golgi apparatus

Ribosomes

Rough endoplasmic reticulum

Nucleolus

Nucleus

Smooth endoplasmic reticulum

ChloroplastCell Wall

Central Vacuole

Absent in animal cells {

CELL ORGANELLES

Cell Organelles

Cell organelles are small structures within the cell, each has a specific job.

Not all cells will have every organelle!

Nucleus

The control center

Contains the DNA

Controls all the cell functions

Has a nuclear membrane

Some have a nucleolus inside

Nucleus

Endoplasmic Reticulum

2 types: smooth ER (no ribosomes)rough ER (with ribosomes)

Snuggles up to the nucleus

Helps with movement of substances within the cell, Smooth ER also helps make steroids & break down toxins.

ER

Golgi Apparatus

Helps finish proteins and package them for shipment out of the cell.

Golgi Apparatus

Ribosomes

Make proteins.

Can be “floating free” in the cytoplasm or attached to rough ER.

Proteins (NOT an organelle)

• Proteins are the building blocks that make up all of the structures in the cell.

Lysosomes

Lysosomes are vesicles that contain digestive enzymes that:

Breaks down old cell parts & some wastes.

Also destroys any invaders (like bacteria)

Mitochondria

Most of the energy cell’s need is made here! (cell respiration)

Changes “food” into energy.

Mitochondria

Cytoplasm/Cytoskeleton

Cytoplasm = jelly like substance in the cell

Cytoskeleton = made up of microtubules & microfiliments

Both are important for providing structural support in intracellular movement.

Cytoplasm/Cytoskeleton

Cell Membrane/Plasma Membrane

Double layer of lipids with carbs & proteins.

Helps maintain cell shape and homeostasis.

Cell membrane

Plant cells

Plant cells have the same organelles & a few new ones!

Plant cells

Chloroplast

…used for photosynthesis

**has its own DNA

Cells in plant leaves have LOTS of chloroplasts!

Chloroplasts

Cell Wall

Rigid structure, mostly made of cellulose.

Outside of the cell membrane.

Helps support the cells (and plant)

Cell wall

Some other cell parts to be aware of…

1) Cilia – hair-like structures usually help cells move

2) Pili – hair-like structures that help bacteria stick to surfaces and share DNA with other bacteria.

3) Flagella (flagellum) – whip-like tail, helps cell move

3) Vacuoles – hold or store wastes, water, food. Plants usually have 1 large vacuole and many smaller ones, animal cells have small ones.

4) Centrioles – only in animal cells, help with cell division

Cells – general information

Cell size is limited by the ratio of surface area to volume.

Cell with particular functions will have more of some organelles & less of some organelles.