CELL NOTESHISTORY, TYPES OF CELLS, ORGANELLES

CELL SIZES CAN VARY

•Most cells are small, about 40 human cells would fit on the dot of this letter i.

•Some cells are big, the yolk of a chicken egg is a single cell.

•The smallest cells are so tiny that you could fit over a million of them on the period at the end of this sentence.

CELL SIZE

•Cells are made of molecules•Molecules are made up of atoms.•The atom is the basic fundamental unit of matter.•Atoms are made up of protons, neutrons and electrons.

•Atoms are NON-LIVING

Molecules • 2 or more bonded atoms

• Form compounds

• NON-living

ATOMS• Smallest part of matter

• NON-living

HOW MANY CELLS ARE IN AN ORGANISM?

•Unicellular or multicellular (review)

• You are made up of trillions of cells.

• You have specialized cells in your body. This means that certain cells only do certain things.

(e.g. a heart cell cannot do what a brain cell does)

•Cells, tissues, and organs from different organ systems can’t be switched around.

What determines the shape of a cell?

The cell’s FUNCTION

Nerve Cells Blood Cells Muscle Cells

CELLS USE ENERGY

•The cells of organisms use energy to do what living things must do, such as grow and repair injured parts.

•Cells are always hard at work.

•Right now ALL of your cells are busy!

White blood cells (above)

HOW DO WE LOOK AT CELLS?

•The invention of the microscope made it possible for people to discover and learn about cells.

•A light microscope that has more than one lens is called a compound microscope.

•The Top 10 Microscope IMAGES!!!

•Cool Microscopic Images

ROBERT HOOKE

•The first person to describe cells

• In the 1660s, he built a microscope and looked at cork

•To Hooke the cork looked like rectangular rooms, which he called cells.

•Cell is Latin for “tiny box”

ANTON VAN LEEUWENHOEK

• At about the same time that Robert Hooke made his discovery, Anton van Leeuwenhoek also began to observe tiny objects with his microscope.

• Leeuwenhoek was a Dutch scientist and when he looked at water from a pond he saw tiny single celled organisms.

• First to see bacteria

• Famous for calling cells “wee beasties”

MATTHIAS SCHLEIDEN

•Discovered plants are made of cells

THEODORE SCHWANN

•Discovered animals are made of cells

RUDOLF VIRCHOW

•A doctor who discovered that cells come from other cells

CELL THEORYThe cell theory states:

•All living things are composed of cells.

•Cells are the basic unit of structure and function in living things.

•All cells are produced from other cells.

CELL THEORY

Did our knowledge of cells come all at once?

No, it came a little at a time and built on what we already knew.

CELL THEORY

Do we know everything about cells?

Absolutely NOT!!!

ORGANELLE

•Cells contain even smaller structures inside of the cell called organelles.

•Definition: a specialized structure inside a cell

LOOKING INSIDE CELLS

•Organelles were called organelles because early scientists thought they looked like “inner organs” kind of like our heart, kidneys, or brain.

•Organelles are made out of MOLECULES which are made from ATOMS

CELL WALL

•Definition: The outermost part of a plant cell. It is found outside of the cell's membrane. It is quite rigid and helps maintain the shape of the plant.

•Cell Walls look rectangular in shape and are only found in plant cells.

CELL MEMBRANE

•Definition: the outer portion of a cell. It surrounds the cell and keeps the contents inside.

•For example, it will let food and oxygen in but keep out harmful waste products.

CYTOPLASM

•Definition: all the material between a cell membrane and the nucleus

•This is a clear, thick, gel-like fluid PLUS the organelles

NUCLEUS•Definition: The control center of the cell. Contains DNA.

•Directs the cell in how to function.

•Like the nucleus of an atom, it’s at the center!

NUCLEOLUS

•Inside the nucleus. It makes ribosomes.

MITOCHONDRIA•The powerhouse of the cell! Produces energy for the cell.

•Muscle cells rely heavily on mitochondria.

•They kind of look like brains.

RIBOSOMES

•Ribosomes are small organelles that make proteins.

ENDOPLASMIC RETICULUM (ER)•The endoplasmic reticulum (ER) looks like a giant maze.

•It moves proteins and other materials from one part of the cell to another.

•Sometimes it has ribosomes on it (rough ER). ER with no ribosomes is smooth ER.

VACUOLES•Throughout the cell you can find large water-filled sacs floating in the cytoplasm.

•These sacs are called vacuoles. Vacuoles store water and other materials needed by the cell.

•All plant cells have a large central vacuole.

CHLOROPLASTS•Only plant cells and some protists have chloroplasts.

•Definition: an organelle in a plant cell that changes sunlight into energy (photosynthesis).

CILIA AND FLAGELLA

•Cilia are hair like structures that are found on the outside of some cells. They help the cell move.

•Flagella (singular: flagellum) is a whip like structure on the outside of some cells. They help the cells move.

BACTERIA VS. PLANT VS. ANIMAL CELL

HOW ARE PLANT CELLS AND ANIMAL CELLS DIFFERENT?

•Plant Cells are rectangular in shape due to their Cell Walls.

•Plant cells have chloroplasts which perform photosynthesis.

•Plant cells have a large central vacuole.

LEARNING BIOLOGY!

• http://www.pixton.com/comic/p62dxv9o

LABEL YOUR ANIMAL CELL

LABEL YOUR PLANT CELL

CAN YOU SEE THE…

• Cell wall

• Chloroplasts

• Cell membrane

• Nucleus

CAN YOU SEE THE…

• Cell wall

• Chloroplasts

• Cell membrane

• Nucleus

CAN YOU SEE THE…

• Cell wall

• Chloroplasts

• Cell membrane

• Nucleus

THE IMPORTANCE OF CELLS

• Think about every time you need energy to move your cells have to actively be working so that you can move.

• Think about every time you breathe in your individual cells have to take in oxygen and use it to make energy.

• All of our energy needs are met by small tiny parts of our body that we barely even think of.

OUR CELLULAR NEEDS ARE MET BY TISSUES AND ORGANS

•Cells need

• AIR

•FOOD

•to have their WASTE REMOVED

•These needs are met

by…• Lungs provide oxygen to blood,

blood gives oxygen to cells

•Digestive system breaks down food into small pieces that enter cells

•Organs like the liver and kidneys filter and clean our bodies from waste

WHAT GOES IN AND WHAT GOES OUT…

•Diffusion is the movement of molecules from a high concentration to low concentration.

•Diffusion does not require energy use. It’s like riding your bicycle downhill. You still get somewhere and you still move but you don’t have to use the pedals.

WHAT CAUSES DIFFUSION?

•Molecules are always moving. As they move, the molecules bump into one another. The more molecules there are in an area, the more collisions there will be.

•Collisions cause molecules to push away from one another.

•Over time, the molecules of a substance will continue to spread out.

WHICH WAY WILL THE MOLECULES MOVE?

High concentration of RED

STUFF

LOW concentration of RED

STUFF

WHICH WAY WILL THE MOLECULES MOVE?

High concentration of RED

STUFF

LOW concentration of RED

STUFFThe molecules will move to a less crowded

place

OSMOSIS

•Definition: diffusion of WATER through a membrane

•Requires NO energy

•Does water move from high to low concentrations, or low to high concentrations?

• This is important when plants regulate their water supplies.

•Red blood cells can burst if they don’t use osmosis correctly.

DIFFUSION AND OSMOSIS

•What’s the difference between diffusion and osmosis?

•Membranes only allow some substances in or out of a cell. This means these membranes are SEMI-PERMEABLE.

OSMOSIS – HOW WILL WATER MOVE?

There’s water in the cell and water outside it. Remember, only

water can move.

The inside of the cell is crowded with water.

There is a higher proportion of water to

plus sign outside the cell than inside.

OSMOSIS – HOW WILL WATER MOVE?

Water goes OUT of the cell

We’re trying to get an equal ratio of water to not water both inside and outside the cell.

Water is the only thing that can move in osmosis, so it will move to where there’s less water.

OSMOSIS – HOW WILL WATER MOVE?

Water goes OUT of the cell

We’re trying to get an equal ratio of water to not water both inside and outside the cell.

Water is the only thing that can move in osmosis, so it will move to where there’s less water.

OSMOSIS – HOW WILL WATER MOVE?

OSMOSIS – HOW WILL WATER MOVE?

Water goes INTO the cell

We’re trying to get an equal ratio of water to not water both inside and outside the cell.

Water is the only thing that can move in osmosis, so it will move IN, where there’s less water.

OSMOSIS – HOW WILL WATER MOVE?

Water goes INTO the cell

We’re trying to get an equal ratio of water to not water both inside and outside the cell.

Water is the only thing that can move in osmosis, so it will move IN, where there’s less water.

OSMOSIS IN PLANT AND ANIMAL CELLS

OSMOSIS IN REAL CELLS

DIFFUSION AND OSMOSIS

•Do diffusion and osmosis require energy?•PASSIVE TRANSPORT – movement of molecules from a more crowded area to a less crowded area (requires no energy)

•ACTIVE TRANSPORT - Movement of molecules from a less crowded area to a more crowded area (requires energy)

DIFFUSION AND OSMOSIS

•Diffusion and osmosis are both types of passive transport.

TRANSPORT WITHIN CELLS

Plants only have this structure. It provides a skeleton for the plant to stand up and provide support

Plants only have this structure. Inside of each chloroplast is clorophyll that captures sunlight and makes it into energy

CAN YOU SEE ANY DIFFERENCES?