Cells

What did Robert Hooke call the boxes that he observed in cork?

Why should I care?

So, what is a cell?

Smallest functional unit that can support life

A bacterium is only one self-sustaining cell

You are made up of trillions of

interdependent cells

Too small to see without a microscope

Problem? Miss Apgar wants to view a bacterial cell that

needs to be magnified 1000 times in order to see it. Her compound light microscope has a 10X ocular lens. Which objective lens should she use to see the bacterium? _____________ Where is the ocular lens? ____________________ Where is the objective lens? _________________

What do we remember about microscope history? Robert Hooke

Named the cell Cell – Structural and functional unit of life

Made sketches of the

microscopic world

Anton van Leeuwenhoek Perfected a single

lens microscope

Examined water and milk

Called creatures he saw “cavorting wee beasties”

Some More History Matthias Schleiden

Studied plants Determined that all

plants are made of cells

Theodor Schwann Studied animals Determined that all

animals are made of cells

Some More History Rudolf Virchow

German physician Proposed that cells

divide to form new cells

Used his theory to diagnose patients

Father of pathology

Cell Theory - putting their work together

All organisms are made of cells It can be one solitary cell or many cells working

together

The cell is the basic unit of organization in living organisms

Even in complex organisms like humans, the cell is the basic unit of life

All cells come from pre-existing cells Cells grow and divide, passing genetic

information to the next generation of cells

How do we know that cells come from other cells?

Two types of cells… Prokaryotic cells

Simple interior Considered to be the prototype

Eukaryotic cells Complex interior Considered to be the latest update

Prokaryotes Simple interior DNA in central nucleoid region Cellular functions happen in open space Single cell organisms

Bacteria Archaea

Inside a Prokaryote

The cytoplasm is where cell life takes place

DNA is concentrated in the nucleoid region

Ribosomes make proteins

The Flagellum provides transportation

Capsule, cell wall, and cytoplasmic membrane provide protection and support

Eukaryotes Complex interior

DNA is neatly packaged and protected by nucleus

Organelles perform cellular functions

Single and multiple cell organisms Amoebas – single celled

You are a EU-karyote

4 Kingdoms Animalia

Plantae

Fungi

Protista

Inside a Eukaryote

The cytoplasm is where the organelles are located

DNA is housed in the nucleus

Ribosomes make proteins

There are many other organelles each covered by a membrane

Each organelle has its own function

Cytoplasmic membrane provides protection

Venn Diagram Time… turn to page 18!

Prokaryotic Cells Eukaryotic Cells

Your task now… Look on page 11 in your packet

Read “The Origin of the Eukaryotic Cell” (pgs 19-20) Answer questions pages 21 and 22

Homework if you do not finish!!

More on the Eukaryote cell

Important terminology DNA – genetic material

Organelle – cellular

structures that carry out

specific functions

Means “little organ”

Let’s break it down…

First up: the plasma membrane

The Cell Membrane The cell membrane is selectively permeable

Some things can pass but others can’t Cell membranes are made from a phospholipid

bilayer

Phospholipid Bilayer Structure Each phospholipid has a polar head and two

nonpolar tails Polar head is attracted to water Nonpolar tails are repelled by water

Outside of cell

Inside of cell (cytoplasm)

Cell membrane

Proteins

Protein channel Lipid bilayer

Carbohydrate chains

Phospholipid Bilayer Function

Allows some things in and not others

Polar molecules do not easily pass

H2O is an exception because it is small

Keeps the outside out and the inside in

The plasma membrane is always in

motion

Fluid Mosaic Model Fluid

Membrane is in motion Membrane is flexible

Mosaic There are molecules embedded in the bilayer The scattered arrangement looks like a mosaic

Animal Cells vs. Plant Cells Eukaryotic cell which

makes up tissues in animals

Lack cell walls and chloroplasts, and have smaller vacuoles.

Appears to be circular because of the lack of a rigid cell wall.

Eukaryotic cell that makes up plants

Cell Wall Chloroplast Large Vacuoles

Animal Cell

Plant Cell

Cell Wall – plant cell only Mesh of fibers that surrounds the plasma

membrane Protects and supports the cell Made of carbohydrate, cellulose

Cytoplasm Semi-fluid material inside the plasma

membrane Consists of cytosol and the cellular organelles

(all organelles except the cell nucleus) Cytosol - fluid in which the cellular

organelles are suspended

Cytoskeleton Network of long, thin protein

fibers provide an anchor for organelles

Microtubules-long hollow cylinders that assist in moving substances within the cell

Microfilaments-thin threads that give the cell shape and enable the cell to move

Cytoskeleton in Red and Green

Nucleus

Contains genetic material (DNA)

Nuclear envelope

Nuclear pores allow

substances in and out

Nucleolus in center

Very dense center

Ribosomes Produce proteins Made of RNA and protein Made in the nucleolus Some float freely in the cytoplasm Others attach to endoplasmic reticulum

Endoplasmic Reticulum

Interconnected network of tubules

Two types of Endoplasmic Reticulum

Rough ER

Where ribosomes attach and make proteins

Appear to create bumps and rough areas on the membrane

Smooth ER

No ribosomes Produces complex

carbohydrates and lipids

Golgi Apparatus

Modifies, sorts, and packs proteins in sacs called vesicles

Vesicles fuse with plasma membrane

They release proteins which move through membrane to get outside of the cell

Vacuoles Temporary storage for

materials in the cytoplasm

Store, transport, or digest food and waste

Plant cells – 1 large vacuole

Animal cells – several little vacuoles

Lysosomes

Vesicles that contain digestive enzymes to digest excess or worn-out organelles and food particles

They also digest bacteria and viruses that enter the cell

They are built in the Golgi apparatus.

Centrioles Made of Microtubules Found near nucleus Animal Cells only Assembled right before

replication Aid in cell replication

Mitochondria

Powerhouse Converts organic materials into energy

ATP Outer and inner membranes

with lots of folds Provides large surface

area to break sugar molecule bonds (produce energy)

Chloroplasts- Plant only

Capture light energy and convert it to chemical energy through photosynthesis

Photosynthetic Animals 2010 - found an animal that makes proteins

essential for photosynthesis Elysia chlorotica – sea slug that looks like a giant swimming

leaf Stole chloroplasts from algae it eats can live up to 9 months

without eating Appears green because of

stolen chlorophyll

Lives - Eastern coast of the United States and Canada

Cilia and Flagella

Cilia- short, hair-like projections Move back and forth like oars on a rowboat Move substances along surface of the cell

Flagella- rather long hair-like projections Whip-like motion

Both are composed of microtubules

Move cells through watery environment

Cell Transportation Passive transport

Does not use energy

Goes with the concentration gradient

3 types diffusion facilitated diffusion osmosis

Active Transport Requires energy Goes against the

concentration gradient Endocytosis Exocytosis

Cell Transport Diffusion -net movement of

particles from high concentration to low concentration Doesn’t require energy

because the particle are in motion passive transport

Dynamic equilibrium- the overall concentration does not change, but molecules are still moving randomly

What affects the rate of diffusion?

What makes molecules move faster? High temperature High Pressure High concentration

Facilitated Diffusion Some ions and molecules can’t diffuse across the

cell membrane Facilitated diffusion – uses transport proteins to help

move some molecules across the plasma membrane

Osmosis

Osmosis – diffusion of water Most cells undergo osmosis because

they are surrounded by water

Hyper—Hypo– Iso tonic Solutions These are comparing words

Hypertonic -more solute Hypotonic- less solute Isotonic- same solute as

What would happen if you Put a red blood cell in a hypertonic solution Put a red blood cell in a hypotonic solution Put a red blood cell in an isotonic solution

Active Transport

Goes from low to high concentration

Requires Energy ATP

Moves large substances

Endocytosis Endocytosis- moving large substances into the cell

Exocytosis

Exocytosis- moving large substances out of the cell