Cells and Their Environment for web

Cells and Their Environment

A) Cell Theory

• Cells are the fundamental unit of LIFE

–Cells are the smallest thing that can be called alive

• All Cells come from pre-existing cells• All Cells come from pre-existing cells

• Cells have genetic information from parents

• Organisms must have at least one cell

Prokaryotic

Cell

Eukaryotic cell

Eukaryotic Cells:

Animal cell organelles and characteristicsNucleus Endoplasmic reticulumGolgi apparatus MitochondriaLysososmes

Animal cells do not have a specific shape, and are

often drawn or seen as roundoften drawn or seen as round

Plant cell organelles and characteristicsNucleus Endoplasmic reticulumGolgi apparatus MitochondriaLysososmes Cell wallVacuole chloroplastPlant cells are often seen as square or structured

Nucleus

Stores genetic material-DNAServes and the control center for the cell

Nucleolus

located inside the nucleusresponsible for making ribosomes

Ribosomes

-manufactures proteins – Site of Protein

Synthesis

-it is not membrane bound- it is made of rRNA

Endoplasmic Reticulum ( ER)

-manufactures both lipids and proteins- uses vesicles to transport products to other parts of the cell

Two Types

Smooth ER – no Smooth ER – no

ribosomes���� lipids

Rough ER- w/

ribosomes ���� proteins

Golgi Apparatus ( Bodies)

-packages and ships “goods” from the ER

- processes vesicles and directs their delivery

around the cell or prepares them for excretion

Lysosome

-digests and recycles used “old” organelles and digests food particles coming into the cell, full of digestive enzymes

Mitochondria

-Converts food into energy ( key component to your metabolism )-Contains its own piece of circular DNA (mtDNA)

-Glucose + Oxygen enzymes CO2 + H2O + Energy ( ATP)

Cytoplasm

-gelatinous matrix that holds organelles in

place –mainly water

E ) Cell Structure – Organelles Found Only in Plants

Cell Wall

-hard support structure that surrounds the

cells of all plants

-composed of a polysaccharide –Cellulose

(Fiber���� weee)

Central Vacuole

-storage device for the cell, holds excess water and food

-takes up the majority of a plant cell

Chloroplast

-Structure inside the cell that uses sunlight to turn inorganic compounds into carbohydrates -Sunlight into food-Contains the green pigment – Chlorophyll

-CO2 + H2O Sugar + Oxygen Sunlight

-Has its own set of circular DNA

Which cells in your Which cells in your Which cells in your Which cells in your

body have more body have more body have more body have more body have more body have more body have more body have more

mitochondria?mitochondria?mitochondria?mitochondria?

Cell Structure -- Organelles For Plants and Animals

B) Cell Membranemultiple names

Controls what comes into the cell and what goes out, →it is said to be selectively permeable (lets some things in and keeps others out).→cell membrane is fluid, pieces move around freely

this is called the fluid-mosaic model

•plasma membrane•phospholipid bilayer•lipid bilayer

this is called the fluid-mosaic model

Cell Specialization

All cells are not the same, cells differ in

shape and size depending upon their

particular function in the body

Ex. Stem Cell – a cell Cell – a cell

that can

become any

other cell in

the body

Red Blood Cells –Carry oxygen throughout the body, no nucleus and are contain a protein called hemoglobin

White Blood Cell-Cells that are used to fight pathogens, leukocytes

Nerve Cells – carry electrical signals from the brain to

the parts of the body, use chemical messengers to

transmit signals from nerve to nerve or nerve to tissue

Nematocyst- stinging cell used to capture

prey and for defense in Cnidarians

Lipocyte – specialized cell used to store fat in

the body

Egg Cell-

specialized

haploid sex

cell, gamete,

used to carry

genetic

information,

ovum

Sperm

Cell-

Specializeovum

Specialize

d haploid

sex cell,

gamete

used to

care

genetic

information

E) Cell to Cell Communications (in your body!)

3 Main Methods are used for cells to communicate with

one another:

1.Autocrine- For cells that are in direct contact– Gap

Junctions

2._____- For cells that are close but not touching –

Chemicals like NeurotransmittersChemicals like Neurotransmitters

Ex: Epinephrine, Norepinephrine, Dopamine

3. Endocrine- For cells that are far away, signals

carried in bloodstream – Hormones

Ex : HGH, Testosterone, Estrogen,

Insulin, Adrenaline, Progesterone

F) Biological Membranes and Maintenance of Homeostasis Components of the

Plasma Membrane

Phospholipids –Two

layers, that float over one another

Channel Proteins –allow

large molecule to move into large molecule to move into and out of the cell

Receptor Proteins – used

to identify the cell type,

and allows for cell to cell

communication, through

the use of hormones etc

Maintaining Homeostasis- Passive Transport Osmosis and Diffusion

Passive Transport- movement of materials across

the cell membrane that does not require energy, only works for small molecules

Diffusion – the movement of materials down a concentration gradient from high concentrations to lower concentrationsgradient from high concentrations to lower concentrations

Osmosis- special type of diffusion, that only refers to water moving down a concentration gradient from high to low concentrations

Large molecules are trapped inside the cell, but water can move

freely into and out of the cell

Continued

For a cell to be happy or to be in equilibrium, the cell needs the same concentration of water on the inside of the cell as the outside of the cell

Solutions – homogeneous mixture of 2 or more

substances

Solvent – the stuff that dissolves ( Ex: Water)

Solute- the stuff that is being dissolved ( Ex: Salt)

Osmosis Animation

Types of Solutions - Hypertonic

More water inside the cell then outside the cell

Water moves out of the cell � cause the cell to shrink

Types of Solutions - Hypotonic

Hypo = Hippo

More water outside the cell then inside

Water moves into the cell causes it to swell

Types of Solutions - Isotonic

Same amount water inside the cell as outside

No net movement of water, water moves in and water moves

out but they balance each other out

http://www.youtube.com/watch?v=GbudKs-49jo

Maintaining Homeostasis- Passive Transport

Facilitated DiffusionFacilitated Diffusion-the assisted movement of material across

the cell membrane through the use of channel (membrane)

proteins -requires no energy

Maintaining Homeostasis- Active Transport

Active Transport – the assisted movement of larger molecules

across the cell membrane, through channel proteins. Molecules

move up the concentration gradient from low concentrations to higher concentrations, thus the process requires energy

EX: Sodium-Potassium Pump is required for proper nerve

functioning

Cell Transport - Endo/ Exocytosis

Process used by cells to import or export large

molecules into and out of the cell

Phagocytosis ( Cell Eating)- large objects, used to get

rid of pathogens and to absorb large molecules

Pinocytosis ( Cell Drinking)- used so the cell can obtain

solute and single molecules such as a proteinsolute and single molecules such as a protein

G ) Endosymbiotic Theory

Explains the origins of the mitochondria and the

chloroplast, as well as why they have their own

piece of circular DNA that is very similar to

bacterial DNA

Endosymbiotic Theory