Cell structure and function
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Cell Structure and Function. Cell Discovery and Theory. The Cell. A cell is the basic unit of structure and function Humans have trillions and trillions of cells You can’t see cells with the naked eye. Cell Dudes. Robert Hooke- 1665

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Cell Structure and Function

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Cell structure and function

Cell Structure and Function

Cell Discovery

and

Theory


The cell

The Cell

  • A cell is the basic unit of structure and function

    • Humans have trillions and trillions of cells

    • You can’t see cells with the naked eye


Cell dudes

Cell Dudes

  • Robert Hooke- 1665

    • Looked at cork, saw little box-shaped structures and called it cellulae

  • Anton van Leeuwenhoek- late 1600s

    • Looked at pond water and milk and saw

      “beasties”


Cell dudes1

Cell Dudes

  • Matthias Schleiden- 1838-botanist

    • Studied plants and concluded that all plants are made of cells

  • Theodor Schwann- zoologist

    • Concluded that all animal tissues were made of cells

  • Rudolph Virchow- Suggested that cells come from cells


How do we know cells come from other cells

How do we know cells come from other cells?


Problem

Problem?

  • A compound light microscope has a 10X ocular lens and a 460X objective lens.

    • Where is the ocular lens? ____________________

    • Where is the objective lens? _________________

    • What is the total magnification ___________X


Prokaryotes

Prokaryotes

  • 2 Kingdoms

    • Eubackteria

    • Archeabacteria

  • No nucleus

  • DNA in a central nucleoid

    region

  • Contains ribosomes

  • First organisms on earth


Eukaryotic cells

Eukaryotic Cells

  • 4 Kingdoms

    • Protist (single celled)

    • Plants (cell wall/chloroplasts)

    • Animals (lack cell wall/lack chloroplasts)

    • Fungi (cell wall/lack chloroplasts)

  • Contain membrane bound organelles

    • Organelles are specialized structures that carry out functions


The cell membrane

The Cell Membrane

  • The cell membrane is selectively permeable

    • Some things can pass but others can’t

  • Cell membranes are made from a phospholipidbilayer


Phospholipid bilayer structure

Outside

of cell

Carbohydrate

chains

Proteins

Cell

membrane

Inside

of cell

(cytoplasm)

Protein

channel

Lipid bilayer

PhospholipidBilayer Structure

  • Each phospholipid has a polar head and two nonpolar tails

    • Polar head is attracted to water

    • Nonpolar tails are repelled by water


Phospholipid bilayer function

PhospholipidBilayer Function

  • The function is to let some things in and not others

    • Polar molecules do not easily pass

      • H2O is an exception because it is small

      • Allows membrane to separate environment inside from outside the cell

    • The plasma membrane is always in motion

      • Fluid mosaic model


Animal cells plant cells

Animal Cells/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

Animal Cell


Plant cell

Plant Cell


Cytoplasm

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

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

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

Ribosomes


Endoplasmic reticulum

Endoplasmic Reticulum

  • Interconnected network of tubules

  • 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

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

Vacuoles

  • Act as temporary storage unit for materials in the cytoplasm

  • Store, transport, or digest food and waste

  • Plant cells have one large one

  • Animal cells have little ones


Lysosomes

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

Centrioles

  • Microtubules

  • Found near nucleus

  • Animal Cells only

  • Aid in cell replication


Mitochondria

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

Chloroplasts- Plant only

  • Capture light energy and convert it to chemical energy through photosynthesis


Cell wall

Cell Wall

  • Mesh of fibers that surrounds the plasma membrane

  • Protects and supports the cell

  • Made of carbohydrate, cellulose


Cilia and flagella

Cilia and Flagella

  • Cilia- short projections that look like hairs

    • Move back and forth like oars on a rowboat

    • Move substances along surface of the cell

  • Flagella- longer projections that move in a whip-like motion

  • Both are composed of microtubules

  • Move cells through watery environment


Cell transport

Cell Transport

  • Diffusion -net movement of particles from high concentration to low concentration

    • Doesn’t require energy because the particle are in motion

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


What affects the rate of diffusion

What affects the rate of diffusion?

  • What makes molecules move faster

    • High temperature

    • High Pressure

    • High concentration


Facilitated diffusion

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

  • Osmosis – diffusion of water

  • Most cells undergo osmosis because they are surrounded by water


Hyper hypo iso tonic

Hyper—Hypo– Iso tonic

  • These are comparing words

    • Hypertonic -more solute than

    • Hypotonic- less solute than

    • 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

Active Transport

  • Goes from low to high concentration

  • Requires Energy

    • ATP

  • Moves large substances


Endocytosis

Endocytosis

  • Endocytosis- moving large substances into the cell


Exocytosis

Exocytosis

  • Exocytosis- moving large substances out of the cell


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