Cell Structure & Function

Famigletti

TEKS 7.12D) Differentiate between structure and function in plant an animal cell organelles including cell membrane, cell wall, nucleus, cytoplasm, mitochondrion, chloroplast & vacuole

E) Compare the functions of a cell to the functions of organisms such as waste removal

F) Recognize that according to cell theory all organism are composed of cells and cell carry on similar functions such as extracting energy from food to sustain life

• The Cell Theory grew out of the work of many scientists and improvements in the microscope.

Scientists that contributed to the Cell Theory: Hooke: Leeuwenhoek: Schleiden: Schwann: Virchow:

• Early studies led to the development of the cell theory.

The Cell theory has three principles.1. All organisms are made up of cells2. All existing cells are produced by other living cells3. The cell is the most basic unit of lif e

Two Types of Cells

•Prokaryotic•Eukaryotic

Cells are the basic unit of lifeall living things share the following

characteristics:

• Growth• Response to environment• Reproduce• Get & use energy• Get rid of waste• Adapt to changes

There are two cell types: Prokaryotic cells and Eukaryotic cells.

All cells share certain characteristics.

1. All cells are enclosed by a membrane

2. All cells are fi lled with cytoplasm; a jellylike substance that holds things

Bacterium(colored SEM; magnification 8800x)

cell membrane

cytoplasm

Prokaryotic

Pro- NO

• NO nucleus

• NO-membrane bound organelles

• Few internal structures

• One-celled organisms, Bacteria

http://library.thinkquest.org/C004535/prokaryotic_cells.html

Eukaryotic

Eu- YOU• Contain organelles surrounded by membranes,

including nucleus! • Most living organisms including plants & animals

Plant Animal

http://library.thinkquest.org/C004535/eukaryotic_cells.html

“Typical” Animal Cell

http://web.jjay.cuny.edu/~acarpi/NSC/images/cell.gif

http://waynesword.palomar.edu/images/plant3.gif

“Typical” Plant Cell

Examples of CellsAmoeba Proteus

Plant Stem

Red Blood Cell

Nerve Cell

Bacteria

Which is the prokaryote?

Bacteria!

Internal Structures& their functions

Cell Membrane

• Outer membrane of cell that controls movement in and out of the cell

• Cell membrane protects and separates the rest of the cell from external environment.

• Double layer that only allows specific things through

http://library.thinkquest.org/12413/structures.html

The cell membrane is a barrier that separates a cell from the external environment.

Cytoplasm• Jelly-like substance

• Is everywhere inside the cell membrane and outside the nuclear membrane

• Cytoplasm important for cell structure

• Water allows chemical reactions to occur

• Provides medium for chemical reactions and movement between organelles

• Cytoskeletonhas many f unctions1. Microtubules give

cells shape; move DNA

2. I ntermediate fi laments, give cells strength

3. Microfi laments allow cells to move and divide

Cytoskeleton

Centrosome and Centrioles

• Specialized parts of the cytoskeleton

• Centrioles are tubes found in the centrosomes

• Centrioles help divide DNA during mitosis.

• Centrosomes make microtubles which make spindle fibers

NucleusStores genetic information

• Nuclear envelope – double membrane that encloses DNA

• Nuclear Pores –

• Nucleolus – contains tiny organelles f or making proteins

Endoplasmic Reticulum

Series of folded membranes“I ntracellular Highway”

Many processes occur on surface and lumen (interior of membranes)

ex: Production of proteins and lipids

Endoplasmic Reticulum• There are two types:

– Rough Endoplasmic Reticulum (R.E.R.): contain ribosomes

– Smooth Endoplasmic Reticulum (S.E.R.): no ribosomes

Lumen

Ribosome's link amino acids to f orm proteins

Made of protein and RNA

Made in nucleolus; leave through nuclear pores

Ribosome

Golgi Apparatus

• Closely stacked membranes• Package, Sort, and Processes

Proteins f rom the E.R.

Mitochondria• Supply energy to the cell

• Consists of two membranes; inner membrane has lots of folds, Why?

• Have their own DNA and ribosomes

• Fluid-fi lled sacs used f or storage• Central vacuole unique to plant cells

– plants shrivel when central vacuoles don’t have enough water

– Can contain toxins that help the plant survive

Vacuoles

• Contain enzymes inside to digest material; defend cell f rom invading bacteria and viruses

• Surrounded by a membrane; protects cell f rom being broken down

Lysosomes

Plant cellsHave TWO features Animal Cells Do Not

Cell wall: gives protection, support, and shape to cell

Chloroplasts: organelles that perform photosynthesis

Cell Structure & function• Animal cells have various structures so that

they may perform their individual functions to the best of their ability

Neuron• The unique structure of the neuron is

dedicated to the efficient and rapid transmission of neural signals.

Red blood cells• Red blood cells lack a nucleus which

helps them to squeeze through tight capillary spaces

Cell Movement• Some cells have structures to hel them

to move.• These structures are cytoskeleton

extensions, called cilia or flagella.