Transcript Cells - Acpsd.net

Cells:
The Building Blocks of Life
The Cell
• The cell is the smallest form of life
• They are the “building blocks of life”
• There are two types of cells: Prokaryote and Eukaryote
The Discovery of Cells
• Cell theory was articulated in the mid-1800s
by Schleiden, Schwann and Virchow.
– All organisms are composed of one or more cells.
– The cell is the structural unit of life.
– Cells arise from pre-existing cells by division.
Basic Properties of Cells
Cells have ALL of the properties of life:
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Cells are complex and organized
Cells have genetic material
Cells can reproduce
Cells need energy
Cells carry out a variety of chemical reactions
Cells engage in mechanical activities (movements)
Cells are able to respond to stimuli
Cells are capable of self-regulation
Cells evolve and change over time
Eukaryote
• Complex cells
• Animals, plants, fungi, and protists
Prokaryote
• Single celled, like bacteria
• Has no nucleus
• DNA packed in area cytoplasm called nucleoid
region
Prokaryotes vs. Eukaryotes
Prokaryotes
Eukaryotes
Cytoplasm
No membrane-bound
organelles and no
cytoskeleton.
Membrane-bound
organelles.
Cellular reproduction
Divide by simple fission
Divide by mitosis.
Locomotion
Have flagella
Use both cilia and flagella
• Single cell organelle
More complex in structure
Complexity
Relatively simple
and function
• Has no nucleus In nucleoid region
In nucleus
• Genetic
DNAInformation
packed in area
cytoplasm called
nucleoid
Less genetic material
Much more genetic material
region
Organelles: small functional units
within cells. Each mini-organ has a
special job in the cell
The Nucleus
• The nucleus regulates all cell
activity
• It houses the DNA, keeping it
intact
• It controls cell division
Cytoplasm
• Jellylike material (cytosol and organelles),
most of the cell's chemical reactions take
place there
• Made up of mostly water and some chemicals.
• Contains amino acids and proteins.
Mitochondria
• Produce energy when food is broken down,
often called the "powerhouse of the cell".
• Makes energy in the form of adenosine
triphosphate or (ATP)
Lysosomes
• Digests food particles with enzymes
Chloroplast
• Found only in plant cells.
• Found in the cytoplasm of green plant cells,
contain chlorophyll, traps the energy from light.
• Where photosynthesis takes place.
Vacuoles
• Storage
• Remove unwanted waste
• Central vacuoles in plant cells are larger than
vacuoles in animal cells
Ribosomes
• Where proteins are made
• A cell may have as many as 500,000 ribosomes
Endoplasmic Reticulum
• The "transportation system" in the cell,
connects the nuclear membrane with the cell
membrane.
• There are 2 types of ER: smooth and rough
Smooth Endoplasmic Reticulum
• Tubes that function in:
– metabolism of carbohydrates
– calcium storage
– detoxification of the cell.
Rough Endoplasmic Reticulum
• the site of protein synthesis
• being involved in protein sorting and
packaging
Golgi Apparatus
• Flat stacks that package and secrete waste
from cell.
Cilia
• Sticky, hair-like fibers that move in waves to
help the cell move
Flagella
• Whip–like tail that extends from the cell
• Longer than cilia
Cell Membrane
• Skin-like barrier between cell and the
outside world.
• The cell membrane is called a lipid bilayer (it
is made of 2 layers of lipid)
Cell Membrane
• Three main functions:
– gives the cell shape
– holds the cytoplasm and organelles together
– controls what moves into and out of the cell
Microtubles and Microfilaments
• Make the cell more rigid.
• Involved in cell division and transport within
the cell.
Centrioles
• Paired cylinder-shaped organelles near nucleus
• Involved in cellular division
Cell Wall
• Forms a thick outer covering outside the cell
membrane
• Gives the plant support and shape
• ALL CELLS HAVE A CELL MEMBRANE, but only plant
cells and prokaryotic cells can have a cell wall
Capsule
• Protective covering outside the cell wall of bacteria
• Helps bacteria cells stick to surfaces
Nucleoid Region
• Region of genetic material in a
prokaryotic cell.
Prokaryotes
Both Prokaryotes and
Eukaryotes
Eukaryotes
Plant Cells
Only
 Capsule
 Nucleoid
Region
Flagellum (not
plants)
Cell Wall (not
animals)
Ribosomes
Cell Membrane
Cytoplasm
Cilia
Chloroplasts
Both Plant and Animal Cells
Nucleus
Rough Endoplasmic Reticulum
(RER)
Smooth Endoplasmic
Reticulum (SER)
Mitochondria
Microtubules and
Microfilaments
Golgi Complex
Vacuoles
Animals Cells
Only
 Lysosome
 Centrioles
Prokaryotes
Both Prokaryotes and
Eukaryotes
Eukaryotes
Plant Cells
Only
Both Plant and Animal Cells
Animals Cells
Only