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Introduction to the Cell Ch.3 in online textbook.

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Introduction to the Cell Ch.3 in online textbook
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Page 1: Introduction to the Cell Ch.3 in online textbook.

Introduction to the Cell

Ch.3 in online textbook

Page 2: Introduction to the Cell Ch.3 in online textbook.

Discovery of Cell

• Robert Hooke – looked at cork cells and saw tiny units of life named them cell.

• Leeuwenhoek – invented a microscope to look at cells.

Page 3: Introduction to the Cell Ch.3 in online textbook.

The Cell Theory

• Schwann and Schleiden• Proposed:– All living things are made of cells.– Basic building blocks of life.Virchow discovered:- Cells come from other cells.

- These scientists came up with the cell theory.

Page 4: Introduction to the Cell Ch.3 in online textbook.

Cell Theory states:

• All organisms are made of one or more cells.• All the life functions of organisms occur within

cells.• All cells come from already existing cells.

Page 5: Introduction to the Cell Ch.3 in online textbook.

Microscopes

• Light microscopes – view organisms by shining light through them. Must be a small slice of the organism.

• Electron microscope – uses a beam of electrons to observe extremely small objects.– Allowed scientists to see

organelles.

Page 6: Introduction to the Cell Ch.3 in online textbook.

Cell size• To carry out cell functions they must be able

to quickly pass substances into and out of cell.• Anything that enters or leaves a cell must

cross its outer surface.• This limits how large a cell can be.

Page 7: Introduction to the Cell Ch.3 in online textbook.

Surface Area : Volume

• The larger the cube (cell) the smaller surface area to volume ratio.

• Cells can’t get too large because they need enough surface area on the cell membrane to allow substances in and out.

Page 8: Introduction to the Cell Ch.3 in online textbook.

Cell Shape

• Cells with different functions have different shapes.

• Function determines shape.

Page 9: Introduction to the Cell Ch.3 in online textbook.

Parts of all cells• The plasma membrane (also called the cell membrane)

is a thin coat of lipids that surrounds a cell. It forms the physical boundary between the cell and its environment, so you can think of it as the “skin” of the cell.

• Cytoplasm refers to all of the cellular material inside the plasma membrane. Cytoplasm is made up of a watery substance called cytosol and contains other cell structures such as ribosomes.

• Ribosomes are structures in the cytoplasm where proteins are made.

• DNA is a nucleic acid found in cells. It contains the genetic instructions that cells need to make proteins.

Page 10: Introduction to the Cell Ch.3 in online textbook.

Two Types of Cell

• Prokaryotic cells are cells without a nucleus. The DNA in prokaryotic cells is in the cytoplasm rather than enclosed within a nuclear membrane.

• Eukaryotic cells are cells that contain a nucleus.

Page 11: Introduction to the Cell Ch.3 in online textbook.
Page 12: Introduction to the Cell Ch.3 in online textbook.
Page 13: Introduction to the Cell Ch.3 in online textbook.

Organelle

• Structure within the cytoplasm that performs a specific job in the cell.

Organelles:Mitochondria ChloroplastNucleus LysosomeVacuole Cell membraneSmooth Endoplasmic ReticulumRough Endoplasmic Reticulum Golgi Apparatus

Page 14: Introduction to the Cell Ch.3 in online textbook.

Viruses

• Contain DNA• Lack the other parts

shared by all cells like, plasma membrane, cytoplasm, and ribosomes.

• Viruses are not cells.• They are not considered

living, but its debatable in the science community.

Page 15: Introduction to the Cell Ch.3 in online textbook.
Page 16: Introduction to the Cell Ch.3 in online textbook.

Cell Structures

Page 17: Introduction to the Cell Ch.3 in online textbook.

Plasma Membrane

• Forms a barrier between the cytoplasm inside the cell and the outside.

• Protects and supports the cell and controls everything that enters and leaves the cell.

• Allows only certain substances to pass through, while keeping others in or out.

Page 18: Introduction to the Cell Ch.3 in online textbook.

Phospholipid bilayer

• Molecule with a head and two tails.• Head “loves” water, hydrophilic.• Tails “hate” water, hydrophobic.

Page 19: Introduction to the Cell Ch.3 in online textbook.

Crash course – the cell

• https://www.youtube.com/watch?v=cj8dDTHGJBY


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