Biology Chapter 7.1

What can life be found in the form of?

What can life be found in the form of?

Single and multicellular organisms.

Robert Hooke (1665)

First to describe cells when looking at cork (plant) cells with a microscope.

Anton Van Leeuwenhoek (1673)

First to observe protists in pond scum, as well as blood cells, bacterial cells, and yeast cells. Said that cells are the basic unit of life.

Matthias Schleiden (1838)

Said that all plant parts are made of cells.

Theodor Schwann (1839)

Said that animal tissues are made of cells. He also covered nerve cells.

What is the cell theory?

All living things are made up of cells, cells are the basic units of structure and function in living things, new cells are produced from existing cells

Describe a light microscope.

• Light passes through a specimen.

• Two lenses form an image.

What are the problems with a light microscope?

• Only magnifies up to 1000x.

• Cells appear transparent.

• Dyes or stains are needed to help see structures.

Describe an electron microscope.

• Beams of electrons focused by magnetic fields.

• Reveal details 1000 times smaller than a light microscope.

• Can only visualize nonliving, preserved cells and tissue.

All cells are microscopic except?

Amoeba and human egg cells.

What is cell size caused by?

Nutrient and waste needs.

Define organelles.

Little organs; they are structures that perform specific functions within the cell.

Define DNA.

Genetic material codes for the production of cell structures and proteins.

What are the characteristics of a prokaryote?

Small and simple, no nucleus.

What is an example of a prokaryote?

Bacteria.

What are the characteristics of a eukaryote?

Have a nucleus and many other membrane-bound organelles. Some single celled beings (amoeba) and many multi celled beings.

What are examples of a eukaryote?

All plants, animals, fungi, and protists.