Unit 1 Vocabulary

Question 1

Cell Organelle

Answer 1

A specialized structure that performs important cellular functions within a cell.

Question 2

Cell Theory

Answer 2

The fundamental concept of biology that states that all living things are composed of cells; that cells are the basic units of structure and function in living things; and that new cells are produced from existing cells.

Question 3

Eukaryote

Answer 3

An organism whose cells contain a nucleus.

Question 4

Homeostasis

Answer 4

Relatively constant internal physical and chemical conditions that organisms maintain.

Question 5

Prokaryote

Answer 5

A unicellular organism that lacks a nucleus.

Question 6

Virus

Answer 6

A particle made of protein, nucleic acids, and sometimes lipids that can replicate only by infecting living cells.

Question 7

Cells

Answer 7

The basic units of all forms of life.

Question 8

Theodor Schwann

Answer 8

In 1839, he stated that all animals are made of cells.

Question 9

Rudolf Virchow

Answer 9

In 1855, he published the idea that new cells can be produced only from the division of existing cells.

Question 10

Anton Van Leeuwenhoek

Answer 10

In the mid 1660s, he used a single-lens microscope to observe pond water and other things, and discovered a fantastic world of tiny living organisms that seemed to be everywhere.

Question 11

Robert Hooke

Answer 11

In 1665, he, an Englishman, used an early microscope to look at a nonliving slice of cork.

Question 12

Organism

Answer 12

A living thing that has an organized structure, can react to stimuli, reproduce, grow, adapt, and maintain homeostasis.

Question 13

Compound Microscope

Answer 13

A microscope that uses multiple lenses to enlarge the image of a sample.

Question 14

Transmission Electron Microscope

Answer 14

A microscope that uses a particle beam of electrons to visualize specimens and generate a highly-magnified image.

Question 15

Nucleus

Answer 15

The center of an atom, which contains the protons and neutrons; in cells, the structure that contains the cell’s genetic material in the form of DNA.

Question 16

Microscope

Answer 16

It is an instrument that can be used to observe small objects, even cells.

Question 17

Objective Lens

Answer 17

It gathers light from the specimen, magnifies the image of the specimen, and projects the magnified image into the body tube; the lens in a microscope nearest to the object being observed.

Question 18

Ocular Lens

Answer 18

The lens on a microscope closest to the eye. Also known as eyepiece.

Question 19

Matthias Schleiden

Answer 19

In 1838, he concluded that all plants are made of cells.

Question 20

Scanning Electron Microscope

Answer 20

It scans a focused electron beam over a surface to create an image. The electrons in the beam interact with the sample, producing various signals that can be used to obtain information about the surface topography and composition.

Question 21

Stimulus

Answer 21

A signal to which an organism responds.