ch.4 cell theory

Question 1

cell theory:

Answer 1

explain the observation that all organisms are composed of cells

Question 2

cell theory includes 3 principals:

Answer 2

1. all organisms are composed of one or more cells
2. cells are the smallest living things
3. cells arise only by division of a previously existing cell.

Question 3

the rate of diffusion is affected by 4 variables:

Answer 3

1. surface area available for diffusion
2. temperature
3. concentration gradient of diffusing substance
4. the distance over which the diffusion must occur

Question 4

the advantage of small cell size is readily apparent in terms of the _______ ____ - __ - ______ ______. As a cell’s size increases, its volume increases much more rapidly than its surface area.

Answer 4

surface area to volume ratio

Question 5

4 parts of cell structure:

Answer 5

1. nucleoid or nucleus
2. cytoplasm
3. ribosomes to synthesize proteins
4. plasma membrane

Question 6

in ________ the simplest organisms, this consists of a single circular molecule of DNA. It is found near the center of the cell in an area called the _________, which is not surrounded by a membrane.

Answer 6

prokaryotes, nucleoid

Question 7

______ cells are more complex, with DNA organized into linear chromosomes segregated into a ________, which is surrounded by a double-membrane structure called the ______ ________.

Answer 7

eukaryotic, nucleus, nuclear envelope

Question 8

a semifluid matrix called the _________ fills the interior of the cell. the _________ contains all of the sugars, amino acids, and proteins the cell uses to carry out its everyday activities.

Answer 8

cytoplasm, cytoplasm

Question 9

cytosol

Answer 9

=the fluid part of the cytoplasm, which contains organic molecules and ions in solution

Question 10

_______ are large, macromolecular machines composed of RNA and protein that synthesize all cellular proteins.

Answer 10

Ribosomes

Question 11

plasma membrane

Answer 11

=encloses a cell and separates its contents from its surroundings