Biology: Chapter 3

Question 1

cell theory

Answer 1

one of the first unifying concepts developed in biology summarized by accumulated research

Question 2

What are the three major principles of the cell theory?

Answer 2

1. All organisms are made of cells.
2. All existing cells are produced by other living cells.
3. The cell is the most basic unit of life.

Question 3

Name the five scientists who contributed to the cell theory.

Answer 3

Hook, Leeuwenhoek, Schleiden, Schwann, and Virchow

Question 4

cytoplasm

Answer 4

jellylike substance that contains dissolved molecular building blocks-such as proteins, nucleic acids, minerals, and ions

Question 5

organelles

Answer 5

structures specialized to perform distinct processes within a cell

Question 6

prokaryotic cell

Answer 6

HAVE NO nucleus or other membrane bound organelles

Question 7

eukaryotic cell

Answer 7

HAVE a nucleus and other membrane bound organelles

Question 8

cytoskeleton

Answer 8

network of proteins that is constantly changing to meet then needs of a cell in a eukaryotic cell

Question 9

nucleus

Answer 9

the storehouse for most genetic information, or DNA

Question 10

endoplasmic reticulum

Answer 10

an interconnected network of thin folded membranes that produce, process and distribute proteins

Question 11

ribosome

Answer 11

organelle that that link amino acids together to form proteins

Question 12

Golgi apparatus

Answer 12

closely layered stacks of membrane enclosed spaces that process, sort and deliver proteins

Question 13

vesicle

Answer 13

membrane bound sac that divides some materials from the rest of the cytoplasm and transports these materials from place to place

Question 14

mitochondrion

Answer 14

bean-shaped organelle that supplies energy to the cell and has its own ribosomes and DNA

Question 15

vacuole

Answer 15

fluid-filled sac used for the storage of materials needed by a cell, including water, food, or enzymes

Question 16

lysosome

Answer 16

membrane bound organelles that contain enzymes

Question 17

centriole

Answer 17

cylinder shaped organelle made of short microtubules arranged in a circle; aids mitosis

Question 18

cell wall

Answer 18

rigid layer that surrounds cell membrane and gives support, protection and shape to the cells of plants, algae and fungi

Question 19

chloroplast

Answer 19

organelle that carries out photosynthesis- a series of complex chemical reactions that convert solar energy into energy rich molecules that cell can use

Question 20

cell membrane

Answer 20

boundary that forms between a cell and the outside environment and controls the passage of materials into and out of the cells

Question 21

phospholipid

Answer 21

molecule that forms a double layered cell membrane; consists of glycerol, a phospate group and two fatty acids

Question 22

fluid mosaic model

Answer 22

model that describes the arrangement and movement of the molecules that make up a cell membrane

Question 23

selective permeability

Answer 23

property of the cell membrane that allows some, but not all, materials to cross it

Question 24

receptor

Answer 24

protein hat detects a signal molecule and performs an action in response

Question 25

passive transport

Answer 25

the movement of molecules across a cell membrane without energy input from the cell

Question 26

diffusion

Answer 26

movement of molecules in a fluid or gas from a region of higher concentration to region of lower concentration

Question 27

concentration gradient

Answer 27

the difference in the concentration of a substance from one location to another

Question 28

osmosis

Answer 28

diffusion of water molecules across a semipermeable membrane from an area of higer water concentration to an area of lower water concentration

Question 29

isotonic

Answer 29

solution that has an equal concentration of dissolved particles compared with another solution

Question 30

hypertonic

Answer 30

solution that has a higher concentration of dissolved particles compared with another solution

Question 31

hypotonic

Answer 31

solution that has a lower concentration of dissolved particles compared with another solution

Question 32

facilitated diffusion

Answer 32

the diffusion of molecules across a membrane through transport proteins

Question 33

active transport

Answer 33

energy requiring movement of molecules across a membrane from a region of lower concentration to a region of higher concentration

Question 34

endocytosis

Answer 34

the process of taking liquids or fairly large molecules into a cell by engulfing them in a membrane

Question 35

phagocytosis

Answer 35

type of endocytosis in which the cell membrane engulfs large particles

Question 36

exocytosis

Answer 36

the release of substances out of a cell by the fusion of a vesicle with the membrane

Question 36

Name five functions of the cytoskeleton.

Answer 36

1. Supports and shapes
2. Helps position and transport organelles
3. Provides strength
4. Assists in cell division
5. Aids in cell movement

Question 37

Name the two major functions of the cell membrane.

Answer 37

1. Forms boundary between inside and outside of cell

2. Controls passage of materials