Biology Chapter 4

Question 1

Cell Wall

Answer 1

A protective layer external to the plasma membrane in plant cells, bacteria, fungi, and some protists; protects the cell and helps maintain its shape. Enclose and support plant cells.

Question 2

Central Vacuole

Answer 2

In a plant cell, a large membranous sac with diverse roles in growth and the storage of chemicals and wastes.

Question 3

Chlorophyl

Answer 3

• A green pigment located within the chloroplasts of plants and algae and in the membranes of certain prokaryotes. Chlorophyll a participates directly in the light reactions, which convert solar energy to chemical energy.

Question 4

Chloroplast

Answer 4

– An organelle found in plants and algae that absorbs sunlight and uses it to drive the synthesis of organic compounds sugars) from carbon dioxide and water.

Question 5

Chromatin

Answer 5

The complex of DNA and proteins that makes up eukaryotic chromosomes; often used to refer to the diffuse, very extended form taken by chromosomes when a cell is not dividing.

Question 6

Chromosome

Answer 6

A gene-carrying structure found in the nucleus of a eukaryotic cell and most visible during mitosis and meiosis; also, the main gene-carrying structure of a prokaryotic cell. A chromosome consists of one very long DNA molecule and associated proteins.

Question 7

Cilia

Answer 7

The short, numerous appendages that propel Paramecium.

Question 8

Cytoplasm

Answer 8

The contents of a eukaryotic cell between the plasma membrane and the nucleus; consists of a semifluid medium and organelles; can also refer to the interior of a prokaryotic cell.

Question 9

Cytoskeleton

Answer 9

• A network of protein fibers in the cytoplasm of a eukaryotic cell; includes microfilaments, intermediate filaments, and microtubules.

Question 10

Cytosol

Answer 10

The semifluid portion of the cytoplasm.

Question 11

Endomembrane System

Answer 11

A network of membranes inside and surrounding a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles.

Question 12

Endoplasmic Reticulum

Answer 12

An extensive membranous network in a eukaryotic cell, continuous with the outer nuclear membrane and composed of ribosome studded (rough) and ribosome-free (smooth) regions. See also rough ER; smooth ER.

Question 13

Eukaryotic Cell

Answer 13

A type of cell that has a membrane enclosed nucleus and membrane-enclosed organelles. All organisms except bacteria and archaea are composed of eukaryotic cells.

Question 14

Extracellular Matrix

Answer 14

layer that helps hold cells together in tissues and protects and supports the plasma membrane made of collagen, enzymes, and glycoproteins, that provide structural and biochemical support of surrounding cells. Can even influence the activity of genes through
the signals it relays.

Question 15

Golgi Apparatus

Answer 15

An organelle in eukaryotic cells consisting of stacks of membranous sacs that modify, store, and ship products of the endoplasmic reticulum.

Question 16

Lyosome

Answer 16

A digestive organelle in eukaryotic cells; contains hydrolytic enzymes that digest engulfed food or damaged organelles.

Question 17

Mitochondria

Answer 17

An organelle in eukaryotic cells where cellular respiration occurs. Enclosed by two membranes, it is where most of the cell’s ATP is made.

Question 18

Nuclear Envelope

Answer 18

A double membrane that encloses the nucleus, perforated with pores that regulate traffic with the cytoplasm.

Question 19

Nucleus

Answer 19

(1) An atom’s central core, containing protons and neutrons. (2) The organelle of a eukaryotic cell that contains the genetic material in the form of chromosomes, made of chromatin.

Question 20

Nucleoid

Answer 20

A non–membrane-bounded region in a prokaryotic cell where the DNA is concentrated.

Question 21

Organelle

Answer 21

A membrane-enclosed structure with a specialized function within a cell.

Question 22

Plasma Membrane

Answer 22

The membrane at the boundary of every cell that acts as a selective barrier to the passage of ions and molecules into and out of the cell; consists of a phospholipid bilayer with embedded proteins.

Question 23

Plasmodesmata

Answer 23

An open channel in a plant cell wall that connects the cytoplasm of adjacent cells.

Question 24

Ribosome

Answer 24

A cell structure consisting of RNA and protein organized into two subunits and functioning as the site of protein synthesis in the cytoplasm. In eukaryotic cells, the ribosomal subunits are constructed in the nucleolus.

Question 25

Vacuole

Answer 25

A membrane-enclosed sac that is part of the endomembrane system of a eukaryotic cell and has diverse functions in different kinds of cells.

Question 26

Vesicle

Answer 26

A sac made of membrane in the cytoplasm of a eukaryotic cell.