Ch 4

Question 1

What type of cells do organisms of the domains Bacteria and Archaea consist of?

Answer 1

Prokaryotic cells

Prokaryotic cells lack a nucleus and membrane-bound organelles.

Question 2

What is a key characteristic of prokaryotic cells?

Answer 2

No nucleus

Instead, they have a nucleoid.

Question 3

What are eukaryotic cells characterized by?

Answer 3

A membrane-bound nucleus and membrane-bound organelles

Eukaryotic cells include fungi, animals, and plants.

Question 4

What is the plasma membrane?

Answer 4

A selective barrier

It is a double layer of phospholipids.

Question 5

What is cytoplasm?

Answer 5

The area between the plasma membrane and the nuclear envelope

It contains gel-like cytosol.

Question 6

What does the nucleus contain?

Answer 6

Most of the DNA in a eukaryotic cell

The nucleus organizes DNA into discrete units called chromosomes.

Question 7

What is the function of ribosomes?

Answer 7

Protein synthesis

Ribosomes use information from DNA to make proteins.

Question 8

What is the structure of the nuclear membrane?

Answer 8

A double membrane, each consisting of a lipid bilayer

It regulates the entry and exit of molecules from the nucleus.

Question 9

What are ribosomes made of?

Answer 9

Ribosomal RNA and protein

They are complexes responsible for protein synthesis.

Question 10

Fill in the blank: The plasma membrane is a _______ barrier.

Answer 10

selective

It allows certain molecules to enter or exit the cell.

Question 11

True or False: Prokaryotic cells have membrane-bound organelles.

Answer 11

False

Prokaryotic cells do not have membrane-bound organelles.

Question 12

All organisms are made of what

Answer 12

Cells

Question 13

What are mitochondria?

Answer 13

Sites of cellular respiration, a metabolic process that uses oxygen to generate ATP

Question 14

What does ATP stand for?

Answer 14

Adenosine triphosphate

Question 15

What are vesicles and vacuoles?

Answer 15

Membrane-bound sacs for storage and transport

Question 16

How are vacuoles formed?

Answer 16

Large vesicles derived from the ER and Golgi apparatus

Question 17

What is the function of the cell wall in plants?

Answer 17

External to plasma membrane, provides structure and support

Question 18

What is the role of chloroplasts?

Answer 18

Carry out photosynthesis and contain the green pigment chlorophyll

Question 19

What do central vacuoles in plants hold?

Answer 19

Organic compounds and water

Question 20

What are the components of the endomembrane system?

Answer 20

• Endoplasmic reticulum
• Golgi apparatus
• Lysosomes

Question 21

What is the relationship between the ER membrane and the nuclear envelope?

Answer 21

The ER membrane is continuous with the outer parts of the nucleus

Question 22

What are the two distinct regions of the endoplasmic reticulum?

Answer 22

• Rough ER
• Smooth ER

Question 23

What characterizes rough ER?

Answer 23

Surface is studded with ribosomes

Question 24

What characterizes smooth ER?

Answer 24

Lacks ribosomes

Question 25

What does rough ER secrete?

Answer 25

Glycoproteins (proteins covalently bonded to carbohydrates)

Question 26

Centrosomes (animals)

Answer 26

Microtuble organizing center containing a pair of centrioles

Question 27

Lysosomes (animals)

Answer 27

Contains enzymes that break down food and recycle cell parts

Question 28

What is the function of the rough ER?

Answer 28

Distributes transport vesicles, proteins surrounded by membranes ## Footnote The rough ER is also known as a membrane factory for the cell.

Question 29

What are the main functions of the smooth ER?

Answer 29

* Synthesis of carbohydrates * Synthesis of lipids * Detoxifies drugs and poisons * Stores calcium ions ## Footnote The smooth ER plays a crucial role in lipid metabolism and detoxification.

Question 30

What is the Golgi apparatus often referred to as?

Answer 30

Shipping and receiving center ## Footnote It modifies products of the ER, manufactures certain macromolecules, and sorts and packages materials into transport vesicles.

Question 31

What is a lysosome?

Answer 31

A membranous sac of enzymes that can digest proteins, fats, polysaccharides, and nucleic acids ## Footnote Lysosomes are considered digestive compartments within the cell.

Question 32

What is the cytoskeleton?

Answer 32

A network of fibers extending throughout the cytoplasm ## Footnote It organizes cell structures and activities, anchoring many organelles.

Question 33

What are the three main types of fibers that make up the cytoskeleton?

Answer 33

* Microtubules * Microfilaments (also called actin filaments) * Intermediate filaments ## Footnote These fibers play different roles in maintaining cell structure and function.

Question 34

What role do microtubules play in flagella and cilia?

Answer 34

Control the beating of microtubule-containing extensions projecting from some cells ## Footnote Flagella and cilia are important for cell movement and fluid movement across cell surfaces.

Question 35

What covers animal cells instead of cell walls?

Answer 35

Elaborate extracellular matrix (ECM) ## Footnote The ECM provides structural and biochemical support to surrounding cells.

Question 36

What are plasmodesmata?

Answer 36

Channels that perforate plant cell walls allowing water and small solutes to pass from cell to cell

Question 37

What do plasmodesmata allow to pass between plant cells?

Answer 37

Water and small solutes

Question 38

True or False: Plasmodesmata are found in animal cells.

Answer 38

False

Question 39

Fill in the blank: Plasmodesmata are channels that perforate _______.

Answer 39

plant cell walls