Chapter 2: The Cell (Overview)

Question 1

Describe the cell theory

Answer 1

• all organisms are composed of one or more cells
• the cell is the basic structural + functional unit of all living organisms
• cells arise only from the division of preexisting cells

Question 2

What basic features of cell structure and function are shared by all living cells?

Answer 2

plasma membrane, cytoplasm, ribosomes, DNA

Question 3

Describe optical microscopy and give an example

Answer 3

uses light for illumination; light microscope

Question 4

Describe electron microscopy and give an example

Answer 4

uses an electron beam; TEM (electrons transmitted through sample), SEM (sample coated with heavy metal, beams scans surface to make 3D image)

Question 5

Define magnification

Answer 5

ratio between the size of an image produced by a microscope and its actual size

Question 6

Define resolution

Answer 6

ability to observe two adjacent objects as distinct from one another

Question 7

Define contrast

Answer 7

how different one structure looks from another; enhanced by dyes

Question 8

Why are cells so small?

Answer 8

• constantly have to be repaired or discarded
• easy to replace without disrupting function
• so they can fit through tiny spaces and travel long distances
• surface area for diffusion

Question 9

plasma membrane.

Answer 9

• selectively permeable bilayer (hydrophobic) made of lipids w/ embedded protein molecules
• regulates passage of substances in and out of the cell

Question 10

cytoplasm.

Answer 10

• contains cytosol and cytoskeleton

- cellular activities including metabolic pathways, glycolysis, and cell division

Question 11

ribosome.

Answer 11

-free in the cytoplasm or attached to ER and assemble amino acids into proteins

Question 12

nucleus

Answer 12

-contains the cell’s genetic material, controls cell function, DNA synthesis, and RNA transcription

Question 13

rough ER

Answer 13

-initial synthesis, sorting proteins for export

Question 14

smooth ER

Answer 14

-lipid synthesis + modifications; detox of alcohol and drugs, calcium storage, and glycogen breakdown

Question 15

golgi complex

Answer 15

modifies, stores, and ship products of the ER

Question 16

lysosomes

Answer 16

-contain hydrolytic enzymes that digest a cell’s food and waste

Question 17

mitochondria

Answer 17

-responsible for cellular respiration and supplies majority of ATP

Question 18

chloroplasts

Answer 18

-where photosynthesis occurs and contains chlorophyll

Question 19

Explain the endomembrane system

Answer 19

• proteins made by ribosomes enter ER membrane
• vesicles bud from ER and transport to golgi
• protein and lipid modification complete at golgi and sorted into vesicles
• secretory vesicles bud out and transport finished products to plasma membrane and are released by exocytosis

Question 20

Shape, size, and organization vary considerably among different species and among different cell types of the same species, therefore….

Answer 20

same genome, different proteome

Question 21

What are the 3 shapes common to all prokaryotes?

Answer 21

spherical (cocci), rodlike (bacilli), and spiral (spirochetes)

Question 22

cytoskeleton

Answer 22

-found throughout the cytoplasm in all cells; microtubules, intermediate filaments, and microfilaments

Question 23

microtubules

Answer 23

provide tracks along which vesicles move

Question 24

intermediate filaments

Answer 24

structural support and are tissue-specific

Question 25

microfilaments

Answer 25

• protein fibres wound in a helical spiral

- components of contractile elements in muscle fibres