Chapter 5

Question 1

cell theory

Answer 1

all organisms are composed of cells
cell is basic structural and fundamental unit of all living organisms
cells arise only from the division of preexisting cells

Question 2

resolution

Answer 2

minimum distance two points in the spectrum can be separated and still be seen as two points

Question 3

plasma membrane

Answer 3

bilayer made of lipids with imbedded protein molecules

Question 4

cytoplasm

Answer 4

all the parts of the cell between the plasma membrane and the central region

Question 5

organelles

Answer 5

small organized structures important for cell function

Question 6

cytosol

Answer 6

aqueous solution containing ions and various organic molecules

Question 7

cytoskeleton

Answer 7

protein based framework of filamentous structures that help maintain proper cell shape and plays a key role in cell division

Question 8

prokarytoes

Answer 8

dna is not separated from rest of cell

Question 9

nucleoid

Answer 9

dna containing region for prokaryotes

Question 10

eukaryotes

Answer 10

dna is separate from rest of cell

Question 11

nucleus

Answer 11

dna containing region for eukaryotes

Question 12

prokaryotic chromosome

Answer 12

single circular molecule that unfolds when released from the cell

Question 13

prokaryotic cells

Answer 13

o Prokaryotic chromosome- single circular molecule that unfolds when released from the cell
o Ribosomes- small spherical particles in the cytoplasm that use info in mRNA to assemble amino acids into proteins
o Cell Wall- rigid external layer of material
o Glycocalyx- layer of polysaccharides that coat cell wall
 Slime Layer- when loosely associated with the cells
 Capsule- more firmly attached to cells
o Flagella- long thread-like protein fibers that move cell
o Bacterial flagella- helically shaped that rotate to move cell
o Pili- hair like shafts of protein

Question 14

nuclear envelope

Answer 14

two membranes that separate the cytoplasm from the nucleus; reinformed by lamins

Question 15

nuclear pore complex

Answer 15

large cylindrical structure formed of many proteins(nucleoporins) that exchange components between nucleus and cytoplasm

Question 16

nuclear location signal

Answer 16

short amino acid sequence that distinguishes between proteins that need to be imported into the nucleus from those in the cytoplasm

Question 17

nucleoplasm

Answer 17

liquid substance within nucleus

Question 18

chromatin

Answer 18

combination of dna and proteins

Question 19

nucleoli

Answer 19

irregular masses of small fibers and granules where rRNA genes become rRNA molecules

Question 20

vesicles

Answer 20

small membrane bound compartments that transfer substances between parts of the system

Question 21

endoplasmic reticulum

Answer 21

interconnected network of membrane channels and vesicles called cisternae

Question 22

er lumen

Answer 22

enclosed space in endoplasmic reticulum

Question 23

rough er

Answer 23

has ribosomes on outsides; proteins are folded into final form

Question 24

smooth er

Answer 24

no ribosomes; synthesis of lipids that become part of cell membrane

Question 25

golgi complex

Answer 25

stacks of flattened membraneous sacs known as cisternae
no ribosomes
cis-where proteins are modified
trans-sorted into veiscles that bud off
regulates movement of proteins
secretory vesicles- transport proteins to plasma membrane
exocytosis-when the vesicles release the proteins
endocytic vesicle-carry susbtances from plasma membrane to rest of cell

Question 26

lysosomes

Answer 26

small membrane bound vesicles that are for the digestion of complex molecules
only in animals
formed by budding form golgi complex
enzymes made in rough er
acidic
phagocytosis-process where some cells enfulf bacteria or other debris to break them down

Question 27

mitochondria

Answer 27

where cellular respiration occurs
require oxygen
outer mitochondrial membrane-smooth and covers the outside of the organelle
inner mitochondrial membrane- expanded by folds called cristae
mitochondrial matrix-innermost compartment of mitochondria
atp generating reaction occur in cristae and matrix

Question 28

microbodies

Answer 28

small organelles found in various form in all eukarytoic cells
proteins and phosphoiipids are constantly transported into them
contain enzymes that conduct intermediate reactions linking major pathways
peroxisomes- microbodies that produce hydrogen peroxide
in plants convert oils or fats to sugars

Question 29

cytoskeleton-microtubules

Answer 29

• Alpha tubulin and beta tubulin noncovalently bonded together
• Change length to fit function
• Cell center/centrosome- site near nucleus where microtubules radiate from
• Centrioles- short, barrel shaped structure at midpoint
• Provide anchor for some organelles and tracts for some vesicles

Question 30

cytoskeleton-intermediate filaments

Answer 30

only found in multicellular organisms

provide strucutral support

Question 31

cytoskeleton-microfilaments

Answer 31

structural and locomotor functions

actively flowing motion of cytoplasm

Question 32

flagella

Answer 32

basal body-structure that anchors flagella and cilia to surface of cell
three types

Question 33

plant cells-chloroplasts

Answer 33

 Collectively known as plastids
 Amyloplasts- colorless plastids that store starch
 Chromoplasts- responsible for colors of ripening fruits and autumn leaves
 Have an outer and inner boundary membrane
 Grana- thylakoids stacked on top of each other
 Stoma- inner compartment

Question 34

plant cells-central vaculoues

Answer 34

pressure from it supports the cell
tonoplast-membrane that surrounds central vacuole
produce color of flowers

Question 35

plant cells-cell walls

Answer 35

support and mantain pressure in cell
primary cell wall-soft and flexible
secondary cell wall-more rigid and thicker;reiforced with lingin
middle lamella-gel like polysaccarides that hold adjacent cells together
plasmodesmata-minute channels between two walls

Question 36

animal cells-cell adhesion

Answer 36

bind cells together; helps maintain body form and structure; bind to specific molecules on other cells
connections are eventually made permanent by cell junction

Question 37

animal cells-cell junctions

Answer 37

seals spaces between cells and provides communication between them
anchoring junctions-weld adjacent cells together
desosomes-intermediate filaments anchor the junction in the underlying cytoplasm
adherens junctions-uses microfilaments
 Tight junctions- regions of tight connections
• Formed by direct fusion of proteins on outer surfaces of membranes of adjacent cells
 Gap junctions- open direct channels to allow ions and small molecules to pass from one cell to another

Question 38

extracellular matrix

Answer 38

provides cells and provides mechanical linkage